IR decoding using BPF

This makes is it possible for bpf prog detach to return -ENOENT.

Signed-off-by Sean Young <[email protected]>

Add support for BPF_PROG_LIRC_MODE2. This type of BPF program can call rc_keydown() to reported decoded IR scancodes, or rc_repeat() to report that the last key should be repeated.

The bpf program can be attached to using the bpf(BPF_PROG_ATTACH) syscall; the target_fd must be the /dev/lircN device.

Signed-off-by Sean Young <[email protected]>

---
 drivers/media/rc/Kconfig        |  13 ++
 drivers/media/rc/Makefile       |   1 +
 drivers/media/rc/bpf-lirc.c     | 308 ++++++++++++++++++++++++++++++++
 drivers/media/rc/lirc_dev.c     |  30 ++++
 drivers/media/rc/rc-core-priv.h |  22 +++
 drivers/media/rc/rc-ir-raw.c    |  12 +-
 include/linux/bpf_rcdev.h       |  30 ++++
 include/linux/bpf_types.h       |   3 +
 include/uapi/linux/bpf.h        |  53 +++++-
 kernel/bpf/syscall.c            |   7 +
 10 files changed, 476 insertions(+), 3 deletions(-)
 create mode 100644 drivers/media/rc/bpf-lirc.c
 create mode 100644 include/linux/bpf_rcdev.h

drivers/media/rc/Kconfig +13 -0

index eb2c3b6eca7f..d5b35a6ba899 100644
@@ -25,6 +25,19 @@ config LIRC
           passes raw IR to and from userspace, which is needed for
           IR transmitting (aka "blasting") and for the lirc daemon.
 
+config BPF_LIRC_MODE2
+       bool "Support for eBPF programs attached to lirc devices"
+       depends on BPF_SYSCALL
+       depends on RC_CORE=y
+       depends on LIRC
+       help
+          Allow attaching eBPF programs to a lirc device using the bpf(2)
+          syscall command BPF_PROG_ATTACH. This is supported for raw IR
+          receivers.
+
+          These eBPF programs can be used to decode IR into scancodes, for
+          IR protocols not supported by the kernel decoders.
+
 menuconfig RC_DECODERS
        bool "Remote controller decoders"
        depends on RC_CORE

drivers/media/rc/Makefile +1 -0

index 2e1c87066f6c..e0340d043fe8 100644
@@ -5,6 +5,7 @@ obj-y += keymaps/
 obj-$(CONFIG_RC_CORE) += rc-core.o
 rc-core-y := rc-main.o rc-ir-raw.o
 rc-core-$(CONFIG_LIRC) += lirc_dev.o
+rc-core-$(CONFIG_BPF_LIRC_MODE2) += bpf-lirc.o
 obj-$(CONFIG_IR_NEC_DECODER) += ir-nec-decoder.o
 obj-$(CONFIG_IR_RC5_DECODER) += ir-rc5-decoder.o
 obj-$(CONFIG_IR_RC6_DECODER) += ir-rc6-decoder.o

drivers/media/rc/bpf-lirc.c new file +308 -0

new file mode 100644
index 000000000000..c9673df2d9cd
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0
+// bpf-lirc.c - handles bpf
+//
+// Copyright (C) 2018 Sean Young <[email protected]>
+
+#include <linux/bpf.h>
+#include <linux/filter.h>
+#include <linux/bpf_rcdev.h>
+#include "rc-core-priv.h"
+
+/*
+ * BPF interface for raw IR
+ */
+const struct bpf_prog_ops lirc_mode2_prog_ops = {
+};
+
+BPF_CALL_1(bpf_rc_repeat, u32*, sample)
+{
+       struct ir_raw_event_ctrl *ctrl;
+
+       ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);
+
+       rc_repeat(ctrl->dev);
+
+       return 0;
+}
+
+static const struct bpf_func_proto rc_repeat_proto = {
+       .func      = bpf_rc_repeat,
+       .gpl_only  = true, /* rc_repeat is EXPORT_SYMBOL_GPL */
+       .ret_type  = RET_INTEGER,
+       .arg1_type = ARG_PTR_TO_CTX,
+};
+
+/*
+ * Currently rc-core does not support 64-bit scancodes, but there are many
+ * known protocols with more than 32 bits. So, define the interface as u64
+ * as a future-proof.
+ */
+BPF_CALL_4(bpf_rc_keydown, u32*, sample, u32, protocol, u64, scancode,
+          u32, toggle)
+{
+       struct ir_raw_event_ctrl *ctrl;
+
+       ctrl = container_of(sample, struct ir_raw_event_ctrl, bpf_sample);
+
+       rc_keydown(ctrl->dev, protocol, scancode, toggle != 0);
+
+       return 0;
+}
+
+static const struct bpf_func_proto rc_keydown_proto = {
+       .func      = bpf_rc_keydown,
+       .gpl_only  = true, /* rc_keydown is EXPORT_SYMBOL_GPL */
+       .ret_type  = RET_INTEGER,
+       .arg1_type = ARG_PTR_TO_CTX,
+       .arg2_type = ARG_ANYTHING,
+       .arg3_type = ARG_ANYTHING,
+       .arg4_type = ARG_ANYTHING,
+};
+
+static const struct bpf_func_proto *
+lirc_mode2_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+       switch (func_id) {
+       case BPF_FUNC_rc_repeat:
+               return &rc_repeat_proto;
+       case BPF_FUNC_rc_keydown:
+               return &rc_keydown_proto;
+       case BPF_FUNC_map_lookup_elem:
+               return &bpf_map_lookup_elem_proto;
+       case BPF_FUNC_map_update_elem:
+               return &bpf_map_update_elem_proto;
+       case BPF_FUNC_map_delete_elem:
+               return &bpf_map_delete_elem_proto;
+       case BPF_FUNC_ktime_get_ns:
+               return &bpf_ktime_get_ns_proto;
+       case BPF_FUNC_tail_call:
+               return &bpf_tail_call_proto;
+       case BPF_FUNC_get_prandom_u32:
+               return &bpf_get_prandom_u32_proto;
+       case BPF_FUNC_trace_printk:
+               if (capable(CAP_SYS_ADMIN))
+                       return bpf_get_trace_printk_proto();
+               /* fall through */
+       default:
+               return NULL;
+       }
+}
+
+static bool lirc_mode2_is_valid_access(int off, int size,
+                                      enum bpf_access_type type,
+                                      const struct bpf_prog *prog,
+                                      struct bpf_insn_access_aux *info)
+{
+       /* We have one field of u32 */
+       return type == BPF_READ && off == 0 && size == sizeof(u32);
+}
+
+const struct bpf_verifier_ops lirc_mode2_verifier_ops = {
+       .get_func_proto  = lirc_mode2_func_proto,
+       .is_valid_access = lirc_mode2_is_valid_access
+};
+
+#define BPF_MAX_PROGS 64
+
+static int rc_dev_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog)
+{
+       struct bpf_prog_array __rcu *old_array;
+       struct bpf_prog_array *new_array;
+       struct ir_raw_event_ctrl *raw;
+       int ret;
+
+       if (rcdev->driver_type != RC_DRIVER_IR_RAW)
+               return -EINVAL;
+
+       ret = mutex_lock_interruptible(&ir_raw_handler_lock);
+       if (ret)
+               return ret;
+
+       raw = rcdev->raw;
+       if (!raw) {
+               ret = -ENODEV;
+               goto unlock;
+       }
+
+       if (raw->progs && bpf_prog_array_length(raw->progs) >= BPF_MAX_PROGS) {
+               ret = -E2BIG;
+               goto unlock;
+       }
+
+       old_array = raw->progs;
+       ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array);
+       if (ret < 0)
+               goto unlock;
+
+       rcu_assign_pointer(raw->progs, new_array);
+       bpf_prog_array_free(old_array);
+
+unlock:
+       mutex_unlock(&ir_raw_handler_lock);
+       return ret;
+}
+
+static int rc_dev_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog)
+{
+       struct bpf_prog_array __rcu *old_array;
+       struct bpf_prog_array *new_array;
+       struct ir_raw_event_ctrl *raw;
+       int ret;
+
+       if (rcdev->driver_type != RC_DRIVER_IR_RAW)
+               return -EINVAL;
+
+       ret = mutex_lock_interruptible(&ir_raw_handler_lock);
+       if (ret)
+               return ret;
+
+       raw = rcdev->raw;
+       if (!raw) {
+               ret = -ENODEV;
+               goto unlock;
+       }
+
+       old_array = raw->progs;
+       ret = bpf_prog_array_copy(old_array, prog, NULL, &new_array);
+       /*
+        * Do not use bpf_prog_array_delete_safe() as we would end up
+        * with a dummy entry in the array, and the we would free the
+        * dummy in rc_dev_bpf_free()
+        */
+       if (ret == 0) {
+               rcu_assign_pointer(raw->progs, new_array);
+               bpf_prog_array_free(old_array);
+       }
+unlock:
+       mutex_unlock(&ir_raw_handler_lock);
+       return ret;
+}
+
+void rc_dev_bpf_run(struct rc_dev *rcdev, u32 sample)
+{
+       struct ir_raw_event_ctrl *raw = rcdev->raw;
+
+       raw->bpf_sample = sample;
+
+       if (raw->progs)
+               BPF_PROG_RUN_ARRAY(raw->progs, &raw->bpf_sample, BPF_PROG_RUN);
+}
+
+/*
+ * This should be called once the rc thread has been stopped, so there can be
+ * no concurrent bpf execution.
+ */
+void rc_dev_bpf_free(struct rc_dev *rcdev)
+{
+       struct bpf_prog **progs;
+
+       if (!rcdev->raw->progs)
+               return;
+
+       progs = rcu_dereference(rcdev->raw->progs)->progs;
+       while (*progs)
+               bpf_prog_put(*progs++);
+
+       bpf_prog_array_free(rcdev->raw->progs);
+}
+
+int rc_dev_prog_attach(const union bpf_attr *attr)
+{
+       struct bpf_prog *prog;
+       struct rc_dev *rcdev;
+       int ret;
+
+       if (attr->attach_flags)
+               return -EINVAL;
+
+       prog = bpf_prog_get_type(attr->attach_bpf_fd,
+                                BPF_PROG_TYPE_LIRC_MODE2);
+       if (IS_ERR(prog))
+               return PTR_ERR(prog);
+
+       rcdev = rc_dev_get_from_fd(attr->target_fd);
+       if (IS_ERR(rcdev)) {
+               bpf_prog_put(prog);
+               return PTR_ERR(rcdev);
+       }
+
+       ret = rc_dev_bpf_attach(rcdev, prog);
+       if (ret)
+               bpf_prog_put(prog);
+
+       put_device(&rcdev->dev);
+
+       return ret;
+}
+
+int rc_dev_prog_detach(const union bpf_attr *attr)
+{
+       struct bpf_prog *prog;
+       struct rc_dev *rcdev;
+       int ret;
+
+       if (attr->attach_flags)
+               return -EINVAL;
+
+       prog = bpf_prog_get_type(attr->attach_bpf_fd,
+                                BPF_PROG_TYPE_LIRC_MODE2);
+       if (IS_ERR(prog))
+               return PTR_ERR(prog);
+
+       rcdev = rc_dev_get_from_fd(attr->target_fd);
+       if (IS_ERR(rcdev)) {
+               bpf_prog_put(prog);
+               return PTR_ERR(rcdev);
+       }
+
+       ret = rc_dev_bpf_detach(rcdev, prog);
+
+       bpf_prog_put(prog);
+       put_device(&rcdev->dev);
+
+       return ret;
+}
+
+int rc_dev_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr)
+{
+       __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+       struct bpf_prog_array __rcu *progs;
+       struct rc_dev *rcdev;
+       u32 cnt, flags = 0;
+       int ret;
+
+       if (attr->query.query_flags)
+               return -EINVAL;
+
+       rcdev = rc_dev_get_from_fd(attr->query.target_fd);
+       if (IS_ERR(rcdev))
+               return PTR_ERR(rcdev);
+
+       if (rcdev->driver_type != RC_DRIVER_IR_RAW)
+               return -EINVAL;
+
+       ret = mutex_lock_interruptible(&ir_raw_handler_lock);
+       if (ret)
+               return ret;
+
+       progs = rcdev->raw->progs;
+       cnt = progs ? bpf_prog_array_length(progs) : 0;
+
+       if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) {
+               ret = -EFAULT;
+               goto unlock;
+       }
+       if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags))) {
+               ret = -EFAULT;
+               goto unlock;
+       }
+
+       if (attr->query.prog_cnt != 0 && prog_ids && cnt)
+               ret = bpf_prog_array_copy_to_user(progs, prog_ids, cnt);
+
+unlock:
+       mutex_unlock(&ir_raw_handler_lock);
+       put_device(&rcdev->dev);
+
+       return ret;
+}

drivers/media/rc/lirc_dev.c +30 -0

index 24e9fbb80e81..7e760bf11a51 100644
@@ -20,6 +20,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/device.h>
+#include <linux/file.h>
 #include <linux/idr.h>
 #include <linux/poll.h>
 #include <linux/sched.h>

@@ -104,6 +105,12 @@ void ir_lirc_raw_event(struct rc_dev *dev, struct ir_raw_event ev)
                        TO_US(ev.duration), TO_STR(ev.pulse));
        }
 
+       /*
+        * bpf does not care about the gap generated above; that exists
+        * for backwards compatibility
+        */
+       rc_dev_bpf_run(dev, sample);
+
        spin_lock_irqsave(&dev->lirc_fh_lock, flags);
        list_for_each_entry(fh, &dev->lirc_fh, list) {
                if (LIRC_IS_TIMEOUT(sample) && !fh->send_timeout_reports)

@@ -816,4 +823,27 @@ void __exit lirc_dev_exit(void)
        unregister_chrdev_region(lirc_base_dev, RC_DEV_MAX);
 }
 
+struct rc_dev *rc_dev_get_from_fd(int fd)
+{
+       struct fd f = fdget(fd);
+       struct lirc_fh *fh;
+       struct rc_dev *dev;
+
+       if (!f.file)
+               return ERR_PTR(-EBADF);
+
+       if (f.file->f_op != &lirc_fops) {
+               fdput(f);
+               return ERR_PTR(-EINVAL);
+       }
+
+       fh = f.file->private_data;
+       dev = fh->rc;
+
+       get_device(&dev->dev);
+       fdput(f);
+
+       return dev;
+}
+
 MODULE_ALIAS("lirc_dev");

drivers/media/rc/rc-core-priv.h +22 -0

index e0e6a17460f6..511e4a2dc2d5 100644
@@ -13,6 +13,7 @@
 #define        MAX_IR_EVENT_SIZE       512
 
 #include <linux/slab.h>
+#include <uapi/linux/bpf.h>
 #include <media/rc-core.h>
 
 /**

@@ -57,6 +58,11 @@ struct ir_raw_event_ctrl {
        /* raw decoder state follows */
        struct ir_raw_event prev_ev;
        struct ir_raw_event this_ev;
+
+#ifdef CONFIG_BPF_LIRC_MODE2
+       u32                             bpf_sample;
+       struct bpf_prog_array __rcu     *progs;
+#endif
        struct nec_dec {
                int state;
                unsigned count;

@@ -126,6 +132,9 @@ struct ir_raw_event_ctrl {
        } imon;
 };
 
+/* Mutex for locking raw IR processing and handler change */
+extern struct mutex ir_raw_handler_lock;
+
 /* macros for IR decoders */
 static inline bool geq_margin(unsigned d1, unsigned d2, unsigned margin)
 {

@@ -288,6 +297,7 @@ void ir_lirc_raw_event(struct rc_dev *dev, struct ir_raw_event ev);
 void ir_lirc_scancode_event(struct rc_dev *dev, struct lirc_scancode *lsc);
 int ir_lirc_register(struct rc_dev *dev);
 void ir_lirc_unregister(struct rc_dev *dev);
+struct rc_dev *rc_dev_get_from_fd(int fd);
 #else
 static inline int lirc_dev_init(void) { return 0; }
 static inline void lirc_dev_exit(void) {}

@@ -299,4 +309,16 @@ static inline int ir_lirc_register(struct rc_dev *dev) { return 0; }
 static inline void ir_lirc_unregister(struct rc_dev *dev) { }
 #endif
 
+/*
+ * bpf interface
+ */
+#ifdef CONFIG_BPF_LIRC_MODE2
+void rc_dev_bpf_free(struct rc_dev *dev);
+void rc_dev_bpf_run(struct rc_dev *dev, u32 sample);
+#else
+static inline void rc_dev_bpf_free(struct rc_dev *dev) { }
+static inline void rc_dev_bpf_run(struct rc_dev *dev, u32 sample)
+{ }
+#endif
+
 #endif /* _RC_CORE_PRIV */

drivers/media/rc/rc-ir-raw.c +10 -2

index 374f83105a23..a3131d4236b3 100644
@@ -14,7 +14,7 @@
 static LIST_HEAD(ir_raw_client_list);
 
 /* Used to handle IR raw handler extensions */
-static DEFINE_MUTEX(ir_raw_handler_lock);
+DEFINE_MUTEX(ir_raw_handler_lock);
 static LIST_HEAD(ir_raw_handler_list);
 static atomic64_t available_protocols = ATOMIC64_INIT(0);
 

@@ -621,9 +621,17 @@ void ir_raw_event_unregister(struct rc_dev *dev)
        list_for_each_entry(handler, &ir_raw_handler_list, list)
                if (handler->raw_unregister)
                        handler->raw_unregister(dev);
-       mutex_unlock(&ir_raw_handler_lock);
+
+       rc_dev_bpf_free(dev);
 
        ir_raw_event_free(dev);
+
+       /*
+        * A user can be calling bpf(BPF_PROG_{QUERY|ATTACH|DETACH}), so
+        * ensure that the raw member is null on unlock; this is how
+        * "device gone" is checked.
+        */
+       mutex_unlock(&ir_raw_handler_lock);
 }
 
 /*

include/linux/bpf_rcdev.h new file +30 -0

new file mode 100644
index 000000000000..570ca0036cf5
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BPF_RCDEV_H
+#define _BPF_RCDEV_H
+
+#include <linux/bpf.h>
+#include <uapi/linux/bpf.h>
+
+#ifdef CONFIG_BPF_LIRC_MODE2
+int rc_dev_prog_attach(const union bpf_attr *attr);
+int rc_dev_prog_detach(const union bpf_attr *attr);
+int rc_dev_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr);
+#else
+static inline int rc_dev_prog_attach(const union bpf_attr *attr)
+{
+       return -EINVAL;
+}
+
+static inline int rc_dev_prog_detach(const union bpf_attr *attr)
+{
+       return -EINVAL;
+}
+
+static inline int rc_dev_prog_query(const union bpf_attr *attr,
+                                   union bpf_attr __user *uattr)
+{
+       return -EINVAL;
+}
+#endif
+
+#endif /* _BPF_RCDEV_H */

include/linux/bpf_types.h +3 -0

index b67f8793de0d..47b771421d40 100644
@@ -25,6 +25,9 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT, raw_tracepoint)
 #ifdef CONFIG_CGROUP_BPF
 BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_DEVICE, cg_dev)
 #endif
+#ifdef CONFIG_BPF_LIRC_MODE2
+BPF_PROG_TYPE(BPF_PROG_TYPE_LIRC_MODE2, lirc_mode2)
+#endif
 
 BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops)

include/uapi/linux/bpf.h +52 -1

index d94d333a8225..8227832b713e 100644
@@ -141,6 +141,7 @@ enum bpf_prog_type {
        BPF_PROG_TYPE_SK_MSG,
        BPF_PROG_TYPE_RAW_TRACEPOINT,
        BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+       BPF_PROG_TYPE_LIRC_MODE2,
 };
 
 enum bpf_attach_type {

@@ -158,6 +159,7 @@ enum bpf_attach_type {
        BPF_CGROUP_INET6_CONNECT,
        BPF_CGROUP_INET4_POST_BIND,
        BPF_CGROUP_INET6_POST_BIND,
+       BPF_LIRC_MODE2,
        __MAX_BPF_ATTACH_TYPE
 };
 

@@ -1902,6 +1904,53 @@ union bpf_attr {
  *             egress otherwise). This is the only flag supported for now.
  *     Return
  *             **SK_PASS** on success, or **SK_DROP** on error.
+ *
+ * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
+ *     Description
+ *             This helper is used in programs implementing IR decoding, to
+ *             report a successfully decoded key press with *scancode*,
+ *             *toggle* value in the given *protocol*. The scancode will be
+ *             translated to a keycode using the rc keymap, and reported as
+ *             an input key down event. After a period a key up event is
+ *             generated. This period can be extended by calling either
+ *             **bpf_rc_keydown** () with the same values, or calling
+ *             **bpf_rc_repeat** ().
+ *
+ *             Some protocols include a toggle bit, in case the button
+ *             was released and pressed again between consecutive scancodes
+ *
+ *             The *ctx* should point to the lirc sample as passed into
+ *             the program.
+ *
+ *             The *protocol* is the decoded protocol number (see
+ *             **enum rc_proto** for some predefined values).
+ *
+ *             This helper is only available is the kernel was compiled with
+ *             the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ *             "**y**".
+ *
+ *     Return
+ *             0
+ *
+ * int bpf_rc_repeat(void *ctx)
+ *     Description
+ *             This helper is used in programs implementing IR decoding, to
+ *             report a successfully decoded repeat key message. This delays
+ *             the generation of a key up event for previously generated
+ *             key down event.
+ *
+ *             Some IR protocols like NEC have a special IR message for
+ *             repeating last button, for when a button is held down.
+ *
+ *             The *ctx* should point to the lirc sample as passed into
+ *             the program.
+ *
+ *             This helper is only available is the kernel was compiled with
+ *             the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ *             "**y**".
+ *
+ *     Return
+ *             0
  */
 #define __BPF_FUNC_MAPPER(FN)          \
        FN(unspec),                     \

@@ -1976,7 +2025,9 @@ union bpf_attr {
        FN(fib_lookup),                 \
        FN(sock_hash_update),           \
        FN(msg_redirect_hash),          \
-       FN(sk_redirect_hash),
+       FN(sk_redirect_hash),           \
+       FN(rc_repeat),                  \
+       FN(rc_keydown),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call

kernel/bpf/syscall.c +7 -1

index bfcde949c7f8..6e9a4cbc14b9 100644
@@ -11,6 +11,7 @@
  */
 #include <linux/bpf.h>
 #include <linux/bpf_trace.h>
+#include <linux/bpf_rcdev.h>
 #include <linux/btf.h>
 #include <linux/syscalls.h>
 #include <linux/slab.h>

@@ -1576,6 +1577,8 @@ static int bpf_prog_attach(const union bpf_attr *attr)
        case BPF_SK_SKB_STREAM_PARSER:
        case BPF_SK_SKB_STREAM_VERDICT:
                return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, true);
+       case BPF_LIRC_MODE2:
+               return rc_dev_prog_attach(attr);
        default:
                return -EINVAL;
        }

@@ -1646,6 +1649,8 @@ static int bpf_prog_detach(const union bpf_attr *attr)
        case BPF_SK_SKB_STREAM_PARSER:
        case BPF_SK_SKB_STREAM_VERDICT:
                return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, false);
+       case BPF_LIRC_MODE2:
+               return rc_dev_prog_detach(attr);
        default:
                return -EINVAL;
        }

@@ -1693,6 +1698,8 @@ static int bpf_prog_query(const union bpf_attr *attr,
        case BPF_CGROUP_SOCK_OPS:
        case BPF_CGROUP_DEVICE:
                break;
+       case BPF_LIRC_MODE2:
+               return rc_dev_prog_query(attr, uattr);
        default:
                return -EINVAL;
        }
--

2.17.0

This is simple test over rc-loopback.

Signed-off-by Sean Young <[email protected]>

---
 tools/bpf/bpftool/prog.c                      |   1 +
 tools/include/uapi/linux/bpf.h                |  53 ++++-
 tools/include/uapi/linux/lirc.h               | 217 ++++++++++++++++++
 tools/lib/bpf/libbpf.c                        |   1 +
 tools/testing/selftests/bpf/Makefile          |   8 +-
 tools/testing/selftests/bpf/bpf_helpers.h     |   6 +
 .../testing/selftests/bpf/test_lirc_mode2.sh  |  28 +++
 .../selftests/bpf/test_lirc_mode2_kern.c      |  23 ++
 .../selftests/bpf/test_lirc_mode2_user.c      | 154 +++++++++++++
 9 files changed, 487 insertions(+), 4 deletions(-)
 create mode 100644 tools/include/uapi/linux/lirc.h
 create mode 100755 tools/testing/selftests/bpf/test_lirc_mode2.sh
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_kern.c
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_user.c

tools/bpf/bpftool/prog.c +1 -0

index 9bdfdf2d3fbe..07f1ace39a46 100644
@@ -71,6 +71,7 @@ static const char * const prog_type_name[] = {
        [BPF_PROG_TYPE_SK_MSG]          = "sk_msg",
        [BPF_PROG_TYPE_RAW_TRACEPOINT]  = "raw_tracepoint",
        [BPF_PROG_TYPE_CGROUP_SOCK_ADDR] = "cgroup_sock_addr",
+       [BPF_PROG_TYPE_LIRC_MODE2]      = "lirc_mode2",
 };
 
 static void print_boot_time(__u64 nsecs, char *buf, unsigned int size)

tools/include/uapi/linux/bpf.h +52 -1

index d94d333a8225..8227832b713e 100644
@@ -141,6 +141,7 @@ enum bpf_prog_type {
        BPF_PROG_TYPE_SK_MSG,
        BPF_PROG_TYPE_RAW_TRACEPOINT,
        BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+       BPF_PROG_TYPE_LIRC_MODE2,
 };
 
 enum bpf_attach_type {

@@ -158,6 +159,7 @@ enum bpf_attach_type {
        BPF_CGROUP_INET6_CONNECT,
        BPF_CGROUP_INET4_POST_BIND,
        BPF_CGROUP_INET6_POST_BIND,
+       BPF_LIRC_MODE2,
        __MAX_BPF_ATTACH_TYPE
 };
 

@@ -1902,6 +1904,53 @@ union bpf_attr {
  *             egress otherwise). This is the only flag supported for now.
  *     Return
  *             **SK_PASS** on success, or **SK_DROP** on error.
+ *
+ * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
+ *     Description
+ *             This helper is used in programs implementing IR decoding, to
+ *             report a successfully decoded key press with *scancode*,
+ *             *toggle* value in the given *protocol*. The scancode will be
+ *             translated to a keycode using the rc keymap, and reported as
+ *             an input key down event. After a period a key up event is
+ *             generated. This period can be extended by calling either
+ *             **bpf_rc_keydown** () with the same values, or calling
+ *             **bpf_rc_repeat** ().
+ *
+ *             Some protocols include a toggle bit, in case the button
+ *             was released and pressed again between consecutive scancodes
+ *
+ *             The *ctx* should point to the lirc sample as passed into
+ *             the program.
+ *
+ *             The *protocol* is the decoded protocol number (see
+ *             **enum rc_proto** for some predefined values).
+ *
+ *             This helper is only available is the kernel was compiled with
+ *             the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ *             "**y**".
+ *
+ *     Return
+ *             0
+ *
+ * int bpf_rc_repeat(void *ctx)
+ *     Description
+ *             This helper is used in programs implementing IR decoding, to
+ *             report a successfully decoded repeat key message. This delays
+ *             the generation of a key up event for previously generated
+ *             key down event.
+ *
+ *             Some IR protocols like NEC have a special IR message for
+ *             repeating last button, for when a button is held down.
+ *
+ *             The *ctx* should point to the lirc sample as passed into
+ *             the program.
+ *
+ *             This helper is only available is the kernel was compiled with
+ *             the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ *             "**y**".
+ *
+ *     Return
+ *             0
  */
 #define __BPF_FUNC_MAPPER(FN)          \
        FN(unspec),                     \

@@ -1976,7 +2025,9 @@ union bpf_attr {
        FN(fib_lookup),                 \
        FN(sock_hash_update),           \
        FN(msg_redirect_hash),          \
-       FN(sk_redirect_hash),
+       FN(sk_redirect_hash),           \
+       FN(rc_repeat),                  \
+       FN(rc_keydown),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call

tools/include/uapi/linux/lirc.h new file +217 -0

new file mode 100644
index 000000000000..f189931042a7
@@ -0,0 +1,217 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * lirc.h - linux infrared remote control header file
+ * last modified 2010/07/13 by Jarod Wilson
+ */
+
+#ifndef _LINUX_LIRC_H
+#define _LINUX_LIRC_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#define PULSE_BIT       0x01000000
+#define PULSE_MASK      0x00FFFFFF
+
+#define LIRC_MODE2_SPACE     0x00000000
+#define LIRC_MODE2_PULSE     0x01000000
+#define LIRC_MODE2_FREQUENCY 0x02000000
+#define LIRC_MODE2_TIMEOUT   0x03000000
+
+#define LIRC_VALUE_MASK      0x00FFFFFF
+#define LIRC_MODE2_MASK      0xFF000000
+
+#define LIRC_SPACE(val) (((val)&LIRC_VALUE_MASK) | LIRC_MODE2_SPACE)
+#define LIRC_PULSE(val) (((val)&LIRC_VALUE_MASK) | LIRC_MODE2_PULSE)
+#define LIRC_FREQUENCY(val) (((val)&LIRC_VALUE_MASK) | LIRC_MODE2_FREQUENCY)
+#define LIRC_TIMEOUT(val) (((val)&LIRC_VALUE_MASK) | LIRC_MODE2_TIMEOUT)
+
+#define LIRC_VALUE(val) ((val)&LIRC_VALUE_MASK)
+#define LIRC_MODE2(val) ((val)&LIRC_MODE2_MASK)
+
+#define LIRC_IS_SPACE(val) (LIRC_MODE2(val) == LIRC_MODE2_SPACE)
+#define LIRC_IS_PULSE(val) (LIRC_MODE2(val) == LIRC_MODE2_PULSE)
+#define LIRC_IS_FREQUENCY(val) (LIRC_MODE2(val) == LIRC_MODE2_FREQUENCY)
+#define LIRC_IS_TIMEOUT(val) (LIRC_MODE2(val) == LIRC_MODE2_TIMEOUT)
+
+/* used heavily by lirc userspace */
+#define lirc_t int
+
+/*** lirc compatible hardware features ***/
+
+#define LIRC_MODE2SEND(x) (x)
+#define LIRC_SEND2MODE(x) (x)
+#define LIRC_MODE2REC(x) ((x) << 16)
+#define LIRC_REC2MODE(x) ((x) >> 16)
+
+#define LIRC_MODE_RAW                  0x00000001
+#define LIRC_MODE_PULSE                0x00000002
+#define LIRC_MODE_MODE2                0x00000004
+#define LIRC_MODE_SCANCODE             0x00000008
+#define LIRC_MODE_LIRCCODE             0x00000010
+
+
+#define LIRC_CAN_SEND_RAW              LIRC_MODE2SEND(LIRC_MODE_RAW)
+#define LIRC_CAN_SEND_PULSE            LIRC_MODE2SEND(LIRC_MODE_PULSE)
+#define LIRC_CAN_SEND_MODE2            LIRC_MODE2SEND(LIRC_MODE_MODE2)
+#define LIRC_CAN_SEND_LIRCCODE         LIRC_MODE2SEND(LIRC_MODE_LIRCCODE)
+
+#define LIRC_CAN_SEND_MASK             0x0000003f
+
+#define LIRC_CAN_SET_SEND_CARRIER      0x00000100
+#define LIRC_CAN_SET_SEND_DUTY_CYCLE   0x00000200
+#define LIRC_CAN_SET_TRANSMITTER_MASK  0x00000400
+
+#define LIRC_CAN_REC_RAW               LIRC_MODE2REC(LIRC_MODE_RAW)
+#define LIRC_CAN_REC_PULSE             LIRC_MODE2REC(LIRC_MODE_PULSE)
+#define LIRC_CAN_REC_MODE2             LIRC_MODE2REC(LIRC_MODE_MODE2)
+#define LIRC_CAN_REC_SCANCODE          LIRC_MODE2REC(LIRC_MODE_SCANCODE)
+#define LIRC_CAN_REC_LIRCCODE          LIRC_MODE2REC(LIRC_MODE_LIRCCODE)
+
+#define LIRC_CAN_REC_MASK              LIRC_MODE2REC(LIRC_CAN_SEND_MASK)
+
+#define LIRC_CAN_SET_REC_CARRIER       (LIRC_CAN_SET_SEND_CARRIER << 16)
+#define LIRC_CAN_SET_REC_DUTY_CYCLE    (LIRC_CAN_SET_SEND_DUTY_CYCLE << 16)
+
+#define LIRC_CAN_SET_REC_DUTY_CYCLE_RANGE 0x40000000
+#define LIRC_CAN_SET_REC_CARRIER_RANGE    0x80000000
+#define LIRC_CAN_GET_REC_RESOLUTION       0x20000000
+#define LIRC_CAN_SET_REC_TIMEOUT          0x10000000
+#define LIRC_CAN_SET_REC_FILTER           0x08000000
+
+#define LIRC_CAN_MEASURE_CARRIER          0x02000000
+#define LIRC_CAN_USE_WIDEBAND_RECEIVER    0x04000000
+
+#define LIRC_CAN_SEND(x) ((x)&LIRC_CAN_SEND_MASK)
+#define LIRC_CAN_REC(x) ((x)&LIRC_CAN_REC_MASK)
+
+#define LIRC_CAN_NOTIFY_DECODE            0x01000000
+
+/*** IOCTL commands for lirc driver ***/
+
+#define LIRC_GET_FEATURES              _IOR('i', 0x00000000, __u32)
+
+#define LIRC_GET_SEND_MODE             _IOR('i', 0x00000001, __u32)
+#define LIRC_GET_REC_MODE              _IOR('i', 0x00000002, __u32)
+#define LIRC_GET_REC_RESOLUTION        _IOR('i', 0x00000007, __u32)
+
+#define LIRC_GET_MIN_TIMEOUT           _IOR('i', 0x00000008, __u32)
+#define LIRC_GET_MAX_TIMEOUT           _IOR('i', 0x00000009, __u32)
+
+/* code length in bits, currently only for LIRC_MODE_LIRCCODE */
+#define LIRC_GET_LENGTH                _IOR('i', 0x0000000f, __u32)
+
+#define LIRC_SET_SEND_MODE             _IOW('i', 0x00000011, __u32)
+#define LIRC_SET_REC_MODE              _IOW('i', 0x00000012, __u32)
+/* Note: these can reset the according pulse_width */
+#define LIRC_SET_SEND_CARRIER          _IOW('i', 0x00000013, __u32)
+#define LIRC_SET_REC_CARRIER           _IOW('i', 0x00000014, __u32)
+#define LIRC_SET_SEND_DUTY_CYCLE       _IOW('i', 0x00000015, __u32)
+#define LIRC_SET_TRANSMITTER_MASK      _IOW('i', 0x00000017, __u32)
+
+/*
+ * when a timeout != 0 is set the driver will send a
+ * LIRC_MODE2_TIMEOUT data packet, otherwise LIRC_MODE2_TIMEOUT is
+ * never sent, timeout is disabled by default
+ */
+#define LIRC_SET_REC_TIMEOUT           _IOW('i', 0x00000018, __u32)
+
+/* 1 enables, 0 disables timeout reports in MODE2 */
+#define LIRC_SET_REC_TIMEOUT_REPORTS   _IOW('i', 0x00000019, __u32)
+
+/*
+ * if enabled from the next key press on the driver will send
+ * LIRC_MODE2_FREQUENCY packets
+ */
+#define LIRC_SET_MEASURE_CARRIER_MODE  _IOW('i', 0x0000001d, __u32)
+
+/*
+ * to set a range use LIRC_SET_REC_CARRIER_RANGE with the
+ * lower bound first and later LIRC_SET_REC_CARRIER with the upper bound
+ */
+#define LIRC_SET_REC_CARRIER_RANGE     _IOW('i', 0x0000001f, __u32)
+
+#define LIRC_SET_WIDEBAND_RECEIVER     _IOW('i', 0x00000023, __u32)
+
+/*
+ * struct lirc_scancode - decoded scancode with protocol for use with
+ *     LIRC_MODE_SCANCODE
+ *
+ * @timestamp: Timestamp in nanoseconds using CLOCK_MONOTONIC when IR
+ *     was decoded.
+ * @flags: should be 0 for transmit. When receiving scancodes,
+ *     LIRC_SCANCODE_FLAG_TOGGLE or LIRC_SCANCODE_FLAG_REPEAT can be set
+ *     depending on the protocol
+ * @rc_proto: see enum rc_proto
+ * @keycode: the translated keycode. Set to 0 for transmit.
+ * @scancode: the scancode received or to be sent
+ */
+struct lirc_scancode {
+       __u64   timestamp;
+       __u16   flags;
+       __u16   rc_proto;
+       __u32   keycode;
+       __u64   scancode;
+};
+
+/* Set if the toggle bit of rc-5 or rc-6 is enabled */
+#define LIRC_SCANCODE_FLAG_TOGGLE      1
+/* Set if this is a nec or sanyo repeat */
+#define LIRC_SCANCODE_FLAG_REPEAT      2
+
+/**
+ * enum rc_proto - the Remote Controller protocol
+ *
+ * @RC_PROTO_UNKNOWN: Protocol not known
+ * @RC_PROTO_OTHER: Protocol known but proprietary
+ * @RC_PROTO_RC5: Philips RC5 protocol
+ * @RC_PROTO_RC5X_20: Philips RC5x 20 bit protocol
+ * @RC_PROTO_RC5_SZ: StreamZap variant of RC5
+ * @RC_PROTO_JVC: JVC protocol
+ * @RC_PROTO_SONY12: Sony 12 bit protocol
+ * @RC_PROTO_SONY15: Sony 15 bit protocol
+ * @RC_PROTO_SONY20: Sony 20 bit protocol
+ * @RC_PROTO_NEC: NEC protocol
+ * @RC_PROTO_NECX: Extended NEC protocol
+ * @RC_PROTO_NEC32: NEC 32 bit protocol
+ * @RC_PROTO_SANYO: Sanyo protocol
+ * @RC_PROTO_MCIR2_KBD: RC6-ish MCE keyboard
+ * @RC_PROTO_MCIR2_MSE: RC6-ish MCE mouse
+ * @RC_PROTO_RC6_0: Philips RC6-0-16 protocol
+ * @RC_PROTO_RC6_6A_20: Philips RC6-6A-20 protocol
+ * @RC_PROTO_RC6_6A_24: Philips RC6-6A-24 protocol
+ * @RC_PROTO_RC6_6A_32: Philips RC6-6A-32 protocol
+ * @RC_PROTO_RC6_MCE: MCE (Philips RC6-6A-32 subtype) protocol
+ * @RC_PROTO_SHARP: Sharp protocol
+ * @RC_PROTO_XMP: XMP protocol
+ * @RC_PROTO_CEC: CEC protocol
+ * @RC_PROTO_IMON: iMon Pad protocol
+ */
+enum rc_proto {
+       RC_PROTO_UNKNOWN        = 0,
+       RC_PROTO_OTHER          = 1,
+       RC_PROTO_RC5            = 2,
+       RC_PROTO_RC5X_20        = 3,
+       RC_PROTO_RC5_SZ         = 4,
+       RC_PROTO_JVC            = 5,
+       RC_PROTO_SONY12         = 6,
+       RC_PROTO_SONY15         = 7,
+       RC_PROTO_SONY20         = 8,
+       RC_PROTO_NEC            = 9,
+       RC_PROTO_NECX           = 10,
+       RC_PROTO_NEC32          = 11,
+       RC_PROTO_SANYO          = 12,
+       RC_PROTO_MCIR2_KBD      = 13,
+       RC_PROTO_MCIR2_MSE      = 14,
+       RC_PROTO_RC6_0          = 15,
+       RC_PROTO_RC6_6A_20      = 16,
+       RC_PROTO_RC6_6A_24      = 17,
+       RC_PROTO_RC6_6A_32      = 18,
+       RC_PROTO_RC6_MCE        = 19,
+       RC_PROTO_SHARP          = 20,
+       RC_PROTO_XMP            = 21,
+       RC_PROTO_CEC            = 22,
+       RC_PROTO_IMON           = 23,
+};
+
+#endif

tools/lib/bpf/libbpf.c +1 -0

index 3dbe217bf23e..01e514479f6b 100644
@@ -1461,6 +1461,7 @@ static bool bpf_prog_type__needs_kver(enum bpf_prog_type type)
        case BPF_PROG_TYPE_CGROUP_DEVICE:
        case BPF_PROG_TYPE_SK_MSG:
        case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+       case BPF_PROG_TYPE_LIRC_MODE2:
                return false;
        case BPF_PROG_TYPE_UNSPEC:
        case BPF_PROG_TYPE_KPROBE:

tools/testing/selftests/bpf/Makefile +5 -3

index 1eb0fa2aba92..ee6d49f18be5 100644
@@ -24,7 +24,7 @@ urandom_read: urandom_read.c
 # Order correspond to 'make run_tests' order
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
        test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \
-       test_sock test_btf test_sockmap
+       test_sock test_btf test_sockmap test_lirc_mode2_user
 
 TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
        test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o     \

@@ -33,7 +33,8 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
        sample_map_ret0.o test_tcpbpf_kern.o test_stacktrace_build_id.o \
        sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \
        test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \
-       test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o
+       test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \
+       test_lirc_mode2_kern.o
 
 # Order correspond to 'make run_tests' order
 TEST_PROGS := test_kmod.sh \

@@ -42,7 +43,8 @@ TEST_PROGS := test_kmod.sh \
        test_xdp_meta.sh \
        test_offload.py \
        test_sock_addr.sh \
-       test_tunnel.sh
+       test_tunnel.sh \
+       test_lirc_mode2.sh
 
 # Compile but not part of 'make run_tests'
 TEST_GEN_PROGS_EXTENDED = test_libbpf_open test_sock_addr

tools/testing/selftests/bpf/bpf_helpers.h +6 -0

index 8f143dfb3700..a6864827ed34 100644
@@ -114,6 +114,12 @@ static int (*bpf_get_stack)(void *ctx, void *buf, int size, int flags) =
 static int (*bpf_fib_lookup)(void *ctx, struct bpf_fib_lookup *params,
                             int plen, __u32 flags) =
        (void *) BPF_FUNC_fib_lookup;
+static int (*bpf_rc_repeat)(void *ctx) =
+       (void *) BPF_FUNC_rc_repeat;
+static int (*bpf_rc_keydown)(void *ctx, unsigned int protocol,
+                            unsigned long long scancode, unsigned int toggle) =
+       (void *) BPF_FUNC_rc_keydown;
+
 
 /* llvm builtin functions that eBPF C program may use to
  * emit BPF_LD_ABS and BPF_LD_IND instructions

tools/testing/selftests/bpf/test_lirc_mode2.sh new file +28 -0

new file mode 100755
index 000000000000..ce2e15e4f976
@@ -0,0 +1,28 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+GREEN='\033[0;92m'
+RED='\033[0;31m'
+NC='\033[0m' # No Color
+
+modprobe rc-loopback
+
+for i in /sys/class/rc/rc*
+do
+       if grep -q DRV_NAME=rc-loopback $i/uevent
+       then
+               LIRCDEV=$(grep DEVNAME= $i/lirc*/uevent | sed sQDEVNAME=Q/dev/Q)
+       fi
+done
+
+if [ -n $LIRCDEV ];
+then
+       TYPE=lirc_mode2
+       ./test_lirc_mode2_user $LIRCDEV
+       ret=$?
+       if [ $ret -ne 0 ]; then
+               echo -e ${RED}"FAIL: $TYPE"${NC}
+       else
+               echo -e ${GREEN}"PASS: $TYPE"${NC}
+       fi
+fi

tools/testing/selftests/bpf/test_lirc_mode2_kern.c new file +23 -0

new file mode 100644
index 000000000000..ba26855563a5
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+// test ir decoder
+//
+// Copyright (C) 2018 Sean Young <[email protected]>
+
+#include <linux/bpf.h>
+#include <linux/lirc.h>
+#include "bpf_helpers.h"
+
+SEC("lirc_mode2")
+int bpf_decoder(unsigned int *sample)
+{
+       if (LIRC_IS_PULSE(*sample)) {
+               unsigned int duration = LIRC_VALUE(*sample);
+
+               if (duration & 0x10000)
+                       bpf_rc_keydown(sample, 0x40, duration & 0xffff, 0);
+       }
+
+       return 0;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_lirc_mode2_user.c new file +154 -1

new file mode 100644
index 000000000000..bd77688c8277
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+// test ir decoder
+//
+// Copyright (C) 2018 Sean Young <[email protected]>
+
+// A lirc chardev is a device representing a consumer IR (cir) device which
+// can receive infrared signals from remote control (and/or transmit IR)
+//
+// IR is sent as a series of pulses and space somewhat like morse code. The
+// BPF program can decode this into scancodes so that rc-core can translate
+// this into input key codes using the rc keymap
+//
+// This test works by sending IR over rc-loopback, so the IR is processed by
+// BPF and then decoded into scancodes. The/ lirc chardev must be the one
+// associated with rc-loopback, see the output of ir-keytable(1)".
+//
+// The following CONFIG options must be enabled for the test to succeed:
+// CONFIG_RC_CORE=y
+// CONFIG_BPF_RAWIR_EVENT=y
+// CONFIG_RC_LOOPBACK=y
+
+// Steps:
+// 1. Open the /dev/lircN device for rc-loopback (given on command line)
+// 2. Attach bpf_lirc_mode2 program which decodes some IR.
+// 3. Send some IR to the same IR device; since it is loopback, this will
+//    end up in the bpf program
+// 4. bpf program should decode IR and report keycode
+// 5. We can read keycode from same /dev/lirc device
+
+#include <linux/bpf.h>
+#include <linux/lirc.h>
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <poll.h>
+#include <libgen.h>
+#include <sys/resource.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "bpf_util.h"
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+int main(int argc, char **argv)
+{
+       struct bpf_object *obj;
+       int ret, lircfd, progfd, mode;
+       int testir = 0x1dead;
+       u32 prog_ids[10], prog_flags[10], prog_cnt;
+
+       if (argc != 2) {
+               printf("Usage: %s /dev/lircN\n", argv[0]);
+               return 2;
+       }
+
+       ret = bpf_prog_load("test_lirc_mode2_kern.o",
+                           BPF_PROG_TYPE_LIRC_MODE2, &obj, &progfd);
+       if (ret) {
+               printf("Failed to load bpf program\n");
+               return 1;
+       }
+
+       lircfd = open(argv[1], O_RDWR | O_NONBLOCK);
+       if (lircfd == -1) {
+               printf("failed to open lirc device %s: %m\n", argv[1]);
+               return 1;
+       }
+
+       /* Let's try detach it before it was ever attached */
+       ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
+       if (ret != -1 || errno != ENOENT) {
+               printf("bpf_prog_detach2 not attached should fail: %m\n");
+               return 1;
+       }
+
+       mode = LIRC_MODE_SCANCODE;
+       if (ioctl(lircfd, LIRC_SET_REC_MODE, &mode)) {
+               printf("failed to set rec mode: %m\n");
+               return 1;
+       }
+
+       prog_cnt = 10;
+       ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
+                            &prog_cnt);
+       if (ret) {
+               printf("Failed to query bpf programs on lirc device: %m\n");
+               return 1;
+       }
+
+       if (prog_cnt != 0) {
+               printf("Expected nothing to be attached\n");
+               return 1;
+       }
+
+       ret = bpf_prog_attach(progfd, lircfd, BPF_LIRC_MODE2, 0);
+       if (ret) {
+               printf("Failed to attach bpf to lirc device: %m\n");
+               return 1;
+       }
+
+       /* Write raw IR */
+       ret = write(lircfd, &testir, sizeof(testir));
+       if (ret != sizeof(testir)) {
+               printf("Failed to send test IR message: %m\n");
+               return 1;
+       }
+
+       struct pollfd pfd = { .fd = lircfd, .events = POLLIN };
+       struct lirc_scancode lsc;
+
+       poll(&pfd, 1, 100);
+
+       /* Read decoded IR */
+       ret = read(lircfd, &lsc, sizeof(lsc));
+       if (ret != sizeof(lsc)) {
+               printf("Failed to read decoded IR: %m\n");
+               return 1;
+       }
+
+       if (lsc.scancode != 0xdead || lsc.rc_proto != 64) {
+               printf("Incorrect scancode decoded\n");
+               return 1;
+       }
+
+       prog_cnt = 10;
+       ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
+                            &prog_cnt);
+       if (ret) {
+               printf("Failed to query bpf programs on lirc device: %m\n");
+               return 1;
+       }
+
+       if (prog_cnt != 1) {
+               printf("Expected one program to be attached\n");
+               return 1;
+       }
+
+       /* Let's try detaching it now it is actually attached */
+       ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
+       if (ret) {
+               printf("bpf_prog_detach2: returned %m\n");
+               return 1;
+       }
+
+       return 0;
+}
--

2.17.0

Quoted 3 lines · Sean Young

This is simple test over rc-loopback.

Signed-off-by Sean Young <[email protected]>

Acked-by Yonghong Song <[email protected]>

Quoted 625 lines

---
 tools/bpf/bpftool/prog.c                      |   1 +
 tools/include/uapi/linux/bpf.h                |  53 ++++-
 tools/include/uapi/linux/lirc.h               | 217 ++++++++++++++++++
 tools/lib/bpf/libbpf.c                        |   1 +
 tools/testing/selftests/bpf/Makefile          |   8 +-
 tools/testing/selftests/bpf/bpf_helpers.h     |   6 +
 .../testing/selftests/bpf/test_lirc_mode2.sh  |  28 +++
 .../selftests/bpf/test_lirc_mode2_kern.c      |  23 ++
 .../selftests/bpf/test_lirc_mode2_user.c      | 154 +++++++++++++
 9 files changed, 487 insertions(+), 4 deletions(-)
 create mode 100644 tools/include/uapi/linux/lirc.h
 create mode 100755 tools/testing/selftests/bpf/test_lirc_mode2.sh
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_kern.c
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_user.c

tools/bpf/bpftool/prog.c +1 -0

index 9bdfdf2d3fbe..07f1ace39a46 100644
@@ -71,6 +71,7 @@ static const char * const prog_type_name[] = {
        [BPF_PROG_TYPE_SK_MSG]          = "sk_msg",
        [BPF_PROG_TYPE_RAW_TRACEPOINT]  = "raw_tracepoint",
        [BPF_PROG_TYPE_CGROUP_SOCK_ADDR] = "cgroup_sock_addr",
+       [BPF_PROG_TYPE_LIRC_MODE2]      = "lirc_mode2",
 };
 
 static void print_boot_time(__u64 nsecs, char *buf, unsigned int size)

tools/include/uapi/linux/bpf.h +52 -1

index d94d333a8225..8227832b713e 100644
@@ -141,6 +141,7 @@ enum bpf_prog_type {
        BPF_PROG_TYPE_SK_MSG,
        BPF_PROG_TYPE_RAW_TRACEPOINT,
        BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+       BPF_PROG_TYPE_LIRC_MODE2,
 };
 
 enum bpf_attach_type {

@@ -158,6 +159,7 @@ enum bpf_attach_type {
        BPF_CGROUP_INET6_CONNECT,
        BPF_CGROUP_INET4_POST_BIND,
        BPF_CGROUP_INET6_POST_BIND,
+       BPF_LIRC_MODE2,
        __MAX_BPF_ATTACH_TYPE
 };
 

@@ -1902,6 +1904,53 @@ union bpf_attr {
  *             egress otherwise). This is the only flag supported for now.
  *     Return
  *             **SK_PASS** on success, or **SK_DROP** on error.
+ *
+ * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
+ *     Description
+ *             This helper is used in programs implementing IR decoding, to
+ *             report a successfully decoded key press with *scancode*,
+ *             *toggle* value in the given *protocol*. The scancode will be
+ *             translated to a keycode using the rc keymap, and reported as
+ *             an input key down event. After a period a key up event is
+ *             generated. This period can be extended by calling either
+ *             **bpf_rc_keydown** () with the same values, or calling
+ *             **bpf_rc_repeat** ().
+ *
+ *             Some protocols include a toggle bit, in case the button
+ *             was released and pressed again between consecutive scancodes
+ *
+ *             The *ctx* should point to the lirc sample as passed into
+ *             the program.
+ *
+ *             The *protocol* is the decoded protocol number (see
+ *             **enum rc_proto** for some predefined values).
+ *
+ *             This helper is only available is the kernel was compiled with
+ *             the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ *             "**y**".
+ *
+ *     Return
+ *             0
+ *
+ * int bpf_rc_repeat(void *ctx)
+ *     Description
+ *             This helper is used in programs implementing IR decoding, to
+ *             report a successfully decoded repeat key message. This delays
+ *             the generation of a key up event for previously generated
+ *             key down event.
+ *
+ *             Some IR protocols like NEC have a special IR message for
+ *             repeating last button, for when a button is held down.
+ *
+ *             The *ctx* should point to the lirc sample as passed into
+ *             the program.
+ *
+ *             This helper is only available is the kernel was compiled with
+ *             the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ *             "**y**".
+ *
+ *     Return
+ *             0
  */
 #define __BPF_FUNC_MAPPER(FN)          \
        FN(unspec),                     \

@@ -1976,7 +2025,9 @@ union bpf_attr {
        FN(fib_lookup),                 \
        FN(sock_hash_update),           \
        FN(msg_redirect_hash),          \
-       FN(sk_redirect_hash),
+       FN(sk_redirect_hash),           \
+       FN(rc_repeat),                  \
+       FN(rc_keydown),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call

tools/include/uapi/linux/lirc.h new file +217 -0

new file mode 100644
index 000000000000..f189931042a7
@@ -0,0 +1,217 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * lirc.h - linux infrared remote control header file
+ * last modified 2010/07/13 by Jarod Wilson
+ */
+
+#ifndef _LINUX_LIRC_H
+#define _LINUX_LIRC_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#define PULSE_BIT       0x01000000
+#define PULSE_MASK      0x00FFFFFF
+
+#define LIRC_MODE2_SPACE     0x00000000
+#define LIRC_MODE2_PULSE     0x01000000
+#define LIRC_MODE2_FREQUENCY 0x02000000
+#define LIRC_MODE2_TIMEOUT   0x03000000
+
+#define LIRC_VALUE_MASK      0x00FFFFFF
+#define LIRC_MODE2_MASK      0xFF000000
+
+#define LIRC_SPACE(val) (((val)&LIRC_VALUE_MASK) | LIRC_MODE2_SPACE)
+#define LIRC_PULSE(val) (((val)&LIRC_VALUE_MASK) | LIRC_MODE2_PULSE)
+#define LIRC_FREQUENCY(val) (((val)&LIRC_VALUE_MASK) | LIRC_MODE2_FREQUENCY)
+#define LIRC_TIMEOUT(val) (((val)&LIRC_VALUE_MASK) | LIRC_MODE2_TIMEOUT)
+
+#define LIRC_VALUE(val) ((val)&LIRC_VALUE_MASK)
+#define LIRC_MODE2(val) ((val)&LIRC_MODE2_MASK)
+
+#define LIRC_IS_SPACE(val) (LIRC_MODE2(val) == LIRC_MODE2_SPACE)
+#define LIRC_IS_PULSE(val) (LIRC_MODE2(val) == LIRC_MODE2_PULSE)
+#define LIRC_IS_FREQUENCY(val) (LIRC_MODE2(val) == LIRC_MODE2_FREQUENCY)
+#define LIRC_IS_TIMEOUT(val) (LIRC_MODE2(val) == LIRC_MODE2_TIMEOUT)
+
+/* used heavily by lirc userspace */
+#define lirc_t int
+
+/*** lirc compatible hardware features ***/
+
+#define LIRC_MODE2SEND(x) (x)
+#define LIRC_SEND2MODE(x) (x)
+#define LIRC_MODE2REC(x) ((x) << 16)
+#define LIRC_REC2MODE(x) ((x) >> 16)
+
+#define LIRC_MODE_RAW                  0x00000001
+#define LIRC_MODE_PULSE                0x00000002
+#define LIRC_MODE_MODE2                0x00000004
+#define LIRC_MODE_SCANCODE             0x00000008
+#define LIRC_MODE_LIRCCODE             0x00000010
+
+
+#define LIRC_CAN_SEND_RAW              LIRC_MODE2SEND(LIRC_MODE_RAW)
+#define LIRC_CAN_SEND_PULSE            LIRC_MODE2SEND(LIRC_MODE_PULSE)
+#define LIRC_CAN_SEND_MODE2            LIRC_MODE2SEND(LIRC_MODE_MODE2)
+#define LIRC_CAN_SEND_LIRCCODE         LIRC_MODE2SEND(LIRC_MODE_LIRCCODE)
+
+#define LIRC_CAN_SEND_MASK             0x0000003f
+
+#define LIRC_CAN_SET_SEND_CARRIER      0x00000100
+#define LIRC_CAN_SET_SEND_DUTY_CYCLE   0x00000200
+#define LIRC_CAN_SET_TRANSMITTER_MASK  0x00000400
+
+#define LIRC_CAN_REC_RAW               LIRC_MODE2REC(LIRC_MODE_RAW)
+#define LIRC_CAN_REC_PULSE             LIRC_MODE2REC(LIRC_MODE_PULSE)
+#define LIRC_CAN_REC_MODE2             LIRC_MODE2REC(LIRC_MODE_MODE2)
+#define LIRC_CAN_REC_SCANCODE          LIRC_MODE2REC(LIRC_MODE_SCANCODE)
+#define LIRC_CAN_REC_LIRCCODE          LIRC_MODE2REC(LIRC_MODE_LIRCCODE)
+
+#define LIRC_CAN_REC_MASK              LIRC_MODE2REC(LIRC_CAN_SEND_MASK)
+
+#define LIRC_CAN_SET_REC_CARRIER       (LIRC_CAN_SET_SEND_CARRIER << 16)
+#define LIRC_CAN_SET_REC_DUTY_CYCLE    (LIRC_CAN_SET_SEND_DUTY_CYCLE << 16)
+
+#define LIRC_CAN_SET_REC_DUTY_CYCLE_RANGE 0x40000000
+#define LIRC_CAN_SET_REC_CARRIER_RANGE    0x80000000
+#define LIRC_CAN_GET_REC_RESOLUTION       0x20000000
+#define LIRC_CAN_SET_REC_TIMEOUT          0x10000000
+#define LIRC_CAN_SET_REC_FILTER           0x08000000
+
+#define LIRC_CAN_MEASURE_CARRIER          0x02000000
+#define LIRC_CAN_USE_WIDEBAND_RECEIVER    0x04000000
+
+#define LIRC_CAN_SEND(x) ((x)&LIRC_CAN_SEND_MASK)
+#define LIRC_CAN_REC(x) ((x)&LIRC_CAN_REC_MASK)
+
+#define LIRC_CAN_NOTIFY_DECODE            0x01000000
+
+/*** IOCTL commands for lirc driver ***/
+
+#define LIRC_GET_FEATURES              _IOR('i', 0x00000000, __u32)
+
+#define LIRC_GET_SEND_MODE             _IOR('i', 0x00000001, __u32)
+#define LIRC_GET_REC_MODE              _IOR('i', 0x00000002, __u32)
+#define LIRC_GET_REC_RESOLUTION        _IOR('i', 0x00000007, __u32)
+
+#define LIRC_GET_MIN_TIMEOUT           _IOR('i', 0x00000008, __u32)
+#define LIRC_GET_MAX_TIMEOUT           _IOR('i', 0x00000009, __u32)
+
+/* code length in bits, currently only for LIRC_MODE_LIRCCODE */
+#define LIRC_GET_LENGTH                _IOR('i', 0x0000000f, __u32)
+
+#define LIRC_SET_SEND_MODE             _IOW('i', 0x00000011, __u32)
+#define LIRC_SET_REC_MODE              _IOW('i', 0x00000012, __u32)
+/* Note: these can reset the according pulse_width */
+#define LIRC_SET_SEND_CARRIER          _IOW('i', 0x00000013, __u32)
+#define LIRC_SET_REC_CARRIER           _IOW('i', 0x00000014, __u32)
+#define LIRC_SET_SEND_DUTY_CYCLE       _IOW('i', 0x00000015, __u32)
+#define LIRC_SET_TRANSMITTER_MASK      _IOW('i', 0x00000017, __u32)
+
+/*
+ * when a timeout != 0 is set the driver will send a
+ * LIRC_MODE2_TIMEOUT data packet, otherwise LIRC_MODE2_TIMEOUT is
+ * never sent, timeout is disabled by default
+ */
+#define LIRC_SET_REC_TIMEOUT           _IOW('i', 0x00000018, __u32)
+
+/* 1 enables, 0 disables timeout reports in MODE2 */
+#define LIRC_SET_REC_TIMEOUT_REPORTS   _IOW('i', 0x00000019, __u32)
+
+/*
+ * if enabled from the next key press on the driver will send
+ * LIRC_MODE2_FREQUENCY packets
+ */
+#define LIRC_SET_MEASURE_CARRIER_MODE  _IOW('i', 0x0000001d, __u32)
+
+/*
+ * to set a range use LIRC_SET_REC_CARRIER_RANGE with the
+ * lower bound first and later LIRC_SET_REC_CARRIER with the upper bound
+ */
+#define LIRC_SET_REC_CARRIER_RANGE     _IOW('i', 0x0000001f, __u32)
+
+#define LIRC_SET_WIDEBAND_RECEIVER     _IOW('i', 0x00000023, __u32)
+
+/*
+ * struct lirc_scancode - decoded scancode with protocol for use with
+ *     LIRC_MODE_SCANCODE
+ *
+ * @timestamp: Timestamp in nanoseconds using CLOCK_MONOTONIC when IR
+ *     was decoded.
+ * @flags: should be 0 for transmit. When receiving scancodes,
+ *     LIRC_SCANCODE_FLAG_TOGGLE or LIRC_SCANCODE_FLAG_REPEAT can be set
+ *     depending on the protocol
+ * @rc_proto: see enum rc_proto
+ * @keycode: the translated keycode. Set to 0 for transmit.
+ * @scancode: the scancode received or to be sent
+ */
+struct lirc_scancode {
+       __u64   timestamp;
+       __u16   flags;
+       __u16   rc_proto;
+       __u32   keycode;
+       __u64   scancode;
+};
+
+/* Set if the toggle bit of rc-5 or rc-6 is enabled */
+#define LIRC_SCANCODE_FLAG_TOGGLE      1
+/* Set if this is a nec or sanyo repeat */
+#define LIRC_SCANCODE_FLAG_REPEAT      2
+
+/**
+ * enum rc_proto - the Remote Controller protocol
+ *
+ * @RC_PROTO_UNKNOWN: Protocol not known
+ * @RC_PROTO_OTHER: Protocol known but proprietary
+ * @RC_PROTO_RC5: Philips RC5 protocol
+ * @RC_PROTO_RC5X_20: Philips RC5x 20 bit protocol
+ * @RC_PROTO_RC5_SZ: StreamZap variant of RC5
+ * @RC_PROTO_JVC: JVC protocol
+ * @RC_PROTO_SONY12: Sony 12 bit protocol
+ * @RC_PROTO_SONY15: Sony 15 bit protocol
+ * @RC_PROTO_SONY20: Sony 20 bit protocol
+ * @RC_PROTO_NEC: NEC protocol
+ * @RC_PROTO_NECX: Extended NEC protocol
+ * @RC_PROTO_NEC32: NEC 32 bit protocol
+ * @RC_PROTO_SANYO: Sanyo protocol
+ * @RC_PROTO_MCIR2_KBD: RC6-ish MCE keyboard
+ * @RC_PROTO_MCIR2_MSE: RC6-ish MCE mouse
+ * @RC_PROTO_RC6_0: Philips RC6-0-16 protocol
+ * @RC_PROTO_RC6_6A_20: Philips RC6-6A-20 protocol
+ * @RC_PROTO_RC6_6A_24: Philips RC6-6A-24 protocol
+ * @RC_PROTO_RC6_6A_32: Philips RC6-6A-32 protocol
+ * @RC_PROTO_RC6_MCE: MCE (Philips RC6-6A-32 subtype) protocol
+ * @RC_PROTO_SHARP: Sharp protocol
+ * @RC_PROTO_XMP: XMP protocol
+ * @RC_PROTO_CEC: CEC protocol
+ * @RC_PROTO_IMON: iMon Pad protocol
+ */
+enum rc_proto {
+       RC_PROTO_UNKNOWN        = 0,
+       RC_PROTO_OTHER          = 1,
+       RC_PROTO_RC5            = 2,
+       RC_PROTO_RC5X_20        = 3,
+       RC_PROTO_RC5_SZ         = 4,
+       RC_PROTO_JVC            = 5,
+       RC_PROTO_SONY12         = 6,
+       RC_PROTO_SONY15         = 7,
+       RC_PROTO_SONY20         = 8,
+       RC_PROTO_NEC            = 9,
+       RC_PROTO_NECX           = 10,
+       RC_PROTO_NEC32          = 11,
+       RC_PROTO_SANYO          = 12,
+       RC_PROTO_MCIR2_KBD      = 13,
+       RC_PROTO_MCIR2_MSE      = 14,
+       RC_PROTO_RC6_0          = 15,
+       RC_PROTO_RC6_6A_20      = 16,
+       RC_PROTO_RC6_6A_24      = 17,
+       RC_PROTO_RC6_6A_32      = 18,
+       RC_PROTO_RC6_MCE        = 19,
+       RC_PROTO_SHARP          = 20,
+       RC_PROTO_XMP            = 21,
+       RC_PROTO_CEC            = 22,
+       RC_PROTO_IMON           = 23,
+};
+
+#endif

tools/lib/bpf/libbpf.c +1 -0

index 3dbe217bf23e..01e514479f6b 100644
@@ -1461,6 +1461,7 @@ static bool bpf_prog_type__needs_kver(enum bpf_prog_type type)
        case BPF_PROG_TYPE_CGROUP_DEVICE:
        case BPF_PROG_TYPE_SK_MSG:
        case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+       case BPF_PROG_TYPE_LIRC_MODE2:
                return false;
        case BPF_PROG_TYPE_UNSPEC:
        case BPF_PROG_TYPE_KPROBE:

tools/testing/selftests/bpf/Makefile +5 -3

index 1eb0fa2aba92..ee6d49f18be5 100644
@@ -24,7 +24,7 @@ urandom_read: urandom_read.c
 # Order correspond to 'make run_tests' order
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
        test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \
-       test_sock test_btf test_sockmap
+       test_sock test_btf test_sockmap test_lirc_mode2_user
 
 TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
        test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o     \

@@ -33,7 +33,8 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
        sample_map_ret0.o test_tcpbpf_kern.o test_stacktrace_build_id.o \
        sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \
        test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \
-       test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o
+       test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \
+       test_lirc_mode2_kern.o
 
 # Order correspond to 'make run_tests' order
 TEST_PROGS := test_kmod.sh \

@@ -42,7 +43,8 @@ TEST_PROGS := test_kmod.sh \
        test_xdp_meta.sh \
        test_offload.py \
        test_sock_addr.sh \
-       test_tunnel.sh
+       test_tunnel.sh \
+       test_lirc_mode2.sh
 
 # Compile but not part of 'make run_tests'
 TEST_GEN_PROGS_EXTENDED = test_libbpf_open test_sock_addr

tools/testing/selftests/bpf/bpf_helpers.h +6 -0

index 8f143dfb3700..a6864827ed34 100644
@@ -114,6 +114,12 @@ static int (*bpf_get_stack)(void *ctx, void *buf, int size, int flags) =
 static int (*bpf_fib_lookup)(void *ctx, struct bpf_fib_lookup *params,
                             int plen, __u32 flags) =
        (void *) BPF_FUNC_fib_lookup;
+static int (*bpf_rc_repeat)(void *ctx) =
+       (void *) BPF_FUNC_rc_repeat;
+static int (*bpf_rc_keydown)(void *ctx, unsigned int protocol,
+                            unsigned long long scancode, unsigned int toggle) =
+       (void *) BPF_FUNC_rc_keydown;
+
 
 /* llvm builtin functions that eBPF C program may use to
  * emit BPF_LD_ABS and BPF_LD_IND instructions

tools/testing/selftests/bpf/test_lirc_mode2.sh new file +28 -0

new file mode 100755
index 000000000000..ce2e15e4f976
@@ -0,0 +1,28 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+GREEN='\033[0;92m'
+RED='\033[0;31m'
+NC='\033[0m' # No Color
+
+modprobe rc-loopback
+
+for i in /sys/class/rc/rc*
+do
+       if grep -q DRV_NAME=rc-loopback $i/uevent
+       then
+               LIRCDEV=$(grep DEVNAME= $i/lirc*/uevent | sed sQDEVNAME=Q/dev/Q)
+       fi
+done
+
+if [ -n $LIRCDEV ];
+then
+       TYPE=lirc_mode2
+       ./test_lirc_mode2_user $LIRCDEV
+       ret=$?
+       if [ $ret -ne 0 ]; then
+               echo -e ${RED}"FAIL: $TYPE"${NC}
+       else
+               echo -e ${GREEN}"PASS: $TYPE"${NC}
+       fi
+fi

tools/testing/selftests/bpf/test_lirc_mode2_kern.c new file +23 -0

new file mode 100644
index 000000000000..ba26855563a5
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+// test ir decoder
+//
+// Copyright (C) 2018 Sean Young <[email protected]>
+
+#include <linux/bpf.h>
+#include <linux/lirc.h>
+#include "bpf_helpers.h"
+
+SEC("lirc_mode2")
+int bpf_decoder(unsigned int *sample)
+{
+       if (LIRC_IS_PULSE(*sample)) {
+               unsigned int duration = LIRC_VALUE(*sample);
+
+               if (duration & 0x10000)
+                       bpf_rc_keydown(sample, 0x40, duration & 0xffff, 0);
+       }
+
+       return 0;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_lirc_mode2_user.c new file +154 -1

new file mode 100644
index 000000000000..bd77688c8277
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+// test ir decoder
+//
+// Copyright (C) 2018 Sean Young <[email protected]>
+
+// A lirc chardev is a device representing a consumer IR (cir) device which
+// can receive infrared signals from remote control (and/or transmit IR)
+//
+// IR is sent as a series of pulses and space somewhat like morse code. The
+// BPF program can decode this into scancodes so that rc-core can translate
+// this into input key codes using the rc keymap
+//
+// This test works by sending IR over rc-loopback, so the IR is processed by
+// BPF and then decoded into scancodes. The/ lirc chardev must be the one
+// associated with rc-loopback, see the output of ir-keytable(1)".
+//
+// The following CONFIG options must be enabled for the test to succeed:
+// CONFIG_RC_CORE=y
+// CONFIG_BPF_RAWIR_EVENT=y
+// CONFIG_RC_LOOPBACK=y
+
+// Steps:
+// 1. Open the /dev/lircN device for rc-loopback (given on command line)
+// 2. Attach bpf_lirc_mode2 program which decodes some IR.
+// 3. Send some IR to the same IR device; since it is loopback, this will
+//    end up in the bpf program
+// 4. bpf program should decode IR and report keycode
+// 5. We can read keycode from same /dev/lirc device
+
+#include <linux/bpf.h>
+#include <linux/lirc.h>
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <poll.h>
+#include <libgen.h>
+#include <sys/resource.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "bpf_util.h"
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+int main(int argc, char **argv)
+{
+       struct bpf_object *obj;
+       int ret, lircfd, progfd, mode;
+       int testir = 0x1dead;
+       u32 prog_ids[10], prog_flags[10], prog_cnt;
+
+       if (argc != 2) {
+               printf("Usage: %s /dev/lircN\n", argv[0]);
+               return 2;
+       }
+
+       ret = bpf_prog_load("test_lirc_mode2_kern.o",
+                           BPF_PROG_TYPE_LIRC_MODE2, &obj, &progfd);
+       if (ret) {
+               printf("Failed to load bpf program\n");
+               return 1;
+       }
+
+       lircfd = open(argv[1], O_RDWR | O_NONBLOCK);
+       if (lircfd == -1) {
+               printf("failed to open lirc device %s: %m\n", argv[1]);
+               return 1;
+       }
+
+       /* Let's try detach it before it was ever attached */
+       ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
+       if (ret != -1 || errno != ENOENT) {
+               printf("bpf_prog_detach2 not attached should fail: %m\n");
+               return 1;
+       }
+
+       mode = LIRC_MODE_SCANCODE;
+       if (ioctl(lircfd, LIRC_SET_REC_MODE, &mode)) {
+               printf("failed to set rec mode: %m\n");
+               return 1;
+       }
+
+       prog_cnt = 10;
+       ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
+                            &prog_cnt);
+       if (ret) {
+               printf("Failed to query bpf programs on lirc device: %m\n");
+               return 1;
+       }
+
+       if (prog_cnt != 0) {
+               printf("Expected nothing to be attached\n");
+               return 1;
+       }
+
+       ret = bpf_prog_attach(progfd, lircfd, BPF_LIRC_MODE2, 0);
+       if (ret) {
+               printf("Failed to attach bpf to lirc device: %m\n");
+               return 1;
+       }
+
+       /* Write raw IR */
+       ret = write(lircfd, &testir, sizeof(testir));
+       if (ret != sizeof(testir)) {
+               printf("Failed to send test IR message: %m\n");
+               return 1;
+       }
+
+       struct pollfd pfd = { .fd = lircfd, .events = POLLIN };
+       struct lirc_scancode lsc;
+
+       poll(&pfd, 1, 100);
+
+       /* Read decoded IR */
+       ret = read(lircfd, &lsc, sizeof(lsc));
+       if (ret != sizeof(lsc)) {
+               printf("Failed to read decoded IR: %m\n");
+               return 1;
+       }
+
+       if (lsc.scancode != 0xdead || lsc.rc_proto != 64) {
+               printf("Incorrect scancode decoded\n");
+               return 1;
+       }
+
+       prog_cnt = 10;
+       ret = bpf_prog_query(lircfd, BPF_LIRC_MODE2, 0, prog_flags, prog_ids,
+                            &prog_cnt);
+       if (ret) {
+               printf("Failed to query bpf programs on lirc device: %m\n");
+               return 1;
+       }
+
+       if (prog_cnt != 1) {
+               printf("Expected one program to be attached\n");
+               return 1;
+       }
+
+       /* Let's try detaching it now it is actually attached */
+       ret = bpf_prog_detach2(progfd, lircfd, BPF_LIRC_MODE2);
+       if (ret) {
+               printf("bpf_prog_detach2: returned %m\n");
+               return 1;
+       }
+
+       return 0;
+}
--

2.17.0

The kernel IR decoders (drivers/media/rc/ir-*-decoder.c) support the most widely used IR protocols, but there are many protocols which are not supported[1]. For example, the lirc-remotes[2] repo has over 2700 remotes, many of which are not supported by rc-core. There is a "long tail" of unsupported IR protocols, for which lircd is need to decode the IR .

IR encoding is done in such a way that some simple circuit can decode it; therefore, bpf is ideal.

In order to support all these protocols, here we have bpf based IR decoding. The idea is that user-space can define a decoder in bpf, attach it to the rc device through the lirc chardev.

Separate work is underway to extend ir-keytable to have an extensive library of bpf-based decoders, and a much expanded library of rc keymaps.

Another future application would be to compile IRP[3] to a IR BPF program, and so support virtually every remote without having to write a decoder for each. It might also be possible to support non-button devices such as analog directional pads or air conditioning remote controls and decode the target temperature in bpf, and pass that to an input device.

Thanks,

Sean Young

[1] http://www.hifi-remote.com/wiki/index.php?title=DecodeIR
[2] https://sourceforge.net/p/lirc-remotes/code/ci/master/tree/remotes/
[3] http://www.hifi-remote.com/wiki/index.php?title=IRP_Notation

Changes since v3:
- Implemented review comments from Quentin Monnet and Y Song (thanks!)
- More helpful and better formatted bpf helper documentation
- Changed back to bpf_prog_array rather than open-coded implementation
- scancodes can be 64 bit
- bpf gets passed values in microseconds, not nanoseconds. microseconds is more than than enough (IR receivers support carriers upto 70kHz, at which point a single period is already 14 microseconds). Also, this makes it much more consistent with lirc mode2.
- Since it looks much more like lirc mode2, rename the program type to BPF_PROG_TYPE_LIRC_MODE2.
- Rebased on bpf-next

Changes since v2:
- Fixed locking issues
- Improved self-test to cover more cases
- Rebased on bpf-next again

Changes since v1:
- Code review comments from Y Song <[email protected]> and Randy Dunlap <[email protected]>
- Re-wrote sample bpf to be selftest
- Renamed RAWIR_DECODER -> RAWIR_EVENT (Kconfig, context, bpf prog type)
- Rebase on bpf-next
- Introduced bpf_rawir_event context structure with simpler access checking

Sean Young (3):
bpf: bpf_prog_array_copy() should return -ENOENT if exclude_prog not
found
media: rc: introduce BPF_PROG_LIRC_MODE2
bpf: add selftest for lirc_mode2 type program

 drivers/media/rc/Kconfig                      |  13 +
 drivers/media/rc/Makefile                     |   1 +
 drivers/media/rc/bpf-lirc.c                   | 308 ++++++++++++++++++
 drivers/media/rc/lirc_dev.c                   |  30 ++
 drivers/media/rc/rc-core-priv.h               |  22 ++
 drivers/media/rc/rc-ir-raw.c                  |  12 +-
 include/linux/bpf_rcdev.h                     |  30 ++
 include/linux/bpf_types.h                     |   3 +
 include/uapi/linux/bpf.h                      |  53 ++-
 kernel/bpf/core.c                             |  11 +-
 kernel/bpf/syscall.c                          |   7 +
 kernel/trace/bpf_trace.c                      |   2 +
 tools/bpf/bpftool/prog.c                      |   1 +
 tools/include/uapi/linux/bpf.h                |  53 ++-
 tools/include/uapi/linux/lirc.h               | 217 ++++++++++++
 tools/lib/bpf/libbpf.c                        |   1 +
 tools/testing/selftests/bpf/Makefile          |   8 +-
 tools/testing/selftests/bpf/bpf_helpers.h     |   6 +
 .../testing/selftests/bpf/test_lirc_mode2.sh  |  28 ++
 .../selftests/bpf/test_lirc_mode2_kern.c      |  23 ++
 .../selftests/bpf/test_lirc_mode2_user.c      | 154 +++++++++
 21 files changed, 974 insertions(+), 9 deletions(-)
 create mode 100644 drivers/media/rc/bpf-lirc.c
 create mode 100644 include/linux/bpf_rcdev.h
 create mode 100644 tools/include/uapi/linux/lirc.h
 create mode 100755 tools/testing/selftests/bpf/test_lirc_mode2.sh
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_kern.c
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_user.c

Signature · 1 line

2.17.0

Hi Sean,

Quoted 13 lines · Sean Young

The kernel IR decoders (drivers/media/rc/ir-*-decoder.c) support the most widely used IR protocols, but there are many protocols which are not supported[1]. For example, the lirc-remotes[2] repo has over 2700 remotes, many of which are not supported by rc-core. There is a "long tail" of unsupported IR protocols, for which lircd is need to decode the IR .

IR encoding is done in such a way that some simple circuit can decode it; therefore, bpf is ideal.

In order to support all these protocols, here we have bpf based IR decoding. The idea is that user-space can define a decoder in bpf, attach it to the rc device through the lirc chardev.

Quoted 8 lines

Separate work is underway to extend ir-keytable to have an extensive library of bpf-based decoders, and a much expanded library of rc keymaps.

Another future application would be to compile IRP[3] to a IR BPF program, and so support virtually every remote without having to write a decoder for each. It might also be possible to support non-button devices such as analog directional pads or air conditioning remote controls and decode the target temperature in bpf, and pass that to an input device.

Thanks a lot, this looks like a very interesting feature to me!

Unfortunately I don't have time to test it ATM, but please keep me posted - also on ir-keytable progress - I'm rather excited to give it a try.

so long & thanks,

Hias

Quoted 73 lines

Thanks,

Sean Young

[1] http://www.hifi-remote.com/wiki/index.php?title=DecodeIR
[2] https://sourceforge.net/p/lirc-remotes/code/ci/master/tree/remotes/
[3] http://www.hifi-remote.com/wiki/index.php?title=IRP_Notation

Changes since v3:
- Implemented review comments from Quentin Monnet and Y Song (thanks!)
- More helpful and better formatted bpf helper documentation
- Changed back to bpf_prog_array rather than open-coded implementation
- scancodes can be 64 bit
- bpf gets passed values in microseconds, not nanoseconds. microseconds is more than than enough (IR receivers support carriers upto 70kHz, at which point a single period is already 14 microseconds). Also, this makes it much more consistent with lirc mode2.
- Since it looks much more like lirc mode2, rename the program type to BPF_PROG_TYPE_LIRC_MODE2.
- Rebased on bpf-next

Changes since v2:
- Fixed locking issues
- Improved self-test to cover more cases
- Rebased on bpf-next again

Changes since v1:
- Code review comments from Y Song <[email protected]> and Randy Dunlap <[email protected]>
- Re-wrote sample bpf to be selftest
- Renamed RAWIR_DECODER -> RAWIR_EVENT (Kconfig, context, bpf prog type)
- Rebase on bpf-next
- Introduced bpf_rawir_event context structure with simpler access checking

Sean Young (3):
bpf: bpf_prog_array_copy() should return -ENOENT if exclude_prog not
found
media: rc: introduce BPF_PROG_LIRC_MODE2
bpf: add selftest for lirc_mode2 type program

 drivers/media/rc/Kconfig                      |  13 +
 drivers/media/rc/Makefile                     |   1 +
 drivers/media/rc/bpf-lirc.c                   | 308 ++++++++++++++++++
 drivers/media/rc/lirc_dev.c                   |  30 ++
 drivers/media/rc/rc-core-priv.h               |  22 ++
 drivers/media/rc/rc-ir-raw.c                  |  12 +-
 include/linux/bpf_rcdev.h                     |  30 ++
 include/linux/bpf_types.h                     |   3 +
 include/uapi/linux/bpf.h                      |  53 ++-
 kernel/bpf/core.c                             |  11 +-
 kernel/bpf/syscall.c                          |   7 +
 kernel/trace/bpf_trace.c                      |   2 +
 tools/bpf/bpftool/prog.c                      |   1 +
 tools/include/uapi/linux/bpf.h                |  53 ++-
 tools/include/uapi/linux/lirc.h               | 217 ++++++++++++
 tools/lib/bpf/libbpf.c                        |   1 +
 tools/testing/selftests/bpf/Makefile          |   8 +-
 tools/testing/selftests/bpf/bpf_helpers.h     |   6 +
 .../testing/selftests/bpf/test_lirc_mode2.sh  |  28 ++
 .../selftests/bpf/test_lirc_mode2_kern.c      |  23 ++
 .../selftests/bpf/test_lirc_mode2_user.c      | 154 +++++++++
 21 files changed, 974 insertions(+), 9 deletions(-)
 create mode 100644 drivers/media/rc/bpf-lirc.c
 create mode 100644 include/linux/bpf_rcdev.h
 create mode 100644 tools/include/uapi/linux/lirc.h
 create mode 100755 tools/testing/selftests/bpf/test_lirc_mode2.sh
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_kern.c
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_user.c

--
2.17.0

The kernel IR decoders (drivers/media/rc/ir-*-decoder.c) support the most widely used IR protocols, but there are many protocols which are not supported[1]. For example, the lirc-remotes[2] repo has over 2700 remotes, many of which are not supported by rc-core. There is a "long tail" of unsupported IR protocols, for which lircd is need to decode the IR .

IR encoding is done in such a way that some simple circuit can decode it; therefore, bpf is ideal.

In order to support all these protocols, here we have bpf based IR decoding. The idea is that user-space can define a decoder in bpf, attach it to the rc device through the lirc chardev.

Separate work is underway to extend ir-keytable to have an extensive library of bpf-based decoders, and a much expanded library of rc keymaps.

Another future application would be to compile IRP[3] to a IR BPF program, and so support virtually every remote without having to write a decoder for each. It might also be possible to support non-button devices such as analog directional pads or air conditioning remote controls and decode the target temperature in bpf, and pass that to an input device.

Thanks,

Sean Young

[1] http://www.hifi-remote.com/wiki/index.php?title=DecodeIR
[2] https://sourceforge.net/p/lirc-remotes/code/ci/master/tree/remotes/
[3] http://www.hifi-remote.com/wiki/index.php?title=IRP_Notation

Changes since v3:
- Implemented review comments from Quentin Monnet and Y Song (thanks!)
- More helpful and better formatted bpf helper documentation
- Changed back to bpf_prog_array rather than open-coded implementation
- scancodes can be 64 bit
- bpf gets passed values in microseconds, not nanoseconds. microseconds is more than than enough (IR receivers support carriers upto 70kHz, at which point a single period is already 14 microseconds). Also, this makes it much more consistent with lirc mode2.
- Since it looks much more like lirc mode2, rename the program type to BPF_PROG_TYPE_LIRC_MODE2.
- Rebased on bpf-next

Changes since v2:
- Fixed locking issues
- Improved self-test to cover more cases
- Rebased on bpf-next again

Changes since v1:
- Code review comments from Y Song <[email protected]> and Randy Dunlap <[email protected]>
- Re-wrote sample bpf to be selftest
- Renamed RAWIR_DECODER -> RAWIR_EVENT (Kconfig, context, bpf prog type)
- Rebase on bpf-next
- Introduced bpf_rawir_event context structure with simpler access checking

Sean Young (3):
bpf: bpf_prog_array_copy() should return -ENOENT if exclude_prog not
found
media: rc: introduce BPF_PROG_LIRC_MODE2
bpf: add selftest for lirc_mode2 type program

 drivers/media/rc/Kconfig                      |  13 +
 drivers/media/rc/Makefile                     |   1 +
 drivers/media/rc/bpf-lirc.c                   | 308 ++++++++++++++++++
 drivers/media/rc/lirc_dev.c                   |  30 ++
 drivers/media/rc/rc-core-priv.h               |  22 ++
 drivers/media/rc/rc-ir-raw.c                  |  12 +-
 include/linux/bpf_rcdev.h                     |  30 ++
 include/linux/bpf_types.h                     |   3 +
 include/uapi/linux/bpf.h                      |  53 ++-
 kernel/bpf/core.c                             |  11 +-
 kernel/bpf/syscall.c                          |   7 +
 kernel/trace/bpf_trace.c                      |   2 +
 tools/bpf/bpftool/prog.c                      |   1 +
 tools/include/uapi/linux/bpf.h                |  53 ++-
 tools/include/uapi/linux/lirc.h               | 217 ++++++++++++
 tools/lib/bpf/libbpf.c                        |   1 +
 tools/testing/selftests/bpf/Makefile          |   8 +-
 tools/testing/selftests/bpf/bpf_helpers.h     |   6 +
 .../testing/selftests/bpf/test_lirc_mode2.sh  |  28 ++
 .../selftests/bpf/test_lirc_mode2_kern.c      |  23 ++
 .../selftests/bpf/test_lirc_mode2_user.c      | 154 +++++++++
 21 files changed, 974 insertions(+), 9 deletions(-)
 create mode 100644 drivers/media/rc/bpf-lirc.c
 create mode 100644 include/linux/bpf_rcdev.h
 create mode 100644 tools/include/uapi/linux/lirc.h
 create mode 100755 tools/testing/selftests/bpf/test_lirc_mode2.sh
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_kern.c
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_user.c

Quoted 16 lines · Sean Young

The kernel IR decoders (drivers/media/rc/ir-*-decoder.c) support the most widely used IR protocols, but there are many protocols which are not supported[1]. For example, the lirc-remotes[2] repo has over 2700 remotes, many of which are not supported by rc-core. There is a "long tail" of unsupported IR protocols, for which lircd is need to decode the IR .

IR encoding is done in such a way that some simple circuit can decode it; therefore, bpf is ideal.

In order to support all these protocols, here we have bpf based IR decoding. The idea is that user-space can define a decoder in bpf, attach it to the rc device through the lirc chardev.

Separate work is underway to extend ir-keytable to have an extensive library of bpf-based decoders, and a much expanded library of rc keymaps.

Quoted 5 lines

Another future application would be to compile IRP[3] to a IR BPF program, and so support virtually every remote without having to write a decoder for each. It might also be possible to support non-button devices such as analog directional pads or air conditioning remote controls and decode the target temperature in bpf, and pass that to an input device.

Mauro, are you fine with this series going via bpf-next? How ugly would this get with regards to merge conflicts wrt drivers/media/rc/?

Thanks,
Daniel

Quoted 69 lines

Thanks,

Sean Young

[1] http://www.hifi-remote.com/wiki/index.php?title=DecodeIR
[2] https://sourceforge.net/p/lirc-remotes/code/ci/master/tree/remotes/
[3] http://www.hifi-remote.com/wiki/index.php?title=IRP_Notation

Changes since v3:
- Implemented review comments from Quentin Monnet and Y Song (thanks!)
- More helpful and better formatted bpf helper documentation
- Changed back to bpf_prog_array rather than open-coded implementation
- scancodes can be 64 bit
- bpf gets passed values in microseconds, not nanoseconds. microseconds is more than than enough (IR receivers support carriers upto 70kHz, at which point a single period is already 14 microseconds). Also, this makes it much more consistent with lirc mode2.
- Since it looks much more like lirc mode2, rename the program type to BPF_PROG_TYPE_LIRC_MODE2.
- Rebased on bpf-next

Changes since v2:
- Fixed locking issues
- Improved self-test to cover more cases
- Rebased on bpf-next again

Changes since v1:
- Code review comments from Y Song <[email protected]> and Randy Dunlap <[email protected]>
- Re-wrote sample bpf to be selftest
- Renamed RAWIR_DECODER -> RAWIR_EVENT (Kconfig, context, bpf prog type)
- Rebase on bpf-next
- Introduced bpf_rawir_event context structure with simpler access checking

Sean Young (3):
bpf: bpf_prog_array_copy() should return -ENOENT if exclude_prog not
found
media: rc: introduce BPF_PROG_LIRC_MODE2
bpf: add selftest for lirc_mode2 type program

 drivers/media/rc/Kconfig                      |  13 +
 drivers/media/rc/Makefile                     |   1 +
 drivers/media/rc/bpf-lirc.c                   | 308 ++++++++++++++++++
 drivers/media/rc/lirc_dev.c                   |  30 ++
 drivers/media/rc/rc-core-priv.h               |  22 ++
 drivers/media/rc/rc-ir-raw.c                  |  12 +-
 include/linux/bpf_rcdev.h                     |  30 ++
 include/linux/bpf_types.h                     |   3 +
 include/uapi/linux/bpf.h                      |  53 ++-
 kernel/bpf/core.c                             |  11 +-
 kernel/bpf/syscall.c                          |   7 +
 kernel/trace/bpf_trace.c                      |   2 +
 tools/bpf/bpftool/prog.c                      |   1 +
 tools/include/uapi/linux/bpf.h                |  53 ++-
 tools/include/uapi/linux/lirc.h               | 217 ++++++++++++
 tools/lib/bpf/libbpf.c                        |   1 +
 tools/testing/selftests/bpf/Makefile          |   8 +-
 tools/testing/selftests/bpf/bpf_helpers.h     |   6 +
 .../testing/selftests/bpf/test_lirc_mode2.sh  |  28 ++
 .../selftests/bpf/test_lirc_mode2_kern.c      |  23 ++
 .../selftests/bpf/test_lirc_mode2_user.c      | 154 +++++++++
 21 files changed, 974 insertions(+), 9 deletions(-)
 create mode 100644 drivers/media/rc/bpf-lirc.c
 create mode 100644 include/linux/bpf_rcdev.h
 create mode 100644 tools/include/uapi/linux/lirc.h
 create mode 100755 tools/testing/selftests/bpf/test_lirc_mode2.sh
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_kern.c
 create mode 100644 tools/testing/selftests/bpf/test_lirc_mode2_user.c

Add support for BPF_PROG_LIRC_MODE2. This type of BPF program can call rc_keydown() to reported decoded IR scancodes, or rc_repeat() to report that the last key should be repeated.

The bpf program can be attached to using the bpf(BPF_PROG_ATTACH) syscall; the target_fd must be the /dev/lircN device.

Signed-off-by Sean Young <[email protected]>

enum bpf_attach_type {

include/uapi/linux/bpf.h +35 -0

@@ -158,6 +159,7 @@ enum bpf_attach_type {
 	BPF_CGROUP_INET6_CONNECT,
 	BPF_CGROUP_INET4_POST_BIND,
 	BPF_CGROUP_INET6_POST_BIND,
+	BPF_LIRC_MODE2,
 	__MAX_BPF_ATTACH_TYPE
 };
 

@@ -1902,6 +1904,53 @@ union bpf_attr {
  *		egress otherwise). This is the only flag supported for now.
  *	Return
  *		**SK_PASS** on success, or **SK_DROP** on error.
+ *
+ * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
+ *	Description
+ *		This helper is used in programs implementing IR decoding, to
+ *		report a successfully decoded key press with *scancode*,
+ *		*toggle* value in the given *protocol*. The scancode will be
+ *		translated to a keycode using the rc keymap, and reported as
+ *		an input key down event. After a period a key up event is
+ *		generated. This period can be extended by calling either
+ *		**bpf_rc_keydown** () with the same values, or calling
+ *		**bpf_rc_repeat** ().
+ *
+ *		Some protocols include a toggle bit, in case the button
+ *		was released and pressed again between consecutive scancodes
+ *
+ *		The *ctx* should point to the lirc sample as passed into
+ *		the program.
+ *
+ *		The *protocol* is the decoded protocol number (see
+ *		**enum rc_proto** for some predefined values).
+ *
+ *		This helper is only available is the kernel was compiled with
+ *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ *		"**y**".
+ *
+ *	Return
+ *		0
+ *
+ * int bpf_rc_repeat(void *ctx)
+ *	Description
+ *		This helper is used in programs implementing IR decoding, to
+ *		report a successfully decoded repeat key message. This delays
+ *		the generation of a key up event for previously generated
+ *		key down event.

kernel/bpf/syscall.c +2 -0

@@ -1576,6 +1577,8 @@ static int bpf_prog_attach(const union bpf_attr *attr)
 	case BPF_SK_SKB_STREAM_PARSER:
 	case BPF_SK_SKB_STREAM_VERDICT:
 		return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, true);
+	case BPF_LIRC_MODE2:
+		return rc_dev_prog_attach(attr);

Quoted 8 lines · Sean Young

Add support for BPF_PROG_LIRC_MODE2. This type of BPF program can call rc_keydown() to reported decoded IR scancodes, or rc_repeat() to report that the last key should be repeated.

The bpf program can be attached to using the bpf(BPF_PROG_ATTACH) syscall; the target_fd must be the /dev/lircN device.

Signed-off-by Sean Young <[email protected]>

...

Quoted 47 lines

enum bpf_attach_type {

include/uapi/linux/bpf.h +35 -0

@@ -158,6 +159,7 @@ enum bpf_attach_type {
 	BPF_CGROUP_INET6_CONNECT,
 	BPF_CGROUP_INET4_POST_BIND,
 	BPF_CGROUP_INET6_POST_BIND,
+	BPF_LIRC_MODE2,
 	__MAX_BPF_ATTACH_TYPE
 };
 

@@ -1902,6 +1904,53 @@ union bpf_attr {
  *		egress otherwise). This is the only flag supported for now.
  *	Return
  *		**SK_PASS** on success, or **SK_DROP** on error.
+ *
+ * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
+ *	Description
+ *		This helper is used in programs implementing IR decoding, to
+ *		report a successfully decoded key press with *scancode*,
+ *		*toggle* value in the given *protocol*. The scancode will be
+ *		translated to a keycode using the rc keymap, and reported as
+ *		an input key down event. After a period a key up event is
+ *		generated. This period can be extended by calling either
+ *		**bpf_rc_keydown** () with the same values, or calling
+ *		**bpf_rc_repeat** ().
+ *
+ *		Some protocols include a toggle bit, in case the button
+ *		was released and pressed again between consecutive scancodes
+ *
+ *		The *ctx* should point to the lirc sample as passed into
+ *		the program.
+ *
+ *		The *protocol* is the decoded protocol number (see
+ *		**enum rc_proto** for some predefined values).
+ *
+ *		This helper is only available is the kernel was compiled with
+ *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ *		"**y**".
+ *
+ *	Return
+ *		0
+ *
+ * int bpf_rc_repeat(void *ctx)
+ *	Description
+ *		This helper is used in programs implementing IR decoding, to
+ *		report a successfully decoded repeat key message. This delays
+ *		the generation of a key up event for previously generated
+ *		key down event.

include/uapi/linux/bpf.h union bpf_attr { · line 1950

Quoted 10 lines

include/uapi/linux/bpf.h +10 -0

+ *
+ *		Some IR protocols like NEC have a special IR message for
+ *		repeating last button, for when a button is held down.
+ *
+ *		The *ctx* should point to the lirc sample as passed into
+ *		the program.
+ *
+ *		This helper is only available is the kernel was compiled with
+ *		the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ *		"**y**".

Hi Sean,

thank you for working on this. The patch set looks good to me. I'd only ask to change above two helper names to something more specific. Since BPF_PROG_TYPE_LIRC_MODE2 is the name of new prog type and kconfig. May be bpf_lirc2_keydown() and bpf_lirc2_repeat() ?

Quoted 6 lines

kernel/bpf/syscall.c +2 -0

@@ -1576,6 +1577,8 @@ static int bpf_prog_attach(const union bpf_attr *attr)
 	case BPF_SK_SKB_STREAM_PARSER:
 	case BPF_SK_SKB_STREAM_VERDICT:
 		return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, true);
+	case BPF_LIRC_MODE2:
+		return rc_dev_prog_attach(attr);

...

kernel/bpf/syscall.c static int bpf_prog_detach(const union bpf_attr *attr) · line 1653

Quoted 2 lines

kernel/bpf/syscall.c +2 -0

+	case BPF_LIRC_MODE2:
+		return rc_dev_prog_detach(attr);

and similar rename for internal function names that go into bpf core.

Please add accumulated acks when you respin.