hid-sony.c: add sysfs provisioning

Add some sysfs interfaces to cover some corner use cases when provisioning:

1) Allow read access to the IDA index through device/gamepad_number. The IDA index is used to identify the device to the user as the "controller number" and is reflected via the initial LED states when plugged in. This sysfs attribute could be used by userspace for a more seamless transition to userspace drivers without controller numbers changing. Write access is not addressed as it raises the issue of a global IDA that works across different gamepad drivers. Internally, remove the use of the term "device_id" for the gamepad number for code grepability purposes.

From how I always saw it, the IDA for sixaxis controller may be useful

2) Allow manual provisioning of the Sixaxis/Dualshock3 USB "pairing" process through device/master_bdaddr. The bluez plugin has removed the need for sixpair.c or other such utilities for the common use case of autoprovisioning. Under less usual situations, the bluez behavior may not be desired, e.g. if you need to pair a gamepad with a different machine, see what machine a pad is paired to, or restore old pairings after use. This removes the need to use sixpair.c or roll-your-own libusb code for that sort of thing.

Signed-off-by Brian S. Julin <[email protected]>

Tested-by Brian S. Julin <[email protected]>

---

I've tested with both SixAxis and Dualshock 3 on stock Debian kernel 3.16.5. I've also tested a copy of the 3.18 git version inserted into the 3.16.5 kernel. The patch should apply to both (with fuzz on the newer version.) Tests are still needed on pure 3.18.

I do not have access to the non-Sony pads handled by this driver, but did test the with a Dualshock4 to ensure that the sysfs files are harmless vestigials for such devices.

It has been a long time since I popped the hood on the kernel and much has changed. I'm unclear as to under what conditions hid-core relieves the need to lock. Some review is definitely needed there.

General comment on the driver: when a gamepad being used over BT is plugged back in to USB, it continues to use BT rather than switching to USB. This has both benefits and disadvantages.

On the bright side, this prevents the evdev and js devices from being destroyed and recreated. Some applications, many closed-source, may not respond well to that even when udev rules are used to pin the device names.

On the other hand this is not the behavior gamers expect and will not help matters if the reason for plugging the pad in was to decrease latency due to RF contention.

I notice that sysfs-rules.txt mentions that a device's parentage in the tree may change, and teaching the hid core to allow graceful takeover of a device by a different host/bus driver for these devices might be a use case for that.

hid/hid-sony.c renamed from hid/hid-sony.c.orig +1 -0

@@ -8,6 +8,7 @@
  *  Copyright (c) 2012 David Dillow <[email protected]>
  *  Copyright (c) 2006-2013 Jiri Kosina
  *  Copyright (c) 2013 Colin Leitner <[email protected]>
+ *  Copyright (c) 2014 Brian S. Julin <[email protected]>
  */
 
 /*

hid/hid-sony.c renamed from hid/hid-sony.c.orig +1 -1

 #include "hid-ids.h"
 

@@ -750,7 +754,7 @@ union sixaxis_output_report_01 {
 
 static spinlock_t sony_dev_list_lock;
 static LIST_HEAD(sony_device_list);
-static DEFINE_IDA(sony_device_id_allocator);
+static DEFINE_IDA(sony_gamepad_number_allocator);
 
 struct sony_sc {
 	spinlock_t lock;

hid/hid-sony.c renamed from hid/hid-sony.c.orig +211 -20

 #ifdef CONFIG_SONY_FF
 	__u8 left;

@@ -1321,7 +1325,8 @@ static int sony_leds_init(struct sony_sc
 		if (!hid_validate_values(hdev, HID_OUTPUT_REPORT, 0, 0, 7))
 			return -ENODEV;
 	} else if (sc->quirks & DUALSHOCK4_CONTROLLER) {
-		dualshock4_set_leds_from_id(sc->device_id, initial_values);
+		dualshock4_set_leds_from_id(sc->gamepad_number,
+					    initial_values);
 		initial_values[3] = 1;
 		sc->led_count = 4;
 		memset(max_brightness, 255, 3);

@@ -1330,7 +1335,7 @@ static int sony_leds_init(struct sony_sc
 		name_len = 0;
 		name_fmt = "%s:%s";
 	} else {
-		sixaxis_set_leds_from_id(sc->device_id, initial_values);
+		sixaxis_set_leds_from_id(sc->gamepad_number, initial_values);
 		sc->led_count = 4;
 		memset(use_hw_blink, 1, 4);
 		use_ds4_names = 0;

@@ -1758,38 +1763,209 @@ static int sony_check_add(struct sony_sc
 	return sony_check_add_dev_list(sc);
 }
 
-static int sony_set_device_id(struct sony_sc *sc)
+/* PS3 pads do not pair over bluetooth; Instead a USB handshake is used. */
+static ssize_t sony_master_bdaddr_show(struct device *dev,
+				       struct device_attribute *attr,
+				       char *buf)
+{
+	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
+	struct sony_sc *sc = hid_get_drvdata(hdev);
+	size_t count;
+	unsigned char msg[8];
+	int ret;
+
+	if (!sc) {
+		hid_err(hdev, "No device data\n");
+		return 0;
+	}
+
+	if (sc->quirks & SIXAXIS_CONTROLLER_BT) {
+		struct device *parent;
+
+		parent = dev->parent;
+		if (!parent)
+			return 0;
+		parent = parent->parent;
+		if (!parent || !parent->type
+		    || strcmp(parent->type->name, "host"))
+			return 0;
+
+		count = scnprintf(buf, PAGE_SIZE, "%pMR\n",
+				  &(to_hci_dev(parent)->bdaddr));
+		return count;
+	}
+
+	if (!(sc->quirks & SIXAXIS_CONTROLLER_USB))
+		return 0;
+
+	ret = hid_hw_raw_request(hdev, 0xf5, msg, sizeof(msg),
+				 HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
+	if (ret < 0) {
+		/* This matches bluez error message */
+		hid_err(hdev, "failed to read master address\n");
+		return 0;
+	}
+
+	count = scnprintf(buf, PAGE_SIZE, "%pM\n", msg + 2);
+	return count;
+}
+
+/*
+ * This could probably be useful in lib/.
+ *
+ * Convert a string to a MAC address, accepting multiple formats.
+ *
+ * Will take most commonly cut-and-pasted formats without being too liberal.
+ * Accepts any hex with delims [-:.] between any octets, no mixing delims,
+ * no splitting octets.
+ *
+ * *buf should have at least 6 bytes of space and will not be altered on fail
+ * Will halt at null terminator or before reading more than lim chars from *c
+ * Return code is sscanf-style: number of non-null bytes read, or 0 on failure
+ */
+static int sony_kstrntomac(const char *c, u8 *buf, size_t lim)
+{
+	int cnt = 0;
+	int dcnt = 0;
+	char delim = '\0';
+	u8 octet[6];
+
+	while (cnt < 6) {
+		if (lim < 2 || !isxdigit(*c) || !isxdigit(*(c+1)))
+			return 0;
+
+		lim -= 2;
+
+		if (isdigit(*c))
+			octet[cnt] = (*c - '0') << 4;
+		else
+			octet[cnt] = (tolower(*c) - 'a' + 10) << 4;
+		c++;
+
+		if (isdigit(*c))
+			octet[cnt] |= *c - '0';
+		else
+			octet[cnt] |= tolower(*c) - 'a' + 10;
+		c++;
+
+		if (cnt < 5) {
+			if (!lim)
+				return 0;
+			if (!delim && (*c == '-' || *c == ':' || *c == '.'))
+				delim = *c;
+			if (delim && *c == delim) {
+				dcnt++;
+				c++;
+				lim--;
+			}
+		}
+		cnt++;
+	}
+
+	memcpy(buf, octet, 6);
+
+	return cnt * 2 + dcnt;
+}
+
+static ssize_t sony_master_bdaddr_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
+	struct sony_sc *sc = hid_get_drvdata(hdev);
+	u8 msg[8];
+	int ret;
+
+	if (!sc) {
+		hid_err(hdev, "No device data\n");
+		return -EBADFD;
+	}
+
+	if (!(sc->quirks & SIXAXIS_CONTROLLER_USB)) {
+		if (sc->quirks & SIXAXIS_CONTROLLER_BT) {
+			hid_err(hdev,
+				"To set master disconnect BT then use USB\n");
+			return -EOPNOTSUPP;
+		}
+		return -ENOTSUPP;
+	}
+
+	msg[0] = 0x01;
+	msg[1] = 0x00;
+
+	if (!sony_kstrntomac(buf, msg + 2, count))
+		return -EINVAL;
+
+	ret = hid_hw_raw_request(hdev, 0xf5, msg, sizeof(msg),
+				 HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
+	if (ret < 0) {
+		/* This matches bluez error message */
+		hid_err(hdev, "failed to write master address\n");
+		return count;
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR(master_bdaddr, S_IRUGO | S_IWUSR,
+		   sony_master_bdaddr_show, sony_master_bdaddr_store);
+
+static int sony_set_gamepad_number(struct sony_sc *sc)
 {
 	int ret;
 
 	/*
-	 * Only DualShock 4 or Sixaxis controllers get an id.
+	 * Only DualShock 4 or Sixaxis controllers get a number.
 	 * All others are set to -1.
 	 */
 	if ((sc->quirks & SIXAXIS_CONTROLLER) ||
 	    (sc->quirks & DUALSHOCK4_CONTROLLER)) {
-		ret = ida_simple_get(&sony_device_id_allocator, 0, 0,
-					GFP_KERNEL);
+		ret = ida_simple_get(&sony_gamepad_number_allocator, 0, 0,
+				     GFP_KERNEL);
 		if (ret < 0) {
-			sc->device_id = -1;
+			sc->gamepad_number = -1;
 			return ret;
 		}
-		sc->device_id = ret;
+		sc->gamepad_number = ret;
 	} else {
-		sc->device_id = -1;
+		sc->gamepad_number = -1;
 	}
 
 	return 0;
 }
 
-static void sony_release_device_id(struct sony_sc *sc)
+static void sony_release_gamepad_number(struct sony_sc *sc)
 {
-	if (sc->device_id >= 0) {
-		ida_simple_remove(&sony_device_id_allocator, sc->device_id);
-		sc->device_id = -1;
+	if (sc->gamepad_number >= 0) {
+		ida_simple_remove(&sony_gamepad_number_allocator,
+				  sc->gamepad_number);
+		sc->gamepad_number = -1;
 	}
 }
 
+static ssize_t sony_gamepad_number_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
+	struct sony_sc *sc = hid_get_drvdata(hdev);
+	size_t count;
+
+	if (!sc) {
+		hid_err(hdev, "No device data\n");
+		return 0;
+	}
+
+	if (sc->gamepad_number < 0)
+		return 0;
+
+	/* Add one to match console user expectations */
+	count = scnprintf(buf, PAGE_SIZE, "%i\n", sc->gamepad_number + 1);
+	return count;
+}
+
+static DEVICE_ATTR(gamepad_number, S_IRUGO, sony_gamepad_number_show, NULL);
+
 static inline void sony_init_work(struct sony_sc *sc,
 					void (*worker)(struct work_struct *))
 {

@@ -1841,10 +2017,22 @@ static int sony_probe(struct hid_device
 		return ret;
 	}
 
-	ret = sony_set_device_id(sc);
+	ret = sony_set_gamepad_number(sc);
 	if (ret < 0) {
-		hid_err(hdev, "failed to allocate the device id\n");
-		goto err_stop;
+		hid_err(hdev, "failed to allocate the gamepad number\n");
+		goto err_nosysfs2;
+	}
+
+	ret = device_create_file(&hdev->dev, &dev_attr_gamepad_number);
+	if (ret) {
+		hid_err(hdev, "failed to create gamepad_number sysfs file\n");
+		goto err_nosysfs2;
+	}
+
+	ret = device_create_file(&hdev->dev, &dev_attr_master_bdaddr);
+	if (ret) {
+		hid_err(hdev, "failed to create master_bdaddr sysfs file\n");
+		goto err_nosysfs1;
 	}
 
 	if (sc->quirks & SIXAXIS_CONTROLLER_USB) {

@@ -1932,13 +2120,17 @@ static int sony_probe(struct hid_device
 err_close:
 	hid_hw_close(hdev);
 err_stop:
+	device_remove_file(&hdev->dev, &dev_attr_master_bdaddr);
+err_nosysfs1:
+	device_remove_file(&hdev->dev, &dev_attr_gamepad_number);
+err_nosysfs2:
 	if (sc->quirks & SONY_LED_SUPPORT)
 		sony_leds_remove(sc);
 	if (sc->quirks & SONY_BATTERY_SUPPORT)
 		sony_battery_remove(sc);
 	sony_cancel_work_sync(sc);
 	sony_remove_dev_list(sc);
-	sony_release_device_id(sc);
+	sony_release_gamepad_number(sc);
 	hid_hw_stop(hdev);
 	return ret;
 }

@@ -1959,7 +2151,11 @@ static void sony_remove(struct hid_devic
 
 	sony_remove_dev_list(sc);
 
-	sony_release_device_id(sc);
+	device_remove_file(&hdev->dev, &dev_attr_master_bdaddr);
+
+	device_remove_file(&hdev->dev, &dev_attr_gamepad_number);
+
+	sony_release_gamepad_number(sc);
 
 	hid_hw_stop(hdev);
 }

@@ -2017,7 +2213,7 @@ static void __exit sony_exit(void)
 {
 	dbg_hid("Sony:%s\n", __func__);
 
-	ida_destroy(&sony_device_id_allocator);
+	ida_destroy(&sony_gamepad_number_allocator);
 	hid_unregister_driver(&sony_driver);
 }
 module_init(sony_init);
--

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I had tried doing something similar in the past (the parsing was just a sscanf): http://thread.gmane.org/gmane.linux.bluez.kernel/5261 but then we deliberately decided against exposing specific sysfs interfaces for device/master_bdaddr, you can just use generic HID feature reports from userspace to get/set these, write a simple program reusing the code in the BlueZ sixaxis plugin, using the ioclts HIDIOCGFEATURE/HIDIOCSFEATURE, this way you don't depend on libusb. As an historical note, the BlueZ sixaxis plugin was one of the first user of these ioctls.

That said I still don't think the changes you are proposing are strictly necessary in the kernel driver, but let's see what the others have to say about that.

Agreed, I don't see a need for exposing this as a sysfs entry since it's easy enough to use hidraw and an ioctl call to set/get the master address.

What happened when plugging in a DS3 or DS4 via USB when it was already connected via Bluetooth was that you ended up with a duplicate device. In the case of the DS3 the extra controller entry was basically a non-functional "zombie" since the controller itself didn't send any events over USB if it was already running over Bluetooth. If you want to switch from wireless to wired you just have to disconnect first. I don't think it's possible to get around this, at least not in a way that is as seamless as the current solution.

From an end-user perspective, with USB "disconnecting" is something as

Quoted 6 lines · Just one code comment to add to what Antonio already

hid/hid-sony.c renamed from hid/hid-sony.c.orig +5 -0

+
+    ret = device_create_file(&hdev->dev, &dev_attr_master_bdaddr);
+    if (ret) {
+            hid_err(hdev, "failed to create master_bdaddr sysfs file\n");
+            goto err_nosysfs1;

Quoted 1 line

    }

Why even expose this on the DS4 or the Sixaxis when in Bluetooth mode? Put it behind if (sc->quirks & SIXAXIS_CONTROLLER_USB)

hid/hid-sony.c line 41

Quoted 2 lines

hid/hid-sony.c renamed from hid/hid-sony.c.orig +2 -0

+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>

A HID driver should not need to depend on bluetooth, no other HID driver does. Layer violations should be avoided as much as possible.

I'd also try to avoid custom parsing routines in kernel code as much as possible.

You know you can build Debian packages from the official git kernel repository, don't you?
make LOCALVERSION=-brian INSTALL_MOD_STRIP=1 deb-pkg

Quoted 3 lines

On the other hand this is not the behavior gamers expect and will not help matters if the reason for plugging the pad in was to decrease latency due to RF contention.

This is an interesting point, can you show numbers about these latency problems?

Quoted 9 lines · Antonio Ospite

I had tried doing something similar in the past (the parsing was just a sscanf): http://thread.gmane.org/gmane.linux.bluez.kernel/5261 but then we deliberately decided against exposing specific sysfs interfaces for device/master_bdaddr, you can just use generic HID feature reports from userspace to get/set these, write a simple program reusing the code in the BlueZ sixaxis plugin, using the ioclts HIDIOCGFEATURE/HIDIOCSFEATURE, this way you don't depend on libusb. As an historical note, the BlueZ sixaxis plugin was one of the first user of these ioctls.

...

Quoted 3 lines

That said I still don't think the changes you are proposing are strictly necessary in the kernel driver, but let's see what the others have to say about that.

Quoted 2 lines · Frank Praznik

Agreed, I don't see a need for exposing this as a sysfs entry since it's easy enough to use hidraw and an ioctl call to set/get the master address.

For this argument I would offer that "easy" is different for you or I working on a development system than for a less versed person working to personally customize an appliance that didn't come with a gcc package, but probably did come with /bin/sh.

On Mon, 17 Nov 2014 21:01:44 -0500
bri <[email protected]> wrote:
If you can upload a shell script to the target system you may as well upload a static binary; and if you can use a modified kernel you can compile _for_ the target even if not _on_ the target.

And if you need help to write the program which uses the HID ioctls just ask :)

Quoted 5 lines

Yeah, the device ID in the driver is only for tracking devices internally and setting sane default LED values. It has no meaning outside of the module. Like Antonio said, if you want the system number for a controller you are better off just getting it from the joystick device.

Would you be amenable to a patch that removes the IDA entirely and just sets the LEDs to all solid-on? Since the LEDs are available through sysfs, udev rule could probably be made to set the LEDs in the absence of bluez or a higher level controller manager, and then it becomes the distro's responsibility.

Hi Brian,

Quoted 11 lines · bri

Quoted 5 lines

Yeah, the device ID in the driver is only for tracking devices internally and setting sane default LED values. It has no meaning outside of the module. Like Antonio said, if you want the system number for a controller you are better off just getting it from the joystick device.

Would you be amenable to a patch that removes the IDA entirely and just sets the LEDs to all solid-on? Since the LEDs are available through sysfs, udev rule could probably be made to set the LEDs in the absence of bluez or a higher level controller manager, and then it becomes the distro's responsibility.

What would be the benefit of doing this? Nothing is stopping higher level services from setting the LEDs right now. The driver just sets sane defaults for systems that don't have anything else to set the 'real' values. Other controllers like Wiimotes and Xbox gamepads do the same thing. It doesn't get in the way of services like BlueZ setting them once initialization is complete.

Leaving it completely up to the distro just means that there will be situations where there is nothing to set the default values which makes for a bad user experience.

Quoted 22 lines · Frank Praznik

Hi Brian,

Quoted 11 lines · bri

Quoted 5 lines

Yeah, the device ID in the driver is only for tracking devices internally and setting sane default LED values. It has no meaning outside of the module. Like Antonio said, if you want the system number for a controller you are better off just getting it from the joystick device.

Would you be amenable to a patch that removes the IDA entirely and just sets the LEDs to all solid-on? Since the LEDs are available through sysfs, udev rule could probably be made to set the LEDs in the absence of bluez or a higher level controller manager, and then it becomes the distro's responsibility.

What would be the benefit of doing this? Nothing is stopping higher level services from setting the LEDs right now. The driver just sets sane defaults for systems that don't have anything else to set the 'real' values. Other controllers like Wiimotes and Xbox gamepads do the same thing. It doesn't get in the way of services like BlueZ setting them once initialization is complete.

Quoted 3 lines

Leaving it completely up to the distro just means that there will be situations where there is nothing to set the default values which makes for a bad user experience.

It would eliminate 50 to 100 lines of code just for that tiny purpose, which userspace can and probably should take care of, given the disparity with the eventual values. I'm honestly a bit confused of the criteria in use here, as I thought it was mostly deciding between the usefulness of features versus maintainability. In my mind if I weight a master_bdaddr sysfs file and the code to support it versus this feature, I don't see where this one wins out.

But whatever. I made this for my own use, and offered it up, and if the community does not want it I am free to keep using what I made, so I'm happy either way.