drivers: fsi: sbefifo: Add in-kernel API

index 9a13ce3..4b95b00 100644
@@ -15,9 +15,11 @@
 #include <linux/errno.h>
 #include <linux/idr.h>
 #include <linux/fsi.h>
+#include <linux/fsi-sbefifo.h>
 #include <linux/list.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/poll.h>
 #include <linux/sched.h>
 #include <linux/slab.h>

@@ -49,7 +51,9 @@ struct sbefifo {
 	wait_queue_head_t wait;
 	struct list_head link;
 	struct list_head xfrs;
+	struct list_head drv_refs;
 	struct kref kref;
+	struct device_node *node;
 	spinlock_t lock;
 	char name[32];
 	int idx;

@@ -82,6 +86,7 @@ struct sbefifo_client {
 	struct list_head xfrs;
 	struct sbefifo *dev;
 	struct kref kref;
+	unsigned long f_flags;
 };
 
 static struct list_head sbefifo_fifos;

@@ -493,6 +498,7 @@ static int sbefifo_open(struct inode *inode, struct file *file)
 		return -ENOMEM;
 
 	file->private_data = client;
+	client->f_flags = file->f_flags;
 
 	return 0;
 }

@@ -517,24 +523,18 @@ static unsigned int sbefifo_poll(struct file *file, poll_table *wait)
 	return mask;
 }
 
-static ssize_t sbefifo_read(struct file *file, char __user *buf,
-		size_t len, loff_t *offset)
+static ssize_t sbefifo_read_common(struct sbefifo_client *client,
+				   char __user *ubuf, char *kbuf, size_t len)
 {
-	struct sbefifo_client *client = file->private_data;
 	struct sbefifo *sbefifo = client->dev;
 	struct sbefifo_xfr *xfr;
-	ssize_t ret = 0;
 	size_t n;
-
-	WARN_ON(*offset);
-
-	if (!access_ok(VERIFY_WRITE, buf, len))
-		return -EFAULT;
+	ssize_t ret = 0;
 
 	if ((len >> 2) << 2 != len)
 		return -EINVAL;
 
-	if ((file->f_flags & O_NONBLOCK) && !sbefifo_xfr_rsp_pending(client))
+	if ((client->f_flags & O_NONBLOCK) && !sbefifo_xfr_rsp_pending(client))
 		return -EAGAIN;
 
 	sbefifo_get_client(client);

@@ -553,10 +553,14 @@ static ssize_t sbefifo_read(struct file *file, char __user *buf,
 
 	n = min_t(size_t, n, len);
 
-	if (copy_to_user(buf, READ_ONCE(client->rbuf.rpos), n)) {
-		sbefifo_put_client(client);
-		return -EFAULT;
+	if (ubuf) {
+		if (copy_to_user(ubuf, READ_ONCE(client->rbuf.rpos), n)) {
+			sbefifo_put_client(client);
+			return -EFAULT;
+		}
 	}
+	else
+		memcpy(kbuf, READ_ONCE(client->rbuf.rpos), n);
 
 	if (sbefifo_buf_readnb(&client->rbuf, n)) {
 		xfr = sbefifo_client_next_xfr(client);

@@ -579,20 +583,28 @@ static ssize_t sbefifo_read(struct file *file, char __user *buf,
 	return n;
 }
 
-static ssize_t sbefifo_write(struct file *file, const char __user *buf,
+static ssize_t sbefifo_read(struct file *file, char __user *buf,
 		size_t len, loff_t *offset)
 {
 	struct sbefifo_client *client = file->private_data;
-	struct sbefifo *sbefifo = client->dev;
-	struct sbefifo_xfr *xfr;
-	ssize_t ret = 0;
-	size_t n;
 
 	WARN_ON(*offset);
 
-	if (!access_ok(VERIFY_READ, buf, len))
+	if (!access_ok(VERIFY_WRITE, buf, len))
 		return -EFAULT;
 
+	return sbefifo_read_common(client, buf, NULL, len);
+}
+
+static ssize_t sbefifo_write_common(struct sbefifo_client *client,
+				    const char __user *ubuf, const char *kbuf,
+				    size_t len)
+{
+	struct sbefifo *sbefifo = client->dev;
+	struct sbefifo_xfr *xfr;
+	ssize_t ret = 0;
+	size_t n;
+
 	if ((len >> 2) << 2 != len)
 		return -EINVAL;
 

@@ -604,7 +616,7 @@ static ssize_t sbefifo_write(struct file *file, const char __user *buf,
 	spin_lock_irq(&sbefifo->lock);
 	xfr = sbefifo_next_xfr(sbefifo);
 
-	if ((file->f_flags & O_NONBLOCK) && xfr && n < len) {
+	if ((client->f_flags & O_NONBLOCK) && xfr && n < len) {
 		spin_unlock_irq(&sbefifo->lock);
 		return -EAGAIN;
 	}

@@ -644,18 +656,26 @@ static ssize_t sbefifo_write(struct file *file, const char __user *buf,
 
 		n = min_t(size_t, n, len);
 
-		if (copy_from_user(READ_ONCE(client->wbuf.wpos), buf, n)) {
-			set_bit(SBEFIFO_XFR_CANCEL, &xfr->flags);
-			sbefifo_get(sbefifo);
-			if (mod_timer(&sbefifo->poll_timer, jiffies))
-				sbefifo_put(sbefifo);
-			sbefifo_put_client(client);
-			return -EFAULT;
+		if (ubuf) {
+			if (copy_from_user(READ_ONCE(client->wbuf.wpos), ubuf,
+			    n)) {
+				set_bit(SBEFIFO_XFR_CANCEL, &xfr->flags);
+				sbefifo_get(sbefifo);
+				if (mod_timer(&sbefifo->poll_timer, jiffies))
+					sbefifo_put(sbefifo);
+				sbefifo_put_client(client);
+				return -EFAULT;
+			}
+
+			ubuf += n;
+		}
+		else {
+			memcpy(READ_ONCE(client->wbuf.wpos), kbuf, n);
+			kbuf += n;
 		}
 
 		sbefifo_buf_wrotenb(&client->wbuf, n);
 		len -= n;
-		buf += n;
 		ret += n;
 
 		/*

@@ -672,6 +692,19 @@ static ssize_t sbefifo_write(struct file *file, const char __user *buf,
 	return ret;
 }
 
+static ssize_t sbefifo_write(struct file *file, const char __user *buf,
+		size_t len, loff_t *offset)
+{
+	struct sbefifo_client *client = file->private_data;
+
+	WARN_ON(*offset);
+
+	if (!access_ok(VERIFY_READ, buf, len))
+		return -EFAULT;
+
+	return sbefifo_write_common(client, buf, NULL, len);
+}
+
 static int sbefifo_release(struct inode *inode, struct file *file)
 {
 	struct sbefifo_client *client = file->private_data;

@@ -691,11 +724,72 @@ static const struct file_operations sbefifo_fops = {
 	.release	= sbefifo_release,
 };
 
+struct sbefifo *sbefifo_drv_reference(struct device_node *node,
+				      struct sbefifo_drv_ref *ref)
+{
+	struct sbefifo *sbefifo;
+
+	list_for_each_entry(sbefifo, &sbefifo_fifos, link) {
+		if (node == sbefifo->node) {
+			if (ref)
+				list_add(&ref->link, &sbefifo->drv_refs);
+			return sbefifo;
+		}
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(sbefifo_drv_reference);
+
+struct sbefifo_client *sbefifo_drv_open(struct sbefifo *sbefifo,
+					unsigned long flags)
+{
+	struct sbefifo_client *client;
+
+	if (!sbefifo)
+		return NULL;
+
+	client = sbefifo_new_client(sbefifo);
+	if (client)
+		client->f_flags = flags;
+
+	return client;
+}
+EXPORT_SYMBOL_GPL(sbefifo_drv_open);
+
+int sbefifo_drv_read(struct sbefifo_client *client, char *buf, size_t len)
+{
+	return sbefifo_read_common(client, NULL, buf, len);
+}
+EXPORT_SYMBOL_GPL(sbefifo_drv_read);
+
+int sbefifo_drv_write(struct sbefifo_client *client, const char *buf,
+		      size_t len)
+{
+	return sbefifo_write_common(client, NULL, buf, len);
+}
+EXPORT_SYMBOL_GPL(sbefifo_drv_write);
+
+void sbefifo_drv_release(struct sbefifo_client *client)
+{
+	if (!client)
+		return;
+
+	sbefifo_put_client(client);
+}
+EXPORT_SYMBOL_GPL(sbefifo_drv_release);
+
+int sbefifo_drv_get_idx(struct sbefifo *sbefifo)
+{
+	return sbefifo->idx;
+}
+
 static int sbefifo_probe(struct device *dev)
 {
 	struct fsi_device *fsi_dev = to_fsi_dev(dev);
 	struct sbefifo *sbefifo;
-	u32 sts;
+	struct device_node *np;
+	u32 sts, addr;
 	int ret;
 
 	dev_info(dev, "Found sbefifo device\n");

@@ -736,6 +830,19 @@ static int sbefifo_probe(struct device *dev)
 			sbefifo->idx);
 	init_waitqueue_head(&sbefifo->wait);
 	INIT_LIST_HEAD(&sbefifo->xfrs);
+	INIT_LIST_HEAD(&sbefifo->drv_refs);
+
+	for_each_compatible_node(np, NULL, "ibm,power9-sbefifo") {
+		ret = of_property_read_u32(np, "reg", &addr);
+		if (ret)
+			continue;
+
+		/* TODO: get real address, not cfam offset */
+		if (addr == fsi_dev->addr) {
+			sbefifo->node = np;
+			break;
+		}
+	}
 
 	/* This bit of silicon doesn't offer any interrupts... */
 	setup_timer(&sbefifo->poll_timer, sbefifo_poll_timer,

@@ -749,11 +856,19 @@ static int sbefifo_remove(struct device *dev)
 {
 	struct fsi_device *fsi_dev = to_fsi_dev(dev);
 	struct sbefifo *sbefifo, *sbefifo_tmp;
+	struct sbefifo_drv_ref *ref, *ref_tmp;
 	struct sbefifo_xfr *xfr;
 
 	list_for_each_entry_safe(sbefifo, sbefifo_tmp, &sbefifo_fifos, link) {
 		if (sbefifo->fsi_dev != fsi_dev)
 			continue;
+
+		list_for_each_entry_safe(ref, ref_tmp, &sbefifo->drv_refs,
+					 link) {
+			ref->notify(ref);
+			list_del(&ref->link);
+		}
+
 		misc_deregister(&sbefifo->mdev);
 		list_del(&sbefifo->link);
 		ida_simple_remove(&sbefifo_ida, sbefifo->idx);

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