Merge tag 'for-v4.6-rc/omap-fixes-a' of git://git.kernel.org/pub/scm/linux/kernel/git/pjw/omap-pending into omap-for-v4.6/fixes

ARM: OMAP2+: first hwmod fix for v4.6-rc

Fix a longstanding bug in the hwmod code that could cause
hardware SYSCONFIG register values to not match the kernel's
idea of what they should be, and that could result in lower
performance during IP block idle entry.

Basic build, boot, and PM test logs are available here:

http://www.pwsan.com/omap/testlogs/omap-hwmod-fixes-a-for-v4.6-rc/20160326231727/

1 files changed, 83 insertions, 39 deletions

diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c
index 23c794813e6a..76350e4ee807 100644
--- a/drivers/usb/misc/chaoskey.c
+++ b/drivers/usb/misc/chaoskey.c
@@ -73,6 +73,8 @@ static const struct usb_device_id chaoskey_table[] = {
 };
 MODULE_DEVICE_TABLE(usb, chaoskey_table);
 
+static void chaos_read_callback(struct urb *urb);
+
 /* Driver-local specific stuff */
 struct chaoskey {
 	struct usb_interface *interface;
@@ -80,7 +82,8 @@ struct chaoskey {
 	struct mutex lock;
 	struct mutex rng_lock;
 	int open;			/* open count */
-	int present;			/* device not disconnected */
+	bool present;			/* device not disconnected */
+	bool reading;			/* ongoing IO */
 	int size;			/* size of buf */
 	int valid;			/* bytes of buf read */
 	int used;			/* bytes of buf consumed */
@@ -88,15 +91,19 @@ struct chaoskey {
 	struct hwrng hwrng;		/* Embedded struct for hwrng */
 	int hwrng_registered;		/* registered with hwrng API */
 	wait_queue_head_t wait_q;	/* for timeouts */
+	struct urb *urb;		/* for performing IO */
 	char *buf;
 };
 
 static void chaoskey_free(struct chaoskey *dev)
 {
-	usb_dbg(dev->interface, "free");
-	kfree(dev->name);
-	kfree(dev->buf);
-	kfree(dev);
+	if (dev) {
+		usb_dbg(dev->interface, "free");
+		usb_free_urb(dev->urb);
+		kfree(dev->name);
+		kfree(dev->buf);
+		kfree(dev);
+	}
 }
 
 static int chaoskey_probe(struct usb_interface *interface,
@@ -107,7 +114,7 @@ static int chaoskey_probe(struct usb_interface *interface,
 	int i;
 	int in_ep = -1;
 	struct chaoskey *dev;
-	int result;
+	int result = -ENOMEM;
 	int size;
 
 	usb_dbg(interface, "probe %s-%s", udev->product, udev->serial);
@@ -142,14 +149,25 @@ static int chaoskey_probe(struct usb_interface *interface,
 	dev = kzalloc(sizeof(struct chaoskey), GFP_KERNEL);
 
 	if (dev == NULL)
-		return -ENOMEM;
+		goto out;
 
 	dev->buf = kmalloc(size, GFP_KERNEL);
 
-	if (dev->buf == NULL) {
-		kfree(dev);
-		return -ENOMEM;
-	}
+	if (dev->buf == NULL)
+		goto out;
+
+	dev->urb = usb_alloc_urb(0, GFP_KERNEL);
+
+	if (!dev->urb)
+		goto out;
+
+	usb_fill_bulk_urb(dev->urb,
+		udev,
+		usb_rcvbulkpipe(udev, in_ep),
+		dev->buf,
+		size,
+		chaos_read_callback,
+		dev);
 
 	/* Construct a name using the product and serial values. Each
 	 * device needs a unique name for the hwrng code
@@ -158,11 +176,8 @@ static int chaoskey_probe(struct usb_interface *interface,
 	if (udev->product && udev->serial) {
 		dev->name = kmalloc(strlen(udev->product) + 1 +
 				    strlen(udev->serial) + 1, GFP_KERNEL);
-		if (dev->name == NULL) {
-			kfree(dev->buf);
-			kfree(dev);
-			return -ENOMEM;
-		}
+		if (dev->name == NULL)
+			goto out;
 
 		strcpy(dev->name, udev->product);
 		strcat(dev->name, "-");
@@ -186,9 +201,7 @@ static int chaoskey_probe(struct usb_interface *interface,
 	result = usb_register_dev(interface, &chaoskey_class);
 	if (result) {
 		usb_err(interface, "Unable to allocate minor number.");
-		usb_set_intfdata(interface, NULL);
-		chaoskey_free(dev);
-		return result;
+		goto out;
 	}
 
 	dev->hwrng.name = dev->name ? dev->name : chaoskey_driver.name;
@@ -215,6 +228,11 @@ static int chaoskey_probe(struct usb_interface *interface,
 
 	usb_dbg(interface, "chaoskey probe success, size %d", dev->size);
 	return 0;
+
+out:
+	usb_set_intfdata(interface, NULL);
+	chaoskey_free(dev);
+	return result;
 }
 
 static void chaoskey_disconnect(struct usb_interface *interface)
@@ -237,6 +255,7 @@ static void chaoskey_disconnect(struct usb_interface *interface)
 	mutex_lock(&dev->lock);
 
 	dev->present = 0;
+	usb_poison_urb(dev->urb);
 
 	if (!dev->open) {
 		mutex_unlock(&dev->lock);
@@ -311,14 +330,33 @@ static int chaoskey_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
+static void chaos_read_callback(struct urb *urb)
+{
+	struct chaoskey *dev = urb->context;
+	int status = urb->status;
+
+	usb_dbg(dev->interface, "callback status (%d)", status);
+
+	if (status == 0)
+		dev->valid = urb->actual_length;
+	else
+		dev->valid = 0;
+
+	dev->used = 0;
+
+	/* must be seen first before validity is announced */
+	smp_wmb();
+
+	dev->reading = false;
+	wake_up(&dev->wait_q);
+}
+
 /* Fill the buffer. Called with dev->lock held
  */
 static int _chaoskey_fill(struct chaoskey *dev)
 {
 	DEFINE_WAIT(wait);
 	int result;
-	int this_read;
-	struct usb_device *udev = interface_to_usbdev(dev->interface);
 
 	usb_dbg(dev->interface, "fill");
 
@@ -343,21 +381,31 @@ static int _chaoskey_fill(struct chaoskey *dev)
 		return result;
 	}
 
-	result = usb_bulk_msg(udev,
-			      usb_rcvbulkpipe(udev, dev->in_ep),
-			      dev->buf, dev->size, &this_read,
-			      NAK_TIMEOUT);
+	dev->reading = true;
+	result = usb_submit_urb(dev->urb, GFP_KERNEL);
+	if (result < 0) {
+		result = usb_translate_errors(result);
+		dev->reading = false;
+		goto out;
+	}
+
+	result = wait_event_interruptible_timeout(
+		dev->wait_q,
+		!dev->reading,
+		NAK_TIMEOUT);
+
+	if (result < 0)
+		goto out;
 
+	if (result == 0)
+		result = -ETIMEDOUT;
+	else
+		result = dev->valid;
+out:
 	/* Let the device go back to sleep eventually */
 	usb_autopm_put_interface(dev->interface);
 
-	if (result == 0) {
-		dev->valid = this_read;
-		dev->used = 0;
-	}
-
-	usb_dbg(dev->interface, "bulk_msg result %d this_read %d",
-		result, this_read);
+	usb_dbg(dev->interface, "read %d bytes", dev->valid);
 
 	return result;
 }
@@ -395,13 +443,7 @@ static ssize_t chaoskey_read(struct file *file,
 			goto bail;
 		if (dev->valid == dev->used) {
 			result = _chaoskey_fill(dev);
-			if (result) {
-				mutex_unlock(&dev->lock);
-				goto bail;
-			}
-
-			/* Read returned zero bytes */
-			if (dev->used == dev->valid) {
+			if (result < 0) {
 				mutex_unlock(&dev->lock);
 				goto bail;
 			}
@@ -435,6 +477,8 @@ bail:
 		return read_count;
 	}
 	usb_dbg(dev->interface, "empty read, result %d", result);
+	if (result == -ETIMEDOUT)
+		result = -EAGAIN;
 	return result;
 }