[PATCH v7 0/5] add gadget quirk to adapt f_fs for DWC3

[PATCH v7 0/5] add gadget quirk to adapt f_fs for DWC3

[David Cohen]

Hi,

These patches are a proposal to add gadget quirks in an immediate objective to
adapt f_fs when using DWC3 controller. But the quirk solution is generic and
can be used by other controllers to adapt gadget functions to their
non-standard restrictions.

This change is necessary to make Android's adbd service to work on Intel
Merrifield with f_fs instead of out-of-tree android gadget.

This new patch set was tested and validated in my environment:
 - Intel Merrifield was able to use DWC3/f_fs with adbd service (it wasn't
   before).

Changes from v6 to v7:
 - Downgraded patch set version to v5 as per Felipe Balbi request, with some
   changes:
   - usb_ep_align_maxpacketsize() macro was change to usp_ep_align_maybe()
     in order to check gadget->quirk_ep_out_aligned_size internally.
   - updated patch 4/5 to use new macro usp_ep_align_maybe() and to fix
     following compilation warning:
     $ drivers/usb/gadget/f_fs.c: In function 'ffs_epfile_io':
     $ drivers/usb/gadget/f_fs.c:857:124: warning: comparison of distinct pointer types lacks a cast [enabled by default]

---
David Cohen (3):
  usb: gadget: move bitflags to the end of usb_gadget struct
  usb: gadget: add quirk_ep_out_aligned_size field to struct usb_gadget
  usb: dwc3: set gadget's quirk ep_out_align_size

Michal Nazarewicz (2):
  usb: gadget: f_fs: remove loop from I/O function
  usb: f_fs: check quirk to pad epout buf size when not aligned to
    maxpacketsize

 drivers/usb/dwc3/gadget.c  |   6 +++
 drivers/usb/gadget/f_fs.c  | 115 +++++++++++++++++++++++----------------------
 include/linux/usb/gadget.h |  39 +++++++++++----
 3 files changed, 94 insertions(+), 66 deletions(-)

-- 
1.8.4.2

[PATCH v7 1/5] usb: gadget: move bitflags to the end of usb_gadget struct

[David Cohen]

This patch moves all bitflags to the end of usb_gadget struct in order
to improve readability.

Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
---
 include/linux/usb/gadget.h | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 942ef5e053bf..23b3bfd0a842 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -485,6 +485,11 @@ struct usb_gadget_ops {
  * @max_speed: Maximal speed the UDC can handle.  UDC must support this
  *      and all slower speeds.
  * @state: the state we are now (attached, suspended, configured, etc)
+ * @name: Identifies the controller hardware type.  Used in diagnostics
+ *	and sometimes configuration.
+ * @dev: Driver model state for this abstract device.
+ * @out_epnum: last used out ep number
+ * @in_epnum: last used in ep number
  * @sg_supported: true if we can handle scatter-gather
  * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
  *	gadget driver must provide a USB OTG descriptor.
@@ -497,11 +502,6 @@ struct usb_gadget_ops {
  *	only supports HNP on a different root port.
  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
  *	enabled HNP support.
- * @name: Identifies the controller hardware type.  Used in diagnostics
- *	and sometimes configuration.
- * @dev: Driver model state for this abstract device.
- * @out_epnum: last used out ep number
- * @in_epnum: last used in ep number
  *
  * Gadgets have a mostly-portable "gadget driver" implementing device
  * functions, handling all usb configurations and interfaces.  Gadget
@@ -530,16 +530,17 @@ struct usb_gadget {
 	enum usb_device_speed		speed;
 	enum usb_device_speed		max_speed;
 	enum usb_device_state		state;
+	const char			*name;
+	struct device			dev;
+	unsigned			out_epnum;
+	unsigned			in_epnum;
+
 	unsigned			sg_supported:1;
 	unsigned			is_otg:1;
 	unsigned			is_a_peripheral:1;
 	unsigned			b_hnp_enable:1;
 	unsigned			a_hnp_support:1;
 	unsigned			a_alt_hnp_support:1;
-	const char			*name;
-	struct device			dev;
-	unsigned			out_epnum;
-	unsigned			in_epnum;
 };
 #define work_to_gadget(w)	(container_of((w), struct usb_gadget, work))
 
-- 
1.8.4.2

[PATCH v7 2/5] usb: gadget: add quirk_ep_out_aligned_size field to struct usb_gadget

[David Cohen]

Due to USB controllers may have different restrictions, usb gadget layer
needs to provide a generic way to inform gadget functions to complain
with non-standard requirements.

This patch adds 'quirk_ep_out_aligned_size' field to struct usb_gadget
to inform when controller's epout requires buffer size to be aligned to
MaxPacketSize. A helper is also provided to align buffer size when
necessary.

Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Michal Nazarewicz <mina86@mina86.com>
---
 include/linux/usb/gadget.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 23b3bfd0a842..cae8a6216551 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -502,6 +502,8 @@ struct usb_gadget_ops {
  *	only supports HNP on a different root port.
  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
  *	enabled HNP support.
+ * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
+ *	MaxPacketSize.
  *
  * Gadgets have a mostly-portable "gadget driver" implementing device
  * functions, handling all usb configurations and interfaces.  Gadget
@@ -541,6 +543,7 @@ struct usb_gadget {
 	unsigned			b_hnp_enable:1;
 	unsigned			a_hnp_support:1;
 	unsigned			a_alt_hnp_support:1;
+	unsigned			quirk_ep_out_aligned_size:1;
 };
 #define work_to_gadget(w)	(container_of((w), struct usb_gadget, work))
 
@@ -559,6 +562,23 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
 
 
 /**
+ * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
+ *	requires quirk_ep_out_aligned_size, otherwise reguens len.
+ * @g: controller to check for quirk
+ * @ep: the endpoint whose maxpacketsize is used to align @len
+ * @len: buffer size's length to align to @ep's maxpacketsize
+ *
+ * This helper is used in case it's required for any reason to check and maybe
+ * align buffer's size to an ep's maxpacketsize.
+ */
+static inline size_t
+usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
+{
+	return !g->quirk_ep_out_aligned_size ? len :
+			round_up(len, (size_t)ep->desc->wMaxPacketSize);
+}
+
+/**
  * gadget_is_dualspeed - return true iff the hardware handles high speed
  * @g: controller that might support both high and full speeds
  */
-- 
1.8.4.2

Re: [PATCH v7 2/5] usb: gadget: add quirk_ep_out_aligned_size field to struct usb_gadget

[Michal Nazarewicz]

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dOn Tue, Dec 10 2013, David Cohen wrote:
> Due to USB controllers may have different restrictions, usb gadget layer
> needs to provide a generic way to inform gadget functions to complain
> with non-standard requirements.
>
> This patch adds 'quirk_ep_out_aligned_size' field to struct usb_gadget
> to inform when controller's epout requires buffer size to be aligned to
> MaxPacketSize. A helper is also provided to align buffer size when
> necessary.
>
> Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
> Cc: Alan Stern <stern@rowland.harvard.edu>
> Cc: Michal Nazarewicz <mina86@mina86.com>

Acked-by: Michal Nazarewicz <mina86@mina86.com>

> ---
>  include/linux/usb/gadget.h | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index 23b3bfd0a842..cae8a6216551 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -502,6 +502,8 @@ struct usb_gadget_ops {
>   *	only supports HNP on a different root port.
>   * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
>   *	enabled HNP support.
> + * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
> + *	MaxPacketSize.
>   *
>   * Gadgets have a mostly-portable "gadget driver" implementing device
>   * functions, handling all usb configurations and interfaces.  Gadget
> @@ -541,6 +543,7 @@ struct usb_gadget {
>  	unsigned			b_hnp_enable:1;
>  	unsigned			a_hnp_support:1;
>  	unsigned			a_alt_hnp_support:1;
> +	unsigned			quirk_ep_out_aligned_size:1;
>  };
>  #define work_to_gadget(w)	(container_of((w), struct usb_gadget, work))
>  
> @@ -559,6 +562,23 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
>  
>  
>  /**
> + * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
> + *	requires quirk_ep_out_aligned_size, otherwise reguens len.

“returns”

> + * @g: controller to check for quirk
> + * @ep: the endpoint whose maxpacketsize is used to align @len
> + * @len: buffer size's length to align to @ep's maxpacketsize
> + *
> + * This helper is used in case it's required for any reason to check and maybe
> + * align buffer's size to an ep's maxpacketsize.
> + */
> +static inline size_t
> +usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
> +{
> +	return !g->quirk_ep_out_aligned_size ? len :
> +			round_up(len, (size_t)ep->desc->wMaxPacketSize);
> +}
> +
> +/**
>   * gadget_is_dualspeed - return true iff the hardware handles high speed
>   * @g: controller that might support both high and full speeds
>   */

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +--<mpn@google.com>--<xmpp:mina86@jabber.org>--ooO--(_)--Ooo--

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Re: [PATCH v7 2/5] usb: gadget: add quirk_ep_out_aligned_size field to struct usb_gadget

[David Cohen]

On 12/09/2013 06:34 PM, Michal Nazarewicz wrote:
> dOn Tue, Dec 10 2013, David Cohen wrote:
>> Due to USB controllers may have different restrictions, usb gadget layer
>> needs to provide a generic way to inform gadget functions to complain
>> with non-standard requirements.
>>
>> This patch adds 'quirk_ep_out_aligned_size' field to struct usb_gadget
>> to inform when controller's epout requires buffer size to be aligned to
>> MaxPacketSize. A helper is also provided to align buffer size when
>> necessary.
>>
>> Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
>> Cc: Alan Stern <stern@rowland.harvard.edu>
>> Cc: Michal Nazarewicz <mina86@mina86.com>
> 
> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> 
>> ---
>>  include/linux/usb/gadget.h | 20 ++++++++++++++++++++
>>  1 file changed, 20 insertions(+)
>>
>> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
>> index 23b3bfd0a842..cae8a6216551 100644
>> --- a/include/linux/usb/gadget.h
>> +++ b/include/linux/usb/gadget.h
>> @@ -502,6 +502,8 @@ struct usb_gadget_ops {
>>   *	only supports HNP on a different root port.
>>   * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
>>   *	enabled HNP support.
>> + * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
>> + *	MaxPacketSize.
>>   *
>>   * Gadgets have a mostly-portable "gadget driver" implementing device
>>   * functions, handling all usb configurations and interfaces.  Gadget
>> @@ -541,6 +543,7 @@ struct usb_gadget {
>>  	unsigned			b_hnp_enable:1;
>>  	unsigned			a_hnp_support:1;
>>  	unsigned			a_alt_hnp_support:1;
>> +	unsigned			quirk_ep_out_aligned_size:1;
>>  };
>>  #define work_to_gadget(w)	(container_of((w), struct usb_gadget, work))
>>  
>> @@ -559,6 +562,23 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
>>  
>>  
>>  /**
>> + * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
>> + *	requires quirk_ep_out_aligned_size, otherwise reguens len.
> 
> “returns”

I've got no idea how returns became reguens :)
But maybe Felipe can fix it when applying?

Br, David

Re: [PATCH v7 2/5] usb: gadget: add quirk_ep_out_aligned_size field to struct usb_gadget

[Felipe Balbi]

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On Mon, Dec 09, 2013 at 07:35:19PM -0800, David Cohen wrote:
> On 12/09/2013 06:34 PM, Michal Nazarewicz wrote:
> > dOn Tue, Dec 10 2013, David Cohen wrote:
> >> Due to USB controllers may have different restrictions, usb gadget layer
> >> needs to provide a generic way to inform gadget functions to complain
> >> with non-standard requirements.
> >>
> >> This patch adds 'quirk_ep_out_aligned_size' field to struct usb_gadget
> >> to inform when controller's epout requires buffer size to be aligned to
> >> MaxPacketSize. A helper is also provided to align buffer size when
> >> necessary.
> >>
> >> Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
> >> Cc: Alan Stern <stern@rowland.harvard.edu>
> >> Cc: Michal Nazarewicz <mina86@mina86.com>
> > 
> > Acked-by: Michal Nazarewicz <mina86@mina86.com>
> > 
> >> ---
> >>  include/linux/usb/gadget.h | 20 ++++++++++++++++++++
> >>  1 file changed, 20 insertions(+)
> >>
> >> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> >> index 23b3bfd0a842..cae8a6216551 100644
> >> --- a/include/linux/usb/gadget.h
> >> +++ b/include/linux/usb/gadget.h
> >> @@ -502,6 +502,8 @@ struct usb_gadget_ops {
> >>   *	only supports HNP on a different root port.
> >>   * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
> >>   *	enabled HNP support.
> >> + * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
> >> + *	MaxPacketSize.
> >>   *
> >>   * Gadgets have a mostly-portable "gadget driver" implementing device
> >>   * functions, handling all usb configurations and interfaces.  Gadget
> >> @@ -541,6 +543,7 @@ struct usb_gadget {
> >>  	unsigned			b_hnp_enable:1;
> >>  	unsigned			a_hnp_support:1;
> >>  	unsigned			a_alt_hnp_support:1;
> >> +	unsigned			quirk_ep_out_aligned_size:1;
> >>  };
> >>  #define work_to_gadget(w)	(container_of((w), struct usb_gadget, work))
> >>  
> >> @@ -559,6 +562,23 @@ static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
> >>  
> >>  
> >>  /**
> >> + * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
> >> + *	requires quirk_ep_out_aligned_size, otherwise reguens len.
> > 
> > “returns”
> 
> I've got no idea how returns became reguens :)
> But maybe Felipe can fix it when applying?

Sure, but you owe me a beer hehe :-)

-- 
balbi

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Re: [PATCH v7 2/5] usb: gadget: add quirk_ep_out_aligned_size field to struct usb_gadget

[David Cohen]

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>>>>  /**
>>>> + * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
>>>> + *	requires quirk_ep_out_aligned_size, otherwise reguens len.
>>>
>>> “returns”
>>
>> I've got no idea how returns became reguens :)
>> But maybe Felipe can fix it when applying?
> 
> Sure, but you owe me a beer hehe :-)

Just print this e-mail and you can redeem one as soon as you visit
Portland :P

Br, David



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Re: [PATCH v7 2/5] usb: gadget: add quirk_ep_out_aligned_size field to struct usb_gadget

[Michal Nazarewicz]

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On Tue, Dec 10 2013, David Cohen wrote:
> I've got no idea how returns became reguens :)

The keys are like right next to each other <http://bash.org/?5300>. ;)

> But maybe Felipe can fix it when applying?

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +--<mpn@google.com>--<xmpp:mina86@jabber.org>--ooO--(_)--Ooo--

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Re: [PATCH v7 2/5] usb: gadget: add quirk_ep_out_aligned_size field to struct usb_gadget

[David Cohen]

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On 12/10/2013 07:01 AM, Michal Nazarewicz wrote:
> On Tue, Dec 10 2013, David Cohen wrote:
>> I've got no idea how returns became reguens :)
> 
> The keys are like right next to each other <http://bash.org/?5300>. ;)

I'll remember this excuse if I need some day :)

> 
>> But maybe Felipe can fix it when applying?
> 
> 
> 



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[PATCH v7 3/5] usb: gadget: f_fs: remove loop from I/O function

[David Cohen]

From: Michal Nazarewicz <mina86@mina86.com>

When endpoint changes (due to it being disabled or alt setting changed),
mimic the action as if the change happened after the request has been
queued, instead of retrying with the new endpoint.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>
---
 drivers/usb/gadget/f_fs.c | 94 ++++++++++++++++++++---------------------------
 1 file changed, 40 insertions(+), 54 deletions(-)

diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index 75e4b7846a8d..efa1152a4c15 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -760,73 +760,59 @@ static ssize_t ffs_epfile_io(struct file *file,
 	ssize_t ret;
 	int halt;
 
-	goto first_try;
-	do {
-		spin_unlock_irq(&epfile->ffs->eps_lock);
-		mutex_unlock(&epfile->mutex);
+	/* Are we still active? */
+	if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
+		ret = -ENODEV;
+		goto error;
+	}
 
-first_try:
-		/* Are we still active? */
-		if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) {
-			ret = -ENODEV;
+	/* Wait for endpoint to be enabled */
+	ep = epfile->ep;
+	if (!ep) {
+		if (file->f_flags & O_NONBLOCK) {
+			ret = -EAGAIN;
 			goto error;
 		}
 
-		/* Wait for endpoint to be enabled */
-		ep = epfile->ep;
-		if (!ep) {
-			if (file->f_flags & O_NONBLOCK) {
-				ret = -EAGAIN;
-				goto error;
-			}
-
-			if (wait_event_interruptible(epfile->wait,
-						     (ep = epfile->ep))) {
-				ret = -EINTR;
-				goto error;
-			}
-		}
-
-		/* Do we halt? */
-		halt = !read == !epfile->in;
-		if (halt && epfile->isoc) {
-			ret = -EINVAL;
+		ret = wait_event_interruptible(epfile->wait, (ep = epfile->ep));
+		if (ret) {
+			ret = -EINTR;
 			goto error;
 		}
+	}
 
-		/* Allocate & copy */
-		if (!halt && !data) {
-			data = kzalloc(len, GFP_KERNEL);
-			if (unlikely(!data))
-				return -ENOMEM;
+	/* Do we halt? */
+	halt = !read == !epfile->in;
+	if (halt && epfile->isoc) {
+		ret = -EINVAL;
+		goto error;
+	}
 
-			if (!read &&
-			    unlikely(__copy_from_user(data, buf, len))) {
-				ret = -EFAULT;
-				goto error;
-			}
-		}
+	/* Allocate & copy */
+	if (!halt) {
+		data = kmalloc(len, GFP_KERNEL);
+		if (unlikely(!data))
+			return -ENOMEM;
 
-		/* We will be using request */
-		ret = ffs_mutex_lock(&epfile->mutex,
-				     file->f_flags & O_NONBLOCK);
-		if (unlikely(ret))
+		if (!read && unlikely(copy_from_user(data, buf, len))) {
+			ret = -EFAULT;
 			goto error;
+		}
+	}
 
-		/*
-		 * We're called from user space, we can use _irq rather then
-		 * _irqsave
-		 */
-		spin_lock_irq(&epfile->ffs->eps_lock);
+	/* We will be using request */
+	ret = ffs_mutex_lock(&epfile->mutex, file->f_flags & O_NONBLOCK);
+	if (unlikely(ret))
+		goto error;
 
-		/*
-		 * While we were acquiring mutex endpoint got disabled
-		 * or changed?
-		 */
-	} while (unlikely(epfile->ep != ep));
+	spin_lock_irq(&epfile->ffs->eps_lock);
 
-	/* Halt */
-	if (unlikely(halt)) {
+	if (epfile->ep != ep) {
+		/* In the meantime, endpoint got disabled or changed. */
+		ret = -ESHUTDOWN;
+		spin_unlock_irq(&epfile->ffs->eps_lock);
+	} else if (halt) {
+		/* Halt */
 		if (likely(epfile->ep == ep) && !WARN_ON(!ep->ep))
 			usb_ep_set_halt(ep->ep);
 		spin_unlock_irq(&epfile->ffs->eps_lock);
-- 
1.8.4.2

[PATCH v7 4/5] usb: f_fs: check quirk to pad epout buf size when not aligned to maxpacketsize

[David Cohen]

From: Michal Nazarewicz <mina86@mina86.com>

Check gadget.quirk_ep_out_aligned_size to decide if buffer size requires
to be aligned to maxpacketsize of an out endpoint.  ffs_epfile_io() needs
to pad epout buffer to match above condition if quirk is found.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
---
 drivers/usb/gadget/f_fs.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index efa1152a4c15..918c21885d49 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -755,9 +755,10 @@ static ssize_t ffs_epfile_io(struct file *file,
 			     char __user *buf, size_t len, int read)
 {
 	struct ffs_epfile *epfile = file->private_data;
+	struct usb_gadget *gadget = epfile->ffs->gadget;
 	struct ffs_ep *ep;
 	char *data = NULL;
-	ssize_t ret;
+	ssize_t ret, data_len;
 	int halt;
 
 	/* Are we still active? */
@@ -790,7 +791,13 @@ static ssize_t ffs_epfile_io(struct file *file,
 
 	/* Allocate & copy */
 	if (!halt) {
-		data = kmalloc(len, GFP_KERNEL);
+		/*
+		 * Controller may require buffer size to be aligned to
+		 * maxpacketsize of an out endpoint.
+		 */
+		data_len = read ? usb_ep_align_maybe(gadget, ep->ep, len) : len;
+
+		data = kmalloc(data_len, GFP_KERNEL);
 		if (unlikely(!data))
 			return -ENOMEM;
 
@@ -825,7 +832,7 @@ static ssize_t ffs_epfile_io(struct file *file,
 		req->context  = &done;
 		req->complete = ffs_epfile_io_complete;
 		req->buf      = data;
-		req->length   = len;
+		req->length   = data_len;
 
 		ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
 
@@ -837,9 +844,17 @@ static ssize_t ffs_epfile_io(struct file *file,
 			ret = -EINTR;
 			usb_ep_dequeue(ep->ep, req);
 		} else {
+			/*
+			 * XXX We may end up silently droping data here.
+			 * Since data_len (i.e. req->length) may be bigger
+			 * than len (after being rounded up to maxpacketsize),
+			 * we may end up with more data then user space has
+			 * space for.
+			 */
 			ret = ep->status;
 			if (read && ret > 0 &&
-			    unlikely(copy_to_user(buf, data, ret)))
+			    unlikely(copy_to_user(buf, data,
+						  min_t(size_t, ret, len))))
 				ret = -EFAULT;
 		}
 	}
-- 
1.8.4.2

[PATCH v7 5/5] usb: dwc3: set gadget's quirk ep_out_align_size

[David Cohen]

DWC3 requires epout to have buffer size aligned to MaxPacketSize value.
This patch sets necessary quirk for it.

Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
---
 drivers/usb/dwc3/gadget.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 5452c0fce360..b85ec110d6a0 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2600,6 +2600,12 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 	dwc->gadget.name		= "dwc3-gadget";
 
 	/*
+	 * Per databook, DWC3 needs buffer size to be aligned to MaxPacketSize
+	 * on ep out.
+	 */
+	dwc->gadget.quirk_ep_out_aligned_size = true;
+
+	/*
 	 * REVISIT: Here we should clear all pending IRQs to be
 	 * sure we're starting from a well known location.
 	 */
-- 
1.8.4.2