Patchwork [U-Boot,2/2] usb: gadget: Use unaligned access for wMaxPacketSize

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Submitter Vivek Gautam
Date May 13, 2013, 10:23 a.m.
Message ID <1368440618-11359-2-git-send-email-gautam.vivek@samsung.com>
Download mbox | patch
Permalink /patch/243355/
State Awaiting Upstream
Delegated to: Marek Vasut
Headers show

Comments

Vivek Gautam - May 13, 2013, 10:23 a.m.
Use get_unaligned() while fetching wMaxPacketSize to avoid
voilating any alignment rules.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Cc: Lukasz Majewski <l.majewski@samsung.com>
Cc: Piotr Wilczek <p.wilczek@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lukasz Dalek <luk0104@gmail.com>
Cc: Marek Vasut <marex@denx.de>
---

Just did a build test on u-boot-usb/master branch.
Need to be tested further.

Based on u-boot-usb/next.

 drivers/usb/gadget/f_mass_storage.c |    3 ++-
 drivers/usb/gadget/pxa25x_udc.c     |   13 +++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)
Kyungmin Park - May 13, 2013, 10:50 a.m.
On Mon, May 13, 2013 at 7:23 PM, Vivek Gautam <gautam.vivek@samsung.com>wrote:

> Use get_unaligned() while fetching wMaxPacketSize to avoid
> voilating any alignment rules.
>

It's another story, can we get performance gain with unaligned access
feature? In case of kernel, we got some gains.

Anyway, good job!

Acked-by: Kyungmin Park <kyungmin.park@samsung.com>

>
> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
> Cc: Lukasz Majewski <l.majewski@samsung.com>
> Cc: Piotr Wilczek <p.wilczek@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Lukasz Dalek <luk0104@gmail.com>
> Cc: Marek Vasut <marex@denx.de>
> ---
>
> Just did a build test on u-boot-usb/master branch.
> Need to be tested further.
>
> Based on u-boot-usb/next.
>
>  drivers/usb/gadget/f_mass_storage.c |    3 ++-
>  drivers/usb/gadget/pxa25x_udc.c     |   13 +++++++------
>  2 files changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/usb/gadget/f_mass_storage.c
> b/drivers/usb/gadget/f_mass_storage.c
> index c28866f..45bc132 100644
> --- a/drivers/usb/gadget/f_mass_storage.c
> +++ b/drivers/usb/gadget/f_mass_storage.c
> @@ -2261,7 +2261,8 @@ reset:
>         if (rc)
>                 goto reset;
>         fsg->bulk_out_enabled = 1;
> -       common->bulk_out_maxpacket = le16_to_cpu(d->wMaxPacketSize);
> +       common->bulk_out_maxpacket =
> +
> le16_to_cpu(get_unaligned(&d->wMaxPacketSize));
>         clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
>
>         /* Allocate the requests */
> diff --git a/drivers/usb/gadget/pxa25x_udc.c
> b/drivers/usb/gadget/pxa25x_udc.c
> index 9ce98f0..085503d 100644
> --- a/drivers/usb/gadget/pxa25x_udc.c
> +++ b/drivers/usb/gadget/pxa25x_udc.c
> @@ -314,7 +314,8 @@ static int pxa25x_ep_enable(struct usb_ep *_ep,
>         if (!_ep || !desc || ep->desc || _ep->name == ep0name
>                         || desc->bDescriptorType != USB_DT_ENDPOINT
>                         || ep->bEndpointAddress != desc->bEndpointAddress
> -                       || ep->fifo_size <
> le16_to_cpu(desc->wMaxPacketSize)) {
> +                       || ep->fifo_size <
> +
>  le16_to_cpu(get_unaligned(&desc->wMaxPacketSize))) {
>                 printf("%s, bad ep or descriptor\n", __func__);
>                 return -EINVAL;
>         }
> @@ -329,9 +330,9 @@ static int pxa25x_ep_enable(struct usb_ep *_ep,
>
>         /* hardware _could_ do smaller, but driver doesn't */
>         if ((desc->bmAttributes == USB_ENDPOINT_XFER_BULK
> -                               && le16_to_cpu(desc->wMaxPacketSize)
> +                       &&
> le16_to_cpu(get_unaligned(&desc->wMaxPacketSize))
>                                                 != BULK_FIFO_SIZE)
> -                       || !desc->wMaxPacketSize) {
> +                       || !get_unaligned(&desc->wMaxPacketSize)) {
>                 printf("%s, bad %s maxpacket\n", __func__, _ep->name);
>                 return -ERANGE;
>         }
> @@ -345,7 +346,7 @@ static int pxa25x_ep_enable(struct usb_ep *_ep,
>         ep->desc = desc;
>         ep->stopped = 0;
>         ep->pio_irqs = 0;
> -       ep->ep.maxpacket = le16_to_cpu(desc->wMaxPacketSize);
> +       ep->ep.maxpacket =
> le16_to_cpu(get_unaligned(&desc->wMaxPacketSize));
>
>         /* flush fifo (mostly for OUT buffers) */
>         pxa25x_ep_fifo_flush(_ep);
> @@ -485,7 +486,7 @@ write_fifo(struct pxa25x_ep *ep, struct pxa25x_request
> *req)
>  {
>         unsigned max;
>
> -       max = le16_to_cpu(ep->desc->wMaxPacketSize);
> +       max = le16_to_cpu(get_unaligned(&ep->desc->wMaxPacketSize));
>         do {
>                 unsigned count;
>                 int is_last, is_short;
> @@ -766,7 +767,7 @@ pxa25x_ep_queue(struct usb_ep *_ep, struct usb_request
> *_req, gfp_t gfp_flags)
>          */
>         if (unlikely(ep->bmAttributes == USB_ENDPOINT_XFER_ISOC
>                         && req->req.length >
> -                       le16_to_cpu(ep->desc->wMaxPacketSize)))
> +
> le16_to_cpu(get_unaligned(&ep->desc->wMaxPacketSize))))
>                 return -EMSGSIZE;
>
>         debug_cond(NOISY, "%s queue req %p, len %d buf %p\n",
> --
> 1.7.6.5
>
> _______________________________________________
> U-Boot mailing list
> U-Boot@lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot
>
Vivek Gautam - May 13, 2013, 11:46 a.m.
Hi,


On Mon, May 13, 2013 at 4:20 PM, Kyungmin Park <kmpark@infradead.org> wrote:
> On Mon, May 13, 2013 at 7:23 PM, Vivek Gautam <gautam.vivek@samsung.com>wrote:
>
>> Use get_unaligned() while fetching wMaxPacketSize to avoid
>> voilating any alignment rules.

typo here s/voilating/violating

>>
>
> It's another story, can we get performance gain with unaligned access
> feature? In case of kernel, we got some gains.

This change was necessary since we get data abort if we try to fetch
wMaxPacketSize
which violates the natural alignment rules being a member of "struct
usb_endpoint_descriptor".

I am not sure of the performance gains with this. However, if you can
guide me how to
measure that, we can get the numbers if any.

>
> Anyway, good job!

Thanks !

>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
>
>>
>> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
>> Cc: Lukasz Majewski <l.majewski@samsung.com>
>> Cc: Piotr Wilczek <p.wilczek@samsung.com>
>> Cc: Kyungmin Park <kyungmin.park@samsung.com>
>> Cc: Lukasz Dalek <luk0104@gmail.com>
>> Cc: Marek Vasut <marex@denx.de>
>> ---
>>
>> Just did a build test on u-boot-usb/master branch.
>> Need to be tested further.
>>
>> Based on u-boot-usb/next.
>>
>>  drivers/usb/gadget/f_mass_storage.c |    3 ++-
>>  drivers/usb/gadget/pxa25x_udc.c     |   13 +++++++------
>>  2 files changed, 9 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/usb/gadget/f_mass_storage.c
>> b/drivers/usb/gadget/f_mass_storage.c
>> index c28866f..45bc132 100644
>> --- a/drivers/usb/gadget/f_mass_storage.c
>> +++ b/drivers/usb/gadget/f_mass_storage.c
>> @@ -2261,7 +2261,8 @@ reset:
>>         if (rc)
>>                 goto reset;
>>         fsg->bulk_out_enabled = 1;
>> -       common->bulk_out_maxpacket = le16_to_cpu(d->wMaxPacketSize);
>> +       common->bulk_out_maxpacket =
>> +
>> le16_to_cpu(get_unaligned(&d->wMaxPacketSize));
>>         clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
>>
>>         /* Allocate the requests */
>> diff --git a/drivers/usb/gadget/pxa25x_udc.c
>> b/drivers/usb/gadget/pxa25x_udc.c
>> index 9ce98f0..085503d 100644
>> --- a/drivers/usb/gadget/pxa25x_udc.c
>> +++ b/drivers/usb/gadget/pxa25x_udc.c
>> @@ -314,7 +314,8 @@ static int pxa25x_ep_enable(struct usb_ep *_ep,
>>         if (!_ep || !desc || ep->desc || _ep->name == ep0name
>>                         || desc->bDescriptorType != USB_DT_ENDPOINT
>>                         || ep->bEndpointAddress != desc->bEndpointAddress
>> -                       || ep->fifo_size <
>> le16_to_cpu(desc->wMaxPacketSize)) {
>> +                       || ep->fifo_size <
>> +
>>  le16_to_cpu(get_unaligned(&desc->wMaxPacketSize))) {
>>                 printf("%s, bad ep or descriptor\n", __func__);
>>                 return -EINVAL;
>>         }
>> @@ -329,9 +330,9 @@ static int pxa25x_ep_enable(struct usb_ep *_ep,
>>
>>         /* hardware _could_ do smaller, but driver doesn't */
>>         if ((desc->bmAttributes == USB_ENDPOINT_XFER_BULK
>> -                               && le16_to_cpu(desc->wMaxPacketSize)
>> +                       &&
>> le16_to_cpu(get_unaligned(&desc->wMaxPacketSize))
>>                                                 != BULK_FIFO_SIZE)
>> -                       || !desc->wMaxPacketSize) {
>> +                       || !get_unaligned(&desc->wMaxPacketSize)) {
>>                 printf("%s, bad %s maxpacket\n", __func__, _ep->name);
>>                 return -ERANGE;
>>         }
>> @@ -345,7 +346,7 @@ static int pxa25x_ep_enable(struct usb_ep *_ep,
>>         ep->desc = desc;
>>         ep->stopped = 0;
>>         ep->pio_irqs = 0;
>> -       ep->ep.maxpacket = le16_to_cpu(desc->wMaxPacketSize);
>> +       ep->ep.maxpacket =
>> le16_to_cpu(get_unaligned(&desc->wMaxPacketSize));
>>
>>         /* flush fifo (mostly for OUT buffers) */
>>         pxa25x_ep_fifo_flush(_ep);
>> @@ -485,7 +486,7 @@ write_fifo(struct pxa25x_ep *ep, struct pxa25x_request
>> *req)
>>  {
>>         unsigned max;
>>
>> -       max = le16_to_cpu(ep->desc->wMaxPacketSize);
>> +       max = le16_to_cpu(get_unaligned(&ep->desc->wMaxPacketSize));
>>         do {
>>                 unsigned count;
>>                 int is_last, is_short;
>> @@ -766,7 +767,7 @@ pxa25x_ep_queue(struct usb_ep *_ep, struct usb_request
>> *_req, gfp_t gfp_flags)
>>          */
>>         if (unlikely(ep->bmAttributes == USB_ENDPOINT_XFER_ISOC
>>                         && req->req.length >
>> -                       le16_to_cpu(ep->desc->wMaxPacketSize)))
>> +
>> le16_to_cpu(get_unaligned(&ep->desc->wMaxPacketSize))))
>>                 return -EMSGSIZE;
>>
>>         debug_cond(NOISY, "%s queue req %p, len %d buf %p\n",
>> --
>> 1.7.6.5
>>
>> _______________________________________________
>> U-Boot mailing list
>> U-Boot@lists.denx.de
>> http://lists.denx.de/mailman/listinfo/u-boot
>>
>
> _______________________________________________
> U-Boot mailing list
> U-Boot@lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot
>
Albert ARIBAUD - May 13, 2013, 11:56 a.m.
Hi Kyungmin,

On Mon, 13 May 2013 19:50:28 +0900, Kyungmin Park
<kmpark@infradead.org> wrote:

> On Mon, May 13, 2013 at 7:23 PM, Vivek Gautam <gautam.vivek@samsung.com>wrote:
> 
> > Use get_unaligned() while fetching wMaxPacketSize to avoid
> > voilating any alignment rules.
> >
> 
> It's another story, can we get performance gain with unaligned access
> feature? In case of kernel, we got some gains.

Please do not forget that U-Boot does not run on ARMv7+ only; it runs
on many ARM generations and on many non-ARM architectures too. Some of
these targets have a severe penalty on unaligned access; some cannot
even perform unaligned accesses.

File drivers/usb/gadget/f_mass_storage.c is generic and must build and
run for such targets too.

The best approach is to properly align fields wherever possible, and
when not possible, to use unaligned access macros (and if posisble
detect unaligned accesses at runtime).

Amicalement,
Łukasz Dałek - May 13, 2013, 12:03 p.m.
On 13.05.2013 12:23, Vivek Gautam wrote:
> Use get_unaligned() while fetching wMaxPacketSize to avoid
> voilating any alignment rules.
>
> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
> Cc: Lukasz Majewski <l.majewski@samsung.com>
> Cc: Piotr Wilczek <p.wilczek@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Lukasz Dalek <luk0104@gmail.com>
> Cc: Marek Vasut <marex@denx.de>
> ---
>
> Just did a build test on u-boot-usb/master branch.
> Need to be tested further.
>
> Based on u-boot-usb/next.
>
>   drivers/usb/gadget/f_mass_storage.c |    3 ++-
>   drivers/usb/gadget/pxa25x_udc.c     |   13 +++++++------
>   2 files changed, 9 insertions(+), 7 deletions(-)

Tested pxa25x_udc.c on u-boot/master on h2200 (PXA255) and works fine.

Yours sincerely,
Lukasz Dalek
Piotr Wilczek - May 14, 2013, 1:37 p.m.
> -----Original Message-----
> From: Vivek Gautam [mailto:gautam.vivek@samsung.com]
> Sent: Monday, May 13, 2013 12:24 PM
> To: u-boot@lists.denx.de
> Cc: gautam.vivek@samsung.com; Lukasz Majewski; Piotr Wilczek; Kyungmin
> Park; Lukasz Dalek; Marek Vasut
> Subject: [PATCH 2/2] usb: gadget: Use unaligned access for
> wMaxPacketSize
> 
> Use get_unaligned() while fetching wMaxPacketSize to avoid voilating
> any alignment rules.
> 
> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
> Cc: Lukasz Majewski <l.majewski@samsung.com>
> Cc: Piotr Wilczek <p.wilczek@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Lukasz Dalek <luk0104@gmail.com>
> Cc: Marek Vasut <marex@denx.de>
> ---
> 
> Just did a build test on u-boot-usb/master branch.
> Need to be tested further.
> 
> Based on u-boot-usb/next.
> 
>  drivers/usb/gadget/f_mass_storage.c |    3 ++-
>  drivers/usb/gadget/pxa25x_udc.c     |   13 +++++++------
>  2 files changed, 9 insertions(+), 7 deletions(-)
> 

Tested 'f_mass_storage.c' on u-boot/samsung.
It works fine with or without this patch on Trats2.

Best regards,
Piotr Wilczek
Marek Vasut - May 14, 2013, 1:49 p.m.
Dear Vivek Gautam,

> Use get_unaligned() while fetching wMaxPacketSize to avoid
> voilating any alignment rules.
> 
> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
> Cc: Lukasz Majewski <l.majewski@samsung.com>
> Cc: Piotr Wilczek <p.wilczek@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Lukasz Dalek <luk0104@gmail.com>
> Cc: Marek Vasut <marex@denx.de>

I'll pick both, thanks.

Best regards,
Marek Vasut

Patch

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index c28866f..45bc132 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -2261,7 +2261,8 @@  reset:
 	if (rc)
 		goto reset;
 	fsg->bulk_out_enabled = 1;
-	common->bulk_out_maxpacket = le16_to_cpu(d->wMaxPacketSize);
+	common->bulk_out_maxpacket =
+				le16_to_cpu(get_unaligned(&d->wMaxPacketSize));
 	clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
 
 	/* Allocate the requests */
diff --git a/drivers/usb/gadget/pxa25x_udc.c b/drivers/usb/gadget/pxa25x_udc.c
index 9ce98f0..085503d 100644
--- a/drivers/usb/gadget/pxa25x_udc.c
+++ b/drivers/usb/gadget/pxa25x_udc.c
@@ -314,7 +314,8 @@  static int pxa25x_ep_enable(struct usb_ep *_ep,
 	if (!_ep || !desc || ep->desc || _ep->name == ep0name
 			|| desc->bDescriptorType != USB_DT_ENDPOINT
 			|| ep->bEndpointAddress != desc->bEndpointAddress
-			|| ep->fifo_size < le16_to_cpu(desc->wMaxPacketSize)) {
+			|| ep->fifo_size <
+			   le16_to_cpu(get_unaligned(&desc->wMaxPacketSize))) {
 		printf("%s, bad ep or descriptor\n", __func__);
 		return -EINVAL;
 	}
@@ -329,9 +330,9 @@  static int pxa25x_ep_enable(struct usb_ep *_ep,
 
 	/* hardware _could_ do smaller, but driver doesn't */
 	if ((desc->bmAttributes == USB_ENDPOINT_XFER_BULK
-				&& le16_to_cpu(desc->wMaxPacketSize)
+			&& le16_to_cpu(get_unaligned(&desc->wMaxPacketSize))
 						!= BULK_FIFO_SIZE)
-			|| !desc->wMaxPacketSize) {
+			|| !get_unaligned(&desc->wMaxPacketSize)) {
 		printf("%s, bad %s maxpacket\n", __func__, _ep->name);
 		return -ERANGE;
 	}
@@ -345,7 +346,7 @@  static int pxa25x_ep_enable(struct usb_ep *_ep,
 	ep->desc = desc;
 	ep->stopped = 0;
 	ep->pio_irqs = 0;
-	ep->ep.maxpacket = le16_to_cpu(desc->wMaxPacketSize);
+	ep->ep.maxpacket = le16_to_cpu(get_unaligned(&desc->wMaxPacketSize));
 
 	/* flush fifo (mostly for OUT buffers) */
 	pxa25x_ep_fifo_flush(_ep);
@@ -485,7 +486,7 @@  write_fifo(struct pxa25x_ep *ep, struct pxa25x_request *req)
 {
 	unsigned max;
 
-	max = le16_to_cpu(ep->desc->wMaxPacketSize);
+	max = le16_to_cpu(get_unaligned(&ep->desc->wMaxPacketSize));
 	do {
 		unsigned count;
 		int is_last, is_short;
@@ -766,7 +767,7 @@  pxa25x_ep_queue(struct usb_ep *_ep, struct usb_request *_req, gfp_t gfp_flags)
 	 */
 	if (unlikely(ep->bmAttributes == USB_ENDPOINT_XFER_ISOC
 			&& req->req.length >
-			le16_to_cpu(ep->desc->wMaxPacketSize)))
+			le16_to_cpu(get_unaligned(&ep->desc->wMaxPacketSize))))
 		return -EMSGSIZE;
 
 	debug_cond(NOISY, "%s queue req %p, len %d buf %p\n",