Patchwork [U-Boot] usb: gadget: Fix data aborts during USB ethernet boot

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Submitter Joel Fernandes
Date Aug. 20, 2013, 11:32 p.m.
Message ID <1377041578-9149-1-git-send-email-joelf@ti.com>
Download mbox | patch
Permalink /patch/268659/
State Superseded
Delegated to: Marek Vasut
Headers show

Comments

Joel Fernandes - Aug. 20, 2013, 11:32 p.m.
As seen on GCC 4.6 Linaro compiler, control_req buffer is not aligned
on 4 byte boundaray causing data aborts in eth_setup -> conf_buf
during dhcp boot over usb_ether. Fix the issue my aligning control_req
buffer to 4-byte boundary.

Tested on am335x_evm platform (beaglebone).
Applies on 2013.10-rc1 branch.

Cc: Tom Rini <trini@ti.com>
Signed-off-by: Joel Fernandes <joelf@ti.com>
---
 drivers/usb/gadget/ether.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Marek Vasut - Aug. 27, 2013, 1:52 p.m.
Dear Joel Fernandes,

> As seen on GCC 4.6 Linaro compiler, control_req buffer is not aligned
> on 4 byte boundaray causing data aborts in eth_setup -> conf_buf
> during dhcp boot over usb_ether. Fix the issue my aligning control_req
> buffer to 4-byte boundary.
> 
> Tested on am335x_evm platform (beaglebone).
> Applies on 2013.10-rc1 branch.
> 
> Cc: Tom Rini <trini@ti.com>
> Signed-off-by: Joel Fernandes <joelf@ti.com>

Please keep me in the CC next time.

> ---
>  drivers/usb/gadget/ether.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
> index 579893c..251d7b2 100644
> --- a/drivers/usb/gadget/ether.c
> +++ b/drivers/usb/gadget/ether.c
> @@ -849,7 +849,7 @@ static struct usb_gadget_strings	stringtab = {
>  };
> 
>  /*========================================================================
> ====*/ -static u8 control_req[USB_BUFSIZ];
> +static u8 control_req[USB_BUFSIZ] __attribute__ ((aligned(4)));

Please make this cacheline aligned, so we get rid of bounce buffering of the 
requests on stupid hardware.

>  #if defined(CONFIG_USB_ETH_CDC) || defined(CONFIG_USB_ETH_RNDIS)
>  static u8 status_req[STATUS_BYTECOUNT] __attribute__ ((aligned(4)));

This could also use fixing, but the STATUS_BYTECOUNT would need to be up-aligned 
as well then. Some DEFINE_CACHE_ALIGN_BUFFER might help in both cases here.

>  #endif

Best regards,
Marek Vasut
Joel Fernandes - Sept. 4, 2013, 9:30 p.m.
On 08/27/2013 08:52 AM, Marek Vasut wrote:
> Dear Joel Fernandes,
> 
>> As seen on GCC 4.6 Linaro compiler, control_req buffer is not aligned
>> on 4 byte boundaray causing data aborts in eth_setup -> conf_buf
>> during dhcp boot over usb_ether. Fix the issue my aligning control_req
>> buffer to 4-byte boundary.
>>
>> Tested on am335x_evm platform (beaglebone).
>> Applies on 2013.10-rc1 branch.
>>
>> Cc: Tom Rini <trini@ti.com>
>> Signed-off-by: Joel Fernandes <joelf@ti.com>
> 
> Please keep me in the CC next time.

Ok.

>> ---
>>  drivers/usb/gadget/ether.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
>> index 579893c..251d7b2 100644
>> --- a/drivers/usb/gadget/ether.c
>> +++ b/drivers/usb/gadget/ether.c
>> @@ -849,7 +849,7 @@ static struct usb_gadget_strings	stringtab = {
>>  };
>>
>>  /*========================================================================
>> ====*/ -static u8 control_req[USB_BUFSIZ];
>> +static u8 control_req[USB_BUFSIZ] __attribute__ ((aligned(4)));
> 
> Please make this cacheline aligned, so we get rid of bounce buffering of the 
> requests on stupid hardware.
>>  #if defined(CONFIG_USB_ETH_CDC) || defined(CONFIG_USB_ETH_RNDIS)
>>  static u8 status_req[STATUS_BYTECOUNT] __attribute__ ((aligned(4)));
> 
> This could also use fixing, but the STATUS_BYTECOUNT would need to be up-aligned 
> as well then. Some DEFINE_CACHE_ALIGN_BUFFER might help in both cases here.

Ok, how about __aligned(CONFIG_SYS_CACHELINE_SIZE) instead of defining
a new DEFINE_CACHE_ALIGN_BUFFER macro?

Can you explain what you meant by STATUS_BYTECOUNT up-aligned and why its needed
to be up-aligned?

Regards,

-Joel

> 
>>  #endif
> 
> Best regards,
> Marek Vasut
>
Marek Vasut - Sept. 4, 2013, 9:38 p.m.
Dear Joel Fernandes,

> On 08/27/2013 08:52 AM, Marek Vasut wrote:
> > Dear Joel Fernandes,
> > 
> >> As seen on GCC 4.6 Linaro compiler, control_req buffer is not aligned
> >> on 4 byte boundaray causing data aborts in eth_setup -> conf_buf
> >> during dhcp boot over usb_ether. Fix the issue my aligning control_req
> >> buffer to 4-byte boundary.
> >> 
> >> Tested on am335x_evm platform (beaglebone).
> >> Applies on 2013.10-rc1 branch.
> >> 
> >> Cc: Tom Rini <trini@ti.com>
> >> Signed-off-by: Joel Fernandes <joelf@ti.com>
> > 
> > Please keep me in the CC next time.
> 
> Ok.
> 
> >> ---
> >> 
> >>  drivers/usb/gadget/ether.c |    2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >> 
> >> diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
> >> index 579893c..251d7b2 100644
> >> --- a/drivers/usb/gadget/ether.c
> >> +++ b/drivers/usb/gadget/ether.c
> >> @@ -849,7 +849,7 @@ static struct usb_gadget_strings	stringtab = {
> >> 
> >>  };
> >>  
> >>  /*=====================================================================
> >>  ===
> >> 
> >> ====*/ -static u8 control_req[USB_BUFSIZ];
> >> +static u8 control_req[USB_BUFSIZ] __attribute__ ((aligned(4)));
> > 
> > Please make this cacheline aligned, so we get rid of bounce buffering of
> > the requests on stupid hardware.
> > 
> >>  #if defined(CONFIG_USB_ETH_CDC) || defined(CONFIG_USB_ETH_RNDIS)
> >>  static u8 status_req[STATUS_BYTECOUNT] __attribute__ ((aligned(4)));
> > 
> > This could also use fixing, but the STATUS_BYTECOUNT would need to be
> > up-aligned as well then. Some DEFINE_CACHE_ALIGN_BUFFER might help in
> > both cases here.
> 
> Ok, how about __aligned(CONFIG_SYS_CACHELINE_SIZE) instead of defining
> a new DEFINE_CACHE_ALIGN_BUFFER macro?

THis is already defined and used throughout the USB code, check include/common.h 
IIRC.

> Can you explain what you meant by STATUS_BYTECOUNT up-aligned and why its
> needed to be up-aligned?

it's 16 bytes now, no? Up-align it to cacheline size.

Best regards,
Marek Vasut

Patch

diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
index 579893c..251d7b2 100644
--- a/drivers/usb/gadget/ether.c
+++ b/drivers/usb/gadget/ether.c
@@ -849,7 +849,7 @@  static struct usb_gadget_strings	stringtab = {
 };
 
 /*============================================================================*/
-static u8 control_req[USB_BUFSIZ];
+static u8 control_req[USB_BUFSIZ] __attribute__ ((aligned(4)));
 #if defined(CONFIG_USB_ETH_CDC) || defined(CONFIG_USB_ETH_RNDIS)
 static u8 status_req[STATUS_BYTECOUNT] __attribute__ ((aligned(4)));
 #endif