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

[Joel Fernandes <joelf@ti.com>]

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
>