Dear Joel Fernandes, > On 09/04/2013 04:38 PM, Marek Vasut wrote: > > 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 <tr...@ti.com> > >>>> Signed-off-by: Joel Fernandes <jo...@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. > > Ok, that makes sense. Thanks. Hope below patch is OK, but I have to test it > more once I am near a setup and can send out a proper patch later today. > > If its ok can you explain technical reason for need to up-align array size > to cacheline size, and why aligning only buffer location is not enough? > > Also I saw the following comment before the macro definition: > * Usage of this macro shall be avoided or used with extreme care! > > Regards, > > -Joel > > diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c > index 579893c..700d5fb 100644 > --- a/drivers/usb/gadget/ether.c > +++ b/drivers/usb/gadget/ether.c > @@ -849,9 +849,10 @@ static struct usb_gadget_strings stringtab = { > }; > > /*======================================================================== > ====*/ -static u8 control_req[USB_BUFSIZ]; > +DEFINE_CACHE_ALIGN_BUFFER(u8, control_req, USB_BUFSIZ); > + > #if defined(CONFIG_USB_ETH_CDC) || defined(CONFIG_USB_ETH_RNDIS) > -static u8 status_req[STATUS_BYTECOUNT] __attribute__ ((aligned(4))); > +DEFINE_CACHE_ALIGN_BUFFER(u8, status_req, STATUS_BYTECOUNT); > #endif
Yeah, I think so. Repost V2 and we should be cool here. Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot