[U-Boot] [PATCH V3] net: fec_mxc: allow use with cache enabled

[Marek Vasut]

Dear Eric Nelson,

> Thanks Mike,
> 
> On 03/13/2012 07:41 AM, Mike Frysinger wrote:
> > On Tuesday 13 March 2012 10:04:31 Eric Nelson wrote:
> >> --- a/drivers/net/fec_mxc.c
> >> +++ b/drivers/net/fec_mxc.c
> >> 
> >> +#if ARCH_DMA_MINALIGN>  CONFIG_SYS_CACHELINE_SIZE
> >> +#define CONFIG_FEC_ALIGN ARCH_DMA_MINALIGN
> >> +#else
> >> +#define CONFIG_FEC_ALIGN CONFIG_SYS_CACHELINE_SIZE
> >> +#endif
> > 
> > i don't think this is something you should be checking.  if this is an
> > actual problem (and i don't think it is), it's something we should
> > handle in common code.  if you need to dma from memory, then use
> > ARCH_DMA_MINALIGN.
> 
> Marek, you've mentioned some restrictions for other i.MX devices.
> 
> Are you aware of any problem collapsing this?

Well yes, there exists a CPU which has 32byte cacheline, but FEC such that needs 
DMA areas aligned to 16 bytes. That's why you need higher of those two to be 
safe.
> 
> Note that other CPUs will need to have CONFIG_SYS_CACHELINE_SIZE to
> prevent the default of 64.

Agreed

> 
> >> +#error	"CONFIG_FEC_ALIGN must be multiple of 16!"
> >> +#error	"PKTALIGN must be multiple of CONFIG_FEC_ALIGN!"
> > 
> > please don't use tabs after #define/#error/etc... just one space
> 
> Ok. I'll address in V4.

This is actually my work, Mike, I just love it neatly aligned with tabs :-p

Best regards,
Marek Vasut