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

[Marek Vasut]

Dear Mike Frysinger,

> On Tuesday 13 March 2012 14:42:29 Eric Nelson wrote:
> > 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?
> > 
> > Note that other CPUs will need to have CONFIG_SYS_CACHELINE_SIZE to
> > prevent the default of 64.
> 
> and those cores should be making sure that ARCH_DMA_MINALIGN is sufficient
> to handle those larger cache lines.  this define provides two meanings:
> minimum alignment for the DMA itself, and for sanely flushing the cache on
> that dma buffer.  so there should be no situation where ARCH_DMA_MINALIGN
> is smaller than the cacheline size.
> 
> the few boards i see defining CONFIG_SYS_CACHELINE_SIZE to 64 are all ARM
> based, and ARM sets ARCH_DMA_MINALIGN to CONFIG_SYS_CACHELINE_SIZE if it's
> defined
> -mike

Eric, can you check also PPC /wrt to this? This driver is also used on PPC.


Best regards,
Marek Vasut