[U-Boot] [PATCH] ARM926ejs: Add routines to invalidate D-Cache

[Marek Vasut <marek.vasut@gmail.com>]

On Tuesday, August 09, 2011 03:57:41 AM Hong Xu wrote:
> Hi Marek Vasut,
> 
> On 08/09/2011 01:34 AM, Marek Vasut wrote:
> > On Monday, August 08, 2011 10:01:19 AM Albert ARIBAUD wrote:
> >> Hi Hong Xu,
> >> 
> >> Le 08/08/2011 05:20, Hong Xu a ?crit :
> >>> After DMA operation, we need to maintain D-Cache coherency.
> >>> So that the DCache must be invalidated (hence CPU will fetch
> >>> data written by DMA controller from RAM).
> >>> 
> >>> Tested on AT91SAM9261EK with Peripheral DMA controller.
> >>> 
> >>> Signed-off-by: Hong Xu<hong.xu@atmel.com>
> >>> Tested-by: Elen Song<elen.song@atmel.com>
> >>> CC: Albert Aribaud<albert.u.boot@aribaud.net>
> >>> CC: Aneesh V<aneesh@ti.com>
> >>> CC: Reinhard Meyer<u-boot@emk-elektronik.de>
> >>> CC: Heiko Schocher<hs@denx.de>
> >>> ---
> >>> 
> >>> V2:
> >>>     Per Albert's suggestion, add invalidate_dcache_range
> >>> 
> >>> V3:
> >>>     invalidate_dcache_range emits warning when detecting unaligned
> >>>     buffer
> >>>     
> >>>     invalidate_dcache_range won't clean any adjacent cache line when
> >>>     detecting unaligned buffer and only round up/down the buffer
> >>>     address
> >>> 
> >>> +	mva = start;
> >>> +	if ((mva&   (cache_line_len - 1)) != 0) {
> >>> +		printf("WARNING: %s - unaligned buffer detected, starting "
> >> 
> >> I'd rather have a message about "cache", not "buffer", e.g.
> >> 
> >>     printf("WARNING: %s - start address %x is not aligned\n"
> >>     
> >>       __FUNCTION__, start);
> > 
> > __func__ is prefered in linux kernel :-)
> 
> __func__ is C99 standard. __FUNCTION__ appears more in U-Boot. ;-)

This doesn't mean it's correct ;-) "majority proof" isn't a proof really.

> GCC manual says some older GCC only recognize __FUNCTION__ .
> If we rely on GCC, it looks __FUNCTION__ will reduce troubles.

Do we support such ancient versions of GCC anyway ? Just to be clear, I'm fine 
with either way, just my 2.7183 cents ;-)
> 
> BR,
> Eric
> 
> >>> +		mva&= ~(cache_line_len - 1);
> >>> +	}
> >>> +	if ((stop&   (cache_line_len - 1)) != 0) {
> >>> +		printf("WARNING: %s - unaligned buffer detected, ending "
> >>> +			"address: 0x%08x\n", __FUNCTION__, stop);
> >> 
> >> Ditto.
> > 
> > Ditto.
> 
> [...]