[U-Boot] [PATCH 1/2 V2] arm926: Flush the data cache before disabling it.

Tom Rini
2012-01-16T17:57:05Z

On Fri, Jan 13, 2012 at 10:38 AM, Sughosh Ganu <urwithsughosh@gmail.com> wrote:
> hi Heiko,
>
> On Fri Jan 13, 2012 at 04:29:29PM +0100, Heiko Schocher wrote:
>> Hello Sugosh,
>>
>> Sughosh Ganu wrote:
>> > hi Christian,
>> >
>> > On Fri Jan 13, 2012 at 09:06:26AM +0100, Christian Riesch wrote:
>> >> Hi Sughosh,
>> >> I had a look at the patch and I tried to understand what's going on
>> >> here (I must confess that I didn't know anything about this cache
>> >> stuff).
>> >
>> > ? Ok, thanks for taking time off to understand this issue.
>> >
>> >> On Tue, Jan 10, 2012 at 7:12 PM, Sughosh Ganu <urwithsughosh@gmail.com> wrote:
>> >>> The current implementation invalidates the cache instead of flushing
>> >>> it. This causes problems on platforms where the spl/u-boot is already
>> >>> loaded to the RAM, with caches enabled by a first stage bootloader.
>>
>> Hmm.. how did u-boot work on such boards? How can u-boot work with D-Cache
>> enabled, if u-boot is not initializing it? (And I think, on davinci SoC
>> we have a none working uboot ethernet driver if d-cache is enabled too).
>> There must be a page_table in DRAM for using D-Cache in U-Boot, if u-boot
>> don't initialize it, it maybe overrides it ... or miss I something?
>
> ?Well, there is some data in the cache, which if not flushed creates
> ?problems on my board. I get the board to boot just by commenting out
> ?cpu_init_crit call. My hypothesis that the D-cache is enabled is
> ?simply because cache invalidation followed by cache disabling breaks
> ?the board, while flushing it prior to disabling gets it to boot
> ?fine. This(invalidation) would not have been a problem if the cache
> ?was in the disabled state.

Putting my TI hat on, I've confirmed with the RBL folks that they
aren't turning on ICACHE/DCACHE.

--
Tom