[U-Boot] [PATCH] i.MX: fsl_esdhc: allow use with cache enabled.

[Stefano Babic]

On 24/03/2012 23:36, Eric Nelson wrote:
> Hi Stefano,
> 

Hi Eric,

> Sorry I let this linger.
> 
> On 03/17/2012 03:50 AM, Stefano Babic wrote:
>> On 03/03/2012 23:37, Eric Nelson wrote:
>>> Signed-off-by: Eric Nelson<eric.nelson at boundarydevices.com>
>>> ---
>>
>> Hi Eric,
>>
>> I have added Andy in CC as MMC Maintainer
>>
>>>   drivers/mmc/fsl_esdhc.c |   12 +++++++++++-
>>>   1 files changed, 11 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
>>> index a2f35e3..8e4bcef 100644
>>> --- a/drivers/mmc/fsl_esdhc.c
>>> +++ b/drivers/mmc/fsl_esdhc.c
>>> @@ -190,6 +190,8 @@ static int esdhc_setup_data(struct mmc *mmc,
>>> struct mmc_data *data)
>>>           esdhc_clrsetbits32(&regs->wml, WML_RD_WML_MASK, wml_value);
>>>           esdhc_write32(&regs->dsaddr, (u32)data->dest);
>>>       } else {
>>> +               
>>> flush_dcache_range((ulong)data->src,(ulong)data->src+data->blocks*data->blocksize);
>>>
>>
>> This breaks PowerPC boards.
>>
> 
> Can you tell me how?


./MAKEALL MPC8536DS
Configuring for MPC8536DS board...
fsl_esdhc.c: In function 'check_and_invalidate_dcache_range':
fsl_esdhc.c:255:19: warning: initialization makes integer from pointer
without a cast [enabled by default]
drivers/mmc/libmmc.o: In function `esdhc_setup_data':
/home/stefano/Projects/imx/u-boot-imx/drivers/mmc/fsl_esdhc.c:193:
undefined reference to `flush_dcache_range'
drivers/mmc/libmmc.o: In function `check_and_invalidate_dcache_range':
/home/stefano/Projects/imx/u-boot-imx/drivers/mmc/fsl_esdhc.c:258:
undefined reference to `invalidate_dcache_range'
make: *** [u-boot] Fehler 1

Main reason is that PowerPC (this is a PowerQuickIII) has a "snooping"
mechanism, and it is enough to set a bit in the SOC to make things working.

Maybe can we add these functions as empty in 85xx ? Or we can add an
intermediate layer in fsl_eshc.h that manage this, such as
fsl_esdhc_flush_dcache_range. This was already done to solve the
endianess problem (PowerPC is big endian).

Andy, what do you think about ?

> 
> AFAIK, blocksize needs to be a multiple of 512 so this should be
> cache-safe with
> any cacheline size.

Yes, I think your changes are correct in the i.MX case.

Best regards,
Stefano

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