[U-Boot] [RFC PATCH 2/2] mmc: add support for block device cache

Simon Glass
2016-04-09T17:55:27Z

Hi Eric,

On 20 March 2016 at 16:54, Eric Nelson <eric@nelint.com> wrote:
> Hi Tom,
>
> On 03/20/2016 03:13 PM, Tom Rini wrote:
>> On Sun, Mar 20, 2016 at 12:35:53PM -0700, Eric Nelson wrote:
>>> Hi Stephen,
>>>
>>> On 03/17/2016 02:23 PM, Stephen Warren wrote:
>>>> On 03/16/2016 03:40 PM, Eric Nelson wrote:
>>>>> Signed-off-by: Eric Nelson <eric@nelint.com>
>>>>
>>>> Patch description.
>>>>
>>>>> ---
>>>>> drivers/mmc/mmc.c | 10 +++++++++-
>>>>> drivers/mmc/mmc_write.c | 7 +++++++
>>>>
>>>> Presumably it makes sense for the cache to work for IDE, SATA, USB,
>>>> SCSI, ... too. I wonder if it's possible to put this code somewhere more
>>>> central than mmc*.c so it automatically applies to
>>>> dev_desc->block_read() (see include/part.h). Perhaps not since each
>>>> implementation supplies its own block_read function directly, so the
>>>> cache calls do need to be duplicated everywhere.
>>>>
>>>
>>> Yeah. I haven't found a spot that would allow interception of
>>> the various block_read/write functions.
>>
>> Shouldn't DM also help here?
>>
>
> I haven't yet looked, but this may be true.
>
> I'm seeing some build breakage on master surrounding the use
> of DM though.
>
> If I select DM and BLK on top of nitrogen6q_defconfig, I get
> lots of build errors.
>
> I want to get a V2 RFC patch out before digging through the
> details of that.

I'm about to send out a series that rationalises the block devices a
bit. In the meantime, see u-boot-dm/blkb-working for some MMC ideas.

Regards,
Simon