[U-Boot] [PATCH v2 3/7] drivers: block: disk-uclass: implement scsi_init()

[Simon Glass]

Hi Muganthan,

On 8 February 2016 at 04:23, Mugunthan V N <mugunthanvnm at ti.com> wrote:
> On Sunday 07 February 2016 01:59 AM, Simon Glass wrote:
>> Hi Bin,
>>
>> On 3 February 2016 at 04:59, Mugunthan V N <mugunthanvnm at ti.com> wrote:
>>>
>>> Implement scsi_init() api to probe driver model based sata
>>> devices.
>>>
>>> Signed-off-by: Mugunthan V N <mugunthanvnm at ti.com>
>>> ---
>>>  drivers/block/disk-uclass.c | 39 +++++++++++++++++++++++++++++++++++++++
>>>  1 file changed, 39 insertions(+)
>>
>> This patch seems odd to me. I would hope that scsi_init() would go
>> away with driver model and it would happen as part of the controller
>> probe. But of course we cannot probe SCSI from UCLASS_DISK. I think
>> the uclass 'disk' is too broad to be useful.
>>
>> So I am wondering whether the decision to use UCLASS_DISK instead of
>> UCLASS_AHCI was a mistake.
>>
>> Perhaps instead we should have:
>>
>> UCLASS_AHCI
>> UCLASS_SCSI
>> UCLASS_MMC
>> etc...
>>
>> and each of these devices can have a UCLASS_BLK under them (the block device).
>>
>> Possibly we could even have a dummy UCLASS_DISK device under each of
>> the above, but I'm not sure that is useful.
>>
>> What do you think?
>>
>
> Hmmm, this sounds a better approach to me also. So that we can abstract
> all bulk related activities to UCLASS_BLK. I can do an RFC if you are okay?

I have been working on a block uclass and tidying up the partition
stuff. I'll see if I can get patches out next week. In the meantime
I'd like to get comments from Bin and others about this too.

I suspect we will end up apply what you have (or similar) for this
release, but I'd like to figure out the best approach here.

Thinking about it more I suggest this:

UCLASS_AHCI / SCSI / MMC etc. for the controllers
each with a UCLASS_DISK child device for each disk attached to the controller
each with a (single) UCLASS_BLK child device

>
> Regards
> Mugunthan V N
>

Regards,
Simon