[U-Boot] [PATCH V2 1/2] cmd_mmc: eliminate device num in the mmc command

[Andy Fleming]

On Wed, Apr 27, 2011 at 2:12 PM, Wolfgang Denk <wd at denx.de> wrote:
> Dear Andy Fleming,
>
> In message <BANLkTimmtV9L9P75A-PLez5rhVy4hYg=gA at mail.gmail.com> you wrote:
>>
>> > From now on, follow the general rule "mmc dev [dev]" to change the
>> > mmc command applied device, like ide and usb...
> ...
>> I'd really prefer if there were still the option to specify the device
>> in the read/write commands. I appreciate the convenience of not having
>> to specify it every time, but I feel that by doing things this way, we
>> create an artificial separation between a transaction, and the target
>> of the transaction. It tends to encourage a notion that a transaction
>> can only be done to the global-current device, which is fine for
>> command-line interfaces, but can result in broken programming
>> interfaces
>
> PLease see the preceeding thread for the reasons for this interface
> (make it the same as what we have with USB, IDE, etc.).
>
> Yes, it is not a nice one.  We really want a beter device model.


I'm fine with supporting a consistent interface, but I think what I'm
suggesting doesn't break that.  After all, if we follow my suggestion,
one can quite happily pretend that the command line interface
requires:

mmc dev x:y
mmc read <addr> <blk> <cnt>

It's just that the other way would also be possible. I re-read the
thread where this was discussed, and while I definitely agree that the
originally proposed solution was highly error-prone, I think
*allowing* users to do this is fine:

mmc read <dev>:<part> <addr> <blk> <cnt>

Is there a reason that this wouldn't work with the current model?

Andy