[PATCH 02/18] mmc: meson-gx: remove code for unsupported CMD23

[Heiner Kallweit]

Am 16.02.2017 um 09:14 schrieb Ulf Hansson:
> On 16 February 2017 at 08:03, Heiner Kallweit <hkallweit1 at gmail.com> wrote:
>> Am 15.02.2017 um 17:54 schrieb Kevin Hilman:
>>> Heiner Kallweit <hkallweit1 at gmail.com> writes:
>>>
>>>> CMD23 isn't supported on meson-gx and therefore the "set block count"
>>>> command isn't used. So remove this dead code.
>>>
>>> I'm admittedly a bit unfamiliar with the MMC spec and wrote this driver
>>> mostly by looking at the vendor driver, so forgive the silly
>>> questions...
>>>
>>> Why isn't CMD23 supported, and should we support instead of deleting
>>> this support?
>>>
>> As far as I understand this needs to be supported by the host controller.
>> And setting the respective host flag to enable CMD23 mode lead to a
>> non-working driver when testing on my system.
> 
> CMD23 can be supported by the host *driver*, you don't need HW-support
> to implement this.
> 
Thanks for the explanation. I think I got confused by this comment in
core/block.c: "If CMD23 is supported by card and host, [..]"
I interpreted this as "host controller needs to support this feature".

> You may for example be inspired by the mmci.c driver to understand how
> to implement this. Looks for "mrq->sbc".
> 
> [...]
> 
> Kind regards
> Uffe
>