[PATCH v4] mmc: meson: Add driver for the SD/MMC host found on Amlogic MesonX SoCs

[Carlo Caione]

On Tue, Feb 2, 2016 at 12:21 PM, Ulf Hansson <ulf.hansson at linaro.org> wrote:
> On 1 February 2016 at 23:05, Carlo Caione <carlo at caione.org> wrote:
>> On Tue, Dec 8, 2015 at 9:35 PM, Ulf Hansson <ulf.hansson at linaro.org> wrote:

[cut]

>> I still fail to see what the correct behaviour should be.
>> Using the v4 of this driver with a "broken-cd" binding and a timeout
>> of 10s my SD card takes 30s to be identified as removed after I take
>> it out from the SD slot.
>> Also, if I take it out and insert it again, I still have to wait 30s
>> to be able to access it again. Is this a limitation / bug of my driver
>> or is this the expected behaviour when we do not have a dedicated GPIO
>> for card detection?
>
> It's *not* an expected a behaviour.
>
> Using MMC_CAP_NEEDS_POLL, means that the mmc core will send CMD13
> commands in a polling manner to find out whether a card has been
> removed.
>
> It seems like when the card is removed, the host driver doesn't get an
> IRQ which indicates a command timeout. Instead it waits for the 10 s
> timeout to expire.
>
> My question is then; why don't the driver get an IRQ for the command
> timeout? Is that because of non-correct setup of the IRQ masks or
> because the controller HW doesn't support this?

I just verified that apparently the HW doesn't support this (no
register for commands timeout and no IRQ generated).
Anything wrong with implementing this in software with a timer on
mrq->data->timeout_ns?

-- 
Carlo Caione