[PATCH 1/2] mmc: core: use card pointer as the first parameter of execute_tuning()

Ulf Hansson ulf.hansson at linaro.org
Tue Jan 27 07:18:06 PST 2015

On 26 January 2015 at 18:45, Doug Anderson <dianders at chromium.org> wrote:
> Ulf,
> On Mon, Jan 26, 2015 at 7:15 AM, Ulf Hansson <ulf.hansson at linaro.org> wrote:
>> On 26 January 2015 at 12:19, Addy Ke <addy.ke at rock-chips.com> wrote:
>>> We need to take the card pointer in execute_tuning() for mmc_send_status(),
>> mmc_send_status() is an mmc core function, not intended for host's to call.
>>> but mmc->card is NULL in tuning state. So we need change the first parameter
>>> of execute_tuning() to card pointer(struct mmc_card * card).
>> So, why do we need this?
> I asked Addy to post upstream against mmc_send_tuning(), but I guess
> he didn't (he posted against Alex's NAKed patch instead).
> ...when I talked to him about it, Addy was asserting that when tuning
> fails it is important (at least on dw_mmc on rk3288) that we wait for
> the card to stop being busy and that the way to detect was using
> mmc_send_status().

So, could that be due to the internal logic of the error handling in
dw_mmc driver? Or you think this is a generic issue?

According to the specifications (eMMC and SD) both states that the
tuning command has an R1 response. So, there shouldn't be any busy
signalling involved - at least according to spec.

> That would mean that against upstream you'd need to change
> mmc_send_tuning() to take in the card as well (or move the "host->card
> = card" assignment to before UHS init, which seems less desirable?)
> What do you think about that?  Is there a better solution?

Why do we need to change mmc_send_tuning()? I thought the issue was
that mmc_send_status(), which currently takes "card" as a parameter.

Kind regards

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