linux-kernel - Re: [PATCH V1 1/2] mmc: sdhci: Introduce new quirk to use reserved timeout

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Message-ID: <eddfacfd-ecb6-fda3-5911-48e03046b8d5@intel.com>
Date:   Sun, 24 May 2020 18:57:42 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     sartgarg@...eaurora.org, Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Veerabhadrarao Badiganti <vbadigan@...eaurora.org>,
        Sahitya Tummala <stummala@...eaurora.org>,
        linux-mmc@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        linux-mmc-owner@...r.kernel.org
Subject: Re: [PATCH V1 1/2] mmc: sdhci: Introduce new quirk to use reserved
 timeout

On 19/05/20 5:08 pm, sartgarg@...eaurora.org wrote:
> On 2020-05-18 18:20, Ulf Hansson wrote:
>> On Mon, 18 May 2020 at 13:45, Adrian Hunter <adrian.hunter@...el.com> wrote:
>>>
>>> On 18/05/20 12:39 pm, Ulf Hansson wrote:
>>> > On Wed, 6 May 2020 at 15:53, Sarthak Garg <sartgarg@...eaurora.org> wrote:
>>> >>
>>> >> Introduce a new quirk for letting vendor drivers to use reserved
>>> >> timeout value (0xF) in timeout control register.
>>> >>
>>> >> Signed-off-by: Sahitya Tummala <stummala@...eaurora.org>
>>> >> Signed-off-by: Sarthak Garg <sartgarg@...eaurora.org>
>>> >> ---
>>> >>  drivers/mmc/host/sdhci.c | 3 ++-
>>> >>  drivers/mmc/host/sdhci.h | 5 +++++
>>> >>  2 files changed, 7 insertions(+), 1 deletion(-)
>>> >>
>>> >> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> >> index 1bb6b67..07528a9 100644
>>> >> --- a/drivers/mmc/host/sdhci.c
>>> >> +++ b/drivers/mmc/host/sdhci.c
>>> >> @@ -967,7 +967,8 @@ static u8 sdhci_calc_timeout(struct sdhci_host
>>> *host, struct mmc_command *cmd,
>>> >>         }
>>> >>
>>> >>         if (count >= 0xF) {
>>> >> -               if (!(host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT))
>>> >> +               if (!(host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT) ||
>>> >> +               !(host->quirks2 & SDHCI_QUIRK2_USE_RESERVED_MAX_TIMEOUT))
>>> >
>>> > I don't quite get how this can make your variant use 0xF rather than 0xE?
>>> >
>>> > To me it looks like an updated conditional check to print a debug
>>> message, no?
>>>
>>> Probably need to introduce host->max_timeout_count, set it to 0xE in
>>> sdhci_alloc_host(), and change sdhci_calc_timeout() to use it in place of
>>> all the 0xE and 0xF constants.
>>
>> Yep, that seems like a reasonable approach to me as well.
>>
>> [...]
>>
>> Kind regards
>> Uffe
> 
> Resending the mail again as can't see my comment on the
> https://patchwork.kernel.org/ page.
> Sorry for the mistake just want to update the logic as below.
> -               count = 0xE;
> +               if(!(host->quirks2 & SDHCI_QUIRK2_USE_RESERVED_MAX_TIMEOUT))
> +                       count = 0xE;

I think it is conceptually simpler to define SDHCI constants as variables
and let vendor drivers change them if need be.  In other words, what I wrote
above.  It changes more code, but the overall result is more consistent.