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

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Date:   Mon, 18 May 2020 14:46:02 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>,
        Sarthak Garg <sartgarg@...eaurora.org>
Cc:     Veerabhadrarao Badiganti <vbadigan@...eaurora.org>,
        Sahitya Tummala <stummala@...eaurora.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH V1 1/2] mmc: sdhci: Introduce new quirk to use reserved
 timeout

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.

> 
>>                         DBG("Too large timeout 0x%x requested for CMD%d!\n",
>>                             count, cmd->opcode);
>>                 count = 0xE;
>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>> index 8d2a096..02f8779 100644
>> --- a/drivers/mmc/host/sdhci.h
>> +++ b/drivers/mmc/host/sdhci.h
>> @@ -476,6 +476,11 @@ struct sdhci_host {
>>   * block count.
>>   */
>>  #define SDHCI_QUIRK2_USE_32BIT_BLK_CNT                 (1<<18)
>> +/*
>> + * Some controllers define the usage of 0xF in data timeout counter
>> + * register (0x2E) which is actually a reserved bit as per specification.
>> + */
>> +#define SDHCI_QUIRK2_USE_RESERVED_MAX_TIMEOUT          (1<<19)
>>
>>         int irq;                /* Device IRQ */
>>         void __iomem *ioaddr;   /* Mapped address */
>> --
>> 2.7.4
>>
> 
> Kind regards
> Uffe
>