Re: [PATCH V4 5/7] mmc: sdhci: add Auto CMD Auto Select support

[Chunyan Zhang]

On 31 July 2018 at 16:05, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 31/07/18 10:04, Chunyan Zhang wrote:
>> Hi Adrian,
>>
>> On 30 July 2018 at 21:06, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>>> On 23/07/18 13:08, Chunyan Zhang wrote:
>>>> As SD Host Controller Specification v4.10 documents:
>>>> Host Controller Version 4.10 defines this "Auto CMD Auto Select" mode.
>>>> Selection of Auto CMD depends on setting of CMD23 Enable in the Host
>>>> Control 2 register which indicates whether card supports CMD23. If CMD23
>>>> Enable =1, Auto CMD23 is used and if CMD23 Enable =0, Auto CMD12 is
>>>> used. In case of Version 4.10 or later, use of Auto CMD Auto Select is
>>>> recommended rather than use of Auto CMD12 Enable or Auto CMD23
>>>> Enable.
>>>>
>>>> This patch add this new mode support.
>>>>
>>>> Signed-off-by: Chunyan Zhang <zhang.chunyan@xxxxxxxxxx>
>>>> ---
>>>>  drivers/mmc/host/sdhci.c | 61 +++++++++++++++++++++++++++++++++++++++---------
>>>>  drivers/mmc/host/sdhci.h |  2 ++
>>>>  2 files changed, 52 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>> index 5acea3d..5c60590 100644
>>>> --- a/drivers/mmc/host/sdhci.c
>>>> +++ b/drivers/mmc/host/sdhci.c
>>>> @@ -311,6 +311,23 @@ static void sdhci_config_dma(struct sdhci_host *host)
>>>>       sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
>>>>  }
>>>>
>>>> +static void sdhci_enable_cmd23(struct sdhci_host *host)
>>>> +{
>>>> +     u16 ctrl2;
>>>> +
>>>> +     /*
>>>> +      * This is used along with "Auto CMD Auto Select" feature,
>>>> +      * which is introduced from v4.10, if card supports CMD23,
>>>> +      * Auto CMD23 should be used instead of Auto CMD12.
>>>> +      */
>>>> +     if (host->version >= SDHCI_SPEC_410 &&
>>>> +         (host->mmc->caps & MMC_CAP_CMD23)) {
>>>
>>> That is the host capability.  It needs to be the card capability.
>>
>> Could you please elaborate the issue?
>>
>> I thought we're setting for host here.  Do you mean we need to see the
>> card capability?
>
> Yes. SDHCI_TRNS_AUTO_SEL selects auto-CMD23 or auto-CMD12 based on this
> setting, so this must reflect the card's capability.

Got it, but how to know if the card supports CMD23?

>
>>
>>>
>>>> +             ctrl2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
>>>> +             ctrl2 |= SDHCI_CMD23_ENABLE;
>>>> +             sdhci_writew(host, ctrl2, SDHCI_HOST_CONTROL2);
>>>> +     }
>>>> +}
>>>> +
>>>>  static void sdhci_init(struct sdhci_host *host, int soft)
>>>>  {
>>>>       struct mmc_host *mmc = host->mmc;
>>>> @@ -329,6 +346,8 @@ static void sdhci_init(struct sdhci_host *host, int soft)
>>>>               host->clock = 0;
>>>>               mmc->ops->set_ios(mmc, &mmc->ios);
>>>>       }
>>>> +
>>>> +     sdhci_enable_cmd23(host);
>>>>  }
>>>>
>>>>  static void sdhci_reinit(struct sdhci_host *host)
>>>> @@ -1093,6 +1112,36 @@ static inline bool sdhci_auto_cmd12(struct sdhci_host *host,
>>>>              !mrq->cap_cmd_during_tfr;
>>>>  }
>>>>
>>>> +static inline void sdhci_auto_cmd_select(struct sdhci_host *host,
>>>> +                                      struct mmc_command *cmd,
>>>> +                                      u16 *mode)
>>>> +{
>>>> +     bool use_cmd12 = sdhci_auto_cmd12(host, cmd->mrq) &&
>>>> +                      (cmd->opcode != SD_IO_RW_EXTENDED);
>>>> +     bool use_cmd23 = cmd->mrq->sbc && (host->flags & SDHCI_AUTO_CMD23);
>>>> +
>>>> +     /*
>>>> +      * In case of Version 4.10 or later, use of 'Auto CMD Auto
>>>> +      * Select' is recommended rather than use of 'Auto CMD12
>>>> +      * Enable' or 'Auto CMD23 Enable'.
>>>> +      */
>>>> +     if (host->version >= SDHCI_SPEC_410 && (use_cmd12 || use_cmd23)) {
>>>> +             *mode |= SDHCI_TRNS_AUTO_SEL;
>>>
>>> As noted in patch 4, the CMD23 argument is not just the block count for eMMC.
>>
>> Probably I haven't got your point...
>>
>>>From what I understand, auto_sel mode doesn't need argument2. Doesn't
>> this work for eMMC?
>
> CMD23 always needs an argument

But setting argument for CMD23 will cover the block count value we set
before, that will lead mounting emmc to fail.

>
>>
>> The test platform I used was just eMMC only, haven't found problem.
>
> Because the bits that are missing from the CMD23 argument (reliable write,
> context id, etc) will not make the command fail.
>
>>
>> Thanks,
>> Chunyan
>>
>>>
>>>> +             return;
>>>> +     }
>>>> +
>>>> +     /*
>>>> +      * If we are sending CMD23, CMD12 never gets sent
>>>> +      * on successful completion (so no Auto-CMD12).
>>>> +      */
>>>> +     if (use_cmd12) {
>>>> +             *mode |= SDHCI_TRNS_AUTO_CMD12;
>>>> +     } else if (use_cmd23) {
>>>> +             *mode |= SDHCI_TRNS_AUTO_CMD23;
>>>> +             sdhci_writel(host, cmd->mrq->sbc->arg, SDHCI_ARGUMENT2);
>>>> +     }
>>>> +}
>>>> +
>>>>  static void sdhci_set_transfer_mode(struct sdhci_host *host,
>>>>       struct mmc_command *cmd)
>>>>  {
>>>> @@ -1119,17 +1168,7 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host,
>>>>
>>>>       if (mmc_op_multi(cmd->opcode) || data->blocks > 1) {
>>>>               mode = SDHCI_TRNS_BLK_CNT_EN | SDHCI_TRNS_MULTI;
>>>> -             /*
>>>> -              * If we are sending CMD23, CMD12 never gets sent
>>>> -              * on successful completion (so no Auto-CMD12).
>>>> -              */
>>>> -             if (sdhci_auto_cmd12(host, cmd->mrq) &&
>>>> -                 (cmd->opcode != SD_IO_RW_EXTENDED))
>>>> -                     mode |= SDHCI_TRNS_AUTO_CMD12;
>>>> -             else if (cmd->mrq->sbc && (host->flags & SDHCI_AUTO_CMD23)) {
>>>> -                     mode |= SDHCI_TRNS_AUTO_CMD23;
>>>> -                     sdhci_writel(host, cmd->mrq->sbc->arg, SDHCI_ARGUMENT2);
>>>> -             }
>>>> +             sdhci_auto_cmd_select(host, cmd, &mode);
>>>>       }
>>>>
>>>>       if (data->flags & MMC_DATA_READ)
>>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>>> index 81aae07..a8f4ec2 100644
>>>> --- a/drivers/mmc/host/sdhci.h
>>>> +++ b/drivers/mmc/host/sdhci.h
>>>> @@ -42,6 +42,7 @@
>>>>  #define  SDHCI_TRNS_BLK_CNT_EN       0x02
>>>>  #define  SDHCI_TRNS_AUTO_CMD12       0x04
>>>>  #define  SDHCI_TRNS_AUTO_CMD23       0x08
>>>> +#define  SDHCI_TRNS_AUTO_SEL 0x0C
>>>>  #define  SDHCI_TRNS_READ     0x10
>>>>  #define  SDHCI_TRNS_MULTI    0x20
>>>>
>>>> @@ -185,6 +186,7 @@
>>>>  #define   SDHCI_CTRL_DRV_TYPE_D              0x0030
>>>>  #define  SDHCI_CTRL_EXEC_TUNING              0x0040
>>>>  #define  SDHCI_CTRL_TUNED_CLK                0x0080
>>>> +#define  SDHCI_CMD23_ENABLE          0x0800
>>>>  #define  SDHCI_CTRL_V4_MODE          0x1000
>>>>  #define  SDHCI_CTRL_64BIT_ADDR               0x2000
>>>>  #define  SDHCI_CTRL_PRESET_VAL_ENABLE        0x8000
>>>>
>>>
>>
>