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

[Chunyan Zhang]

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?

>
>> +             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?

The test platform I used was just eMMC only, haven't found problem.

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
>>
>