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

From: Chunyan Zhang
Date: Wed Aug 01 2018 - 05:27:11 EST

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On 31 July 2018 at 17:36, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 31/07/18 12:20, Chunyan Zhang wrote:
>> On 31 July 2018 at 16:56, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>>> On 31/07/18 11:36, Chunyan Zhang wrote:
>>>> 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?
>>>
>>> At the moment the only way of knowing is if a request is received with mrq->sbc
>>>
>>>>
>>>>>
>>>>>>
>>>>>>>
>>>>>>>> + 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.
>>>
>>> Does it fail because it contains cmd->mrq->sbc->arg or does it fail because
>>> it gets written twice?
>>
>> Seems that the argument is too big compared with block count, hardware
>> think it is a super block count.
>>
>> More details of the error information:
>> https://www.irccloud.com/pastebin/uYlVEUsP/
>
> Does it work with auto-CMD23 instead of auto-CMD-auto-select?

No, so long as SDHCI_32BIT_BLK_CNT was set with cmd->mrq->sbc->arg
which is a big value, it would report error "I/O error while writing
superblock" when mounting emmc.

> Does it work if the 16-bit block count register is used?

16-bit block count register is Read Only on my board :-(

>
> Obviously, if we can't pass the CMD23 argument correctly then we can't use
> auto-CMD23.

On my board, if argument2 was limited to the maximum of 65535, then
everything works, otherwise I would see an error "EXT4-fs
(mmcblk0p28): I/O error while writing superblock". Haven't found the
root cause. I will continue to look at the problem, any comments would
be appreciated.

Thanks,
Chunyan

>
>>
>>>
>>>>
>>>>>
>>>>>>
>>>>>> 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
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>

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