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Message-ID: <23282747-4ae1-d627-a537-590b9315b941@intel.com>
Date: Tue, 31 Jul 2018 11:56:27 +0300
From: Adrian Hunter <adrian.hunter@...el.com>
To: Chunyan Zhang <zhang.lyra@...il.com>
Cc: Chunyan Zhang <zhang.chunyan@...aro.org>,
Ulf Hansson <ulf.hansson@...aro.org>,
linux-mmc@...r.kernel.org,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Orson Zhai <orsonzhai@...il.com>,
Baolin Wang <baolin.wang@...aro.org>,
Billows Wu <billows.wu@...eadtrum.com>,
Jason Wu <jason.wu@...soc.com>
Subject: Re: [PATCH V4 5/7] mmc: sdhci: add Auto CMD Auto Select support
On 31/07/18 11:36, Chunyan Zhang wrote:
> On 31 July 2018 at 16:05, Adrian Hunter <adrian.hunter@...el.com> wrote:
>> On 31/07/18 10:04, Chunyan Zhang wrote:
>>> Hi Adrian,
>>>
>>> On 30 July 2018 at 21:06, Adrian Hunter <adrian.hunter@...el.com> 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@...aro.org>
>>>>> ---
>>>>> 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?
>
>>
>>>
>>> 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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