Re: [RFC PATCH 2/2] Make cmdq_en attribute writeable

[Ulf Hansson <ulf.hansson@linaro.org>]

+ Adrian

On Mon, 15 Feb 2021 at 01:33, Luca Porzio <porzio@gmail.com> wrote:
>
> cmdq_en attribute in sysfs now can now be written.
> When 0 is written:
>   CMDQ is disabled and kept disabled across device reboots.
> When 1 is written:
>   CMDQ mode is instantly reneabled (if supported).
>
> Signed-off-by: Luca Porzio <lporzio@micron.com>
> Signed-off-by: Zhan Liu <zliua@micron.com>

Luca, thanks for your patch! I am about to start to review this.

I have also looped in Adrian to get his opinions.

Get back to you soon!

Kind regards
Uffe

> ---
>  drivers/mmc/core/mmc.c   | 152 ++++++++++++++++++++++++++++++---------
>  include/linux/mmc/card.h |   1 +
>  2 files changed, 118 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 0d80b72ddde8..5c7d5bac5c00 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -794,7 +794,120 @@ MMC_DEV_ATTR(enhanced_rpmb_supported, "%#x\n",
>  MMC_DEV_ATTR(rel_sectors, "%#x\n", card->ext_csd.rel_sectors);
>  MMC_DEV_ATTR(ocr, "0x%08x\n", card->ocr);
>  MMC_DEV_ATTR(rca, "0x%04x\n", card->rca);
> -MMC_DEV_ATTR(cmdq_en, "%d\n", card->ext_csd.cmdq_en);
> +
> +
> +/* Setup command queue mode and CQE if underling hw supports it
> + * and assuming force_disable_cmdq has not been set.
> + */
> +static int mmc_cmdq_setup(struct mmc_host *host, struct mmc_card *card)
> +{
> +       int err;
> +
> +       /* Check HW support */
> +       if (!card->ext_csd.cmdq_support || !(host->caps2 & MMC_CAP2_CQE))
> +               card->force_disable_cmdq = true;
> +
> +       /* Enable/Disable  CMDQ mode */
> +       if (!card->ext_csd.cmdq_en && !card->force_disable_cmdq) {
> +               err = mmc_cmdq_enable(card);
> +               if (err && err != -EBADMSG)
> +                       return err;
> +               if (err) {
> +                       pr_warn("%s: Enabling CMDQ failed\n",
> +                           mmc_hostname(card->host));
> +                       card->ext_csd.cmdq_support = false;
> +                       card->ext_csd.cmdq_depth = 0;
> +               }
> +
> +       } else if (card->ext_csd.cmdq_en && card->force_disable_cmdq) {
> +               err = mmc_cmdq_disable(card);
> +               if (err) {
> +                       pr_warn("%s: Disabling CMDQ failed, error %d\n",
> +                           mmc_hostname(card->host), err);
> +                       err = 0;
> +               }
> +       }
> +
> +       /*
> +        * In some cases (e.g. RPMB or mmc_test), the Command Queue must be
> +        * disabled for a time, so a flag is needed to indicate to re-enable the
> +        * Command Queue.
> +        */
> +       card->reenable_cmdq = card->ext_csd.cmdq_en;
> +
> +       /* Enable/Disable Host CQE */
> +       if (!card->force_disable_cmdq) {
> +
> +               if (host->cqe_ops && !host->cqe_enabled) {
> +                       err = host->cqe_ops->cqe_enable(host, card);
> +                       if (!err) {
> +                               host->cqe_enabled = true;
> +
> +                               if (card->ext_csd.cmdq_en) {
> +                                       pr_info("%s: Command Queue Engine enabled\n",
> +                                           mmc_hostname(host));
> +                               } else {
> +                                       host->hsq_enabled = true;
> +                                       pr_info("%s: Host Software Queue enabled\n",
> +                                           mmc_hostname(host));
> +                               }
> +                       }
> +               }
> +
> +       } else {
> +
> +               if (host->cqe_enabled) {
> +                       host->cqe_ops->cqe_disable(host);
> +                       host->cqe_enabled = false;
> +                       pr_info("%s: Command Queue Engine disabled\n",
> +                           mmc_hostname(host));
> +               }
> +
> +               host->hsq_enabled = false;
> +               err = 0;
> +       }
> +
> +       return err;
> +}
> +
> +
> +static ssize_t cmdq_en_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +       struct mmc_card *card = mmc_dev_to_card(dev);
> +
> +       return sprintf(buf, "%d\n", card->ext_csd.cmdq_en);
> +}
> +
> +static ssize_t cmdq_en_store(struct device *dev, struct device_attribute *attr,
> +                                const char *buf, size_t count)
> +{
> +       struct mmc_card *card = mmc_dev_to_card(dev);
> +       struct mmc_host *host = card->host;
> +       unsigned long enable;
> +       int err;
> +
> +       if (!card || kstrtoul(buf, 0, &enable))
> +               return -EINVAL;
> +       if (!card->ext_csd.cmdq_support)
> +               return -EOPNOTSUPP;
> +
> +       enable = !!enable;
> +       if (enable == card->ext_csd.cmdq_en)
> +               return count;
> +
> +       mmc_get_card(card, NULL);
> +       card->force_disable_cmdq = !enable;
> +       err = mmc_cmdq_setup(host, card);
> +       mmc_put_card(card, NULL);
> +
> +       if (err)
> +               return err;
> +       else
> +               return count;
> +}
> +
> +static DEVICE_ATTR_RW(cmdq_en);
> +
>
>  static ssize_t mmc_fwrev_show(struct device *dev,
>                               struct device_attribute *attr,
> @@ -1838,40 +1951,9 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
>          * Enable Command Queue if supported. Note that Packed Commands cannot
>          * be used with Command Queue.
>          */
> -       card->ext_csd.cmdq_en = false;
> -       if (card->ext_csd.cmdq_support && host->caps2 & MMC_CAP2_CQE) {
> -               err = mmc_cmdq_enable(card);
> -               if (err && err != -EBADMSG)
> -                       goto free_card;
> -               if (err) {
> -                       pr_warn("%s: Enabling CMDQ failed\n",
> -                               mmc_hostname(card->host));
> -                       card->ext_csd.cmdq_support = false;
> -                       card->ext_csd.cmdq_depth = 0;
> -               }
> -       }
> -       /*
> -        * In some cases (e.g. RPMB or mmc_test), the Command Queue must be
> -        * disabled for a time, so a flag is needed to indicate to re-enable the
> -        * Command Queue.
> -        */
> -       card->reenable_cmdq = card->ext_csd.cmdq_en;
> -
> -       if (host->cqe_ops && !host->cqe_enabled) {
> -               err = host->cqe_ops->cqe_enable(host, card);
> -               if (!err) {
> -                       host->cqe_enabled = true;
> -
> -                       if (card->ext_csd.cmdq_en) {
> -                               pr_info("%s: Command Queue Engine enabled\n",
> -                                       mmc_hostname(host));
> -                       } else {
> -                               host->hsq_enabled = true;
> -                               pr_info("%s: Host Software Queue enabled\n",
> -                                       mmc_hostname(host));
> -                       }
> -               }
> -       }
> +       err = mmc_cmdq_setup(host, card);
> +       if (err)
> +               goto free_card;
>
>         if (host->caps2 & MMC_CAP2_AVOID_3_3V &&
>             host->ios.signal_voltage == MMC_SIGNAL_VOLTAGE_330) {
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index f9ad35dd6012..e554bb0cf722 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -272,6 +272,7 @@ struct mmc_card {
>  #define MMC_QUIRK_BROKEN_HPI   (1<<13)         /* Disable broken HPI support */
>
>         bool                    reenable_cmdq;  /* Re-enable Command Queue */
> +       bool                    force_disable_cmdq; /* Keep Command Queue disabled */
>
>         unsigned int            erase_size;     /* erase size in sectors */
>         unsigned int            erase_shift;    /* if erase unit is power 2 */
> --
> 2.17.1
>