Re: [PATCH V7 10/25] mmc: mmc: Add functions to enable / disable the Command Queue

[Ritesh Harjani <riteshh@codeaurora.org>]

On 11/25/2016 3:37 PM, Adrian Hunter wrote:
> Add helper functions to enable or disable the Command Queue.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
>  Documentation/mmc/mmc-dev-attrs.txt |  1 +
>  drivers/mmc/core/mmc.c              |  2 ++
>  drivers/mmc/core/mmc_ops.c          | 27 +++++++++++++++++++++++++++
>  include/linux/mmc/card.h            |  1 +
>  include/linux/mmc/core.h            |  2 ++
>  5 files changed, 33 insertions(+)
>
> diff --git a/Documentation/mmc/mmc-dev-attrs.txt b/Documentation/mmc/mmc-dev-attrs.txt
> index 404a0e9e92b0..dcd1252877fb 100644
> --- a/Documentation/mmc/mmc-dev-attrs.txt
> +++ b/Documentation/mmc/mmc-dev-attrs.txt
> @@ -30,6 +30,7 @@ All attributes are read-only.
>  	rel_sectors		Reliable write sector count
>  	ocr 			Operation Conditions Register
>  	dsr			Driver Stage Register
> +	cmdq_en			Command Queue enabled: 1 => enabled, 0 => not enabled
>
>  Note on Erase Size and Preferred Erase Size:
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 6e9830997eef..d6a30bbd399d 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -770,6 +770,7 @@ static int mmc_compare_ext_csds(struct mmc_card *card, unsigned bus_width)
>  MMC_DEV_ATTR(raw_rpmb_size_mult, "%#x\n", card->ext_csd.raw_rpmb_size_mult);
>  MMC_DEV_ATTR(rel_sectors, "%#x\n", card->ext_csd.rel_sectors);
>  MMC_DEV_ATTR(ocr, "%08x\n", card->ocr);
> +MMC_DEV_ATTR(cmdq_en, "%d\n", card->ext_csd.cmdq_en);
>
>  static ssize_t mmc_fwrev_show(struct device *dev,
>  			      struct device_attribute *attr,
> @@ -823,6 +824,7 @@ static ssize_t mmc_dsr_show(struct device *dev,
>  	&dev_attr_rel_sectors.attr,
>  	&dev_attr_ocr.attr,
>  	&dev_attr_dsr.attr,
> +	&dev_attr_cmdq_en.attr,
>  	NULL,
>  };
>  ATTRIBUTE_GROUPS(mmc_std);
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 9b2617cfff67..92a1de9b4981 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -824,3 +824,30 @@ int mmc_can_ext_csd(struct mmc_card *card)
>  {
>  	return (card && card->csd.mmca_vsn > CSD_SPEC_VER_3);
>  }
> +
> +int mmc_cmdq_switch(struct mmc_card *card, int enable)
> +{
> +	int err;
> +
> +	if (!card->ext_csd.cmdq_support)
> +		return -EOPNOTSUPP;
> +
> +	err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_CMDQ_MODE_EN,
> +			 enable, card->ext_csd.generic_cmd6_time);
> +	if (!err)
> +		card->ext_csd.cmdq_en = enable;
> +
> +	return err;
> +}
> +
> +int mmc_cmdq_enable(struct mmc_card *card)
> +{
> +	return mmc_cmdq_switch(card, EXT_CSD_CMDQ_MODE_ENABLED);

EXT_CSD_CMDQ_MODE_ENABLED is defined as a BIT(0), but getting used here 
as a value of 1. EXT_CSD_CMDQ_MODE_ENABLED seems redundant anyways.
Do you think we can remove it and pass 1 directly?

> +}
> +EXPORT_SYMBOL_GPL(mmc_cmdq_enable);
> +
> +int mmc_cmdq_disable(struct mmc_card *card)
> +{
> +	return mmc_cmdq_switch(card, 0);
> +}
> +EXPORT_SYMBOL_GPL(mmc_cmdq_disable);
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 95d69d498296..2d9c24f4e88e 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -89,6 +89,7 @@ struct mmc_ext_csd {
>  	unsigned int		boot_ro_lock;		/* ro lock support */
>  	bool			boot_ro_lockable;
>  	bool			ffu_capable;	/* Firmware upgrade support */
> +	bool			cmdq_en;	/* Command Queue enabled */
>  	bool			cmdq_support;	/* Command Queue supported */
>  	unsigned int		cmdq_depth;	/* Command Queue depth */
>  #define MMC_FIRMWARE_LEN 8
> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> index 0ce928b3ce90..d045b06fc7ea 100644
> --- a/include/linux/mmc/core.h
> +++ b/include/linux/mmc/core.h
> @@ -177,6 +177,8 @@ extern int mmc_wait_for_app_cmd(struct mmc_host *, struct mmc_card *,
>  extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int);
>  extern int mmc_send_tuning(struct mmc_host *host, u32 opcode, int *cmd_error);
>  extern int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd);
> +extern int mmc_cmdq_enable(struct mmc_card *card);
> +extern int mmc_cmdq_disable(struct mmc_card *card);
>
>  #define MMC_ERASE_ARG		0x00000000
>  #define MMC_SECURE_ERASE_ARG	0x80000000
>

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