Re: [PATCH V4 06/11] mmc: mmc: Enable Command Queuing

Ulf Hansson
2017-08-07T14:34:10Z

On 21 July 2017 at 11:49, Adrian Hunter <adrian.hunter@intel.com> wrote:
> Enable the Command Queue if the host controller supports i a command queue

Perhaps clarify the above to:
Enable the eMMC Command Queue if the card supports it and if the host
controller also supports the command queue engine.

> engine. It is not compatible with Packed Commands, so do not enable that
> at the same time.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
> drivers/mmc/core/mmc.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 4ffea14b7eb6..2ff0caf92bc8 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1783,6 +1783,20 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
> }
> }
>
> + /* Enable Command Queue if supported */
> + 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;
> + 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
> @@ -1796,7 +1810,8 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
> */
> if (card->ext_csd.max_packed_writes >= 3 &&
> card->ext_csd.max_packed_reads >= 5 &&
> - host->caps2 & MMC_CAP2_PACKED_CMD) {
> + host->caps2 & MMC_CAP2_PACKED_CMD &&

There are currently no host using MMC_CAP2_PACKED_CMD and we have
recently removed the support for it in the mmc block device layer.
It turned out we still have some leftovers. Would you mind folding in
a cleanup patch removing the support for packed command altogether and
adopt this change to it?

I guess adding a comment that CMDQ can't be used together with packed
command is still relevant. Especially if we would consider re-adding
the support for it.

> + !card->ext_csd.cmdq_en) {
> err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_EXP_EVENTS_CTRL,
> EXT_CSD_PACKED_EVENT_EN,
> --
> 1.9.1
>

Kind regards
Uffe