On 22/03/21 3:36 pm, Avri Altman wrote:
> The cache may be flushed to the nonvolatile storage by writing to
> FLUSH_CACHE byte (EXT_CSD byte [32]). When in command queueing mode, the
> cache may be flushed by issuing a CMDQ_TASK_ DEV_MGMT (CMD48) with a
> FLUSH_CACHE op-code. Either way, verify that The cache function is
> turned ON before doing so.
>
> fixes: 1e8e55b67030 (mmc: block: Add CQE support)
>
> Reported-by: Brendan Peter <bpe...@lytx.com>
> Tested-by: Brendan Peter <bpe...@lytx.com>
> Signed-off-by: Avri Altman <avri.alt...@wdc.com>
> ---
> drivers/mmc/core/block.c | 3 +++
> drivers/mmc/core/mmc_ops.c | 4 +---
> drivers/mmc/core/mmc_ops.h | 5 +++++
> 3 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index 42e27a298218..a93c66aa91db 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -1473,6 +1473,9 @@ static int mmc_blk_cqe_issue_flush(struct mmc_queue
> *mq, struct request *req)
> struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
> struct mmc_request *mrq = mmc_blk_cqe_prep_dcmd(mqrq, req);
>
> + if (mmc_card_mmc(mq->card) && !mmc_flush_allowed(mq->card))
> + return 0;
Returning 0 means the flush was issued successfully. i.e. it is in
flight.
Instead, a call to blk_mq_end_request(req, BLK_STS_OK) is needed,
and mmc_blk_mq_issue_rq() must be amended so that it will return
MMC_REQ_DONE for this case.
> +
> mrq->cmd->opcode = MMC_SWITCH;
> mrq->cmd->arg = (MMC_SWITCH_MODE_WRITE_BYTE << 24) |
> (EXT_CSD_FLUSH_CACHE << 16) |
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index baa6314f69b4..b8a0c9ac8a20 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -988,9 +988,7 @@ int mmc_flush_cache(struct mmc_card *card)
> {
> int err = 0;
>
> - if (mmc_card_mmc(card) &&
> - (card->ext_csd.cache_size > 0) &&
> - (card->ext_csd.cache_ctrl & 1)) {
> + if (mmc_card_mmc(card) && mmc_flush_allowed(card)) {
> err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_FLUSH_CACHE, 1,
> MMC_CACHE_FLUSH_TIMEOUT_MS);
> diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h
> index 632009260e51..bf2b315addd7 100644
> --- a/drivers/mmc/core/mmc_ops.h
> +++ b/drivers/mmc/core/mmc_ops.h
> @@ -19,6 +19,11 @@ enum mmc_busy_cmd {
> struct mmc_host;
> struct mmc_card;
>
> +static inline bool mmc_flush_allowed(struct mmc_card *card)
> +{
> + return card->ext_csd.cache_size > 0 && (card->ext_csd.cache_ctrl & 1);
> +}
> +
> int mmc_select_card(struct mmc_card *card);
> int mmc_deselect_cards(struct mmc_host *host);
> int mmc_set_dsr(struct mmc_host *host);
>
