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 <bpeter@xxxxxxxx> Tested-by: Brendan Peter <bpeter@xxxxxxxx> Signed-off-by: Avri Altman <avri.altman@xxxxxxx> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> --- drivers/mmc/core/block.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 6cd5d03bcc64..e3062bbf110e 100644 --- a/drivers/mmc/core/block.c +++ b/drivers/mmc/core/block.c @@ -2198,6 +2198,11 @@ static int mmc_blk_wait_for_idle(struct mmc_queue *mq, struct mmc_host *host) return mmc_blk_rw_wait(mq, NULL); } +static bool mmc_blk_cache_disabled(struct mmc_host *host) +{ + return !mmc_cache_enabled(host); +} + enum mmc_issued mmc_blk_mq_issue_rq(struct mmc_queue *mq, struct request *req) { struct mmc_blk_data *md = mq->blkdata; @@ -2237,6 +2242,10 @@ enum mmc_issued mmc_blk_mq_issue_rq(struct mmc_queue *mq, struct request *req) case MMC_ISSUE_ASYNC: switch (req_op(req)) { case REQ_OP_FLUSH: + if (mmc_blk_cache_disabled(host)) { + blk_mq_end_request(req, BLK_STS_OK); + return MMC_REQ_FINISHED; + } ret = mmc_blk_cqe_issue_flush(mq, req); break; case REQ_OP_READ: -- 2.25.1