[PATCH] mmc: fix mmc dma operation

From: Jianxin Pan
Date: Mon Oct 21 2019 - 01:59:09 EST


From: Nan Li <nan.li@xxxxxxxxxxx>

In MMC dma transfer, the region requested by dma_map_sg() may be released
by dma_unmap_sg() before the transfer is completed.

Put the unmap operation in front of mmc_request_done() to avoid this.

Signed-off-by: Nan Li <nan.li@xxxxxxxxxxx>
Signed-off-by: Jianxin Pan <jianxin.pan@xxxxxxxxxxx>
---
drivers/mmc/host/meson-gx-mmc.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index e712315..7667e8a 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -173,6 +173,7 @@ struct meson_host {
int irq;

bool vqmmc_enabled;
+ bool needs_pre_post_req;
};

#define CMD_CFG_LENGTH_MASK GENMASK(8, 0)
@@ -654,6 +655,8 @@ static void meson_mmc_request_done(struct mmc_host *mmc,
struct meson_host *host = mmc_priv(mmc);

host->cmd = NULL;
+ if (host->needs_pre_post_req)
+ meson_mmc_post_req(mmc, mrq, 0);
mmc_request_done(host->mmc, mrq);
}

@@ -803,25 +806,23 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
struct meson_host *host = mmc_priv(mmc);
- bool needs_pre_post_req = mrq->data &&
+
+ host->needs_pre_post_req = mrq->data &&
!(mrq->data->host_cookie & SD_EMMC_PRE_REQ_DONE);

- if (needs_pre_post_req) {
+ if (host->needs_pre_post_req) {
meson_mmc_get_transfer_mode(mmc, mrq);
if (!meson_mmc_desc_chain_mode(mrq->data))
- needs_pre_post_req = false;
+ host->needs_pre_post_req = false;
}

- if (needs_pre_post_req)
+ if (host->needs_pre_post_req)
meson_mmc_pre_req(mmc, mrq);

/* Stop execution */
writel(0, host->regs + SD_EMMC_START);

meson_mmc_start_cmd(mmc, mrq->sbc ?: mrq->cmd);
-
- if (needs_pre_post_req)
- meson_mmc_post_req(mmc, mrq, 0);
}

static void meson_mmc_read_resp(struct mmc_host *mmc, struct mmc_command *cmd)
--
2.7.4