[PATCH v2] mmc: meson: Fix usage of meson_mmc_post_req()

[PATCH v2] mmc: meson: Fix usage of meson_mmc_post_req()

[Rong Chen]

Currently meson_mmc_post_req() is called in meson_mmc_request() right
after meson_mmc_start_cmd(). This could lead to DMA unmapping before the request
is actually finished.

To fix, don't call meson_mmc_post_req() until meson_mmc_request_done().

Signed-off-by: Rong Chen <rong.chen@amlogic.com>
---
 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 8f36536cb1b6..58ab9d90bc8b 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -173,6 +173,8 @@ struct meson_host {
 	int irq;
 
 	bool vqmmc_enabled;
+	bool needs_pre_post_req;
+
 };
 
 #define CMD_CFG_LENGTH_MASK GENMASK(8, 0)
@@ -663,6 +665,8 @@ 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);
 }
 
@@ -880,7 +884,7 @@ static int meson_mmc_validate_dram_access(struct mmc_host *mmc, struct mmc_data
 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);
 
 	/*
@@ -896,22 +900,19 @@ static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
 		}
 	}
 
-	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)
-- 
2.25.1

Re: [PATCH v2] mmc: meson: Fix usage of meson_mmc_post_req()

[Kevin Hilman]

Rong Chen <rong.chen@amlogic.com> writes:

> Currently meson_mmc_post_req() is called in meson_mmc_request() right
> after meson_mmc_start_cmd(). This could lead to DMA unmapping before the request
> is actually finished.
>
> To fix, don't call meson_mmc_post_req() until meson_mmc_request_done().
>
> Signed-off-by: Rong Chen <rong.chen@amlogic.com>

Reviewed-by: Kevin Hilman <khilman@baylibre.com>

Re: [PATCH v2] mmc: meson: Fix usage of meson_mmc_post_req()

[Ulf Hansson]

+ Hainer

On Wed, 16 Feb 2022 at 13:42, Rong Chen <rong.chen@amlogic.com> wrote:
>
> Currently meson_mmc_post_req() is called in meson_mmc_request() right
> after meson_mmc_start_cmd(). This could lead to DMA unmapping before the request
> is actually finished.
>
> To fix, don't call meson_mmc_post_req() until meson_mmc_request_done().
>
> Signed-off-by: Rong Chen <rong.chen@amlogic.com>

We should probably add a fixes tag to this, right?
Fixes: 79ed05e329c3 ("mmc: meson-gx: add support for descriptor chain mode")

Moreover, you want this tagged for stable kernels too, right?

I have applied it for fixes and added the above tags, please tell if
you want me to change it.

Kind regards
Uffe


> ---
>  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 8f36536cb1b6..58ab9d90bc8b 100644
> --- a/drivers/mmc/host/meson-gx-mmc.c
> +++ b/drivers/mmc/host/meson-gx-mmc.c
> @@ -173,6 +173,8 @@ struct meson_host {
>         int irq;
>
>         bool vqmmc_enabled;
> +       bool needs_pre_post_req;
> +
>  };
>
>  #define CMD_CFG_LENGTH_MASK GENMASK(8, 0)
> @@ -663,6 +665,8 @@ 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);
>  }
>
> @@ -880,7 +884,7 @@ static int meson_mmc_validate_dram_access(struct mmc_host *mmc, struct mmc_data
>  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);
>
>         /*
> @@ -896,22 +900,19 @@ static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
>                 }
>         }
>
> -       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)
> --
> 2.25.1
>