Hello Rong,
First, thank you finding the issue and for submitting a fix!
Rong Chen <rong.chen@xxxxxxxxxxx> writes:
> To ensure the DMA moves data correctly from memory to
> peripherals, DMA unmapping when the MMC request done
> with calls meson_mmc_post_req().
>
> Signed-off-by: Rong Chen <rong.chen@xxxxxxxxxxx>
The patch looks correct, but I think I think the changelog could be
improved. If I understand the code correctly, I think what you're doing
is:
"""
Currently meson_mmc_post_req() is called in meson_mmc_request() right
after _start_cmd(). This could lead to DMA unmapping before the request
is actually finished.
To fix, ton't call meson_mmc_post_req() until _request_done().
"""
Kevin
> ---
> drivers/mmc/host/meson-gx-mmc.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
> index 8f36536cb1b6..6a9554ae4b1c 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)
> @@ -663,6 +664,8 @@ 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 +883,7 @@ 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 +899,19 @@ 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)
>
> base-commit: 356f3f2c5756bbb67a515760966a40fc7043cdda
> --
> 2.25.1
