From: Jerome Brunet <jbrunet@baylibre.com>
To: Jianxin Pan <jianxin.pan@amlogic.com>,
Ulf Hansson <ulf.hansson@linaro.org>,
Kevin Hilman <khilman@baylibre.com>
Cc: Victor Wan <victor.wan@amlogic.com>,
Neil Armstrong <narmstrong@baylibre.com>,
linux-mmc@vger.kernel.org, Nan Li <nan.li@amlogic.com>,
linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org
Subject: Re: [PATCH v2] mmc: meson-gx: fix mmc dma operation
Date: Mon, 04 Nov 2019 17:46:29 +0100 [thread overview]
Message-ID: <1ja79b4mje.fsf@starbuckisacylon.baylibre.com> (raw)
In-Reply-To: <1572868495-84816-1-git-send-email-jianxin.pan@amlogic.com>
On Mon 04 Nov 2019 at 12:54, Jianxin Pan <jianxin.pan@amlogic.com> wrote:
> From: Nan Li <nan.li@amlogic.com>
>
> 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.
In the previous thread, you have described what was the issue you found.
It would be nice to have this information here
>
> Fixes: 79ed05e329c3 ("mmc: meson-gx: add support for descriptor chain mode")
> Signed-off-by: Nan Li <nan.li@amlogic.com>
> Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com>
> ---
> drivers/mmc/host/meson-gx-mmc.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
Based on Uffe comment I tried something else.
Basically, it enables chained mode in the driver only when the framework
calls pre/post_req callback. As far as understood, the framework calls
this when there is more than one request pending ... which seems to be
when chained mode actually make sense
----8<-----
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index e712315c7e8d..399604b4124d 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -126,8 +126,7 @@
#define SD_EMMC_CFG_CMD_GAP 16 /* in clock cycles */
#define SD_EMMC_DESC_BUF_LEN PAGE_SIZE
-#define SD_EMMC_PRE_REQ_DONE BIT(0)
-#define SD_EMMC_DESC_CHAIN_MODE BIT(1)
+#define SD_EMMC_DESC_CHAIN_MODE BIT(0)
#define MUX_CLK_NUM_PARENTS 2
@@ -228,7 +227,6 @@ static void meson_mmc_get_transfer_mode(struct mmc_host *mmc,
struct mmc_data *data = mrq->data;
struct scatterlist *sg;
int i;
- bool use_desc_chain_mode = true;
/*
* When Controller DMA cannot directly access DDR memory, disable
@@ -251,12 +249,11 @@ static void meson_mmc_get_transfer_mode(struct mmc_host *mmc,
/* check for 8 byte alignment */
if (sg->offset & 7) {
WARN_ONCE(1, "unaligned scatterlist buffer\n");
- use_desc_chain_mode = false;
- break;
+ return;
}
- if (use_desc_chain_mode)
- data->host_cookie |= SD_EMMC_DESC_CHAIN_MODE;
+ /* The planets are aligned, let's chain them up */
+ data->host_cookie |= SD_EMMC_DESC_CHAIN_MODE;
}
static inline bool meson_mmc_desc_chain_mode(const struct mmc_data *data)
@@ -278,7 +275,6 @@ static void meson_mmc_pre_req(struct mmc_host *mmc, struct mmc_request *mrq)
return;
meson_mmc_get_transfer_mode(mmc, mrq);
- data->host_cookie |= SD_EMMC_PRE_REQ_DONE;
if (!meson_mmc_desc_chain_mode(data))
return;
@@ -803,25 +799,11 @@ 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 &&
- !(mrq->data->host_cookie & SD_EMMC_PRE_REQ_DONE);
-
- if (needs_pre_post_req) {
- meson_mmc_get_transfer_mode(mmc, mrq);
- if (!meson_mmc_desc_chain_mode(mrq->data))
- needs_pre_post_req = false;
- }
-
- if (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)
---->8-----
No performance hit AFAICT.
From your description, it should address your problem too.
>
> 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)
_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic
next prev parent reply other threads:[~2019-11-04 16:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-04 11:54 [PATCH v2] mmc: meson-gx: fix mmc dma operation Jianxin Pan
2019-11-04 16:46 ` Jerome Brunet [this message]
[not found] ` <e80cb817-e58a-68ce-a3c6-d82636aaf7d3@amlogic.com>
2019-11-05 8:16 ` Jerome Brunet
[not found] ` <7ec2e682-cfec-395e-cf38-58f050440c40@amlogic.com>
2019-11-05 8:54 ` Jerome Brunet
[not found] ` <dee789ae-6825-3f4c-16e7-227e064562d6@amlogic.com>
2019-11-05 13:30 ` Jerome Brunet
2019-11-07 3:07 ` Nan Li
2019-11-12 17:02 ` Jerome Brunet
[not found] ` <ec705819-9763-b0d2-9480-949e7ccd1cb9@amlogic.com>
2019-11-12 17:12 ` Jerome Brunet
2019-11-13 6:04 ` Nan Li
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1ja79b4mje.fsf@starbuckisacylon.baylibre.com \
--to=jbrunet@baylibre.com \
--cc=jianxin.pan@amlogic.com \
--cc=khilman@baylibre.com \
--cc=linux-amlogic@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mmc@vger.kernel.org \
--cc=nan.li@amlogic.com \
--cc=narmstrong@baylibre.com \
--cc=ulf.hansson@linaro.org \
--cc=victor.wan@amlogic.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).