diff mbox series

[v2] mmc: meson-gx: do not use memcpy_to/fromio for dram-access-quirk

Message ID 20210928073652.434690-1-narmstrong@baylibre.com (mailing list archive)
State New, archived
Headers show
Series [v2] mmc: meson-gx: do not use memcpy_to/fromio for dram-access-quirk | expand

Commit Message

Neil Armstrong Sept. 28, 2021, 7:36 a.m. UTC
The memory at the end of the controller only accepts 32bit read/write
accesses, but the arm64 memcpy_to/fromio implementation only uses 64bit
(which will be split into two 32bit access) and 8bit leading to incomplete
copies to/from this memory when the buffer is not multiple of 8bytes.

Add a local copy using writel/readl accesses to make sure we use the right
memory access width.

The switch to memcpy_to/fromio was done because of 285133040e6c
("arm64: Import latest memcpy()/memmove() implementation"), but using memcpy
worked before since it mainly used 32bit memory acceses.

Fixes: 103a5348c22c ("mmc: meson-gx: use memcpy_to/fromio for dram-access-quirk")
Reported-by: Christian Hewitt <christianshewitt@gmail.com>
Suggested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
Changes since v1:
- added sg pre-validation at meson_mmc_request and dropped checks in meson_mmc_copy_buffer

 drivers/mmc/host/meson-gx-mmc.c | 73 ++++++++++++++++++++++++++-------
 1 file changed, 59 insertions(+), 14 deletions(-)

Comments

Ulf Hansson Sept. 30, 2021, 11:24 a.m. UTC | #1
On Tue, 28 Sept 2021 at 09:37, Neil Armstrong <narmstrong@baylibre.com> wrote:
>
> The memory at the end of the controller only accepts 32bit read/write
> accesses, but the arm64 memcpy_to/fromio implementation only uses 64bit
> (which will be split into two 32bit access) and 8bit leading to incomplete
> copies to/from this memory when the buffer is not multiple of 8bytes.
>
> Add a local copy using writel/readl accesses to make sure we use the right
> memory access width.
>
> The switch to memcpy_to/fromio was done because of 285133040e6c
> ("arm64: Import latest memcpy()/memmove() implementation"), but using memcpy
> worked before since it mainly used 32bit memory acceses.
>
> Fixes: 103a5348c22c ("mmc: meson-gx: use memcpy_to/fromio for dram-access-quirk")
> Reported-by: Christian Hewitt <christianshewitt@gmail.com>
> Suggested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

Applied for fixes and by adding a stable tag, thanks!

Kind regards
Uffe


> ---
> Changes since v1:
> - added sg pre-validation at meson_mmc_request and dropped checks in meson_mmc_copy_buffer
>
>  drivers/mmc/host/meson-gx-mmc.c | 73 ++++++++++++++++++++++++++-------
>  1 file changed, 59 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
> index 3f28eb4d17fe..8f36536cb1b6 100644
> --- a/drivers/mmc/host/meson-gx-mmc.c
> +++ b/drivers/mmc/host/meson-gx-mmc.c
> @@ -746,7 +746,7 @@ static void meson_mmc_desc_chain_transfer(struct mmc_host *mmc, u32 cmd_cfg)
>         writel(start, host->regs + SD_EMMC_START);
>  }
>
> -/* local sg copy to buffer version with _to/fromio usage for dram_access_quirk */
> +/* local sg copy for dram_access_quirk */
>  static void meson_mmc_copy_buffer(struct meson_host *host, struct mmc_data *data,
>                                   size_t buflen, bool to_buffer)
>  {
> @@ -764,21 +764,27 @@ static void meson_mmc_copy_buffer(struct meson_host *host, struct mmc_data *data
>         sg_miter_start(&miter, sgl, nents, sg_flags);
>
>         while ((offset < buflen) && sg_miter_next(&miter)) {
> -               unsigned int len;
> +               unsigned int buf_offset = 0;
> +               unsigned int len, left;
> +               u32 *buf = miter.addr;
>
>                 len = min(miter.length, buflen - offset);
> +               left = len;
>
> -               /* When dram_access_quirk, the bounce buffer is a iomem mapping */
> -               if (host->dram_access_quirk) {
> -                       if (to_buffer)
> -                               memcpy_toio(host->bounce_iomem_buf + offset, miter.addr, len);
> -                       else
> -                               memcpy_fromio(miter.addr, host->bounce_iomem_buf + offset, len);
> +               if (to_buffer) {
> +                       do {
> +                               writel(*buf++, host->bounce_iomem_buf + offset + buf_offset);
> +
> +                               buf_offset += 4;
> +                               left -= 4;
> +                       } while (left);
>                 } else {
> -                       if (to_buffer)
> -                               memcpy(host->bounce_buf + offset, miter.addr, len);
> -                       else
> -                               memcpy(miter.addr, host->bounce_buf + offset, len);
> +                       do {
> +                               *buf++ = readl(host->bounce_iomem_buf + offset + buf_offset);
> +
> +                               buf_offset += 4;
> +                               left -= 4;
> +                       } while (left);
>                 }
>
>                 offset += len;
> @@ -830,7 +836,11 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
>                 if (data->flags & MMC_DATA_WRITE) {
>                         cmd_cfg |= CMD_CFG_DATA_WR;
>                         WARN_ON(xfer_bytes > host->bounce_buf_size);
> -                       meson_mmc_copy_buffer(host, data, xfer_bytes, true);
> +                       if (host->dram_access_quirk)
> +                               meson_mmc_copy_buffer(host, data, xfer_bytes, true);
> +                       else
> +                               sg_copy_to_buffer(data->sg, data->sg_len,
> +                                                 host->bounce_buf, xfer_bytes);
>                         dma_wmb();
>                 }
>
> @@ -849,12 +859,43 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
>         writel(cmd->arg, host->regs + SD_EMMC_CMD_ARG);
>  }
>
> +static int meson_mmc_validate_dram_access(struct mmc_host *mmc, struct mmc_data *data)
> +{
> +       struct scatterlist *sg;
> +       int i;
> +
> +       /* Reject request if any element offset or size is not 32bit aligned */
> +       for_each_sg(data->sg, sg, data->sg_len, i) {
> +               if (!IS_ALIGNED(sg->offset, sizeof(u32)) ||
> +                   !IS_ALIGNED(sg->length, sizeof(u32))) {
> +                       dev_err(mmc_dev(mmc), "unaligned sg offset %u len %u\n",
> +                               data->sg->offset, data->sg->length);
> +                       return -EINVAL;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
>  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);
>
> +       /*
> +        * The memory at the end of the controller used as bounce buffer for
> +        * the dram_access_quirk only accepts 32bit read/write access,
> +        * check the aligment and length of the data before starting the request.
> +        */
> +       if (host->dram_access_quirk && mrq->data) {
> +               mrq->cmd->error = meson_mmc_validate_dram_access(mmc, mrq->data);
> +               if (mrq->cmd->error) {
> +                       mmc_request_done(mmc, mrq);
> +                       return;
> +               }
> +       }
> +
>         if (needs_pre_post_req) {
>                 meson_mmc_get_transfer_mode(mmc, mrq);
>                 if (!meson_mmc_desc_chain_mode(mrq->data))
> @@ -999,7 +1040,11 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
>         if (meson_mmc_bounce_buf_read(data)) {
>                 xfer_bytes = data->blksz * data->blocks;
>                 WARN_ON(xfer_bytes > host->bounce_buf_size);
> -               meson_mmc_copy_buffer(host, data, xfer_bytes, false);
> +               if (host->dram_access_quirk)
> +                       meson_mmc_copy_buffer(host, data, xfer_bytes, false);
> +               else
> +                       sg_copy_from_buffer(data->sg, data->sg_len,
> +                                           host->bounce_buf, xfer_bytes);
>         }
>
>         next_cmd = meson_mmc_get_next_command(cmd);
> --
> 2.25.1
>
diff mbox series

Patch

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index 3f28eb4d17fe..8f36536cb1b6 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -746,7 +746,7 @@  static void meson_mmc_desc_chain_transfer(struct mmc_host *mmc, u32 cmd_cfg)
 	writel(start, host->regs + SD_EMMC_START);
 }
 
-/* local sg copy to buffer version with _to/fromio usage for dram_access_quirk */
+/* local sg copy for dram_access_quirk */
 static void meson_mmc_copy_buffer(struct meson_host *host, struct mmc_data *data,
 				  size_t buflen, bool to_buffer)
 {
@@ -764,21 +764,27 @@  static void meson_mmc_copy_buffer(struct meson_host *host, struct mmc_data *data
 	sg_miter_start(&miter, sgl, nents, sg_flags);
 
 	while ((offset < buflen) && sg_miter_next(&miter)) {
-		unsigned int len;
+		unsigned int buf_offset = 0;
+		unsigned int len, left;
+		u32 *buf = miter.addr;
 
 		len = min(miter.length, buflen - offset);
+		left = len;
 
-		/* When dram_access_quirk, the bounce buffer is a iomem mapping */
-		if (host->dram_access_quirk) {
-			if (to_buffer)
-				memcpy_toio(host->bounce_iomem_buf + offset, miter.addr, len);
-			else
-				memcpy_fromio(miter.addr, host->bounce_iomem_buf + offset, len);
+		if (to_buffer) {
+			do {
+				writel(*buf++, host->bounce_iomem_buf + offset + buf_offset);
+
+				buf_offset += 4;
+				left -= 4;
+			} while (left);
 		} else {
-			if (to_buffer)
-				memcpy(host->bounce_buf + offset, miter.addr, len);
-			else
-				memcpy(miter.addr, host->bounce_buf + offset, len);
+			do {
+				*buf++ = readl(host->bounce_iomem_buf + offset + buf_offset);
+
+				buf_offset += 4;
+				left -= 4;
+			} while (left);
 		}
 
 		offset += len;
@@ -830,7 +836,11 @@  static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
 		if (data->flags & MMC_DATA_WRITE) {
 			cmd_cfg |= CMD_CFG_DATA_WR;
 			WARN_ON(xfer_bytes > host->bounce_buf_size);
-			meson_mmc_copy_buffer(host, data, xfer_bytes, true);
+			if (host->dram_access_quirk)
+				meson_mmc_copy_buffer(host, data, xfer_bytes, true);
+			else
+				sg_copy_to_buffer(data->sg, data->sg_len,
+						  host->bounce_buf, xfer_bytes);
 			dma_wmb();
 		}
 
@@ -849,12 +859,43 @@  static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
 	writel(cmd->arg, host->regs + SD_EMMC_CMD_ARG);
 }
 
+static int meson_mmc_validate_dram_access(struct mmc_host *mmc, struct mmc_data *data)
+{
+	struct scatterlist *sg;
+	int i;
+
+	/* Reject request if any element offset or size is not 32bit aligned */
+	for_each_sg(data->sg, sg, data->sg_len, i) {
+		if (!IS_ALIGNED(sg->offset, sizeof(u32)) ||
+		    !IS_ALIGNED(sg->length, sizeof(u32))) {
+			dev_err(mmc_dev(mmc), "unaligned sg offset %u len %u\n",
+				data->sg->offset, data->sg->length);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 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);
 
+	/*
+	 * The memory at the end of the controller used as bounce buffer for
+	 * the dram_access_quirk only accepts 32bit read/write access,
+	 * check the aligment and length of the data before starting the request.
+	 */
+	if (host->dram_access_quirk && mrq->data) {
+		mrq->cmd->error = meson_mmc_validate_dram_access(mmc, mrq->data);
+		if (mrq->cmd->error) {
+			mmc_request_done(mmc, mrq);
+			return;
+		}
+	}
+
 	if (needs_pre_post_req) {
 		meson_mmc_get_transfer_mode(mmc, mrq);
 		if (!meson_mmc_desc_chain_mode(mrq->data))
@@ -999,7 +1040,11 @@  static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
 	if (meson_mmc_bounce_buf_read(data)) {
 		xfer_bytes = data->blksz * data->blocks;
 		WARN_ON(xfer_bytes > host->bounce_buf_size);
-		meson_mmc_copy_buffer(host, data, xfer_bytes, false);
+		if (host->dram_access_quirk)
+			meson_mmc_copy_buffer(host, data, xfer_bytes, false);
+		else
+			sg_copy_from_buffer(data->sg, data->sg_len,
+					    host->bounce_buf, xfer_bytes);
 	}
 
 	next_cmd = meson_mmc_get_next_command(cmd);