[1/2] mmc: host: meson-mx-sdhc: fix manual RX FIFO flushing
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Message ID 20200517222907.1277787-1-martin.blumenstingl@googlemail.com
State Not Applicable
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Series
  • [1/2] mmc: host: meson-mx-sdhc: fix manual RX FIFO flushing
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Commit Message

Martin Blumenstingl May 17, 2020, 10:29 p.m. UTC
For Meson8 and Meson8b SoCs the vendor driver follows the following
pattern:
- for eMMC and SD cards in .set_pdma it sets:
  pdma->rxfifo_manual_flush = 1;
- for SDIO cards in .set_pdma it sets:
  pdma->rxfifo_manual_flush = 0;
- before syncing the DMA read buffer is sets:
  pdma->rxfifo_manual_flush |= 0x02;

Set the second bit of MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH without
clearing the first bit before syncing the DMA read buffer. This fixes a
problem where Meson8 and Meson8b SoCs would read random garbage from SD
cards. It is not clear why it worked for eMMC cards. This manifested in
the following errors when plugging in an SD card:
  unrecognised SCR structure version <random number>

Fixes: 53ded1b676d199 ("mmc: host: meson-mx-sdhc: new driver for the Amlogic Meson SDHC host")
Cc: Thomas Graichen <thomas.graichen@gmail.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 drivers/mmc/host/meson-mx-sdhc.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

Comments

Ulf Hansson May 18, 2020, 11:23 a.m. UTC | #1
On Mon, 18 May 2020 at 00:29, Martin Blumenstingl
<martin.blumenstingl@googlemail.com> wrote:
>
> For Meson8 and Meson8b SoCs the vendor driver follows the following
> pattern:
> - for eMMC and SD cards in .set_pdma it sets:
>   pdma->rxfifo_manual_flush = 1;
> - for SDIO cards in .set_pdma it sets:
>   pdma->rxfifo_manual_flush = 0;
> - before syncing the DMA read buffer is sets:
>   pdma->rxfifo_manual_flush |= 0x02;
>
> Set the second bit of MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH without
> clearing the first bit before syncing the DMA read buffer. This fixes a
> problem where Meson8 and Meson8b SoCs would read random garbage from SD
> cards. It is not clear why it worked for eMMC cards. This manifested in
> the following errors when plugging in an SD card:
>   unrecognised SCR structure version <random number>
>
> Fixes: 53ded1b676d199 ("mmc: host: meson-mx-sdhc: new driver for the Amlogic Meson SDHC host")
> Cc: Thomas Graichen <thomas.graichen@gmail.com>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

Applied for next, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/meson-mx-sdhc.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/meson-mx-sdhc.c b/drivers/mmc/host/meson-mx-sdhc.c
> index 5c00958d7754..53e3f6a4245a 100644
> --- a/drivers/mmc/host/meson-mx-sdhc.c
> +++ b/drivers/mmc/host/meson-mx-sdhc.c
> @@ -586,10 +586,17 @@ static irqreturn_t meson_mx_sdhc_irq_thread(int irq, void *irq_data)
>                     cmd->data->flags & MMC_DATA_READ) {
>                         meson_mx_sdhc_wait_cmd_ready(host->mmc);
>
> +                       /*
> +                        * If MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH was
> +                        * previously 0x1 then it has to be set to 0x3. If it
> +                        * was 0x0 before then it has to be set to 0x2. Without
> +                        * this reading SD cards sometimes transfers garbage,
> +                        * which results in cards not being detected due to:
> +                        *   unrecognised SCR structure version <random number>
> +                        */
>                         val = FIELD_PREP(MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH,
>                                          2);
> -                       regmap_update_bits(host->regmap, MESON_SDHC_PDMA,
> -                                          MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH,
> +                       regmap_update_bits(host->regmap, MESON_SDHC_PDMA, val,
>                                            val);
>                 }
>
> --
> 2.26.2
>
Thomas Graichen May 25, 2020, 6:14 a.m. UTC | #2
On Mon, May 18, 2020 at 12:29 AM Martin Blumenstingl
<martin.blumenstingl@googlemail.com> wrote:
>
> For Meson8 and Meson8b SoCs the vendor driver follows the following
> pattern:
> - for eMMC and SD cards in .set_pdma it sets:
>   pdma->rxfifo_manual_flush = 1;
> - for SDIO cards in .set_pdma it sets:
>   pdma->rxfifo_manual_flush = 0;
> - before syncing the DMA read buffer is sets:
>   pdma->rxfifo_manual_flush |= 0x02;
>
> Set the second bit of MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH without
> clearing the first bit before syncing the DMA read buffer. This fixes a
> problem where Meson8 and Meson8b SoCs would read random garbage from SD
> cards. It is not clear why it worked for eMMC cards. This manifested in
> the following errors when plugging in an SD card:
>   unrecognised SCR structure version <random number>
>
> Fixes: 53ded1b676d199 ("mmc: host: meson-mx-sdhc: new driver for the Amlogic Meson SDHC host")
> Cc: Thomas Graichen <thomas.graichen@gmail.com>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

Tested-by: thomas graichen <thomas.graichen@gmail.com>

BEFORE: on my meson8 based mxiii i got the above error and the sd card
was not useable

AFTER: no more error and sd cards works fine

> ---
>  drivers/mmc/host/meson-mx-sdhc.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/meson-mx-sdhc.c b/drivers/mmc/host/meson-mx-sdhc.c
> index 5c00958d7754..53e3f6a4245a 100644
> --- a/drivers/mmc/host/meson-mx-sdhc.c
> +++ b/drivers/mmc/host/meson-mx-sdhc.c
> @@ -586,10 +586,17 @@ static irqreturn_t meson_mx_sdhc_irq_thread(int irq, void *irq_data)
>                     cmd->data->flags & MMC_DATA_READ) {
>                         meson_mx_sdhc_wait_cmd_ready(host->mmc);
>
> +                       /*
> +                        * If MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH was
> +                        * previously 0x1 then it has to be set to 0x3. If it
> +                        * was 0x0 before then it has to be set to 0x2. Without
> +                        * this reading SD cards sometimes transfers garbage,
> +                        * which results in cards not being detected due to:
> +                        *   unrecognised SCR structure version <random number>
> +                        */
>                         val = FIELD_PREP(MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH,
>                                          2);
> -                       regmap_update_bits(host->regmap, MESON_SDHC_PDMA,
> -                                          MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH,
> +                       regmap_update_bits(host->regmap, MESON_SDHC_PDMA, val,
>                                            val);
>                 }
>
> --
> 2.26.2
>

Patch
diff mbox series

diff --git a/drivers/mmc/host/meson-mx-sdhc.c b/drivers/mmc/host/meson-mx-sdhc.c
index 5c00958d7754..53e3f6a4245a 100644
--- a/drivers/mmc/host/meson-mx-sdhc.c
+++ b/drivers/mmc/host/meson-mx-sdhc.c
@@ -586,10 +586,17 @@  static irqreturn_t meson_mx_sdhc_irq_thread(int irq, void *irq_data)
 		    cmd->data->flags & MMC_DATA_READ) {
 			meson_mx_sdhc_wait_cmd_ready(host->mmc);
 
+			/*
+			 * If MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH was
+			 * previously 0x1 then it has to be set to 0x3. If it
+			 * was 0x0 before then it has to be set to 0x2. Without
+			 * this reading SD cards sometimes transfers garbage,
+			 * which results in cards not being detected due to:
+			 *   unrecognised SCR structure version <random number>
+			 */
 			val = FIELD_PREP(MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH,
 					 2);
-			regmap_update_bits(host->regmap, MESON_SDHC_PDMA,
-					   MESON_SDHC_PDMA_RXFIFO_MANUAL_FLUSH,
+			regmap_update_bits(host->regmap, MESON_SDHC_PDMA, val,
 					   val);
 		}