For data writes smaller than 8 bytes (only SDIO case), HW flow
control was disabled but never re-enabled again. This meant that
a following large read request could randomly give buffer overrun
errors.
This patch is based upon a patch from Stefan Nilsson.
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxxxxxx>
Signed-off-by: Stefan Nilsson XK <stefan.xk.nilsson@xxxxxxxxxxxxxx>
Signed-off-by: Fredrik Soderstedt <fredrik.soderstedt@xxxxxxxxxxxxxx>
---
drivers/mmc/host/mmci.c | 38 ++++++++++++++++++++------------------
1 files changed, 20 insertions(+), 18 deletions(-)
diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index d311f83..b949e07 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -638,10 +638,28 @@ static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
if (data->flags & MMC_DATA_READ)
datactrl |= MCI_DPSM_DIRECTION;
- /* The ST Micro variants has a special bit to enable SDIO */
if (variant->sdio && host->mmc->card)
- if (mmc_card_sdio(host->mmc->card))
+ if (mmc_card_sdio(host->mmc->card)) {
+
+ /*
+ * The ST Micro variant for SDIO write transfer sizes
+ * less then 8 bytes must have clock H/W flow control
+ * disabled.
+ */
+ u32 clk;
+ if ((host->size < 8) && (data->flags & MMC_DATA_WRITE))
+ clk = host->clk_reg & ~variant->clkreg_enable;
+ else
+ clk = host->clk_reg | variant->clkreg_enable;
+
+ mmci_write_clkreg(host, clk);
+
+ /*
+ * The ST Micro variants has a special bit
+ * to enable SDIO.
+ */
datactrl |= MCI_ST_DPSM_SDIOEN;
+ }
/*
* Attempt to use DMA operation mode, if this
@@ -846,22 +864,6 @@ static int mmci_pio_write(struct mmci_host *host, char *buffer, unsigned int rem
count = min(remain, maxcnt);
/*
- * The ST Micro variant for SDIO transfer sizes
- * less then 8 bytes should have clock H/W flow
- * control disabled.
- */
- if (variant->sdio &&
- mmc_card_sdio(host->mmc->card)) {
- u32 clk;
- if (count < 8)
- clk = host->clk_reg & ~variant->clkreg_enable;
- else
- clk = host->clk_reg | variant->clkreg_enable;
-
- mmci_write_clkreg(host, clk);
- }
-
- /*
* SDIO especially may want to send something that is
* not divisible by 4 (as opposed to card sectors
* etc), and the FIFO only accept full 32-bit writes.
--
1.7.5.4
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