I'm testing SH-Mobile SDHI driver in DMA mode with a new DMA controller using
'bonnie++' and getting DMA error after which the tmio_mmc_dma.c code falls back
to PIO but all commands time out after that. It turned out that the fallback
code calls tmio_mmc_enable_dma() with RX/TX channels already freed and pointers
to them cleared, so that the function bails out early instead of clearing the
DMA bit in the CTL_DMA_ENABLE register. The regression was introduced by commit
162f43e31c5a376ec16336e5d0ac973373d54c89 (mmc: tmio: fix a deadlock).
Moving tmio_mmc_enable_dma() calls to the top of the PIO fallback code in
tmio_mmc_start_dma_{rx|tx}() helps.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 3.1+
---
The patch is against Chris Ball's 'mmc.git' repo, 'master' branch.
Changes in version 2:
- removed extra check from tmio_mmc_enable_dma();
- moved tmio_mmc_enable_dma() calls to the top of the PIO fallback code in
tmio_mmc_start_dma_{rx|tx}().
drivers/mmc/host/tmio_mmc_dma.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: renesas/drivers/mmc/host/tmio_mmc_dma.c
===================================================================
--- renesas.orig/drivers/mmc/host/tmio_mmc_dma.c
+++ renesas/drivers/mmc/host/tmio_mmc_dma.c
@@ -104,6 +104,7 @@ static void tmio_mmc_start_dma_rx(struct
pio:
if (!desc) {
/* DMA failed, fall back to PIO */
+ tmio_mmc_enable_dma(host, false);
if (ret >= 0)
ret = -EIO;
host->chan_rx = NULL;
@@ -116,7 +117,6 @@ pio:
}
dev_warn(&host->pdev->dev,
"DMA failed: %d, falling back to PIO\n", ret);
- tmio_mmc_enable_dma(host, false);
}
dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
@@ -185,6 +185,7 @@ static void tmio_mmc_start_dma_tx(struct
pio:
if (!desc) {
/* DMA failed, fall back to PIO */
+ tmio_mmc_enable_dma(host, false);
if (ret >= 0)
ret = -EIO;
host->chan_tx = NULL;
@@ -197,7 +198,6 @@ pio:
}
dev_warn(&host->pdev->dev,
"DMA failed: %d, falling back to PIO\n", ret);
- tmio_mmc_enable_dma(host, false);
}
dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
--
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