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. Fixing the RX/TX channel check so that
it takes place only when enabling DMA helps with the PIO fallback.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
---
The patch is against Chris Ball's 'mmc.git' repo, 'master' branch.
drivers/mmc/host/tmio_mmc_dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: mmc/drivers/mmc/host/tmio_mmc_dma.c
===================================================================
--- mmc.orig/drivers/mmc/host/tmio_mmc_dma.c
+++ mmc/drivers/mmc/host/tmio_mmc_dma.c
@@ -25,7 +25,7 @@
void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
{
- if (!host->chan_tx || !host->chan_rx)
+ if (enable && !(host->chan_tx && host->chan_rx))
return;
#if defined(CONFIG_SUPERH) || defined(CONFIG_ARCH_SHMOBILE)
--
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