commit f936f9b67b upstream.
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
162f43e31c (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@cogentembedded.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
c0da08882e