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author | Geert Uytterhoeven <geert+renesas@glider.be> | 2015-07-10 12:07:25 +0200 |
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committer | Vinod Koul <vinod.koul@intel.com> | 2015-08-05 08:48:00 +0530 |
commit | 056f6c87028544de934f27caf95aa1545d585767 (patch) | |
tree | 1db2b5d6a36041ccb75936c5c45dcef8e8b6f92b /drivers/dma/coh901318.c | |
parent | 8391ecf465ec5c8ccef547267df6d40beb8999a4 (diff) | |
download | linux-056f6c87028544de934f27caf95aa1545d585767.tar.bz2 |
dmaengine: shdma: Make dummy shdma_chan_filter() always return false
If CONFIG_SH_DMAE_BASE (which is required for DMA engine support for
legacy SH, SH/R-Mobile, and R-Car Gen1, but not for R-Car Gen2) is not
enabled, but CONFIG_RCAR_DMAC (for R-Car Gen2 DMA engine support) is,
and the DTS doesn't provide a "dmas" property for a device,
dma_request_slave_channel_compat() incorrectly succeeds, and returns a
DMA channel.
However, when trying to use that DMA channel later, it fails with:
rcar-dmac e6700000.dma-controller: rcar_dmac_prep_slave_sg: bad parameter: len=1, id=-22
(Fortunately most drivers can handle this failure, and fall back to
PIO)
The reason for this is that a NULL legacy filter function is used, which
actually means "all channels are OK", not "do not match".
If CONFIG_SH_DMAE_BASE is enabled (like in shmobile_defconfig, which
supports other SoCs besides R-Car Gen2), shdma_chan_filter() correctly
returns false, as no available channel on R-Car Gen2 matches a
shdma-base channel.
If the DTS does provide a "dmas" property, dma_request_slave_channel()
succeeds, and legacy filter-based matching is not used.
To fix this, change shdma_chan_filter from being NULL to a dummy
function that always returns false, like is done on other platforms.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma/coh901318.c')
0 files changed, 0 insertions, 0 deletions