linux-toradex.git/include/linux/shdma-base.h, branch v4.16-rc4

dmaengine: shdma: Make dummy shdma_chan_filter() always return false

2015-08-05T03:18:00+00:00

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 
Signed-off-by: Vinod Koul

dmaengine: shdma: use normal interface for passing slave id

2015-02-23T10:42:24+00:00

in dma_slave_config, which is incompatible with the way that the
dmaengine API normally works.

I've had a closer look at the existing code now and found that all
slave drivers that pass a slave_id in dma_slave_config for SH do that
right after passing the same ID into shdma_chan_filter, so we can just
rely on that. However, the various shdma drivers currently do not
remember the slave ID that was passed into the filter function when
used in non-DT mode and only check the value to find a matching channel,
unlike all other drivers.

There might still be drivers that are not part of the kernel that rely
on setting the slave_id to some other value, so to be on the safe side,
this adds another 'real_slave_id' field to shdma_chan that remembers
the ID and uses it when a driver passes a zero slave_id in dma_slave_config,
like most drivers do.

Eventually, the real_slave_id and slave_id fields should just get merged
into one field, but that requires other changes.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Kuninori Morimoto 
Signed-off-by: Vinod Koul

DMA: shdma: add cyclic transfer support

2014-05-02T16:18:33+00:00

This patch add cyclic transfer support and enables dmaengine_prep_dma_cyclic()

Signed-off-by: Kuninori Morimoto 
[reflown changelog for readablity]
Signed-off-by: Vinod Koul

DMA: shdma: switch DT mode to use configuration data from a match table

2013-08-27T08:55:09+00:00

This facilitates DMAC DT support by eliminating the need in AUXDATA and
avoiding creating complex DT data. This also fits well with DMAC devices,
of which SoCs often have multiple identical copies and it is perfectly
valid to use a single configuration data set for all of them.

Signed-off-by: Guennadi Liakhovetski 
Signed-off-by: Vinod Koul

DMA: shdma: switch to managed resource allocation

2013-08-27T08:54:19+00:00

Switch shdma to using devm_* managed functions for allocation of memory,
requesting IRQs, mapping IO resources etc.

Signed-off-by: Guennadi Liakhovetski 
Signed-off-by: Vinod Koul

dmaengine: shdma: fix a build failure on platforms with no DMA support

2013-07-23T02:40:01+00:00

On platforms with no support for the shdma dmaengine driver build is
currently failing with

drivers/built-in.o: In function `sh_mobile_sdhi_probe':
drivers/mmc/host/sh_mobile_sdhi.c:170: undefined reference to`shdma_chan_filter'

Fix the breakage by defining shdma_chan_filter to NULL in such
configurations.

Signed-off-by: Guennadi Liakhovetski 
[horms+renesas@verge.net.au: Apply change to shdma-base.h instead of sh_dma.h]
Signed-off-by: Simon Horman 
Signed-off-by: Olof Johansson

DMA: shdma: add DT support

2013-07-05T06:11:00+00:00

This patch adds Device Tree support to the shdma driver. No special DT
properties are used, only standard DMA DT bindings are implemented. Since
shdma controllers reside on SoCs, their configuration is SoC-specific and
shall be passed to the driver from the SoC platform data, using the
auxdata procedure.

Signed-off-by: Guennadi Liakhovetski 
Acked-by: Arnd Bergmann 
Signed-off-by: Vinod Koul

DMA: shdma: shdma_chan_filter() has to be in shdma-base.h

2013-07-05T06:10:59+00:00

shdma_chan_filter() is a function, provided by the shdma-base.c module,
move its declaration to the appropriate header.

Signed-off-by: Guennadi Liakhovetski 
Signed-off-by: Vinod Koul

dmaengine: shdma: restore partial transfer calculation

2012-08-01T04:48:52+00:00

The recent shdma driver split has mistakenly removed support for partial
DMA transfer size calculation on forced termination. This patch restores
it.

Signed-off-by: Guennadi Liakhovetski 
Acked-by: Vinod Koul 
Signed-off-by: Paul Mundt

dma: sh: provide a migration path for slave drivers to stop using .private

2012-07-20T05:58:20+00:00

This patch extends the sh dmaengine driver to support the preferred channel
selection and configuration method, instead of using the "private" field
from struct dma_chan. We add a standard filter function to be used by
slave drivers instead of implementing their own ones, and add support for
the DMA_SLAVE_CONFIG control operation, which must accompany the new
channel selection method. We still support the legacy .private channel
allocation method to cater for a smooth driver migration.

Signed-off-by: Guennadi Liakhovetski 
[applied a trvial checkpath fix]
Signed-off-by: Vinod Koul