diff options
| author | Serge Semin <Sergey.Semin@baikalelectronics.ru> | 2022-05-24 18:21:56 +0300 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2022-06-23 22:56:34 +0300 |
| commit | 794a0f7b6f5ccbcb3bbb504b90d980bf2240d110 (patch) | |
| tree | e59eb471561ce2aaf3bc405605770406de9eb3f8 /scripts/gdb/linux/proc.py | |
| parent | 6951ee96c649f6e963b98c11b2b1a92697d3c45c (diff) | |
| download | linux-794a0f7b6f5ccbcb3bbb504b90d980bf2240d110.tar.xz | |
dmaengine: dw-edma: Drop dma_slave_config.direction field usage
The dma_slave_config.direction field usage in the DW eDMA driver was
introduced by bd96f1b2f43a ("dmaengine: dw-edma: support local dma device
transfer semantics"). Mainly the change introduced there was correct
(indeed DEV_TO_MEM means using RD-channel and MEM_TO_DEV - WR-channel for
the case of having eDMA accessed locally from CPU/Application side), but
providing an additional MEM_TO_MEM/DEV_TO_DEV-based semantics was quite
redundant if not to say potentially harmful (when it comes to removing the
denoted field). First of all since the dma_slave_config.direction field has
been marked as obsolete (see [1] and the struct dma_slave_config [2]) and
will be discarded in future, using it especially in a non-standard way is
discouraged. Secondly in accordance with the commit denoted above the
default dw_edma_device_transfer() semantics has been changed despite what
its message said. So claiming that the method was left backward compatible
was wrong.
Fix the problems denoted above and simplify the dw_edma_device_transfer()
method by dropping the parsing of the DMA-channel direction field. Instead
of having that implicit dma_slave_config.direction field semantic, use the
recently added DW_EDMA_CHIP_LOCAL flag to distinguish between the local and
remote DW eDMA setups thus preserving support for both cases. Add an ASCII
figure to clarify the situation.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/driver-api/dmaengine/provider.rst?id=v5.18#n478
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/dmaengine.h?id=v5.18#n389
[bhelgaas: convert references to specific URLs]
Co-developed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220524152159.2370739-6-Frank.Li@nxp.com
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'scripts/gdb/linux/proc.py')
0 files changed, 0 insertions, 0 deletions