linux-toradex.git/drivers/dma/dmaengine.c, branch v6.2-rc2

dmaengine: remove DMA_MEMCPY_SG once again

2022-06-27T06:31:40+00:00

This was removed before due to the complete lack of users, but
3218910fd585 ("dmaengine: Add core function and capability check for
DMA_MEMCPY_SG") and 29cf37fa6dd9 ("dmaengine: Add consumer for the new
DMA_MEMCPY_SG API function.") added it back despite still not having
any users whatsoever.

Fixes: 3218910fd585 ("dmaengine: Add core function and capability check for DMA_MEMCPY_SG")
Fixes: 29cf37fa6dd9 ("dmaengine: Add consumer for the new DMA_MEMCPY_SG API function.")
Signed-off-by: Christoph Hellwig 
Acked-by: Michal Simek 
Link: https://lore.kernel.org/r/20220606074733.622616-1-hch@lst.de
Signed-off-by: Vinod Koul

dmaengine: Remove a useless mutex

2022-04-11T14:22:40+00:00

According to lib/idr.c,
   The IDA handles its own locking.  It is safe to call any of the IDA
   functions without synchronisation in your code.

so the 'chan_mutex' mutex can just be removed.
It is here only to protect some ida_alloc()/ida_free() calls.

Signed-off-by: Christophe JAILLET 
Link: https://lore.kernel.org/r/7180452c1d77b039e27b6f9418e0e7d9dd33c431.1644140845.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Vinod Koul

dmaengine: Add core function and capability check for DMA_MEMCPY_SG

2021-11-22T06:08:05+00:00

This is the old DMA_SG interface that was removed in commit
c678fa66341c ("dmaengine: remove DMA_SG as it is dead code in kernel"). It
has been renamed to DMA_MEMCPY_SG to better match the MEMSET and MEMSET_SG
naming convention.

It should only be used for mem2mem copies, either main system memory or
CPU-addressable device memory (like video memory on a PCI graphics card).

Bringing back this interface was prompted by the need to use the Xilinx
CDMA device for mem2mem SG transfers.

Signed-off-by: Adrian Larumbe 
Link: https://lore.kernel.org/r/20211101180825.241048-3-adrianml@alumnos.upm.es
Signed-off-by: Vinod Koul

dmaengine: Remove redundant initialization of variable err

2021-10-18T04:08:05+00:00

The variable err is being initialized with a value that is never read, it
is being updated later on. The assignment is redundant and can be removed
and move the declaration into the local scope.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King 
Link: https://lore.kernel.org/r/20211015123447.27560-1-colin.king@canonical.com
Signed-off-by: Vinod Koul

dmaengine: Fix a double free in dma_async_device_register

2021-04-12T09:35:58+00:00

In the first list_for_each_entry() macro of dma_async_device_register,
it gets the chan from list and calls __dma_async_device_channel_register
(..,chan). We can see that chan->local is allocated by alloc_percpu() and
it is freed chan->local by free_percpu(chan->local) when
__dma_async_device_channel_register() failed.

But after __dma_async_device_channel_register() failed, the caller will
goto err_out and freed the chan->local in the second time by free_percpu().

The cause of this problem is forget to set chan->local to NULL when
chan->local was freed in __dma_async_device_channel_register(). My
patch sets chan->local to NULL when the callee failed to avoid double free.

Fixes: d2fb0a0438384 ("dmaengine: break out channel registration")
Signed-off-by: Lv Yunlong 
Reviewed-by: Dave Jiang 
Link: https://lore.kernel.org/r/20210331014458.3944-1-lyl2019@mail.ustc.edu.cn
Signed-off-by: Vinod Koul

dmaengine: move channel device_node deletion to driver

2021-01-19T16:40:52+00:00

Channel device_node deletion is managed by the device driver rather than
the dmaengine core. The deletion was accidentally introduced when making
channel unregister dynamic. It causes xilinx_dma module to crash on unload
as reported by Radhey. Remove chan->device_node delete in dmaengine and
also fix up idxd driver.

[   42.142705] Internal error: Oops: 96000044 [#1] SMP
[   42.147566] Modules linked in: xilinx_dma(-) clk_xlnx_clock_wizard uio_pdrv_genirq
[   42.155139] CPU: 1 PID: 2075 Comm: rmmod Not tainted 5.10.1-00026-g3a2e6dd7a05-dirty #192
[   42.163302] Hardware name: Enclustra XU5 SOM (DT)
[   42.167992] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
[   42.173996] pc : xilinx_dma_chan_remove+0x74/0xa0 [xilinx_dma]
[   42.179815] lr : xilinx_dma_chan_remove+0x70/0xa0 [xilinx_dma]
[   42.185636] sp : ffffffc01112bca0
[   42.188935] x29: ffffffc01112bca0 x28: ffffff80402ea640

xilinx_dma_chan_remove+0x74/0xa0:
__list_del at ./include/linux/list.h:112 (inlined by)
__list_del_entry at./include/linux/list.h:135 (inlined by)
list_del at ./include/linux/list.h:146 (inlined by)
xilinx_dma_chan_remove at drivers/dma/xilinx/xilinx_dma.c:2546

Fixes: e81274cd6b52 ("dmaengine: add support to dynamic register/unregister of channels")
Reported-by: Radhey Shyam Pandey 
Signed-off-by: Dave Jiang 
Tested-by: Radhey Shyam Pandey 
Link: https://lore.kernel.org/r/161099092469.2495902.5064826526660062342.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul 
Cc: stable@vger.kernel.org # 5.9+

dmaengine: fix error codes in channel_register()

2020-11-18T12:21:51+00:00

The error codes were not set on some of these error paths.

Also the error handling was more confusing than it needed to be so I
cleaned it up and shuffled it around a bit.

Fixes: d2fb0a043838 ("dmaengine: break out channel registration")
Signed-off-by: Dan Carpenter 
Reviewed-by: Peter Ujfalusi 
Link: https://lore.kernel.org/r/20201113101631.GE168908@mwanda
Signed-off-by: Vinod Koul

dmaengine: Save few bytes and increase readability of dma_request_chan()

2020-09-03T06:52:35+00:00

Split IS_ERR_OR_NULL() check followed by additional conditional
to two simple conditionals. This increases readability and saves memory:

Function                                     old     new   delta
dma_request_chan                             700     697      -3
Total: Before=10224, After=10221, chg -0.03%

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200828144519.14483-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul

dmaengine: Mark dma_request_slave_channel() deprecated

2020-09-03T06:51:03+00:00

New drivers should use dma_request_chan() instead
dma_request_slave_channel()

dma_request_slave_channel() is a simple wrapper for dma_request_chan()
eating up the error code for channel request failure and makes deferred
probing impossible.

Move the dma_request_slave_channel() into the header as inline function,
mark it as deprecated.

Signed-off-by: Peter Ujfalusi 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200828110507.22407-1-peter.ujfalusi@ti.com
Signed-off-by: Vinod Koul

dmaengine: Introduce DMA-device device_caps callback

2020-07-27T09:00:55+00:00

There are DMA devices (like ours version of Synopsys DW DMAC) which have
DMA capabilities non-uniformly redistributed between the device channels.
In order to provide a way of exposing the channel-specific parameters to
the DMA engine consumers, we introduce a new DMA-device callback. In case
if provided it gets called from the dma_get_slave_caps() method and is
able to override the generic DMA-device capabilities.

Signed-off-by: Serge Semin 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200723005848.31907-6-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul