linux-toradex.git/drivers/dma/mediatek, branch v6.19

dmaengine: mediatek: Fix a flag reuse error in mtk_cqdma_tx_status()

2025-06-26T22:09:20+00:00

Fixed a flag reuse bug in the mtk_cqdma_tx_status() function.

Fixes: 157ae5ffd76a ("dmaengine: mediatek: Fix a possible deadlock error in mtk_cqdma_tx_status()")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202505270641.MStzJUfU-lkp@intel.com/
Signed-off-by: Qiu-ji Chen 
Reviewed-by: Eugen Hristev 
Reviewed-by: AngeloGioacchino Del Regno 
Link: https://lore.kernel.org/r/20250606090017.5436-1-chenqiuji666@gmail.com
Signed-off-by: Vinod Koul

dmaengine: mediatek: drop unused variable

2025-05-15T10:42:13+00:00

Commit 157ae5ffd76a dmaengine: mediatek: Fix a possible deadlock error
in mtk_cqdma_tx_status() fixed locks but kept unused varibale leading to
warning and build failure (due to warning treated as errors)

drivers/dma/mediatek/mtk-cqdma.c: In function 'mtk_cqdma_find_active_desc':
drivers/dma/mediatek/mtk-cqdma.c:423:23: error: unused variable 'flags' [-Werror=unused-variable]
  423 |         unsigned long flags;
      |                       ^~~~~

Fix by dropping this unused flag

Reported-by: Stephen Rothwell 
Fixes: 157ae5ffd76a ("dmaengine: mediatek: Fix a possible deadlock error in mtk_cqdma_tx_status()")
Signed-off-by: Vinod Koul

dmaengine: mediatek: Fix a possible deadlock error in mtk_cqdma_tx_status()

2025-05-14T13:54:31+00:00

Fix a potential deadlock bug. Observe that in the mtk-cqdma.c
file, functions like mtk_cqdma_issue_pending() and
mtk_cqdma_free_active_desc() properly acquire the pc lock before the vc
lock when handling pc and vc fields. However, mtk_cqdma_tx_status()
violates this order by first acquiring the vc lock before invoking
mtk_cqdma_find_active_desc(), which subsequently takes the pc lock. This
reversed locking sequence (vc → pc) contradicts the established
pc → vc order and creates deadlock risks.

Fix the issue by moving the vc lock acquisition code from
mtk_cqdma_find_active_desc() to mtk_cqdma_tx_status(). Ensure the pc lock
is acquired before the vc lock in the calling function to maintain correct
locking hierarchy. Note that since mtk_cqdma_find_active_desc() is a
static function with only one caller (mtk_cqdma_tx_status()), this
modification safely eliminates the deadlock possibility without affecting
other components.

This possible bug is found by an experimental static analysis tool
developed by our team. This tool analyzes the locking APIs to extract
function pairs that can be concurrently executed, and then analyzes the
instructions in the paired functions to identify possible concurrency bugs
including deadlocks, data races and atomicity violations.

Fixes: b1f01e48df5a ("dmaengine: mediatek: Add MediaTek Command-Queue DMA controller for MT6765 SoC")
Cc: stable@vger.kernel.org
Signed-off-by: Qiu-ji Chen 
Reviewed-by: AngeloGioacchino Del Regno 
Link: https://lore.kernel.org/r/20250508073634.3719-1-chenqiuji666@gmail.com
Signed-off-by: Vinod Koul

dmaengine: Switch back to struct platform_driver::remove()

2024-10-14T18:20:34+00:00

After commit 0edb555a65d1 ("platform: Make platform_driver::remove()
return void") .remove() is (again) the right callback to implement for
platform drivers.

Convert all platform drivers below drivers/dma after the previous
conversion commits apart from the wireless drivers to use .remove(),
with the eventual goal to drop struct platform_driver::remove_new(). As
.remove() and .remove_new() have the same prototypes, conversion is done
by just changing the structure member name in the driver initializer.

Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20241004062227.187726-2-u.kleine-koenig@baylibre.com
Signed-off-by: Vinod Koul

dmaengine: Fix spelling mistakes

2024-09-02T08:26:01+00:00

Correct spelling mistakes in the DMA engine to improve readability
and clarity without altering functionality.

Signed-off-by: Amit Vadhavana 
Reviewed-by: Kees Cook 
Reviewed-by: Dave Jiang 
Reviewed-by: Fenghua Yu 
Link: https://lore.kernel.org/r/20240831172949.13189-1-av2082000@gmail.com
Signed-off-by: Vinod Koul

Merge tag 'dmaengine-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine

2023-11-04T04:56:51+00:00

Pull dmaengine updates from Vinod Koul:

 - Big pile of __counted_by attribute annotations to several structures
   for bounds checking of flexible arrays at run-time

 - Another big pile platform remove callback returning void changes

 - Device tree device_get_match_data() usage and dropping
   of_match_device() calls

 - Minor driver updates to pxa, idxd fsl, hisi etc drivers

* tag 'dmaengine-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine: (106 commits)
  dmaengine: stm32-mdma: correct desc prep when channel running
  dmaengine: dw-axi-dmac: Add support DMAX_NUM_CHANNELS > 16
  dmaengine: xilinx: xilinx_dma: Fix kernel doc about xilinx_dma_remove()
  dmaengine: mmp_tdma: drop unused variable 'of_id'
  MAINTAINERS: Add entries for NXP(Freescale) eDMA drivers
  dmaengine: xilinx: xdma: Support cyclic transfers
  dmaengine: xilinx: xdma: Prepare the introduction of cyclic transfers
  dmaengine: Drop unnecessary of_match_device() calls
  dmaengine: Use device_get_match_data()
  dmaengine: pxa_dma: Annotate struct pxad_desc_sw with __counted_by
  dmaengine: pxa_dma: Remove an erroneous BUG_ON() in pxad_free_desc()
  dmaengine: xilinx: xdma: Use resource_size() in xdma_probe()
  dmaengine: fsl-dpaa2-qdma: Remove redundant initialization owner in dpaa2_qdma_driver
  dmaengine: Remove unused declaration dma_chan_cleanup()
  dmaengine: mmp: fix Wvoid-pointer-to-enum-cast warning
  dmaengine: qcom: fix Wvoid-pointer-to-enum-cast warning
  dmaengine: fsl-edma: Remove redundant dev_err() for platform_get_irq()
  dmaengine: ep93xx_dma: Annotate struct ep93xx_dma_engine with __counted_by
  dmaengine: idxd: add wq driver name support for accel-config user tool
  dmaengine: fsl-edma: Annotate struct struct fsl_edma_engine with __counted_by
  ...

dmaengine: mediatek: Fix deadlock caused by synchronize_irq()

2023-10-04T13:56:36+00:00

The synchronize_irq(c->irq) will not return until the IRQ handler
mtk_uart_apdma_irq_handler() is completed. If the synchronize_irq()
holds a spin_lock and waits the IRQ handler to complete, but the
IRQ handler also needs the same spin_lock. The deadlock will happen.
The process is shown below:

          cpu0                        cpu1
mtk_uart_apdma_device_pause() | mtk_uart_apdma_irq_handler()
  spin_lock_irqsave()         |
                              |   spin_lock_irqsave()
  //hold the lock to wait     |
  synchronize_irq()           |

This patch reorders the synchronize_irq(c->irq) outside the spin_lock
in order to mitigate the bug.

Fixes: 9135408c3ace ("dmaengine: mediatek: Add MediaTek UART APDMA support")
Signed-off-by: Duoming Zhou 
Reviewed-by: Eugen Hristev 
Link: https://lore.kernel.org/r/20230806032511.45263-1-duoming@zju.edu.cn
Signed-off-by: Vinod Koul

dmaengine: mediatek: mtk-uart-apdma: Convert to platform remove callback returning void

2023-09-28T07:40:50+00:00

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new() which already returns void. Eventually after all drivers
are converted, .remove_new() is renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König 
Reviewed-by: AngeloGioacchino Del Regno 
Link: https://lore.kernel.org/r/20230919133207.1400430-25-u.kleine-koenig@pengutronix.de
Signed-off-by: Vinod Koul

dmaengine: mediatek: mtk-hsdma: Convert to platform remove callback returning void

2023-09-28T07:40:50+00:00

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new() which already returns void. Eventually after all drivers
are converted, .remove_new() is renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König 
Reviewed-by: AngeloGioacchino Del Regno 
Link: https://lore.kernel.org/r/20230919133207.1400430-24-u.kleine-koenig@pengutronix.de
Signed-off-by: Vinod Koul

dmaengine: mediatek: mtk-cqdma: Convert to platform remove callback returning void

2023-09-28T07:40:50+00:00

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new() which already returns void. Eventually after all drivers
are converted, .remove_new() is renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König 
Reviewed-by: AngeloGioacchino Del Regno 
Link: https://lore.kernel.org/r/20230919133207.1400430-23-u.kleine-koenig@pengutronix.de
Signed-off-by: Vinod Koul