linux-dev/drivers/dma, branch master

dmaengine: at_hdmac: Check return code of dma_async_device_register

2022-11-08T05:13:57Z

dma_async_device_register() can fail, check the return code and display an error. Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-16-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul

dmaengine: at_hdmac: Fix impossible condition

2022-11-08T05:13:57Z

The iterator can not be greater than ATC_MAX_DSCR_TRIALS, as the for loop will stop when i == ATC_MAX_DSCR_TRIALS. While here, use the common "i" name for the iterator. Fixes: 93dce3a6434f ("dmaengine: at_hdmac: fix residue computation") Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-15-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul

dmaengine: at_hdmac: Don't allow CPU to reorder channel enable

2022-11-08T05:13:57Z

at_hdmac uses __raw_writel for register writes. In the absence of a barrier, the CPU may reorder the register operations. Introduce a write memory barrier so that the CPU does not reorder the channel enable, thus the start of the transfer, without making sure that all the pre-required register fields are already written. Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/ Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-14-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul

dmaengine: at_hdmac: Fix completion of unissued descriptor in case of errors

2022-11-08T05:13:57Z

In case the controller detected an error, the code took the chance to move all the queued (submitted) descriptors to the active (issued) list. This was wrong as if there were any descriptors in the submitted list they were moved to the issued list without actually issuing them to the controller, thus a completion could be raised without even fireing the descriptor. Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/ Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-13-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul

dmaengine: at_hdmac: Fix descriptor handling when issuing it to hardware

2022-11-08T05:13:57Z

As it was before, the descriptor was issued to the hardware without adding it to the active (issued) list. This could result in a completion of other descriptor, or/and in the descriptor never being completed. Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/ Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-12-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul

dmaengine: at_hdmac: Fix concurrency over the active list

2022-11-08T05:13:57Z

The tasklet (atc_advance_work()) did not held the channel lock when retrieving the first active descriptor, causing concurrency problems if issue_pending() was called in between. If issue_pending() was called exactly after the lock was released in the tasklet (atc_advance_work()), atc_chain_complete() could complete a descriptor for which the controller has not yet raised an interrupt. Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/ Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-11-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul

dmaengine: at_hdmac: Free the memset buf without holding the chan lock

2022-11-08T05:13:57Z

There's no need to hold the channel lock when freeing the memset buf, as the operation has already completed. Free the memset buf without holding the channel lock. Fixes: 4d112426c344 ("dmaengine: hdmac: Add memset capabilities") Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-10-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul

dmaengine: at_hdmac: Fix concurrency over descriptor

2022-11-08T05:13:57Z

The descriptor was added to the free_list before calling the callback, which could result in reissuing of the same descriptor and calling of a single callback for both. Move the decriptor to the free list after the callback is invoked. Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/ Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-9-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul

dmaengine: at_hdmac: Fix concurrency problems by removing atc_complete_all()

2022-11-08T05:13:57Z

atc_complete_all() had concurrency bugs, thus remove it: 1/ atc_complete_all() in its entirety was buggy, as when the atchan->queue list (the one that contains descriptors that are not yet issued to the hardware) contained descriptors, it fired just the first from the atchan->queue, but moved all the desc from atchan->queue to atchan->active_list and considered them all as fired. This could result in calling the completion of a descriptor that was not yet issued to the hardware. 2/ when in tasklet at atc_advance_work() time, atchan->active_list was queried without holding the lock of the chan. This can result in atchan->active_list concurrency problems between the tasklet and issue_pending(). Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/ Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-8-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul

dmaengine: at_hdmac: Protect atchan->status with the channel lock

2022-11-08T05:13:56Z

Now that the complete callback call was removed from device_terminate_all(), we can protect the atchan->status with the channel lock. The atomic bitops on atchan->status do not substitute proper locking on the status, as one could still modify the status after the lock was dropped in atc_terminate_all() but before the atomic bitops were executed. Fixes: 078a6506141a ("dmaengine: at_hdmac: Fix deadlocks") Reported-by: Peter Rosin Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/ Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-7-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul