kernel/linux.git/drivers/dma/mediatek, branch v5.15.209

dmaengine: mediatek: uart-apdma: Fix above 4G addressing TX/RX

2026-03-04T12:19:45+00:00

[ Upstream commit 58ab9d7b6651d21e1cff1777529f2d3dd0b4e851 ] The VFF_4G_SUPPORT register is named differently in datasheets, and its name is "VFF_ADDR2"; was this named correctly from the beginning it would've been clearer that there was a mistake in the programming sequence. This register is supposed to hold the high bits to support the DMA addressing above 4G (so, more than 32 bits) and not a bit to "enable" the support for VFF 4G. Fix the name of this register, and also fix its usage by writing the upper 32 bits of the dma_addr_t on it when the SoC supports such feature. Fixes: 9135408c3ace ("dmaengine: mediatek: Add MediaTek UART APDMA support") Signed-off-by: AngeloGioacchino Del Regno Link: https://patch.msgid.link/20251113122229.23998-6-angelogioacchino.delregno@collabora.com Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin

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

2025-09-09T16:50:25+00:00

[ Upstream commit 8eba2187391e5ab49940cd02d6bd45a5617f4daf ] 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 Signed-off-by: Sasha Levin

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

2025-09-09T16:50:23+00:00

[ Upstream commit 157ae5ffd76a2857ccb4b7ce40bc5a344ca00395 ] 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 Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

dmaengine: mediatek: Fix deadlock caused by synchronize_irq()

2023-10-19T21:05:37+00:00

[ Upstream commit 01f1ae2733e2bb4de92fefcea5fda847d92aede1 ] 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 Signed-off-by: Sasha Levin

dmaengine: mediatek:Fix PM usage reference leak of mtk_uart_apdma_alloc_chan_resources

2022-04-27T12:38:52+00:00

[ Upstream commit 545b2baac89b859180e51215468c05d85ea8465a ] pm_runtime_get_sync will increment pm usage counter even it failed. Forgetting to putting operation will result in reference leak here. We fix it: 1) Replacing it with pm_runtime_resume_and_get to keep usage counter balanced. 2) Add putting operation before returning error. Fixes:9135408c3ace4 ("dmaengine: mediatek: Add MediaTek UART APDMA support") Signed-off-by: Zhang Qilong Link: https://lore.kernel.org/r/20220319022142.142709-1-zhangqilong3@huawei.com Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin

dmaengine: mediatek: use GFP_NOWAIT instead of GFP_ATOMIC in prep_dma

2021-06-07T06:53:47+00:00

As recommended by the doc in: Documentation/drivers-api/dmaengine/provider.rst Use GFP_NOWAIT to not deplete the emergency pool. Signed-off-by: Guillaume Ranquet Link: https://lore.kernel.org/r/20210513192642.29446-4-granquet@baylibre.com Signed-off-by: Vinod Koul

dmaengine: mediatek: do not issue a new desc if one is still current

2021-06-07T06:53:47+00:00

Avoid issuing a new desc if one is still being processed as this can lead to some desc never being marked as completed. Signed-off-by: Guillaume Ranquet Link: https://lore.kernel.org/r/20210513192642.29446-3-granquet@baylibre.com Signed-off-by: Vinod Koul

dmaengine: mediatek: free the proper desc in desc_free handler

2021-06-07T06:53:47+00:00

The desc_free handler assumed that the desc we want to free was always the current one associated with the channel. This is seldom the case and this is causing use after free crashes in multiple places (tx/rx/terminate...). BUG: KASAN: use-after-free in mtk_uart_apdma_rx_handler+0x120/0x304 Call trace: dump_backtrace+0x0/0x1b0 show_stack+0x24/0x34 dump_stack+0xe0/0x150 print_address_description+0x8c/0x55c __kasan_report+0x1b8/0x218 kasan_report+0x14/0x20 __asan_load4+0x98/0x9c mtk_uart_apdma_rx_handler+0x120/0x304 mtk_uart_apdma_irq_handler+0x50/0x80 __handle_irq_event_percpu+0xe0/0x210 handle_irq_event+0x8c/0x184 handle_fasteoi_irq+0x1d8/0x3ac __handle_domain_irq+0xb0/0x110 gic_handle_irq+0x50/0xb8 el0_irq_naked+0x60/0x6c Allocated by task 3541: __kasan_kmalloc+0xf0/0x1b0 kasan_kmalloc+0x10/0x1c kmem_cache_alloc_trace+0x90/0x2dc mtk_uart_apdma_prep_slave_sg+0x6c/0x1a0 mtk8250_dma_rx_complete+0x220/0x2e4 vchan_complete+0x290/0x340 tasklet_action_common+0x220/0x298 tasklet_action+0x28/0x34 __do_softirq+0x158/0x35c Freed by task 3541: __kasan_slab_free+0x154/0x224 kasan_slab_free+0x14/0x24 slab_free_freelist_hook+0xf8/0x15c kfree+0xb4/0x278 mtk_uart_apdma_desc_free+0x34/0x44 vchan_complete+0x1bc/0x340 tasklet_action_common+0x220/0x298 tasklet_action+0x28/0x34 __do_softirq+0x158/0x35c The buggy address belongs to the object at ffff000063606800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 176 bytes inside of 256-byte region [ffff000063606800, ffff000063606900) The buggy address belongs to the page: page:fffffe00016d8180 refcount:1 mapcount:0 mapping:ffff00000302f600 index:0x0 compound_mapcount: 0 flags: 0xffff00000010200(slab|head) raw: 0ffff00000010200 dead000000000100 dead000000000122 ffff00000302f600 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Signed-off-by: Guillaume Ranquet Link: https://lore.kernel.org/r/20210513192642.29446-2-granquet@baylibre.com Signed-off-by: Vinod Koul

dmaengine: mediatek: mtk-hsdma: Fix a resource leak in the error handling path of the probe function

2020-12-29T04:37:59+00:00

'mtk_hsdma_hw_deinit()' should be called in the error handling path of the probe function to undo a previous 'mtk_hsdma_hw_init()' call, as already done in the remove function. Fixes: 548c4597e984 ("dmaengine: mediatek: Add MediaTek High-Speed DMA controller for MT7622 and MT7623 SoC") Signed-off-by: Christophe JAILLET Link: https://lore.kernel.org/r/20201219124718.182664-1-christophe.jaillet@wanadoo.fr Signed-off-by: Vinod Koul

Merge branch 'topic/tasklet' into next

2020-10-01T04:48:59+00:00