Fix two more RP1 DMA bugs #6734
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axi_desc_put often gets called in error paths, and so can't assume that the descriptor passed in has been completely initialised. Guard against unallocated LLIs. See: raspberrypi#6733 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Remove a bogus memory alignment check - transfers will be run bytewise if needed - and add a check that the overall length is multiple of the register size, otherwise there is residue. See: raspberrypi#6733 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
popcornmix
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Mar 20, 2025
P33M
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Mar 20, 2025
| @@ -798,6 +794,11 @@ static int dw_axi_dma_set_hw_desc(struct axi_dma_chan *chan, | |||
| return -EINVAL; | |||
| } | |||
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| if (len % reg_width) { | |||
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(Thinking aloud, not an issue at the moment) I wonder if use-cases that have memory buffers spanning a page boundary with odd alignment are broken when using this driver - and this error message makes this case known.
But fixing this means rewriting dw_axi_dma_chan_prep_[cyclic|slave]_sg to dynamically allocate hardware descriptors inside for_each_sg().
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kernel: fixup! dmaengine: dw-axi-dmac: Fixes for RP1 See: raspberrypi/linux#6729 kernel: drm/vc4: Correct arithmetic for shifting between columns of SAND images See: raspberrypi/linux#6730 kernel: Adding Pisound Micro kernel module based on rpi-6.12.y See: raspberrypi/linux#6731 kernel: Fix two more RP1 DMA bugs See: raspberrypi/linux#6734 kernel: dts: bcm2712-rpi: Add uart0_nodma See: raspberrypi/linux#6365
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kernel: fixup! dmaengine: dw-axi-dmac: Fixes for RP1 See: raspberrypi/linux#6729 kernel: drm/vc4: Correct arithmetic for shifting between columns of SAND images See: raspberrypi/linux#6730 kernel: Adding Pisound Micro kernel module based on rpi-6.12.y See: raspberrypi/linux#6731 kernel: Fix two more RP1 DMA bugs See: raspberrypi/linux#6734 kernel: dts: bcm2712-rpi: Add uart0_nodma See: raspberrypi/linux#6365
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Two bugs discovered while investigating #6733: