On 28.09.2017 12:29, Vinod Koul wrote: >> + default: >> + return -EINVAL; >> + } >> + >> + ahb_seq = burst << TEGRA_AHBDMA_CHANNEL_AHB_BURST_SHIFT; >> + ahb_seq |= TEGRA_AHBDMA_CHANNEL_ADDR_WRAP; >> + ahb_seq |= TEGRA_AHBDMA_CHANNEL_INTR_ENB; >> + >> + writel_relaxed(ahb_seq, >> + ahbdma_chan->regs + TEGRA_AHBDMA_CHANNEL_AHB_SEQ); >> + >> + writel_relaxed(ahb_addr, >> + ahbdma_chan->regs + TEGRA_AHBDMA_CHANNEL_AHB_PTR); > > oh no, you don't write to HW here. This can be called anytime when you have > txn running! You should save these and use them in prep_ calls. >
BTW, some of the DMA drivers have exactly the same problem. I now see that it is actually documented explicitly in provider.txt, but that's inconsistent across the actual drivers. -- Dmitry
