From: Marek Vasut Date: Mon, 16 Mar 2026 22:25:24 +0000 (+0100) Subject: dmaengine: xilinx: xilinx_dma: Fix unmasked residue subtraction X-Git-Tag: v7.0-rc6~3^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c7d812e33f3e8ca0fa9eeabf71d1c7bc3acedc09;p=thirdparty%2Flinux.git dmaengine: xilinx: xilinx_dma: Fix unmasked residue subtraction The segment .control and .status fields both contain top bits which are not part of the buffer size, the buffer size is located only in the bottom max_buffer_len bits. To avoid interference from those top bits, mask out the size using max_buffer_len first, and only then subtract the values. Fixes: a575d0b4e663 ("dmaengine: xilinx_dma: Introduce xilinx_dma_get_residue") Signed-off-by: Marek Vasut Link: https://patch.msgid.link/20260316222530.163815-1-marex@nabladev.com Signed-off-by: Vinod Koul --- diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c index 9dd5d7388e1d..969343342e86 100644 --- a/drivers/dma/xilinx/xilinx_dma.c +++ b/drivers/dma/xilinx/xilinx_dma.c @@ -997,16 +997,16 @@ static u32 xilinx_dma_get_residue(struct xilinx_dma_chan *chan, struct xilinx_cdma_tx_segment, node); cdma_hw = &cdma_seg->hw; - residue += (cdma_hw->control - cdma_hw->status) & - chan->xdev->max_buffer_len; + residue += (cdma_hw->control & chan->xdev->max_buffer_len) - + (cdma_hw->status & chan->xdev->max_buffer_len); } else if (chan->xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) { axidma_seg = list_entry(entry, struct xilinx_axidma_tx_segment, node); axidma_hw = &axidma_seg->hw; - residue += (axidma_hw->control - axidma_hw->status) & - chan->xdev->max_buffer_len; + residue += (axidma_hw->control & chan->xdev->max_buffer_len) - + (axidma_hw->status & chan->xdev->max_buffer_len); } else { aximcdma_seg = list_entry(entry, @@ -1014,8 +1014,8 @@ static u32 xilinx_dma_get_residue(struct xilinx_dma_chan *chan, node); aximcdma_hw = &aximcdma_seg->hw; residue += - (aximcdma_hw->control - aximcdma_hw->status) & - chan->xdev->max_buffer_len; + (aximcdma_hw->control & chan->xdev->max_buffer_len) - + (aximcdma_hw->status & chan->xdev->max_buffer_len); } }