diff options
| author | Jia Wang <wangjia@ultrarisc.com> | 2026-09-02 17:26:11 +0800 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2026-09-10 19:27:22 +0530 |
| commit | 0d59891c42e11c3840276d8a632dbc355d6ddc4f (patch) | |
| tree | 9f85082b2e6feabb63985e55c072673cbef9d348 | |
| parent | 26d48e9fb6997f4026dd86daecf8d2c12258f698 (diff) | |
| download | linux-next-0d59891c42e11c3840276d8a632dbc355d6ddc4f.tar.gz linux-next-0d59891c42e11c3840276d8a632dbc355d6ddc4f.zip | |
dmaengine: dw-axi-dmac: Fix AXI burst length encoding
The snps,axi-max-burst-len property describes the number of beats in an
AXI burst, while the ARLEN and AWLEN fields encode that value minus one.
The driver keeps axi_rw_burst_len as the actual burst length so that
dma_device.max_burst reports the correct value. However, it also programs
that unencoded value directly into the hardware fields. A value of 256
therefore overflows the 8-bit fields and can cause AXI decode errors.
Subtract one only when constructing hardware descriptors, while keeping
the actual value for dma_device.max_burst.
Fixes: c454d16a7d5a ("dmaengine: dw-axi-dmac: Burst length settings")
Signed-off-by: Jia Wang <wangjia@ultrarisc.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260902-dma-fix-v3-1-414c6449fbcc@ultrarisc.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
| -rw-r--r-- | drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c index 9c21a5479437..ea26ebc328bc 100644 --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c @@ -706,7 +706,7 @@ static int dw_axi_dma_set_hw_desc(struct axi_dma_chan *chan, ctlhi = CH_CTL_H_LLI_VALID; if (chan->chip->dw->hdata->restrict_axi_burst_len) { - burst_len = chan->chip->dw->hdata->axi_rw_burst_len; + burst_len = chan->chip->dw->hdata->axi_rw_burst_len - 1; ctlhi |= CH_CTL_H_ARLEN_EN | CH_CTL_H_AWLEN_EN | burst_len << CH_CTL_H_ARLEN_POS | burst_len << CH_CTL_H_AWLEN_POS; @@ -975,7 +975,7 @@ dma_chan_prep_dma_memcpy(struct dma_chan *dchan, dma_addr_t dst_adr, reg = CH_CTL_H_LLI_VALID; if (chan->chip->dw->hdata->restrict_axi_burst_len) { - u32 burst_len = chan->chip->dw->hdata->axi_rw_burst_len; + u32 burst_len = chan->chip->dw->hdata->axi_rw_burst_len - 1; reg |= (CH_CTL_H_ARLEN_EN | burst_len << CH_CTL_H_ARLEN_POS | |