diff options
author | Serge Semin <Sergey.Semin@baikalelectronics.ru> | 2023-01-13 20:13:48 +0300 |
---|---|---|
committer | Lorenzo Pieralisi <lpieralisi@kernel.org> | 2023-01-27 19:15:33 +0300 |
commit | 7ad06f218491bf30f13fd88933bb807de5330cdd (patch) | |
tree | ac92e89dab7ab3f55089266b54bd7526b8e9dc2d /drivers/dma | |
parent | c8ed49182286cb9c64f0c503b98090bd11a3fb60 (diff) | |
download | linux-7ad06f218491bf30f13fd88933bb807de5330cdd.tar.xz |
dmaengine: dw-edma: Fix invalid interleaved xfers semantics
The interleaved DMA transfer support added by 85e7518f42c8 ("dmaengine:
dw-edma: Add device_prep_interleave_dma() support") seems contradictory to
what the DMA engine defines. The next conditional statements:
if (!xfer->xfer.il->numf)
return NULL;
if (xfer->xfer.il->numf > 0 && xfer->xfer.il->frame_size > 0)
return NULL;
mean that numf can't be zero and frame_size must always be zero, otherwise
the transfer won't be executed. Furthermore, the transfer execution method
takes the frame size from the dma_interleaved_template.sgl[] array for each
frame. That array in accordance with [1] is supposed to be of
dma_interleaved_template.frame_size size, which as we discovered before the
code expects to be zero. So judging by the dw_edma_device_transfer()
implementation, the method implies the dma_interleaved_template.sgl[] array
being of dma_interleaved_template.numf size, which is wrong. Since the
dw_edma_device_transfer() method doesn't permit
dma_interleaved_template.frame_size being non-zero, the multi-chunk
interleaved transfer turns to be unsupported even though the code implies
having it supported.
Add fully functioning support of interleaved DMA transfers.
First of all, dma_interleaved_template.frame_size is supposed to be greater
or equal to one thus having at least simple linear chunked frames.
Secondly, we can create a walk-through over all the chunks and frames by
initializing the number of the eDMA burst transactions as a multiple of
dma_interleaved_template.numf and dma_interleaved_template.frame_size and
getting the frame_size-modulo of the iteration step as an index of the
dma_interleaved_template.sgl[] array.
[1] include/linux/dmaengine.h: doc struct dma_interleaved_template
Link: https://lore.kernel.org/r/20230113171409.30470-7-Sergey.Semin@baikalelectronics.ru
Fixes: 85e7518f42c8 ("dmaengine: dw-edma: Add device_prep_interleave_dma() support")
Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma')
-rw-r--r-- | drivers/dma/dw-edma/dw-edma-core.c | 18 |
1 files changed, 7 insertions, 11 deletions
diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c index 35588e14f79a..d5c4192141ef 100644 --- a/drivers/dma/dw-edma/dw-edma-core.c +++ b/drivers/dma/dw-edma/dw-edma-core.c @@ -332,6 +332,7 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer) struct dw_edma_chunk *chunk; struct dw_edma_burst *burst; struct dw_edma_desc *desc; + size_t fsz = 0; u32 cnt = 0; int i; @@ -381,9 +382,7 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer) if (xfer->xfer.sg.len < 1) return NULL; } else if (xfer->type == EDMA_XFER_INTERLEAVED) { - if (!xfer->xfer.il->numf) - return NULL; - if (xfer->xfer.il->numf > 0 && xfer->xfer.il->frame_size > 0) + if (!xfer->xfer.il->numf || xfer->xfer.il->frame_size < 1) return NULL; if (!xfer->xfer.il->src_inc || !xfer->xfer.il->dst_inc) return NULL; @@ -413,10 +412,8 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer) cnt = xfer->xfer.sg.len; sg = xfer->xfer.sg.sgl; } else if (xfer->type == EDMA_XFER_INTERLEAVED) { - if (xfer->xfer.il->numf > 0) - cnt = xfer->xfer.il->numf; - else - cnt = xfer->xfer.il->frame_size; + cnt = xfer->xfer.il->numf * xfer->xfer.il->frame_size; + fsz = xfer->xfer.il->frame_size; } for (i = 0; i < cnt; i++) { @@ -438,7 +435,7 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer) else if (xfer->type == EDMA_XFER_SCATTER_GATHER) burst->sz = sg_dma_len(sg); else if (xfer->type == EDMA_XFER_INTERLEAVED) - burst->sz = xfer->xfer.il->sgl[i].size; + burst->sz = xfer->xfer.il->sgl[i % fsz].size; chunk->ll_region.sz += burst->sz; desc->alloc_sz += burst->sz; @@ -481,10 +478,9 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer) if (xfer->type == EDMA_XFER_SCATTER_GATHER) { sg = sg_next(sg); - } else if (xfer->type == EDMA_XFER_INTERLEAVED && - xfer->xfer.il->frame_size > 0) { + } else if (xfer->type == EDMA_XFER_INTERLEAVED) { struct dma_interleaved_template *il = xfer->xfer.il; - struct data_chunk *dc = &il->sgl[i]; + struct data_chunk *dc = &il->sgl[i % fsz]; src_addr += burst->sz; if (il->src_sgl) |