| Message ID | 20220503225104.12108-8-Sergey.Semin@baikalelectronics.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | dmaengine: dw-edma: Add RP/EP local DMA controllers support | expand |
On Wed, May 04, 2022 at 01:50:45AM +0300, Serge Semin wrote: > The interleaved DMA transfer support added in commit 85e7518f42c8 > ("dmaengine: dw-edma: Add device_prep_interleave_dma() support") seems > contradicting 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; > basically mean that numf can't be zero and frame_size must always be zero, > otherwise the transfer won't be executed. But further the transfer > execution method takes the frames 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 then actual multi-chunk > interleaved transfer turns to be unsupported even though the code implies > having it supported. > > Let's fix that by adding a fully functioning support of the 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 all over the chunks > and frames just by initializing the number of the eDMA burst transactios > 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. The rest of the dw_edma_device_transfer() method code can be left > unchanged. > > [1] include/linux/dmaengine.h: doc struct dma_interleaved_template > > Fixes: 85e7518f42c8 ("dmaengine: dw-edma: Add device_prep_interleave_dma() support") > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Thanks, Mani > --- > drivers/dma/dw-edma/dw-edma-core.c | 18 +++++++----------- > 1 file 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 225eab58acb7..ef49deb5a7f3 100644 > --- a/drivers/dma/dw-edma/dw-edma-core.c > +++ b/drivers/dma/dw-edma/dw-edma-core.c > @@ -333,6 +333,7 @@ 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; > > @@ -382,9 +383,7 @@ 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; > @@ -414,10 +413,8 @@ 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++) { > @@ -439,7 +436,7 @@ 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; > @@ -482,10 +479,9 @@ 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) > -- > 2.35.1 >
diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c index 225eab58acb7..ef49deb5a7f3 100644 --- a/drivers/dma/dw-edma/dw-edma-core.c +++ b/drivers/dma/dw-edma/dw-edma-core.c @@ -333,6 +333,7 @@ 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; @@ -382,9 +383,7 @@ 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; @@ -414,10 +413,8 @@ 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++) { @@ -439,7 +436,7 @@ 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; @@ -482,10 +479,9 @@ 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)
The interleaved DMA transfer support added in commit 85e7518f42c8 ("dmaengine: dw-edma: Add device_prep_interleave_dma() support") seems contradicting 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; basically mean that numf can't be zero and frame_size must always be zero, otherwise the transfer won't be executed. But further the transfer execution method takes the frames 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 then actual multi-chunk interleaved transfer turns to be unsupported even though the code implies having it supported. Let's fix that by adding a fully functioning support of the 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 all over the chunks and frames just by initializing the number of the eDMA burst transactios 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. The rest of the dw_edma_device_transfer() method code can be left unchanged. [1] include/linux/dmaengine.h: doc struct dma_interleaved_template Fixes: 85e7518f42c8 ("dmaengine: dw-edma: Add device_prep_interleave_dma() support") Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> --- drivers/dma/dw-edma/dw-edma-core.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-)