From: Alain Volmat <alain.volmat@foss.st.com> To: <hugues.fruchet@foss.st.com>, <mchehab@kernel.org> Cc: <mcoquelin.stm32@gmail.com>, <alexandre.torgue@foss.st.com>, <linux-media@vger.kernel.org>, <linux-stm32@st-md-mailman.stormreply.com>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <alain.volmat@foss.st.com> Subject: [PATCH] media: stm32: dcmi: create a dma scatterlist based on DMA max_sg_burst value Date: Mon, 10 Jan 2022 11:37:39 +0100 [thread overview] Message-ID: <20220110103739.118426-1-alain.volmat@foss.st.com> (raw) Prior to submitting a transfer to the DMA, the client should first check the capabilities of the DMA channel in term of maximum of each segment. This is given by the max_sg_burst value reported by dma_get_slave_caps API. Based on that, if the transfer is larger than what can be handled by the DMA channel, we split the transfer into several scatterlist elements. Signed-off-by: Alain Volmat <alain.volmat@foss.st.com> --- drivers/media/platform/stm32/stm32-dcmi.c | 47 ++++++++++++++++++----- 1 file changed, 37 insertions(+), 10 deletions(-) diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c index e1b17c05229c..ee170e999a88 100644 --- a/drivers/media/platform/stm32/stm32-dcmi.c +++ b/drivers/media/platform/stm32/stm32-dcmi.c @@ -113,7 +113,7 @@ struct dcmi_framesize { struct dcmi_buf { struct vb2_v4l2_buffer vb; bool prepared; - dma_addr_t paddr; + struct sg_table sgt; size_t size; struct list_head list; }; @@ -157,6 +157,7 @@ struct stm32_dcmi { enum state state; struct dma_chan *dma_chan; dma_cookie_t dma_cookie; + u32 dma_max_burst; u32 misr; int errors_count; int overrun_count; @@ -326,13 +327,11 @@ static int dcmi_start_dma(struct stm32_dcmi *dcmi, mutex_lock(&dcmi->dma_lock); /* Prepare a DMA transaction */ - desc = dmaengine_prep_slave_single(dcmi->dma_chan, buf->paddr, - buf->size, + desc = dmaengine_prep_slave_sg(dcmi->dma_chan, buf->sgt.sgl, buf->sgt.nents, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT); if (!desc) { - dev_err(dcmi->dev, "%s: DMA dmaengine_prep_slave_single failed for buffer phy=%pad size=%zu\n", - __func__, &buf->paddr, buf->size); + dev_err(dcmi->dev, "%s: DMA dmaengine_prep_slave_sg failed\n", __func__); mutex_unlock(&dcmi->dma_lock); return -EINVAL; } @@ -524,6 +523,10 @@ static int dcmi_buf_prepare(struct vb2_buffer *vb) struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); struct dcmi_buf *buf = container_of(vbuf, struct dcmi_buf, vb); unsigned long size; + unsigned int num_sgs = 1; + dma_addr_t dma_buf; + struct scatterlist *sg; + int i, ret; size = dcmi->fmt.fmt.pix.sizeimage; @@ -537,15 +540,33 @@ static int dcmi_buf_prepare(struct vb2_buffer *vb) if (!buf->prepared) { /* Get memory addresses */ - buf->paddr = - vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0); buf->size = vb2_plane_size(&buf->vb.vb2_buf, 0); - buf->prepared = true; + if (buf->size > dcmi->dma_max_burst) + num_sgs = DIV_ROUND_UP(buf->size, dcmi->dma_max_burst); - vb2_set_plane_payload(&buf->vb.vb2_buf, 0, buf->size); + ret = sg_alloc_table(&buf->sgt, num_sgs, GFP_ATOMIC); + if (ret) { + dev_err(dcmi->dev, "sg table alloc failed\n"); + return ret; + } + + dma_buf = vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0); dev_dbg(dcmi->dev, "buffer[%d] phy=%pad size=%zu\n", - vb->index, &buf->paddr, buf->size); + vb->index, &dma_buf, buf->size); + + for_each_sg(buf->sgt.sgl, sg, num_sgs, i) { + size_t bytes = min_t(size_t, size, dcmi->dma_max_burst); + + sg_dma_address(sg) = dma_buf; + sg_dma_len(sg) = bytes; + dma_buf += bytes; + size -= bytes; + } + + buf->prepared = true; + + vb2_set_plane_payload(&buf->vb.vb2_buf, 0, buf->size); } return 0; @@ -1866,6 +1887,7 @@ static int dcmi_probe(struct platform_device *pdev) struct stm32_dcmi *dcmi; struct vb2_queue *q; struct dma_chan *chan; + struct dma_slave_caps caps; struct clk *mclk; int irq; int ret = 0; @@ -1953,6 +1975,11 @@ static int dcmi_probe(struct platform_device *pdev) return ret; } + dcmi->dma_max_burst = UINT_MAX; + ret = dma_get_slave_caps(chan, &caps); + if (!ret && caps.max_sg_burst) + dcmi->dma_max_burst = caps.max_sg_burst * DMA_SLAVE_BUSWIDTH_4_BYTES; + spin_lock_init(&dcmi->irqlock); mutex_init(&dcmi->lock); mutex_init(&dcmi->dma_lock); -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Alain Volmat <alain.volmat@foss.st.com> To: <hugues.fruchet@foss.st.com>, <mchehab@kernel.org> Cc: <mcoquelin.stm32@gmail.com>, <alexandre.torgue@foss.st.com>, <linux-media@vger.kernel.org>, <linux-stm32@st-md-mailman.stormreply.com>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <alain.volmat@foss.st.com> Subject: [PATCH] media: stm32: dcmi: create a dma scatterlist based on DMA max_sg_burst value Date: Mon, 10 Jan 2022 11:37:39 +0100 [thread overview] Message-ID: <20220110103739.118426-1-alain.volmat@foss.st.com> (raw) Prior to submitting a transfer to the DMA, the client should first check the capabilities of the DMA channel in term of maximum of each segment. This is given by the max_sg_burst value reported by dma_get_slave_caps API. Based on that, if the transfer is larger than what can be handled by the DMA channel, we split the transfer into several scatterlist elements. Signed-off-by: Alain Volmat <alain.volmat@foss.st.com> --- drivers/media/platform/stm32/stm32-dcmi.c | 47 ++++++++++++++++++----- 1 file changed, 37 insertions(+), 10 deletions(-) diff --git a/drivers/media/platform/stm32/stm32-dcmi.c b/drivers/media/platform/stm32/stm32-dcmi.c index e1b17c05229c..ee170e999a88 100644 --- a/drivers/media/platform/stm32/stm32-dcmi.c +++ b/drivers/media/platform/stm32/stm32-dcmi.c @@ -113,7 +113,7 @@ struct dcmi_framesize { struct dcmi_buf { struct vb2_v4l2_buffer vb; bool prepared; - dma_addr_t paddr; + struct sg_table sgt; size_t size; struct list_head list; }; @@ -157,6 +157,7 @@ struct stm32_dcmi { enum state state; struct dma_chan *dma_chan; dma_cookie_t dma_cookie; + u32 dma_max_burst; u32 misr; int errors_count; int overrun_count; @@ -326,13 +327,11 @@ static int dcmi_start_dma(struct stm32_dcmi *dcmi, mutex_lock(&dcmi->dma_lock); /* Prepare a DMA transaction */ - desc = dmaengine_prep_slave_single(dcmi->dma_chan, buf->paddr, - buf->size, + desc = dmaengine_prep_slave_sg(dcmi->dma_chan, buf->sgt.sgl, buf->sgt.nents, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT); if (!desc) { - dev_err(dcmi->dev, "%s: DMA dmaengine_prep_slave_single failed for buffer phy=%pad size=%zu\n", - __func__, &buf->paddr, buf->size); + dev_err(dcmi->dev, "%s: DMA dmaengine_prep_slave_sg failed\n", __func__); mutex_unlock(&dcmi->dma_lock); return -EINVAL; } @@ -524,6 +523,10 @@ static int dcmi_buf_prepare(struct vb2_buffer *vb) struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); struct dcmi_buf *buf = container_of(vbuf, struct dcmi_buf, vb); unsigned long size; + unsigned int num_sgs = 1; + dma_addr_t dma_buf; + struct scatterlist *sg; + int i, ret; size = dcmi->fmt.fmt.pix.sizeimage; @@ -537,15 +540,33 @@ static int dcmi_buf_prepare(struct vb2_buffer *vb) if (!buf->prepared) { /* Get memory addresses */ - buf->paddr = - vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0); buf->size = vb2_plane_size(&buf->vb.vb2_buf, 0); - buf->prepared = true; + if (buf->size > dcmi->dma_max_burst) + num_sgs = DIV_ROUND_UP(buf->size, dcmi->dma_max_burst); - vb2_set_plane_payload(&buf->vb.vb2_buf, 0, buf->size); + ret = sg_alloc_table(&buf->sgt, num_sgs, GFP_ATOMIC); + if (ret) { + dev_err(dcmi->dev, "sg table alloc failed\n"); + return ret; + } + + dma_buf = vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0); dev_dbg(dcmi->dev, "buffer[%d] phy=%pad size=%zu\n", - vb->index, &buf->paddr, buf->size); + vb->index, &dma_buf, buf->size); + + for_each_sg(buf->sgt.sgl, sg, num_sgs, i) { + size_t bytes = min_t(size_t, size, dcmi->dma_max_burst); + + sg_dma_address(sg) = dma_buf; + sg_dma_len(sg) = bytes; + dma_buf += bytes; + size -= bytes; + } + + buf->prepared = true; + + vb2_set_plane_payload(&buf->vb.vb2_buf, 0, buf->size); } return 0; @@ -1866,6 +1887,7 @@ static int dcmi_probe(struct platform_device *pdev) struct stm32_dcmi *dcmi; struct vb2_queue *q; struct dma_chan *chan; + struct dma_slave_caps caps; struct clk *mclk; int irq; int ret = 0; @@ -1953,6 +1975,11 @@ static int dcmi_probe(struct platform_device *pdev) return ret; } + dcmi->dma_max_burst = UINT_MAX; + ret = dma_get_slave_caps(chan, &caps); + if (!ret && caps.max_sg_burst) + dcmi->dma_max_burst = caps.max_sg_burst * DMA_SLAVE_BUSWIDTH_4_BYTES; + spin_lock_init(&dcmi->irqlock); mutex_init(&dcmi->lock); mutex_init(&dcmi->dma_lock); -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2022-01-10 10:38 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-10 10:37 Alain Volmat [this message] 2022-01-10 10:37 ` [PATCH] media: stm32: dcmi: create a dma scatterlist based on DMA max_sg_burst value Alain Volmat 2022-01-24 8:49 ` Alain Volmat 2022-01-24 8:49 ` Alain Volmat
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