[v2,2/2] dmaengine: xilinx: xdma: Support cyclic transfers

Message ID	20230922162056.594933-3-miquel.raynal@bootlin.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org> From: Miquel Raynal <miquel.raynal@bootlin.com> To: Lizhi Hou <lizhi.hou@amd.com>, Brian Xu <brian.xu@amd.com>, Raj Kumar Rampelli <raj.kumar.rampelli@amd.com>, Vinod Koul <vkoul@kernel.org>, Michal Simek <michal.simek@amd.com> Cc: dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Thomas Petazzoni <thomas.petazzoni@bootlin.com>, <linux-kernel@vger.kernel.org>, Miquel Raynal <miquel.raynal@bootlin.com> Subject: [PATCH v2 2/2] dmaengine: xilinx: xdma: Support cyclic transfers Date: Fri, 22 Sep 2023 18:20:56 +0200 Message-Id: <20230922162056.594933-3-miquel.raynal@bootlin.com> In-Reply-To: <20230922162056.594933-1-miquel.raynal@bootlin.com> References: <20230922162056.594933-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org
Series	dmaengine: xdma: Cyclic transfers support \| expand [v2,0/2] dmaengine: xdma: Cyclic transfers support [v2,1/2] dmaengine: xilinx: xdma: Prepare the introduction of cyclic transfers [v2,2/2] dmaengine: xilinx: xdma: Support cyclic transfers

diff --git a/drivers/dma/xilinx/xdma-regs.h b/drivers/dma/xilinx/xdma-regs.h index dd98b4526b90..e641a5083e14 100644 --- a/drivers/dma/xilinx/xdma-regs.h +++ b/drivers/dma/xilinx/xdma-regs.h @@ -44,6 +44,8 @@ FIELD_PREP(XDMA_DESC_FLAGS_BITS, (flag))) #define XDMA_DESC_CONTROL_LAST \ XDMA_DESC_CONTROL(1, XDMA_DESC_STOPPED | XDMA_DESC_COMPLETED) +#define XDMA_DESC_CONTROL_CYCLIC \ + XDMA_DESC_CONTROL(1, XDMA_DESC_COMPLETED) /* * Descriptor for a single contiguous memory block transfer. diff --git a/drivers/dma/xilinx/xdma.c b/drivers/dma/xilinx/xdma.c index 09ed13d6666d..bc9a6ca3353e 100644 --- a/drivers/dma/xilinx/xdma.c +++ b/drivers/dma/xilinx/xdma.c @@ -83,6 +83,9 @@ struct xdma_chan { * @dblk_num: Number of hardware descriptor blocks * @desc_num: Number of hardware descriptors * @completed_desc_num: Completed hardware descriptors + * @cyclic: Cyclic transfer vs. scatter-gather + * @periods: Number of periods in the cyclic transfer + * @period_size: Size of a period in bytes in cyclic transfers */ struct xdma_desc { struct virt_dma_desc vdesc; @@ -93,6 +96,9 @@ struct xdma_desc { u32 dblk_num; u32 desc_num; u32 completed_desc_num; + bool cyclic; + u32 periods; + u32 period_size; }; #define XDMA_DEV_STATUS_REG_DMA BIT(0) @@ -174,6 +180,25 @@ static void xdma_link_sg_desc_blocks(struct xdma_desc *sw_desc) desc->control = cpu_to_le32(XDMA_DESC_CONTROL_LAST); } +/** + * xdma_link_cyclic_desc_blocks - Link cyclic descriptor blocks for DMA transfer + * @sw_desc: Tx descriptor pointer + */ +static void xdma_link_cyclic_desc_blocks(struct xdma_desc *sw_desc) +{ + struct xdma_desc_block *block; + struct xdma_hw_desc *desc; + int i; + + block = sw_desc->desc_blocks; + for (i = 0; i < sw_desc->desc_num - 1; i++) { + desc = block->virt_addr + i * XDMA_DESC_SIZE; + desc->next_desc = cpu_to_le64(block->dma_addr + ((i + 1) * XDMA_DESC_SIZE)); + } + desc = block->virt_addr + i * XDMA_DESC_SIZE; + desc->next_desc = cpu_to_le64(block->dma_addr); +} + static inline struct xdma_chan *to_xdma_chan(struct dma_chan *chan) { return container_of(chan, struct xdma_chan, vchan.chan); @@ -233,7 +258,7 @@ static void xdma_free_desc(struct virt_dma_desc *vdesc) * @desc_num: Number of hardware descriptors */ static struct xdma_desc * -xdma_alloc_desc(struct xdma_chan *chan, u32 desc_num) +xdma_alloc_desc(struct xdma_chan *chan, u32 desc_num, bool cyclic) { struct xdma_desc *sw_desc; struct xdma_hw_desc *desc; @@ -249,13 +274,17 @@ xdma_alloc_desc(struct xdma_chan *chan, u32 desc_num) sw_desc->chan = chan; sw_desc->desc_num = desc_num; + sw_desc->cyclic = cyclic; dblk_num = DIV_ROUND_UP(desc_num, XDMA_DESC_ADJACENT); sw_desc->desc_blocks = kcalloc(dblk_num, sizeof(*sw_desc->desc_blocks), GFP_NOWAIT); if (!sw_desc->desc_blocks) goto failed; - control = XDMA_DESC_CONTROL(1, 0); + if (cyclic) + control = XDMA_DESC_CONTROL_CYCLIC; + else + control = XDMA_DESC_CONTROL(1, 0); sw_desc->dblk_num = dblk_num; for (i = 0; i < sw_desc->dblk_num; i++) { @@ -269,7 +298,10 @@ xdma_alloc_desc(struct xdma_chan *chan, u32 desc_num) desc[j].control = cpu_to_le32(control); } - xdma_link_sg_desc_blocks(sw_desc); + if (cyclic) + xdma_link_cyclic_desc_blocks(sw_desc); + else + xdma_link_sg_desc_blocks(sw_desc); return sw_desc; @@ -469,7 +501,7 @@ xdma_prep_device_sg(struct dma_chan *chan, struct scatterlist *sgl, for_each_sg(sgl, sg, sg_len, i) desc_num += DIV_ROUND_UP(sg_dma_len(sg), XDMA_DESC_BLEN_MAX); - sw_desc = xdma_alloc_desc(xdma_chan, desc_num); + sw_desc = xdma_alloc_desc(xdma_chan, desc_num, false); if (!sw_desc) return NULL; sw_desc->dir = dir; @@ -524,6 +556,81 @@ xdma_prep_device_sg(struct dma_chan *chan, struct scatterlist *sgl, return NULL; } +/** + * xdma_prep_dma_cyclic - prepare for cyclic DMA transactions + * @chan: DMA channel pointer + * @address: Device DMA address to access + * @size: Total length to transfer + * @period_size: Period size to use for each transfer + * @dir: Transfer direction + * @flags: Transfer ack flags + */ +static struct dma_async_tx_descriptor * +xdma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t address, + size_t size, size_t period_size, + enum dma_transfer_direction dir, + unsigned long flags) +{ + struct xdma_chan *xdma_chan = to_xdma_chan(chan); + struct xdma_device *xdev = xdma_chan->xdev_hdl; + unsigned int periods = size / period_size; + struct dma_async_tx_descriptor *tx_desc; + struct xdma_desc_block *dblk; + struct xdma_hw_desc *desc; + struct xdma_desc *sw_desc; + unsigned int i; + + /* + * Simplify the whole logic by preventing an abnormally high number of + * periods and periods size. + */ + if (period_size > XDMA_DESC_BLEN_MAX) { + xdma_err(xdev, "period size limited to %lu bytes\n", XDMA_DESC_BLEN_MAX); + return NULL; + } + + if (periods > XDMA_DESC_ADJACENT) { + xdma_err(xdev, "number of periods limited to %u\n", XDMA_DESC_ADJACENT); + return NULL; + } + + sw_desc = xdma_alloc_desc(xdma_chan, periods, true); + if (!sw_desc) + return NULL; + + sw_desc->periods = periods; + sw_desc->period_size = period_size; + sw_desc->dir = dir; + + dblk = sw_desc->desc_blocks; + desc = dblk->virt_addr; + + /* fill hardware descriptor */ + for (i = 0; i < periods; i++) { + desc->bytes = cpu_to_le32(period_size); + if (dir == DMA_MEM_TO_DEV) { + desc->src_addr = cpu_to_le64(address + i * period_size); + desc->dst_addr = cpu_to_le64(xdma_chan->cfg.dst_addr); + } else { + desc->src_addr = cpu_to_le64(xdma_chan->cfg.src_addr); + desc->dst_addr = cpu_to_le64(address + i * period_size); + } + + desc++; + } + + tx_desc = vchan_tx_prep(&xdma_chan->vchan, &sw_desc->vdesc, flags); + if (!tx_desc) + goto failed; + + return tx_desc; + +failed: + xdma_free_desc(&sw_desc->vdesc); + + return NULL; +} + /** * xdma_device_config - Configure the DMA channel * @chan: DMA channel @@ -583,7 +690,36 @@ static int xdma_alloc_chan_resources(struct dma_chan *chan) static enum dma_status xdma_tx_status(struct dma_chan *chan, dma_cookie_t cookie, struct dma_tx_state *state) { - return dma_cookie_status(chan, cookie, state); + struct xdma_chan *xdma_chan = to_xdma_chan(chan); + struct xdma_desc *desc = NULL; + struct virt_dma_desc *vd; + enum dma_status ret; + unsigned long flags; + unsigned int period_idx; + u32 residue = 0; + + ret = dma_cookie_status(chan, cookie, state); + if (ret == DMA_COMPLETE) + return ret; + + spin_lock_irqsave(&xdma_chan->vchan.lock, flags); + + vd = vchan_find_desc(&xdma_chan->vchan, cookie); + if (vd) + desc = to_xdma_desc(vd); + if (!desc || !desc->cyclic) { + spin_unlock_irqrestore(&xdma_chan->vchan.lock, flags); + return ret; + } + + period_idx = desc->completed_desc_num % desc->periods; + residue = (desc->periods - period_idx) * desc->period_size; + + spin_unlock_irqrestore(&xdma_chan->vchan.lock, flags); + + dma_set_residue(state, residue); + + return ret; } /** @@ -599,6 +735,7 @@ static irqreturn_t xdma_channel_isr(int irq, void *dev_id) struct virt_dma_desc *vd; struct xdma_desc *desc; int ret; + u32 st; spin_lock(&xchan->vchan.lock); @@ -617,6 +754,19 @@ static irqreturn_t xdma_channel_isr(int irq, void *dev_id) goto out; desc->completed_desc_num += complete_desc_num; + + if (desc->cyclic) { + ret = regmap_read(xdev->rmap, xchan->base + XDMA_CHAN_STATUS, + &st); + if (ret) + goto out; + + regmap_write(xdev->rmap, xchan->base + XDMA_CHAN_STATUS, st); + + vchan_cyclic_callback(vd); + goto out; + } + /* * if all data blocks are transferred, remove and complete the request */ @@ -630,7 +780,7 @@ static irqreturn_t xdma_channel_isr(int irq, void *dev_id) complete_desc_num != XDMA_DESC_BLOCK_NUM * XDMA_DESC_ADJACENT) goto out; - /* transfer the rest of data */ + /* transfer the rest of data (SG only) */ xdma_xfer_start(xchan); out: @@ -930,8 +1080,10 @@ static int xdma_probe(struct platform_device *pdev) dma_cap_set(DMA_SLAVE, xdev->dma_dev.cap_mask); dma_cap_set(DMA_PRIVATE, xdev->dma_dev.cap_mask); + dma_cap_set(DMA_CYCLIC, xdev->dma_dev.cap_mask); xdev->dma_dev.dev = &pdev->dev; + xdev->dma_dev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT; xdev->dma_dev.device_free_chan_resources = xdma_free_chan_resources; xdev->dma_dev.device_alloc_chan_resources = xdma_alloc_chan_resources; xdev->dma_dev.device_tx_status = xdma_tx_status; @@ -941,6 +1093,7 @@ static int xdma_probe(struct platform_device *pdev) xdev->dma_dev.filter.map = pdata->device_map; xdev->dma_dev.filter.mapcnt = pdata->device_map_cnt; xdev->dma_dev.filter.fn = xdma_filter_fn; + xdev->dma_dev.device_prep_dma_cyclic = xdma_prep_dma_cyclic; ret = dma_async_device_register(&xdev->dma_dev); if (ret) {

[v2,2/2] dmaengine: xilinx: xdma: Support cyclic transfers

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