dmaengine: owl: Add Slave and Cyclic mode support for Actions Semi Owl S900 SoC

Add Slave and Cyclic mode support for Actions Semi Owl S900 SoC. The slave
mode supports bus width of 4 bytes common for all peripherals and 1 byte
specific for UART.

The cyclic mode supports only block mode transfer.

Signed-off-by: Manivannan Sadhasivam <[e-mail]>
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/owl-dma.c

···
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/of_dma.h>
 #include <linux/slab.h>
 #include "virt-dma.h"
 
···
 struct owl_dma_txd {
 	struct virt_dma_desc	vd;
 	struct list_head	lli_list;
+	bool			cyclic;
 };
 
 /**
···
 	struct virt_dma_chan	vc;
 	struct owl_dma_pchan	*pchan;
 	struct owl_dma_txd	*txd;
+	struct dma_slave_config cfg;
+	u8			drq;
 };
 
 /**
···
 
 static struct owl_dma_lli *owl_dma_add_lli(struct owl_dma_txd *txd,
 					   struct owl_dma_lli *prev,
-					   struct owl_dma_lli *next)
+					   struct owl_dma_lli *next,
+					   bool is_cyclic)
 {
-	list_add_tail(&next->node, &txd->lli_list);
+	if (!is_cyclic)
+		list_add_tail(&next->node, &txd->lli_list);
 
 	if (prev) {
 		prev->hw.next_lli = next->phys;
···
 static inline int owl_dma_cfg_lli(struct owl_dma_vchan *vchan,
 				  struct owl_dma_lli *lli,
 				  dma_addr_t src, dma_addr_t dst,
-				  u32 len, enum dma_transfer_direction dir)
+				  u32 len, enum dma_transfer_direction dir,
+				  struct dma_slave_config *sconfig,
+				  bool is_cyclic)
 {
 	struct owl_dma_lli_hw *hw = &lli->hw;
 	u32 mode;
···
 		mode |= OWL_DMA_MODE_TS(0) | OWL_DMA_MODE_ST_DCU |
 			OWL_DMA_MODE_DT_DCU | OWL_DMA_MODE_SAM_INC |
 			OWL_DMA_MODE_DAM_INC;
+
+		break;
+	case DMA_MEM_TO_DEV:
+		mode |= OWL_DMA_MODE_TS(vchan->drq)
+			| OWL_DMA_MODE_ST_DCU | OWL_DMA_MODE_DT_DEV
+			| OWL_DMA_MODE_SAM_INC | OWL_DMA_MODE_DAM_CONST;
+
+		/*
+		 * Hardware only supports 32bit and 8bit buswidth. Since the
+		 * default is 32bit, select 8bit only when requested.
+		 */
+		if (sconfig->dst_addr_width == DMA_SLAVE_BUSWIDTH_1_BYTE)
+			mode |= OWL_DMA_MODE_NDDBW_8BIT;
+
+		break;
+	case DMA_DEV_TO_MEM:
+		 mode |= OWL_DMA_MODE_TS(vchan->drq)
+			| OWL_DMA_MODE_ST_DEV | OWL_DMA_MODE_DT_DCU
+			| OWL_DMA_MODE_SAM_CONST | OWL_DMA_MODE_DAM_INC;
+
+		/*
+		 * Hardware only supports 32bit and 8bit buswidth. Since the
+		 * default is 32bit, select 8bit only when requested.
+		 */
+		if (sconfig->src_addr_width == DMA_SLAVE_BUSWIDTH_1_BYTE)
+			mode |= OWL_DMA_MODE_NDDBW_8BIT;
 
 		break;
 	default:
···
 				 OWL_DMA_LLC_SAV_LOAD_NEXT |
 				 OWL_DMA_LLC_DAV_LOAD_NEXT);
 
-	hw->ctrlb = llc_hw_ctrlb(OWL_DMA_INTCTL_SUPER_BLOCK);
+	if (is_cyclic)
+		hw->ctrlb = llc_hw_ctrlb(OWL_DMA_INTCTL_BLOCK);
+	else
+		hw->ctrlb = llc_hw_ctrlb(OWL_DMA_INTCTL_SUPER_BLOCK);
 
 	return 0;
 }
···
 	spin_unlock_irqrestore(&od->lock, flags);
 }
 
+static void owl_dma_pause_pchan(struct owl_dma_pchan *pchan)
+{
+	pchan_writel(pchan, 1, OWL_DMAX_PAUSE);
+}
+
+static void owl_dma_resume_pchan(struct owl_dma_pchan *pchan)
+{
+	pchan_writel(pchan, 0, OWL_DMAX_PAUSE);
+}
+
 static int owl_dma_start_next_txd(struct owl_dma_vchan *vchan)
 {
 	struct owl_dma *od = to_owl_dma(vchan->vc.chan.device);
···
 	lli = list_first_entry(&txd->lli_list,
 			       struct owl_dma_lli, node);
 
-	int_ctl = OWL_DMA_INTCTL_SUPER_BLOCK;
+	if (txd->cyclic)
+		int_ctl = OWL_DMA_INTCTL_BLOCK;
+	else
+		int_ctl = OWL_DMA_INTCTL_SUPER_BLOCK;
 
 	pchan_writel(pchan, OWL_DMAX_MODE, OWL_DMA_MODE_LME);
 	pchan_writel(pchan, OWL_DMAX_LINKLIST_CTL,
···
 	return 0;
 }
 
+static int owl_dma_config(struct dma_chan *chan,
+			  struct dma_slave_config *config)
+{
+	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
+
+	/* Reject definitely invalid configurations */
+	if (config->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES ||
+	    config->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
+		return -EINVAL;
+
+	memcpy(&vchan->cfg, config, sizeof(struct dma_slave_config));
+
+	return 0;
+}
+
+static int owl_dma_pause(struct dma_chan *chan)
+{
+	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+
+	owl_dma_pause_pchan(vchan->pchan);
+
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+	return 0;
+}
+
+static int owl_dma_resume(struct dma_chan *chan)
+{
+	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
+	unsigned long flags;
+
+	if (!vchan->pchan && !vchan->txd)
+		return 0;
+
+	dev_dbg(chan2dev(chan), "vchan %p: resume\n", &vchan->vc);
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+
+	owl_dma_resume_pchan(vchan->pchan);
+
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+	return 0;
+}
+
 static u32 owl_dma_getbytes_chan(struct owl_dma_vchan *vchan)
 {
 	struct owl_dma_pchan *pchan;
···
 		bytes = min_t(size_t, (len - offset), OWL_DMA_FRAME_MAX_LENGTH);
 
 		ret = owl_dma_cfg_lli(vchan, lli, src + offset, dst + offset,
-				      bytes, DMA_MEM_TO_MEM);
+				      bytes, DMA_MEM_TO_MEM,
+				      &vchan->cfg, txd->cyclic);
 		if (ret) {
 			dev_warn(chan2dev(chan), "failed to config lli\n");
 			goto err_txd_free;
 		}
 
-		prev = owl_dma_add_lli(txd, prev, lli);
+		prev = owl_dma_add_lli(txd, prev, lli, false);
 	}
 
 	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
 
 err_txd_free:
 	owl_dma_free_txd(od, txd);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor
+		*owl_dma_prep_slave_sg(struct dma_chan *chan,
+				       struct scatterlist *sgl,
+				       unsigned int sg_len,
+				       enum dma_transfer_direction dir,
+				       unsigned long flags, void *context)
+{
+	struct owl_dma *od = to_owl_dma(chan->device);
+	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
+	struct dma_slave_config *sconfig = &vchan->cfg;
+	struct owl_dma_txd *txd;
+	struct owl_dma_lli *lli, *prev = NULL;
+	struct scatterlist *sg;
+	dma_addr_t addr, src = 0, dst = 0;
+	size_t len;
+	int ret, i;
+
+	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
+	if (!txd)
+		return NULL;
+
+	INIT_LIST_HEAD(&txd->lli_list);
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		addr = sg_dma_address(sg);
+		len = sg_dma_len(sg);
+
+		if (len > OWL_DMA_FRAME_MAX_LENGTH) {
+			dev_err(od->dma.dev,
+				"frame length exceeds max supported length");
+			goto err_txd_free;
+		}
+
+		lli = owl_dma_alloc_lli(od);
+		if (!lli) {
+			dev_err(chan2dev(chan), "failed to allocate lli");
+			goto err_txd_free;
+		}
+
+		if (dir == DMA_MEM_TO_DEV) {
+			src = addr;
+			dst = sconfig->dst_addr;
+		} else {
+			src = sconfig->src_addr;
+			dst = addr;
+		}
+
+		ret = owl_dma_cfg_lli(vchan, lli, src, dst, len, dir, sconfig,
+				      txd->cyclic);
+		if (ret) {
+			dev_warn(chan2dev(chan), "failed to config lli");
+			goto err_txd_free;
+		}
+
+		prev = owl_dma_add_lli(txd, prev, lli, false);
+	}
+
+	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
+
+err_txd_free:
+	owl_dma_free_txd(od, txd);
+
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor
+		*owl_prep_dma_cyclic(struct dma_chan *chan,
+				     dma_addr_t buf_addr, size_t buf_len,
+				     size_t period_len,
+				     enum dma_transfer_direction dir,
+				     unsigned long flags)
+{
+	struct owl_dma *od = to_owl_dma(chan->device);
+	struct owl_dma_vchan *vchan = to_owl_vchan(chan);
+	struct dma_slave_config *sconfig = &vchan->cfg;
+	struct owl_dma_txd *txd;
+	struct owl_dma_lli *lli, *prev = NULL, *first = NULL;
+	dma_addr_t src = 0, dst = 0;
+	unsigned int periods = buf_len / period_len;
+	int ret, i;
+
+	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
+	if (!txd)
+		return NULL;
+
+	INIT_LIST_HEAD(&txd->lli_list);
+	txd->cyclic = true;
+
+	for (i = 0; i < periods; i++) {
+		lli = owl_dma_alloc_lli(od);
+		if (!lli) {
+			dev_warn(chan2dev(chan), "failed to allocate lli");
+			goto err_txd_free;
+		}
+
+		if (dir == DMA_MEM_TO_DEV) {
+			src = buf_addr + (period_len * i);
+			dst = sconfig->dst_addr;
+		} else if (dir == DMA_DEV_TO_MEM) {
+			src = sconfig->src_addr;
+			dst = buf_addr + (period_len * i);
+		}
+
+		ret = owl_dma_cfg_lli(vchan, lli, src, dst, period_len,
+				      dir, sconfig, txd->cyclic);
+		if (ret) {
+			dev_warn(chan2dev(chan), "failed to config lli");
+			goto err_txd_free;
+		}
+
+		if (!first)
+			first = lli;
+
+		prev = owl_dma_add_lli(txd, prev, lli, false);
+	}
+
+	/* close the cyclic list */
+	owl_dma_add_lli(txd, prev, first, true);
+
+	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
+
+err_txd_free:
+	owl_dma_free_txd(od, txd);
+
 	return NULL;
 }
 
···
 		list_del(&vchan->vc.chan.device_node);
 		tasklet_kill(&vchan->vc.task);
 	}
+}
+
+static struct dma_chan *owl_dma_of_xlate(struct of_phandle_args *dma_spec,
+					 struct of_dma *ofdma)
+{
+	struct owl_dma *od = ofdma->of_dma_data;
+	struct owl_dma_vchan *vchan;
+	struct dma_chan *chan;
+	u8 drq = dma_spec->args[0];
+
+	if (drq > od->nr_vchans)
+		return NULL;
+
+	chan = dma_get_any_slave_channel(&od->dma);
+	if (!chan)
+		return NULL;
+
+	vchan = to_owl_vchan(chan);
+	vchan->drq = drq;
+
+	return chan;
 }
 
 static int owl_dma_probe(struct platform_device *pdev)
···
 	spin_lock_init(&od->lock);
 
 	dma_cap_set(DMA_MEMCPY, od->dma.cap_mask);
+	dma_cap_set(DMA_SLAVE, od->dma.cap_mask);
+	dma_cap_set(DMA_CYCLIC, od->dma.cap_mask);
 
 	od->dma.dev = &pdev->dev;
 	od->dma.device_free_chan_resources = owl_dma_free_chan_resources;
 	od->dma.device_tx_status = owl_dma_tx_status;
 	od->dma.device_issue_pending = owl_dma_issue_pending;
 	od->dma.device_prep_dma_memcpy = owl_dma_prep_memcpy;
+	od->dma.device_prep_slave_sg = owl_dma_prep_slave_sg;
+	od->dma.device_prep_dma_cyclic = owl_prep_dma_cyclic;
+	od->dma.device_config = owl_dma_config;
+	od->dma.device_pause = owl_dma_pause;
+	od->dma.device_resume = owl_dma_resume;
 	od->dma.device_terminate_all = owl_dma_terminate_all;
 	od->dma.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
 	od->dma.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
···
 		goto err_pool_free;
 	}
 
+	/* Device-tree DMA controller registration */
+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 owl_dma_of_xlate, od);
+	if (ret) {
+		dev_err(&pdev->dev, "of_dma_controller_register failed\n");
+		goto err_dma_unregister;
+	}
+
 	return 0;
 
+err_dma_unregister:
+	dma_async_device_unregister(&od->dma);
 err_pool_free:
 	clk_disable_unprepare(od->clk);
 	dma_pool_destroy(od->lli_pool);
···
 {
 	struct owl_dma *od = platform_get_drvdata(pdev);
 
+	of_dma_controller_free(pdev->dev.of_node);
 	dma_async_device_unregister(&od->dma);
 
 	/* Mask all interrupts for this execution environment */