dmaengine: dw-edma: Add non-LL mode

AMD MDB IP supports Linked List (LL) mode as well as non-LL mode.
The current code does not have the mechanisms to enable the
DMA transactions using the non-LL mode. The following two cases
are added with this patch:
- For the AMD (Xilinx) only, when a valid physical base address of
  the device side DDR is not configured, then the IP can still be
  used in non-LL mode. For all the channels DMA transactions will
  be using the non-LL mode only. This, the default non-LL mode,
  is not applicable for Synopsys IP with the current code addition.

- If the default mode is LL-mode, for both AMD (Xilinx) and Synosys,
  and if user wants to use non-LL mode then user can do so via
  configuring the peripheral_config param of dma_slave_config.

Signed-off-by: Devendra K Verma <devendra.verma@amd.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260318070403.1634706-3-devendra.verma@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/dw-edma/dw-edma-core.c

@@ -223,6 +223,43 @@ static int dw_edma_device_config(struct dma_chan *dchan,
 				 struct dma_slave_config *config)
 {
 	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
+	bool cfg_non_ll;
+	int non_ll = 0;
+
+	chan->non_ll = false;
+	if (chan->dw->chip->mf == EDMA_MF_HDMA_NATIVE) {
+		if (config->peripheral_config &&
+		    config->peripheral_size != sizeof(int)) {
+			dev_err(dchan->device->dev,
+				"config param peripheral size mismatch\n");
+			return -EINVAL;
+		}
+
+		/*
+		 * When there is no valid LLP base address available then the
+		 * default DMA ops will use the non-LL mode.
+		 *
+		 * Cases where LL mode is enabled and client wants to use the
+		 * non-LL mode then also client can do so via providing the
+		 * peripheral_config param.
+		 */
+		cfg_non_ll = chan->dw->chip->cfg_non_ll;
+		if (config->peripheral_config) {
+			non_ll = *(int *)config->peripheral_config;
+
+			if (cfg_non_ll && !non_ll) {
+				dev_err(dchan->device->dev, "invalid configuration\n");
+				return -EINVAL;
+			}
+		}
+
+		if (cfg_non_ll || non_ll)
+			chan->non_ll = true;
+	} else if (config->peripheral_config) {
+		dev_err(dchan->device->dev,
+			"peripheral config param applicable only for HDMA\n");
+		return -EINVAL;
+	}
 
 	memcpy(&chan->config, config, sizeof(*config));
 	chan->configured = true;
@@ -358,6 +395,7 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 	struct dw_edma_desc *desc;
 	u64 src_addr, dst_addr;
 	size_t fsz = 0;
+	u32 bursts_max;
 	u32 cnt = 0;
 	int i;
 
@@ -415,6 +453,13 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 		return NULL;
 	}
 
+	/*
+	 * For non-LL mode, only a single burst can be handled
+	 * in a single chunk unlike LL mode where multiple bursts
+	 * can be configured in a single chunk.
+	 */
+	bursts_max = chan->non_ll ? 1 : chan->ll_max;
+
 	desc = dw_edma_alloc_desc(chan);
 	if (unlikely(!desc))
 		goto err_alloc;
@@ -450,7 +495,7 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
 		if (xfer->type == EDMA_XFER_SCATTER_GATHER && !sg)
 			break;
 
-		if (chunk->bursts_alloc == chan->ll_max) {
+		if (chunk->bursts_alloc == bursts_max) {
 			chunk = dw_edma_alloc_chunk(desc);
 			if (unlikely(!chunk))
 				goto err_alloc;

drivers/dma/dw-edma/dw-edma-core.h

@@ -86,6 +86,7 @@ struct dw_edma_chan {
 	u8				configured;
 
 	struct dma_slave_config		config;
+	bool				non_ll;
 };
 
 struct dw_edma_irq {

drivers/dma/dw-edma/dw-edma-pcie.c

@@ -295,6 +295,15 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
 	pdata->devmem_phys_off = off;
 }
 
+static u64 dw_edma_get_phys_addr(struct pci_dev *pdev,
+				 struct dw_edma_pcie_data *pdata,
+				 enum pci_barno bar)
+{
+	if (pdev->vendor == PCI_VENDOR_ID_XILINX)
+		return pdata->devmem_phys_off;
+	return pci_bus_address(pdev, bar);
+}
+
 static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			      const struct pci_device_id *pid)
 {
@@ -303,6 +312,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 	struct dw_edma_chip *chip;
 	int err, nr_irqs;
 	int i, mask;
+	bool non_ll = false;
 
 	struct dw_edma_pcie_data *vsec_data __free(kfree) =
 		kmalloc_obj(*vsec_data);
@@ -329,21 +339,24 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 
 		/*
 		 * There is no valid address found for the LL memory
-		 * space on the device side.
+		 * space on the device side. In the absence of LL base
+		 * address use the non-LL mode or simple mode supported by
+		 * the HDMA IP.
 		 */
 		if (vsec_data->devmem_phys_off == DW_PCIE_XILINX_MDB_INVALID_ADDR)
-			return -ENOMEM;
+			non_ll = true;
 
 		/*
 		 * Configure the channel LL and data blocks if number of
 		 * channels enabled in VSEC capability are more than the
 		 * channels configured in xilinx_mdb_data.
 		 */
-		dw_edma_set_chan_region_offset(vsec_data, BAR_2, 0,
-					       DW_PCIE_XILINX_MDB_LL_OFF_GAP,
-					       DW_PCIE_XILINX_MDB_LL_SIZE,
-					       DW_PCIE_XILINX_MDB_DT_OFF_GAP,
-					       DW_PCIE_XILINX_MDB_DT_SIZE);
+		if (!non_ll)
+			dw_edma_set_chan_region_offset(vsec_data, BAR_2, 0,
+						       DW_PCIE_XILINX_MDB_LL_OFF_GAP,
+						       DW_PCIE_XILINX_MDB_LL_SIZE,
+						       DW_PCIE_XILINX_MDB_DT_OFF_GAP,
+						       DW_PCIE_XILINX_MDB_DT_SIZE);
 	}
 
 	/* Mapping PCI BAR regions */
@@ -391,6 +404,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 	chip->mf = vsec_data->mf;
 	chip->nr_irqs = nr_irqs;
 	chip->ops = &dw_edma_pcie_plat_ops;
+	chip->cfg_non_ll = non_ll;
 
 	chip->ll_wr_cnt = vsec_data->wr_ch_cnt;
 	chip->ll_rd_cnt = vsec_data->rd_ch_cnt;
@@ -399,7 +413,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 	if (!chip->reg_base)
 		return -ENOMEM;
 
-	for (i = 0; i < chip->ll_wr_cnt; i++) {
+	for (i = 0; i < chip->ll_wr_cnt && !non_ll; i++) {
 		struct dw_edma_region *ll_region = &chip->ll_region_wr[i];
 		struct dw_edma_region *dt_region = &chip->dt_region_wr[i];
 		struct dw_edma_block *ll_block = &vsec_data->ll_wr[i];
@@ -410,7 +424,8 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			return -ENOMEM;
 
 		ll_region->vaddr.io += ll_block->off;
-		ll_region->paddr = pci_bus_address(pdev, ll_block->bar);
+		ll_region->paddr = dw_edma_get_phys_addr(pdev, vsec_data,
+							 ll_block->bar);
 		ll_region->paddr += ll_block->off;
 		ll_region->sz = ll_block->sz;
 
@@ -419,12 +434,13 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			return -ENOMEM;
 
 		dt_region->vaddr.io += dt_block->off;
-		dt_region->paddr = pci_bus_address(pdev, dt_block->bar);
+		dt_region->paddr = dw_edma_get_phys_addr(pdev, vsec_data,
+							 dt_block->bar);
 		dt_region->paddr += dt_block->off;
 		dt_region->sz = dt_block->sz;
 	}
 
-	for (i = 0; i < chip->ll_rd_cnt; i++) {
+	for (i = 0; i < chip->ll_rd_cnt && !non_ll; i++) {
 		struct dw_edma_region *ll_region = &chip->ll_region_rd[i];
 		struct dw_edma_region *dt_region = &chip->dt_region_rd[i];
 		struct dw_edma_block *ll_block = &vsec_data->ll_rd[i];
@@ -435,7 +451,8 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			return -ENOMEM;
 
 		ll_region->vaddr.io += ll_block->off;
-		ll_region->paddr = pci_bus_address(pdev, ll_block->bar);
+		ll_region->paddr = dw_edma_get_phys_addr(pdev, vsec_data,
+							 ll_block->bar);
 		ll_region->paddr += ll_block->off;
 		ll_region->sz = ll_block->sz;
 
@@ -444,7 +461,8 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			return -ENOMEM;
 
 		dt_region->vaddr.io += dt_block->off;
-		dt_region->paddr = pci_bus_address(pdev, dt_block->bar);
+		dt_region->paddr = dw_edma_get_phys_addr(pdev, vsec_data,
+							 dt_block->bar);
 		dt_region->paddr += dt_block->off;
 		dt_region->sz = dt_block->sz;
 	}

drivers/dma/dw-edma/dw-hdma-v0-core.c

@@ -225,7 +225,7 @@ static void dw_hdma_v0_sync_ll_data(struct dw_edma_chunk *chunk)
 		readl(chunk->ll_region.vaddr.io);
 }
 
-static void dw_hdma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+static void dw_hdma_v0_core_ll_start(struct dw_edma_chunk *chunk, bool first)
 {
 	struct dw_edma_chan *chan = chunk->chan;
 	struct dw_edma *dw = chan->dw;
@@ -263,6 +263,68 @@ static void dw_hdma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
 	SET_CH_32(dw, chan->dir, chan->id, doorbell, HDMA_V0_DOORBELL_START);
 }
 
+static void dw_hdma_v0_core_non_ll_start(struct dw_edma_chunk *chunk)
+{
+	struct dw_edma_chan *chan = chunk->chan;
+	struct dw_edma *dw = chan->dw;
+	struct dw_edma_burst *child;
+	u32 val;
+
+	child = list_first_entry_or_null(&chunk->burst->list,
+					 struct dw_edma_burst, list);
+	if (!child)
+		return;
+
+	SET_CH_32(dw, chan->dir, chan->id, ch_en, HDMA_V0_CH_EN);
+
+	/* Source address */
+	SET_CH_32(dw, chan->dir, chan->id, sar.lsb,
+		  lower_32_bits(child->sar));
+	SET_CH_32(dw, chan->dir, chan->id, sar.msb,
+		  upper_32_bits(child->sar));
+
+	/* Destination address */
+	SET_CH_32(dw, chan->dir, chan->id, dar.lsb,
+		  lower_32_bits(child->dar));
+	SET_CH_32(dw, chan->dir, chan->id, dar.msb,
+		  upper_32_bits(child->dar));
+
+	/* Transfer size */
+	SET_CH_32(dw, chan->dir, chan->id, transfer_size, child->sz);
+
+	/* Interrupt setup */
+	val = GET_CH_32(dw, chan->dir, chan->id, int_setup) |
+			HDMA_V0_STOP_INT_MASK |
+			HDMA_V0_ABORT_INT_MASK |
+			HDMA_V0_LOCAL_STOP_INT_EN |
+			HDMA_V0_LOCAL_ABORT_INT_EN;
+
+	if (!(dw->chip->flags & DW_EDMA_CHIP_LOCAL)) {
+		val |= HDMA_V0_REMOTE_STOP_INT_EN |
+		       HDMA_V0_REMOTE_ABORT_INT_EN;
+	}
+
+	SET_CH_32(dw, chan->dir, chan->id, int_setup, val);
+
+	/* Channel control setup */
+	val = GET_CH_32(dw, chan->dir, chan->id, control1);
+	val &= ~HDMA_V0_LINKLIST_EN;
+	SET_CH_32(dw, chan->dir, chan->id, control1, val);
+
+	SET_CH_32(dw, chan->dir, chan->id, doorbell,
+		  HDMA_V0_DOORBELL_START);
+}
+
+static void dw_hdma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
+{
+	struct dw_edma_chan *chan = chunk->chan;
+
+	if (chan->non_ll)
+		dw_hdma_v0_core_non_ll_start(chunk);
+	else
+		dw_hdma_v0_core_ll_start(chunk, first);
+}
+
 static void dw_hdma_v0_core_ch_config(struct dw_edma_chan *chan)
 {
 	struct dw_edma *dw = chan->dw;

drivers/dma/dw-edma/dw-hdma-v0-regs.h

@@ -12,6 +12,7 @@
 #include <linux/dmaengine.h>
 
 #define HDMA_V0_MAX_NR_CH			8
+#define HDMA_V0_CH_EN				BIT(0)
 #define HDMA_V0_LOCAL_ABORT_INT_EN		BIT(6)
 #define HDMA_V0_REMOTE_ABORT_INT_EN		BIT(5)
 #define HDMA_V0_LOCAL_STOP_INT_EN		BIT(4)

include/linux/dma/edma.h

@@ -103,6 +103,7 @@ struct dw_edma_chip {
 	enum dw_edma_map_format	mf;
 
 	struct dw_edma		*dw;
+	bool			cfg_non_ll;
 };
 
 /* Export to the platform drivers */