[PATCH v3 12/13] dmaengine: dw-edma-pcie: Handle optional data blocks

[Koichiro Den]

Skip data block BAR mapping and debug output when a channel has no data
block size. This lets future providers describe channels that only need
descriptor memory exposed.

No functional change intended for existing Synopsys EDDA and
AMD (Xilinx) MDB/CPM6 devices. Their static channel descriptions still
provide data block sizes where data block windows are used. A zero-sized
data block now means "not present" for future metadata providers.

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
Signed-off-by: Koichiro Den <den@xxxxxxxxxxxxx>
---
Changes in v3:
  - Update commit message to describe the AMD (Xilinx) CPM6 match
    present in the new base.

 drivers/dma/dw-edma/dw-edma-pcie.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
index 62740c8c3f93..622ec974a521 100644
--- a/drivers/dma/dw-edma/dw-edma-pcie.c
+++ b/drivers/dma/dw-edma/dw-edma-pcie.c
@@ -430,11 +430,13 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 	mask = BIT(dma_data->rg.bar);
 	for (i = 0; i < dma_data->wr_ch_cnt; i++) {
 		mask |= BIT(dma_data->ll_wr[i].bar);
-		mask |= BIT(dma_data->dt_wr[i].bar);
+		if (dma_data->dt_wr[i].sz)
+			mask |= BIT(dma_data->dt_wr[i].bar);
 	}
 	for (i = 0; i < dma_data->rd_ch_cnt; i++) {
 		mask |= BIT(dma_data->ll_rd[i].bar);
-		mask |= BIT(dma_data->dt_rd[i].bar);
+		if (dma_data->dt_rd[i].sz)
+			mask |= BIT(dma_data->dt_rd[i].bar);
 	}
 	err = pcim_iomap_regions(pdev, mask, pci_name(pdev));
 	if (err) {
@@ -498,6 +500,9 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 							  ll_block);
 		ll_region->sz = ll_block->sz;
 
+		if (!dt_block->sz)
+			continue;
+
 		dt_region->vaddr.io = pcim_iomap_table(pdev)[dt_block->bar];
 		if (!dt_region->vaddr.io)
 			return -ENOMEM;
@@ -523,6 +528,9 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 							  ll_block);
 		ll_region->sz = ll_block->sz;
 
+		if (!dt_block->sz)
+			continue;
+
 		dt_region->vaddr.io = pcim_iomap_table(pdev)[dt_block->bar];
 		if (!dt_region->vaddr.io)
 			return -ENOMEM;
@@ -556,10 +564,14 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			dma_data->ll_wr[i].off, chip->ll_region_wr[i].sz,
 			chip->ll_region_wr[i].vaddr.io, &chip->ll_region_wr[i].paddr);
 
+		if (!dma_data->dt_wr[i].sz)
+			continue;
+
 		pci_dbg(pdev, "Data:\tWRITE CH%.2u, BAR=%u, off=0x%.8lx, sz=0x%zx bytes, addr(v=%p, p=%pa)\n",
 			i, dma_data->dt_wr[i].bar,
 			dma_data->dt_wr[i].off, chip->dt_region_wr[i].sz,
-			chip->dt_region_wr[i].vaddr.io, &chip->dt_region_wr[i].paddr);
+			chip->dt_region_wr[i].vaddr.io,
+			&chip->dt_region_wr[i].paddr);
 	}
 
 	for (i = 0; i < chip->ll_rd_cnt; i++) {
@@ -568,10 +580,14 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 			dma_data->ll_rd[i].off, chip->ll_region_rd[i].sz,
 			chip->ll_region_rd[i].vaddr.io, &chip->ll_region_rd[i].paddr);
 
+		if (!dma_data->dt_rd[i].sz)
+			continue;
+
 		pci_dbg(pdev, "Data:\tREAD CH%.2u, BAR=%u, off=0x%.8lx, sz=0x%zx bytes, addr(v=%p, p=%pa)\n",
 			i, dma_data->dt_rd[i].bar,
 			dma_data->dt_rd[i].off, chip->dt_region_rd[i].sz,
-			chip->dt_region_rd[i].vaddr.io, &chip->dt_region_rd[i].paddr);
+			chip->dt_region_rd[i].vaddr.io,
+			&chip->dt_region_rd[i].paddr);
 	}
 
 	pci_dbg(pdev, "Nr. IRQs:\t%u\n", chip->nr_irqs);
-- 
2.51.0