[PATCH v4 10/14] dmaengine: dw-edma-pcie: Add register offset match flag

[Koichiro Den <den@valinux.co.jp>]

Add a match-data flag for devices whose DMA register block starts at an
offset inside the mapped BAR. Existing Synopsys EDDA and AMD (Xilinx)
MDB/CPM6 matches keep using the BAR mapping base directly.

The offsets handled here come from static, trusted match data. Later
metadata-derived offsets are validated when the endpoint DMA metadata
path parses them at that trust boundary.

No functional change intended.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
The offsets come from static match data and need no bounds check
here; metadata-derived offsets arriving with the part 3 discovery
patch are validated against the mapped BAR size at that trust
boundary.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
Changes in v4:
  - No changes.

 drivers/dma/dw-edma/dw-edma-pcie.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
index 36b18032c835..a19282c15644 100644
--- a/drivers/dma/dw-edma/dw-edma-pcie.c
+++ b/drivers/dma/dw-edma/dw-edma-pcie.c
@@ -89,6 +89,7 @@ struct dw_edma_pcie_match_data {
 };
 
 #define DW_EDMA_PCIE_F_DEVMEM_PHYS_OFF	BIT(0)
+#define DW_EDMA_PCIE_F_REG_OFFSET	BIT(1)
 
 static const struct dw_edma_pcie_data snps_edda_data = {
 	/* eDMA registers location */
@@ -464,6 +465,8 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 	chip->reg_base = pcim_iomap_table(pdev)[dma_data->rg.bar];
 	if (!chip->reg_base)
 		return -ENOMEM;
+	if (match->flags & DW_EDMA_PCIE_F_REG_OFFSET)
+		chip->reg_base += dma_data->rg.off;
 
 	for (i = 0; i < chip->ll_wr_cnt && !dma_data->cfg_non_ll; i++) {
 		struct dw_edma_region *ll_region = &chip->ll_region_wr[i];
-- 
2.51.0