[PATCH 6/9] PCI: dwc: ep: Use 'ranges' from DT if 'addr_space' is missing

[Frank Li <Frank.Li@xxxxxxx>]

Some systems (such as i.MX8QXP) have different CPU and PCI addresses,
requiring address translation. If 'addr_space' is missing, retrieve the
address translation information from the 'ranges' property in the device
tree. This allows support for systems where CPU and PCI addresses differ
without relying solely on 'addr_space'.

Update the driver to use 'ranges' from the device tree when 'addr_space' is
not provided, keeping compatibility with existed systems.

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
 drivers/pci/controller/dwc/pcie-designware-ep.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index feac1a435f764..1b013d2fe694a 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -294,7 +294,7 @@ static int dw_pcie_ep_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 
 	atu.func_no = func_no;
 	atu.type = PCIE_ATU_TYPE_MEM;
-	atu.cpu_addr = addr;
+	atu.cpu_addr = addr + ep->range.bus_addr - ep->range.cpu_addr;
 	atu.pci_addr = pci_addr;
 	atu.size = size;
 	ret = dw_pcie_ep_outbound_atu(ep, &atu);
@@ -861,6 +861,7 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 	struct device *dev = pci->dev;
 	struct platform_device *pdev = to_platform_device(dev);
 	struct device_node *np = dev->of_node;
+	struct of_pci_range_parser parser;
 
 	INIT_LIST_HEAD(&ep->func_list);
 
@@ -869,11 +870,21 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 		return ret;
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
-	if (!res)
-		return -EINVAL;
+	if (!res) {
+		ret = of_pci_range_parser_init(&parser, np);
+		if (ret)
+			return ret;
+
+		for_each_of_pci_range(&parser, &ep->range)
+			if ((ep->range.flags & IORESOURCE_TYPE_BITS) == IORESOURCE_MEM)
+				break;
 
-	ep->range.cpu_addr = ep->range.pci_addr = res->start;
-	ep->range.size = resource_size(res);
+		if (!ep->range.size)
+			return -EINVAL;
+	} else {
+		ep->range.cpu_addr = ep->range.bus_addr = res->start;
+		ep->range.size = resource_size(res);
+	}
 
 	if (ep->ops->pre_init)
 		ep->ops->pre_init(ep);

-- 
2.34.1