PCI: rcar: Allow DT to override default window settings

If the DTB specifies dma-ranges, use those values.  Otherwise, default to
the values that were previously hardcoded into the driver.
Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Simon Horman <horms+renesas@verge.net.au>

Documentation/devicetree/bindings/pci/pci-rcar-gen2.txt

@@ -24,6 +24,11 @@ Required properties:
 - interrupt-map-mask: standard property that helps to define the interrupt
   mapping.
 
+Optional properties:
+- dma-ranges: a single range for the inbound memory region. If not supplied,
+  defaults to 1GiB at 0x40000000. Note there are hardware restrictions on the
+  allowed combinations of address and size.
+
 Example SoC configuration:
 
 	pci0: pci@ee090000  {
@@ -38,6 +43,7 @@ Example SoC configuration:
 		#address-cells = <3>;
 		#size-cells = <2>;
 		#interrupt-cells = <1>;
+		dma-ranges = <0x42000000 0 0x40000000 0 0x40000000 0 0x40000000>;
 		interrupt-map-mask = <0xff00 0 0 0x7>;
 		interrupt-map = <0x0000 0 0 1 &gic 0 108 IRQ_TYPE_LEVEL_HIGH
 				 0x0800 0 0 1 &gic 0 108 IRQ_TYPE_LEVEL_HIGH

drivers/pci/host/pci-rcar-gen2.c

@@ -15,6 +15,7 @@
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/of_address.h>
 #include <linux/of_pci.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
@@ -102,6 +103,8 @@ struct rcar_pci_priv {
 	unsigned busnr;
 	int irq;
 	unsigned long window_size;
+	unsigned long window_addr;
+	unsigned long window_pci;
 };
 
 /* PCI configuration space operations */
@@ -239,8 +242,8 @@ static int rcar_pci_setup(int nr, struct pci_sys_data *sys)
 	       RCAR_PCI_ARBITER_PCIBP_MODE;
 	iowrite32(val, reg + RCAR_PCI_ARBITER_CTR_REG);
 
-	/* PCI-AHB mapping: 0x40000000 base */
-	iowrite32(0x40000000 | RCAR_PCIAHB_PREFETCH16,
+	/* PCI-AHB mapping */
+	iowrite32(priv->window_addr | RCAR_PCIAHB_PREFETCH16,
 		  reg + RCAR_PCIAHB_WIN1_CTR_REG);
 
 	/* AHB-PCI mapping: OHCI/EHCI registers */
@@ -251,7 +254,7 @@ static int rcar_pci_setup(int nr, struct pci_sys_data *sys)
 	iowrite32(RCAR_AHBPCI_WIN1_HOST | RCAR_AHBPCI_WIN_CTR_CFG,
 		  reg + RCAR_AHBPCI_WIN1_CTR_REG);
 	/* Set PCI-AHB Window1 address */
-	iowrite32(0x40000000 | PCI_BASE_ADDRESS_MEM_PREFETCH,
+	iowrite32(priv->window_pci | PCI_BASE_ADDRESS_MEM_PREFETCH,
 		  reg + PCI_BASE_ADDRESS_1);
 	/* Set AHB-PCI bridge PCI communication area address */
 	val = priv->cfg_res->start + RCAR_AHBPCI_PCICOM_OFFSET;
@@ -284,6 +287,64 @@ static struct pci_ops rcar_pci_ops = {
 	.write	= pci_generic_config_write,
 };
 
+static int pci_dma_range_parser_init(struct of_pci_range_parser *parser,
+				     struct device_node *node)
+{
+	const int na = 3, ns = 2;
+	int rlen;
+
+	parser->node = node;
+	parser->pna = of_n_addr_cells(node);
+	parser->np = parser->pna + na + ns;
+
+	parser->range = of_get_property(node, "dma-ranges", &rlen);
+	if (!parser->range)
+		return -ENOENT;
+
+	parser->end = parser->range + rlen / sizeof(__be32);
+	return 0;
+}
+
+static int rcar_pci_parse_map_dma_ranges(struct rcar_pci_priv *pci,
+					 struct device_node *np)
+{
+	struct of_pci_range range;
+	struct of_pci_range_parser parser;
+	int index = 0;
+
+	/* Failure to parse is ok as we fall back to defaults */
+	if (pci_dma_range_parser_init(&parser, np))
+		return 0;
+
+	/* Get the dma-ranges from DT */
+	for_each_of_pci_range(&parser, &range) {
+		/* Hardware only allows one inbound 32-bit range */
+		if (index)
+			return -EINVAL;
+
+		pci->window_addr = (unsigned long)range.cpu_addr;
+		pci->window_pci = (unsigned long)range.pci_addr;
+		pci->window_size = (unsigned long)range.size;
+
+		/* Catch HW limitations */
+		if (!(range.flags & IORESOURCE_PREFETCH)) {
+			dev_err(pci->dev, "window must be prefetchable\n");
+			return -EINVAL;
+		}
+		if (pci->window_addr) {
+			u32 lowaddr = 1 << (ffs(pci->window_addr) - 1);
+
+			if (lowaddr < pci->window_size) {
+				dev_err(pci->dev, "invalid window size/addr\n");
+				return -EINVAL;
+			}
+		}
+		index++;
+	}
+
+	return 0;
+}
+
 static int rcar_pci_probe(struct platform_device *pdev)
 {
 	struct resource *cfg_res, *mem_res;
@@ -329,6 +390,9 @@ static int rcar_pci_probe(struct platform_device *pdev)
 		return priv->irq;
 	}
 
+	/* default window addr and size if not specified in DT */
+	priv->window_addr = 0x40000000;
+	priv->window_pci = 0x40000000;
 	priv->window_size = SZ_1G;
 
 	if (pdev->dev.of_node) {
@@ -344,6 +408,12 @@ static int rcar_pci_probe(struct platform_device *pdev)
 		priv->busnr = busnr.start;
 		if (busnr.end != busnr.start)
 			dev_warn(&pdev->dev, "only one bus number supported\n");
+
+		ret = rcar_pci_parse_map_dma_ranges(priv, pdev->dev.of_node);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "failed to parse dma-range\n");
+			return ret;
+		}
 	} else {
 		priv->busnr = pdev->id;
 	}