PCI: rcar: Break out window size handling

Break out the hard coded window size code to allow dynamic setup. The
window size is still left at 1GiB but with this patch changing window size
is easy for testing.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NSimon Horman <horms+renesas@verge.net.au>

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

@@ -18,6 +18,7 @@
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/sizes.h>
 #include <linux/slab.h>
 
 /* AHB-PCI Bridge PCI communication registers */
@@ -98,6 +99,7 @@ struct rcar_pci_priv {
 	struct resource mem_res;
 	struct resource *cfg_res;
 	int irq;
+	unsigned long window_size;
 };
 
 /* PCI configuration space operations */
@@ -241,10 +243,31 @@ static int rcar_pci_setup(int nr, struct pci_sys_data *sys)
 	iowrite32(val, reg + RCAR_USBCTR_REG);
 	udelay(4);
 
-	/* De-assert reset and set PCIAHB window1 size to 1GB */
+	/* De-assert reset and reset PCIAHB window1 size */
 	val &= ~(RCAR_USBCTR_PCIAHB_WIN1_MASK | RCAR_USBCTR_PCICLK_MASK |
 		 RCAR_USBCTR_USBH_RST | RCAR_USBCTR_PLL_RST);
-	iowrite32(val | RCAR_USBCTR_PCIAHB_WIN1_1G, reg + RCAR_USBCTR_REG);
+
+	/* Setup PCIAHB window1 size */
+	switch (priv->window_size) {
+	case SZ_2G:
+		val |= RCAR_USBCTR_PCIAHB_WIN1_2G;
+		break;
+	case SZ_1G:
+		val |= RCAR_USBCTR_PCIAHB_WIN1_1G;
+		break;
+	case SZ_512M:
+		val |= RCAR_USBCTR_PCIAHB_WIN1_512M;
+		break;
+	default:
+		pr_warn("unknown window size %ld - defaulting to 256M\n",
+			priv->window_size);
+		priv->window_size = SZ_256M;
+		/* fall-through */
+	case SZ_256M:
+		val |= RCAR_USBCTR_PCIAHB_WIN1_256M;
+		break;
+	}
+	iowrite32(val, reg + RCAR_USBCTR_REG);
 
 	/* Configure AHB master and slave modes */
 	iowrite32(RCAR_AHB_BUS_MODE, reg + RCAR_AHB_BUS_CTR_REG);
@@ -255,7 +278,7 @@ 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: 0x40000000-0x80000000 */
+	/* PCI-AHB mapping: 0x40000000 base */
 	iowrite32(0x40000000 | RCAR_PCIAHB_PREFETCH16,
 		  reg + RCAR_PCIAHB_WIN1_CTR_REG);
 
@@ -341,6 +364,8 @@ static int rcar_pci_probe(struct platform_device *pdev)
 		return priv->irq;
 	}
 
+	priv->window_size = SZ_1G;
+
 	hw_private[0] = priv;
 	memset(&hw, 0, sizeof(hw));
 	hw.nr_controllers = ARRAY_SIZE(hw_private);