powerpc: Update currituck pci/usb fixup for new board revision

The currituck board uses a different IRQ for the pci usb host
controller depending on the board revision. This patch adds support
for newer board revisions by retrieving the board revision from the
FPGA and mapping the appropriate IRQ.
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Acked-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/boot/dts/currituck.dts

@@ -103,6 +103,11 @@ UART0: serial@10000000 {
 				interrupts = <34 2>;
 			};
 
+			FPGA0: fpga@50000000 {
+				compatible = "ibm,currituck-fpga";
+				reg = <0x50000000 0x4>;
+			};
+
 			IIC0: i2c@00000000 {
 				compatible = "ibm,iic-currituck", "ibm,iic";
 				reg = <0x0 0x00000014>;

arch/powerpc/platforms/44x/currituck.c

@@ -176,13 +176,48 @@ static int __init ppc47x_probe(void)
 	return 1;
 }
 
+static int board_rev = -1;
+static int __init ppc47x_get_board_rev(void)
+{
+	u8 fpga_reg0;
+	void *fpga;
+	struct device_node *np;
+
+	np = of_find_compatible_node(NULL, NULL, "ibm,currituck-fpga");
+	if (!np)
+		goto fail;
+
+	fpga = of_iomap(np, 0);
+	of_node_put(np);
+	if (!fpga)
+		goto fail;
+
+	fpga_reg0 = ioread8(fpga);
+	board_rev = fpga_reg0 & 0x03;
+	pr_info("%s: Found board revision %d\n", __func__, board_rev);
+	iounmap(fpga);
+	return 0;
+
+fail:
+	pr_info("%s: Unable to find board revision\n", __func__);
+	return 0;
+}
+machine_arch_initcall(ppc47x, ppc47x_get_board_rev);
+
 /* Use USB controller should have been hardware swizzled but it wasn't :( */
 static void ppc47x_pci_irq_fixup(struct pci_dev *dev)
 {
 	if (dev->vendor == 0x1033 && (dev->device == 0x0035 ||
 	                              dev->device == 0x00e0)) {
-		dev->irq = irq_create_mapping(NULL, 47);
-		pr_info("%s: Mapping irq 47 %d\n", __func__, dev->irq);
+		if (board_rev == 0) {
+			dev->irq = irq_create_mapping(NULL, 47);
+			pr_info("%s: Mapping irq %d\n", __func__, dev->irq);
+		} else if (board_rev == 2) {
+			dev->irq = irq_create_mapping(NULL, 49);
+			pr_info("%s: Mapping irq %d\n", __func__, dev->irq);
+		} else {
+			pr_alert("%s: Unknown board revision\n", __func__);
+		}
 	}
 }