powerpc/85xx: mpc85xxcds - Fix PCI I/O space resource of PCI bridge

There is a PCI bridge(Tsi310) between the MPC8548 and a VIA
southbridge chip.

The bootloader sets the PCI bridge to open a window from 0x0000
to 0x1fff on the PCI I/O space. But the kernel can't set the I/O
resource. In the routine pci_read_bridge_io(), if the base which
is read from PCI_IO_BASE is equal to zero, the routine don't set
the I/O resource of the child bus.

To allow the legacy I/O space on the VIA southbridge to be accessed,
use the fixup to fix the PCI I/O space of the PCI bridge.

Signed-off-by: Zhao Chenhui <chenhui.zhao@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/platforms/85xx/mpc85xx_cds.c

@@ -3,7 +3,7 @@
  *
  * Maintained by Kumar Gala (see MAINTAINERS for contact information)
  *
- * Copyright 2005 Freescale Semiconductor Inc.
+ * Copyright 2005, 2011-2012 Freescale Semiconductor Inc.
  *
  * This program is free software; you can redistribute  it and/or modify it
  * under  the terms of  the GNU General  Public License as published by the
@@ -158,6 +158,33 @@ DECLARE_PCI_FIXUP_EARLY(0x1957, 0x3fff, skip_fake_bridge);
 DECLARE_PCI_FIXUP_EARLY(0x3fff, 0x1957, skip_fake_bridge);
 DECLARE_PCI_FIXUP_EARLY(0xff3f, 0x5719, skip_fake_bridge);
 
+#define PCI_DEVICE_ID_IDT_TSI310	0x01a7
+
+/*
+ * Fix Tsi310 PCI-X bridge resource.
+ * Force the bridge to open a window from 0x0000-0x1fff in PCI I/O space.
+ * This allows legacy I/O(i8259, etc) on the VIA southbridge to be accessed.
+ */
+void mpc85xx_cds_fixup_bus(struct pci_bus *bus)
+{
+	struct pci_dev *dev = bus->self;
+	struct resource *res = bus->resource[0];
+
+	if (dev != NULL &&
+	    dev->vendor == PCI_VENDOR_ID_IBM &&
+	    dev->device == PCI_DEVICE_ID_IDT_TSI310) {
+		if (res) {
+			res->start = 0;
+			res->end   = 0x1fff;
+			res->flags = IORESOURCE_IO;
+			pr_info("mpc85xx_cds: PCI bridge resource fixup applied\n");
+			pr_info("mpc85xx_cds: %pR\n", res);
+		}
+	}
+
+	fsl_pcibios_fixup_bus(bus);
+}
+
 #ifdef CONFIG_PPC_I8259
 static void mpc85xx_8259_cascade_handler(unsigned int irq,
 					 struct irq_desc *desc)
@@ -322,7 +349,7 @@ define_machine(mpc85xx_cds) {
 	.get_irq	= mpic_get_irq,
 #ifdef CONFIG_PCI
 	.restart	= mpc85xx_cds_restart,
-	.pcibios_fixup_bus	= fsl_pcibios_fixup_bus,
+	.pcibios_fixup_bus	= mpc85xx_cds_fixup_bus,
 #else
 	.restart	= fsl_rstcr_restart,
 #endif