MIPS: Loongson 3: Keep CPU physical (not virtual) addresses in shadow ROM resource

Loongson 3 used the IORESOURCE_ROM_COPY flag for its ROM resource.  There
are two problems with this:

  - When IORESOURCE_ROM_COPY is set, pci_map_rom() assumes the resource
    contains virtual addresses, so it doesn't ioremap the resource.  This
    implies loongson_sysconf.vgabios_addr is a virtual address.  That's a
    problem because resources should contain CPU *physical* addresses not
    virtual addresses.

  - When IORESOURCE_ROM_COPY is set, pci_cleanup_rom() calls kfree() on the
    resource.  We did not kmalloc() the loongson_sysconf.vgabios_addr area,
    so it is incorrect to kfree() it.

If we're using a shadow copy in RAM for the Loongson 3 VGA BIOS area,
disable the ROM BAR and release the address space it was consuming.

Use IORESOURCE_ROM_SHADOW instead of IORESOURCE_ROM_COPY.  This means the
struct resource contains CPU physical addresses, and pci_map_rom() will
ioremap() it as needed.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

arch/mips/pci/fixup-loongson3.c

@@ -48,9 +48,14 @@ static void pci_fixup_radeon(struct pci_dev *pdev)
 	if (!loongson_sysconf.vgabios_addr)
 		return;
 
-	res->start = loongson_sysconf.vgabios_addr;
+	pci_disable_rom(pdev);
+	if (res->parent)
+		release_resource(res);
+
+	res->start = virt_to_phys((void *) loongson_sysconf.vgabios_addr);
 	res->end   = res->start + 256*1024 - 1;
-	res->flags |= IORESOURCE_ROM_COPY;
+	res->flags = IORESOURCE_MEM | IORESOURCE_ROM_SHADOW |
+		     IORESOURCE_PCI_FIXED;
 
 	dev_info(&pdev->dev, "BAR %d: assigned %pR for Radeon ROM\n",
 		 PCI_ROM_RESOURCE, res);