MIPS: cavium-octeon: fix I/O space setup on non-PCI systems

Fix I/O space setup, so that on non-PCI systems using inb()/outb()
won't crash the system. Some drivers may try to probe I/O space and for
that purpose we can just allocate some normal memory initially. Drivers
trying to reserve a region will fail early as we set the size to 0. If
a real I/O space is present, the PCI/PCIe support code will re-adjust
the values accordingly.

Tested with EdgeRouter Lite by enabling CONFIG_SERIO_I8042 that caused
the originally reported crash.

Reported-by: Faidon Liambotis <[e-mail]>
Signed-off-by: Aaro Koskinen <[e-mail]>
Acked-by: David Daney <[e-mail]>
Cc: [e-mail]
Patchwork: https://patchwork.linux-mips.org/patch/5626/
Signed-off-by: Ralf Baechle <[e-mail]>

arch/mips/cavium-octeon/setup.c

···
  *   written by Ralf Baechle <[e-mail]>
  */
 #include <linux/compiler.h>
+#include <linux/vmalloc.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/console.h>
···
 	return err;
 }
 device_initcall(edac_devinit);
+
+static void __initdata *octeon_dummy_iospace;
+
+static int __init octeon_no_pci_init(void)
+{
+	/*
+	 * Initially assume there is no PCI. The PCI/PCIe platform code will
+	 * later re-initialize these to correct values if they are present.
+	 */
+	octeon_dummy_iospace = vzalloc(IO_SPACE_LIMIT);
+	set_io_port_base((unsigned long)octeon_dummy_iospace);
+	ioport_resource.start = MAX_RESOURCE;
+	ioport_resource.end = 0;
+	return 0;
+}
+core_initcall(octeon_no_pci_init);
+
+static int __init octeon_no_pci_release(void)
+{
+	/*
+	 * Release the allocated memory if a real IO space is there.
+	 */
+	if ((unsigned long)octeon_dummy_iospace != mips_io_port_base)
+		vfree(octeon_dummy_iospace);
+	return 0;
+}
+late_initcall(octeon_no_pci_release);

arch/mips/pci/pci-octeon.c

···
 	else
 		octeon_dma_bar_type = OCTEON_DMA_BAR_TYPE_BIG;
 
-	/* PCI I/O and PCI MEM values */
-	set_io_port_base(OCTEON_PCI_IOSPACE_BASE);
-	ioport_resource.start = 0;
-	ioport_resource.end = OCTEON_PCI_IOSPACE_SIZE - 1;
 	if (!octeon_is_pci_host()) {
 		pr_notice("Not in host mode, PCI Controller not initialized\n");
 		return 0;
 	}
+
+	/* PCI I/O and PCI MEM values */
+	set_io_port_base(OCTEON_PCI_IOSPACE_BASE);
+	ioport_resource.start = 0;
+	ioport_resource.end = OCTEON_PCI_IOSPACE_SIZE - 1;
 
 	pr_notice("%s Octeon big bar support\n",
 		  (octeon_dma_bar_type ==