ppc64: Add pciconfig_iobase syscall for 32 bits apps only

This syscall is used by XFree to retreive the IO base of the
bus where the video card is plugged. This is only implemented
for compatibility with existing XFree86, I don't plan to do
a 64 bits version, XFree shall be fixed to use proper PCI access
methods

arch/ppc64/kernel/misc.S

@@ -763,7 +763,7 @@ _GLOBAL(sys_call_table32)
 	.llong .sys_fstat64
 	.llong .sys32_pciconfig_read
 	.llong .sys32_pciconfig_write
-	.llong .sys_ni_syscall		/* 200 - old pciconfig_iobase */
+	.llong .sys32_pciconfig_iobase	/* 200 - pciconfig_iobase */
 	.llong .sys_ni_syscall		/* reserved for MacOnLinux */
 	.llong .sys_getdents64
 	.llong .sys_pivot_root
@@ -1022,7 +1022,7 @@ _GLOBAL(sys_call_table)
 	.llong .sys_ni_syscall		/* 32bit only fstat64 */
 	.llong .sys_ni_syscall		/* 32bit only pciconfig_read */
 	.llong .sys_ni_syscall		/* 32bit only pciconfig_write */
-	.llong .sys_ni_syscall		/* 200 - old pciconfig_iobase */
+	.llong .sys_ni_syscall		/* 32bit only pciconfig_iobase */
 	.llong .sys_ni_syscall		/* reserved for MacOnLinux */
 	.llong .sys_getdents64
 	.llong .sys_pivot_root

arch/ppc64/kernel/sys_ppc32.c

@@ -76,6 +76,8 @@
 #include <asm/ppc32.h>
 #include <asm/mmu_context.h>
 
+#include "pci.h"
+
 typedef ssize_t (*io_fn_t)(struct file *, char *, size_t, loff_t *);
 typedef ssize_t (*iov_fn_t)(struct file *, const struct iovec *, unsigned long, loff_t *);
 
@@ -2221,6 +2223,64 @@ asmlinkage int sys32_pciconfig_write(u32 bus, u32 dfn, u32 off, u32 len, u32 ubu
 				   (unsigned char *)AA(ubuf));
 }
 
+#define IOBASE_BRIDGE_NUMBER	0
+#define IOBASE_MEMORY		1
+#define IOBASE_IO		2
+#define IOBASE_ISA_IO		3
+#define IOBASE_ISA_MEM		4
+
+asmlinkage int sys32_pciconfig_iobase(u32 which, u32 in_bus, u32 in_devfn)
+{
+	struct pci_controller* hose;
+	struct list_head *ln;
+	struct pci_bus *bus = NULL;
+	struct device_node *hose_node;
+
+	/* Argh ! Please forgive me for that hack, but that's the
+	 * simplest way to get existing XFree to not lockup on some
+	 * G5 machines... So when something asks for bus 0 io base
+	 * (bus 0 is HT root), we return the AGP one instead.
+	 */
+#ifdef CONFIG_PPC_PMAC
+	if (systemcfg->platform == PLATFORM_POWERMAC &&
+	    machine_is_compatible("MacRISC4"))
+		if (in_bus == 0)
+			in_bus = 0xf0;
+#endif /* CONFIG_PPC_PMAC */
+
+	/* That syscall isn't quite compatible with PCI domains, but it's
+	 * used on pre-domains setup. We return the first match
+	 */
+
+	for (ln = pci_root_buses.next; ln != &pci_root_buses; ln = ln->next) {
+		bus = pci_bus_b(ln);
+		if (in_bus >= bus->number && in_bus < (bus->number + bus->subordinate))
+			break;
+		bus = NULL;
+	}
+	if (bus == NULL || bus->sysdata == NULL)
+		return -ENODEV;
+
+	hose_node = (struct device_node *)bus->sysdata;
+	hose = hose_node->phb;
+
+	switch (which) {
+	case IOBASE_BRIDGE_NUMBER:
+		return (long)hose->first_busno;
+	case IOBASE_MEMORY:
+		return (long)hose->pci_mem_offset;
+	case IOBASE_IO:
+		return (long)hose->io_base_phys;
+	case IOBASE_ISA_IO:
+		return (long)isa_io_base;
+	case IOBASE_ISA_MEM:
+		return -EINVAL;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+
 extern asmlinkage int sys_newuname(struct new_utsname * name);
 
 asmlinkage int ppc64_newuname(struct new_utsname * name)