[PATCH] ppc32: Fix boot on PowerMac

Tom's recent irq patch broke PowerMac (and possibly others).  I think he
forgot that PReP, CHRP and PowerMac are all built together in a single
kernel image, thus all of those arch_initcall's will end up beeing called,
even on the wrong machine...
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/ppc/platforms/chrp_setup.c

@@ -374,6 +374,9 @@ static void __init chrp_find_openpic(void)
 static int __init
 chrp_request_cascade(void)
 {
+	if (_machine != _MACH_chrp)
+		return 0;
+
 	/* We have a cascade on OpenPIC IRQ 0, Linux IRQ 16 */
 	openpic_hookup_cascade(NUM_8259_INTERRUPTS, "82c59 cascade",
 			       i8259_irq);

arch/ppc/platforms/prep_setup.c

@@ -961,6 +961,9 @@ prep_irq_canonicalize(u_int irq)
 static int __init
 prep_request_cascade(void)
 {
+	if (_machine != _MACH_prep)
+		return 0;
+
 	if (OpenPIC_Addr != NULL)
 		/* We have a cascade on OpenPIC IRQ 0, Linux IRQ 16 */
 		openpic_hookup_cascade(NUM_8259_INTERRUPTS, "82c59 cascade",

arch/ppc/syslib/i8259.c

@@ -13,6 +13,7 @@ unsigned char cached_8259[2] = { 0xff, 0xff };
 static spinlock_t i8259_lock = SPIN_LOCK_UNLOCKED;
 
 int i8259_pic_irq_offset;
+static int i8259_present;
 
 /*
  * Acknowledge the IRQ using either the PCI host bridge's interrupt
@@ -154,6 +155,9 @@ static struct resource pic_edgectrl_iores = {
 static int __init
 i8259_hook_cascade(void)
 {
+	if (!i8259_present)
+		return 0;
+
 	/* reserve our resources */
 	request_irq( i8259_pic_irq_offset + 2, no_action, SA_INTERRUPT,
 				"82c59 secondary cascade", NULL );
@@ -201,4 +205,6 @@ i8259_init(long intack_addr)
 
 	if (intack_addr != 0)
 		pci_intack = ioremap(intack_addr, 1);
+
+	i8259_present = 1;
 }