[PATCH] powerpc: Move xics.[ch] into platforms/pseries

This patch moves the XICS interrupt controller code into the
platforms/pseries directory, since it only appears on pSeries
machines.  If it ever appears on some other machine we can move it to
sysdev, although xics.c itself will need a bunch of changes in that
case to remove pSeries specific assumptions.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 747 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/xics.c b/arch/powerpc/platforms/pseries/xics.c
new file mode 100644
index 000000000000..c72c86f05cb6
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/xics.c
@@ -0,0 +1,747 @@
+/*
+ * arch/powerpc/platforms/pseries/xics.c
+ *
+ * Copyright 2000 IBM Corporation.
+ *
+ *  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 Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ */
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/threads.h>
+#include <linux/kernel.h>
+#include <linux/irq.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/signal.h>
+#include <linux/init.h>
+#include <linux/gfp.h>
+#include <linux/radix-tree.h>
+#include <linux/cpu.h>
+#include <asm/prom.h>
+#include <asm/io.h>
+#include <asm/pgtable.h>
+#include <asm/smp.h>
+#include <asm/rtas.h>
+#include <asm/hvcall.h>
+#include <asm/machdep.h>
+#include <asm/i8259.h>
+
+#include "xics.h"
+
+static unsigned int xics_startup(unsigned int irq);
+static void xics_enable_irq(unsigned int irq);
+static void xics_disable_irq(unsigned int irq);
+static void xics_mask_and_ack_irq(unsigned int irq);
+static void xics_end_irq(unsigned int irq);
+static void xics_set_affinity(unsigned int irq_nr, cpumask_t cpumask);
+
+static struct hw_interrupt_type xics_pic = {
+	.typename = " XICS     ",
+	.startup = xics_startup,
+	.enable = xics_enable_irq,
+	.disable = xics_disable_irq,
+	.ack = xics_mask_and_ack_irq,
+	.end = xics_end_irq,
+	.set_affinity = xics_set_affinity
+};
+
+static struct hw_interrupt_type xics_8259_pic = {
+	.typename = " XICS/8259",
+	.ack = xics_mask_and_ack_irq,
+};
+
+/* This is used to map real irq numbers to virtual */
+static struct radix_tree_root irq_map = RADIX_TREE_INIT(GFP_ATOMIC);
+
+#define XICS_IPI		2
+#define XICS_IRQ_SPURIOUS	0
+
+/* Want a priority other than 0.  Various HW issues require this. */
+#define	DEFAULT_PRIORITY	5
+
+/*
+ * Mark IPIs as higher priority so we can take them inside interrupts that
+ * arent marked SA_INTERRUPT
+ */
+#define IPI_PRIORITY		4
+
+struct xics_ipl {
+	union {
+		u32 word;
+		u8 bytes[4];
+	} xirr_poll;
+	union {
+		u32 word;
+		u8 bytes[4];
+	} xirr;
+	u32 dummy;
+	union {
+		u32 word;
+		u8 bytes[4];
+	} qirr;
+};
+
+static struct xics_ipl __iomem *xics_per_cpu[NR_CPUS];
+
+static int xics_irq_8259_cascade = 0;
+static int xics_irq_8259_cascade_real = 0;
+static unsigned int default_server = 0xFF;
+static unsigned int default_distrib_server = 0;
+static unsigned int interrupt_server_size = 8;
+
+/*
+ * XICS only has a single IPI, so encode the messages per CPU
+ */
+struct xics_ipi_struct xics_ipi_message[NR_CPUS] __cacheline_aligned;
+
+/* RTAS service tokens */
+static int ibm_get_xive;
+static int ibm_set_xive;
+static int ibm_int_on;
+static int ibm_int_off;
+
+typedef struct {
+	int (*xirr_info_get)(int cpu);
+	void (*xirr_info_set)(int cpu, int val);
+	void (*cppr_info)(int cpu, u8 val);
+	void (*qirr_info)(int cpu, u8 val);
+} xics_ops;
+
+
+/* SMP */
+
+static int pSeries_xirr_info_get(int n_cpu)
+{
+	return in_be32(&xics_per_cpu[n_cpu]->xirr.word);
+}
+
+static void pSeries_xirr_info_set(int n_cpu, int value)
+{
+	out_be32(&xics_per_cpu[n_cpu]->xirr.word, value);
+}
+
+static void pSeries_cppr_info(int n_cpu, u8 value)
+{
+	out_8(&xics_per_cpu[n_cpu]->xirr.bytes[0], value);
+}
+
+static void pSeries_qirr_info(int n_cpu, u8 value)
+{
+	out_8(&xics_per_cpu[n_cpu]->qirr.bytes[0], value);
+}
+
+static xics_ops pSeries_ops = {
+	pSeries_xirr_info_get,
+	pSeries_xirr_info_set,
+	pSeries_cppr_info,
+	pSeries_qirr_info
+};
+
+static xics_ops *ops = &pSeries_ops;
+
+
+/* LPAR */
+
+static inline long plpar_eoi(unsigned long xirr)
+{
+	return plpar_hcall_norets(H_EOI, xirr);
+}
+
+static inline long plpar_cppr(unsigned long cppr)
+{
+	return plpar_hcall_norets(H_CPPR, cppr);
+}
+
+static inline long plpar_ipi(unsigned long servernum, unsigned long mfrr)
+{
+	return plpar_hcall_norets(H_IPI, servernum, mfrr);
+}
+
+static inline long plpar_xirr(unsigned long *xirr_ret)
+{
+	unsigned long dummy;
+	return plpar_hcall(H_XIRR, 0, 0, 0, 0, xirr_ret, &dummy, &dummy);
+}
+
+static int pSeriesLP_xirr_info_get(int n_cpu)
+{
+	unsigned long lpar_rc;
+	unsigned long return_value;
+
+	lpar_rc = plpar_xirr(&return_value);
+	if (lpar_rc != H_Success)
+		panic(" bad return code xirr - rc = %lx \n", lpar_rc);
+	return (int)return_value;
+}
+
+static void pSeriesLP_xirr_info_set(int n_cpu, int value)
+{
+	unsigned long lpar_rc;
+	unsigned long val64 = value & 0xffffffff;
+
+	lpar_rc = plpar_eoi(val64);
+	if (lpar_rc != H_Success)
+		panic("bad return code EOI - rc = %ld, value=%lx\n", lpar_rc,
+		      val64);
+}
+
+void pSeriesLP_cppr_info(int n_cpu, u8 value)
+{
+	unsigned long lpar_rc;
+
+	lpar_rc = plpar_cppr(value);
+	if (lpar_rc != H_Success)
+		panic("bad return code cppr - rc = %lx\n", lpar_rc);
+}
+
+static void pSeriesLP_qirr_info(int n_cpu , u8 value)
+{
+	unsigned long lpar_rc;
+
+	lpar_rc = plpar_ipi(get_hard_smp_processor_id(n_cpu), value);
+	if (lpar_rc != H_Success)
+		panic("bad return code qirr - rc = %lx\n", lpar_rc);
+}
+
+xics_ops pSeriesLP_ops = {
+	pSeriesLP_xirr_info_get,
+	pSeriesLP_xirr_info_set,
+	pSeriesLP_cppr_info,
+	pSeriesLP_qirr_info
+};
+
+static unsigned int xics_startup(unsigned int virq)
+{
+	unsigned int irq;
+
+	irq = irq_offset_down(virq);
+	if (radix_tree_insert(&irq_map, virt_irq_to_real(irq),
+			      &virt_irq_to_real_map[irq]) == -ENOMEM)
+		printk(KERN_CRIT "Out of memory creating real -> virtual"
+		       " IRQ mapping for irq %u (real 0x%x)\n",
+		       virq, virt_irq_to_real(irq));
+	xics_enable_irq(virq);
+	return 0;	/* return value is ignored */
+}
+
+static unsigned int real_irq_to_virt(unsigned int real_irq)
+{
+	unsigned int *ptr;
+
+	ptr = radix_tree_lookup(&irq_map, real_irq);
+	if (ptr == NULL)
+		return NO_IRQ;
+	return ptr - virt_irq_to_real_map;
+}
+
+#ifdef CONFIG_SMP
+static int get_irq_server(unsigned int irq)
+{
+	unsigned int server;
+	/* For the moment only implement delivery to all cpus or one cpu */
+	cpumask_t cpumask = irq_affinity[irq];
+	cpumask_t tmp = CPU_MASK_NONE;
+
+	if (!distribute_irqs)
+		return default_server;
+
+	if (cpus_equal(cpumask, CPU_MASK_ALL)) {
+		server = default_distrib_server;
+	} else {
+		cpus_and(tmp, cpu_online_map, cpumask);
+
+		if (cpus_empty(tmp))
+			server = default_distrib_server;
+		else
+			server = get_hard_smp_processor_id(first_cpu(tmp));
+	}
+
+	return server;
+
+}
+#else
+static int get_irq_server(unsigned int irq)
+{
+	return default_server;
+}
+#endif
+
+static void xics_enable_irq(unsigned int virq)
+{
+	unsigned int irq;
+	int call_status;
+	unsigned int server;
+
+	irq = virt_irq_to_real(irq_offset_down(virq));
+	if (irq == XICS_IPI)
+		return;
+
+	server = get_irq_server(virq);
+	call_status = rtas_call(ibm_set_xive, 3, 1, NULL, irq, server,
+				DEFAULT_PRIORITY);
+	if (call_status != 0) {
+		printk(KERN_ERR "xics_enable_irq: irq=%u: ibm_set_xive "
+		       "returned %d\n", irq, call_status);
+		printk("set_xive %x, server %x\n", ibm_set_xive, server);
+		return;
+	}
+
+	/* Now unmask the interrupt (often a no-op) */
+	call_status = rtas_call(ibm_int_on, 1, 1, NULL, irq);
+	if (call_status != 0) {
+		printk(KERN_ERR "xics_enable_irq: irq=%u: ibm_int_on "
+		       "returned %d\n", irq, call_status);
+		return;
+	}
+}
+
+static void xics_disable_real_irq(unsigned int irq)
+{
+	int call_status;
+	unsigned int server;
+
+	if (irq == XICS_IPI)
+		return;
+
+	call_status = rtas_call(ibm_int_off, 1, 1, NULL, irq);
+	if (call_status != 0) {
+		printk(KERN_ERR "xics_disable_real_irq: irq=%u: "
+		       "ibm_int_off returned %d\n", irq, call_status);
+		return;
+	}
+
+	server = get_irq_server(irq);
+	/* Have to set XIVE to 0xff to be able to remove a slot */
+	call_status = rtas_call(ibm_set_xive, 3, 1, NULL, irq, server, 0xff);
+	if (call_status != 0) {
+		printk(KERN_ERR "xics_disable_irq: irq=%u: ibm_set_xive(0xff)"
+		       " returned %d\n", irq, call_status);
+		return;
+	}
+}
+
+static void xics_disable_irq(unsigned int virq)
+{
+	unsigned int irq;
+
+	irq = virt_irq_to_real(irq_offset_down(virq));
+	xics_disable_real_irq(irq);
+}
+
+static void xics_end_irq(unsigned int irq)
+{
+	int cpu = smp_processor_id();
+
+	iosync();
+	ops->xirr_info_set(cpu, ((0xff << 24) |
+				 (virt_irq_to_real(irq_offset_down(irq)))));
+
+}
+
+static void xics_mask_and_ack_irq(unsigned int irq)
+{
+	int cpu = smp_processor_id();
+
+	if (irq < irq_offset_value()) {
+		i8259_pic.ack(irq);
+		iosync();
+		ops->xirr_info_set(cpu, ((0xff<<24) |
+					 xics_irq_8259_cascade_real));
+		iosync();
+	}
+}
+
+int xics_get_irq(struct pt_regs *regs)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned int vec;
+	int irq;
+
+	vec = ops->xirr_info_get(cpu);
+	/*  (vec >> 24) == old priority */
+	vec &= 0x00ffffff;
+
+	/* for sanity, this had better be < NR_IRQS - 16 */
+	if (vec == xics_irq_8259_cascade_real) {
+		irq = i8259_irq(regs);
+		if (irq == -1) {
+			/* Spurious cascaded interrupt.  Still must ack xics */
+			xics_end_irq(irq_offset_up(xics_irq_8259_cascade));
+
+			irq = -1;
+		}
+	} else if (vec == XICS_IRQ_SPURIOUS) {
+		irq = -1;
+	} else {
+		irq = real_irq_to_virt(vec);
+		if (irq == NO_IRQ)
+			irq = real_irq_to_virt_slowpath(vec);
+		if (irq == NO_IRQ) {
+			printk(KERN_ERR "Interrupt %u (real) is invalid,"
+			       " disabling it.\n", vec);
+			xics_disable_real_irq(vec);
+		} else
+			irq = irq_offset_up(irq);
+	}
+	return irq;
+}
+
+#ifdef CONFIG_SMP
+
+irqreturn_t xics_ipi_action(int irq, void *dev_id, struct pt_regs *regs)
+{
+	int cpu = smp_processor_id();
+
+	ops->qirr_info(cpu, 0xff);
+
+	WARN_ON(cpu_is_offline(cpu));
+
+	while (xics_ipi_message[cpu].value) {
+		if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION,
+				       &xics_ipi_message[cpu].value)) {
+			mb();
+			smp_message_recv(PPC_MSG_CALL_FUNCTION, regs);
+		}
+		if (test_and_clear_bit(PPC_MSG_RESCHEDULE,
+				       &xics_ipi_message[cpu].value)) {
+			mb();
+			smp_message_recv(PPC_MSG_RESCHEDULE, regs);
+		}
+#if 0
+		if (test_and_clear_bit(PPC_MSG_MIGRATE_TASK,
+				       &xics_ipi_message[cpu].value)) {
+			mb();
+			smp_message_recv(PPC_MSG_MIGRATE_TASK, regs);
+		}
+#endif
+#ifdef CONFIG_DEBUGGER
+		if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK,
+				       &xics_ipi_message[cpu].value)) {
+			mb();
+			smp_message_recv(PPC_MSG_DEBUGGER_BREAK, regs);
+		}
+#endif
+	}
+	return IRQ_HANDLED;
+}
+
+void xics_cause_IPI(int cpu)
+{
+	ops->qirr_info(cpu, IPI_PRIORITY);
+}
+#endif /* CONFIG_SMP */
+
+void xics_setup_cpu(void)
+{
+	int cpu = smp_processor_id();
+
+	ops->cppr_info(cpu, 0xff);
+	iosync();
+
+	/*
+	 * Put the calling processor into the GIQ.  This is really only
+	 * necessary from a secondary thread as the OF start-cpu interface
+	 * performs this function for us on primary threads.
+	 *
+	 * XXX: undo of teardown on kexec needs this too, as may hotplug
+	 */
+	rtas_set_indicator(GLOBAL_INTERRUPT_QUEUE,
+		(1UL << interrupt_server_size) - 1 - default_distrib_server, 1);
+}
+
+void xics_init_IRQ(void)
+{
+	int i;
+	unsigned long intr_size = 0;
+	struct device_node *np;
+	uint *ireg, ilen, indx = 0;
+	unsigned long intr_base = 0;
+	struct xics_interrupt_node {
+		unsigned long addr;
+		unsigned long size;
+	} intnodes[NR_CPUS];
+
+	ppc64_boot_msg(0x20, "XICS Init");
+
+	ibm_get_xive = rtas_token("ibm,get-xive");
+	ibm_set_xive = rtas_token("ibm,set-xive");
+	ibm_int_on  = rtas_token("ibm,int-on");
+	ibm_int_off = rtas_token("ibm,int-off");
+
+	np = of_find_node_by_type(NULL, "PowerPC-External-Interrupt-Presentation");
+	if (!np)
+		panic("xics_init_IRQ: can't find interrupt presentation");
+
+nextnode:
+	ireg = (uint *)get_property(np, "ibm,interrupt-server-ranges", NULL);
+	if (ireg) {
+		/*
+		 * set node starting index for this node
+		 */
+		indx = *ireg;
+	}
+
+	ireg = (uint *)get_property(np, "reg", &ilen);
+	if (!ireg)
+		panic("xics_init_IRQ: can't find interrupt reg property");
+
+	while (ilen) {
+		intnodes[indx].addr = (unsigned long)*ireg++ << 32;
+		ilen -= sizeof(uint);
+		intnodes[indx].addr |= *ireg++;
+		ilen -= sizeof(uint);
+		intnodes[indx].size = (unsigned long)*ireg++ << 32;
+		ilen -= sizeof(uint);
+		intnodes[indx].size |= *ireg++;
+		ilen -= sizeof(uint);
+		indx++;
+		if (indx >= NR_CPUS) break;
+	}
+
+	np = of_find_node_by_type(np, "PowerPC-External-Interrupt-Presentation");
+	if ((indx < NR_CPUS) && np) goto nextnode;
+
+	/* Find the server numbers for the boot cpu. */
+	for (np = of_find_node_by_type(NULL, "cpu");
+	     np;
+	     np = of_find_node_by_type(np, "cpu")) {
+		ireg = (uint *)get_property(np, "reg", &ilen);
+		if (ireg && ireg[0] == boot_cpuid_phys) {
+			ireg = (uint *)get_property(np, "ibm,ppc-interrupt-gserver#s",
+						    &ilen);
+			i = ilen / sizeof(int);
+			if (ireg && i > 0) {
+				default_server = ireg[0];
+				default_distrib_server = ireg[i-1]; /* take last element */
+			}
+			ireg = (uint *)get_property(np,
+					"ibm,interrupt-server#-size", NULL);
+			if (ireg)
+				interrupt_server_size = *ireg;
+			break;
+		}
+	}
+	of_node_put(np);
+
+	intr_base = intnodes[0].addr;
+	intr_size = intnodes[0].size;
+
+	np = of_find_node_by_type(NULL, "interrupt-controller");
+	if (!np) {
+		printk(KERN_WARNING "xics: no ISA interrupt controller\n");
+		xics_irq_8259_cascade_real = -1;
+		xics_irq_8259_cascade = -1;
+	} else {
+		ireg = (uint *) get_property(np, "interrupts", NULL);
+		if (!ireg)
+			panic("xics_init_IRQ: can't find ISA interrupts property");
+
+		xics_irq_8259_cascade_real = *ireg;
+		xics_irq_8259_cascade
+			= virt_irq_create_mapping(xics_irq_8259_cascade_real);
+		of_node_put(np);
+	}
+
+	if (systemcfg->platform == PLATFORM_PSERIES) {
+#ifdef CONFIG_SMP
+		for_each_cpu(i) {
+			int hard_id;
+
+			/* FIXME: Do this dynamically! --RR */
+			if (!cpu_present(i))
+				continue;
+
+			hard_id = get_hard_smp_processor_id(i);
+			xics_per_cpu[i] = ioremap(intnodes[hard_id].addr,
+						  intnodes[hard_id].size);
+		}
+#else
+		xics_per_cpu[0] = ioremap(intr_base, intr_size);
+#endif /* CONFIG_SMP */
+	} else if (systemcfg->platform == PLATFORM_PSERIES_LPAR) {
+		ops = &pSeriesLP_ops;
+	}
+
+	xics_8259_pic.enable = i8259_pic.enable;
+	xics_8259_pic.disable = i8259_pic.disable;
+	for (i = 0; i < 16; ++i)
+		get_irq_desc(i)->handler = &xics_8259_pic;
+	for (; i < NR_IRQS; ++i)
+		get_irq_desc(i)->handler = &xics_pic;
+
+	xics_setup_cpu();
+
+	ppc64_boot_msg(0x21, "XICS Done");
+}
+
+/*
+ * We cant do this in init_IRQ because we need the memory subsystem up for
+ * request_irq()
+ */
+static int __init xics_setup_i8259(void)
+{
+	if (ppc64_interrupt_controller == IC_PPC_XIC &&
+	    xics_irq_8259_cascade != -1) {
+		if (request_irq(irq_offset_up(xics_irq_8259_cascade),
+				no_action, 0, "8259 cascade", NULL))
+			printk(KERN_ERR "xics_setup_i8259: couldn't get 8259 "
+					"cascade\n");
+		i8259_init(0, 0);
+	}
+	return 0;
+}
+arch_initcall(xics_setup_i8259);
+
+#ifdef CONFIG_SMP
+void xics_request_IPIs(void)
+{
+	virt_irq_to_real_map[XICS_IPI] = XICS_IPI;
+
+	/* IPIs are marked SA_INTERRUPT as they must run with irqs disabled */
+	request_irq(irq_offset_up(XICS_IPI), xics_ipi_action, SA_INTERRUPT,
+		    "IPI", NULL);
+	get_irq_desc(irq_offset_up(XICS_IPI))->status |= IRQ_PER_CPU;
+}
+#endif
+
+static void xics_set_affinity(unsigned int virq, cpumask_t cpumask)
+{
+	unsigned int irq;
+	int status;
+	int xics_status[2];
+	unsigned long newmask;
+	cpumask_t tmp = CPU_MASK_NONE;
+
+	irq = virt_irq_to_real(irq_offset_down(virq));
+	if (irq == XICS_IPI || irq == NO_IRQ)
+		return;
+
+	status = rtas_call(ibm_get_xive, 1, 3, xics_status, irq);
+
+	if (status) {
+		printk(KERN_ERR "xics_set_affinity: irq=%u ibm,get-xive "
+		       "returns %d\n", irq, status);
+		return;
+	}
+
+	/* For the moment only implement delivery to all cpus or one cpu */
+	if (cpus_equal(cpumask, CPU_MASK_ALL)) {
+		newmask = default_distrib_server;
+	} else {
+		cpus_and(tmp, cpu_online_map, cpumask);
+		if (cpus_empty(tmp))
+			return;
+		newmask = get_hard_smp_processor_id(first_cpu(tmp));
+	}
+
+	status = rtas_call(ibm_set_xive, 3, 1, NULL,
+				irq, newmask, xics_status[1]);
+
+	if (status) {
+		printk(KERN_ERR "xics_set_affinity: irq=%u ibm,set-xive "
+		       "returns %d\n", irq, status);
+		return;
+	}
+}
+
+void xics_teardown_cpu(int secondary)
+{
+	int cpu = smp_processor_id();
+
+	ops->cppr_info(cpu, 0x00);
+	iosync();
+
+	/*
+	 * Some machines need to have at least one cpu in the GIQ,
+	 * so leave the master cpu in the group.
+	 */
+	if (secondary) {
+		/*
+		 * we need to EOI the IPI if we got here from kexec down IPI
+		 *
+		 * probably need to check all the other interrupts too
+		 * should we be flagging idle loop instead?
+		 * or creating some task to be scheduled?
+		 */
+		ops->xirr_info_set(cpu, XICS_IPI);
+		rtas_set_indicator(GLOBAL_INTERRUPT_QUEUE,
+			(1UL << interrupt_server_size) - 1 -
+			default_distrib_server, 0);
+	}
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+/* Interrupts are disabled. */
+void xics_migrate_irqs_away(void)
+{
+	int status;
+	unsigned int irq, virq, cpu = smp_processor_id();
+
+	/* Reject any interrupt that was queued to us... */
+	ops->cppr_info(cpu, 0);
+	iosync();
+
+	/* remove ourselves from the global interrupt queue */
+	status = rtas_set_indicator(GLOBAL_INTERRUPT_QUEUE,
+		(1UL << interrupt_server_size) - 1 - default_distrib_server, 0);
+	WARN_ON(status < 0);
+
+	/* Allow IPIs again... */
+	ops->cppr_info(cpu, DEFAULT_PRIORITY);
+	iosync();
+
+	for_each_irq(virq) {
+		irq_desc_t *desc;
+		int xics_status[2];
+		unsigned long flags;
+
+		/* We cant set affinity on ISA interrupts */
+		if (virq < irq_offset_value())
+			continue;
+
+		desc = get_irq_desc(virq);
+		irq = virt_irq_to_real(irq_offset_down(virq));
+
+		/* We need to get IPIs still. */
+		if (irq == XICS_IPI || irq == NO_IRQ)
+			continue;
+
+		/* We only need to migrate enabled IRQS */
+		if (desc == NULL || desc->handler == NULL
+		    || desc->action == NULL
+		    || desc->handler->set_affinity == NULL)
+			continue;
+
+		spin_lock_irqsave(&desc->lock, flags);
+
+		status = rtas_call(ibm_get_xive, 1, 3, xics_status, irq);
+		if (status) {
+			printk(KERN_ERR "migrate_irqs_away: irq=%u "
+					"ibm,get-xive returns %d\n",
+					virq, status);
+			goto unlock;
+		}
+
+		/*
+		 * We only support delivery to all cpus or to one cpu.
+		 * The irq has to be migrated only in the single cpu
+		 * case.
+		 */
+		if (xics_status[0] != get_hard_smp_processor_id(cpu))
+			goto unlock;
+
+		printk(KERN_WARNING "IRQ %u affinity broken off cpu %u\n",
+		       virq, cpu);
+
+		/* Reset affinity to all cpus */
+		desc->handler->set_affinity(virq, CPU_MASK_ALL);
+		irq_affinity[virq] = CPU_MASK_ALL;
+unlock:
+		spin_unlock_irqrestore(&desc->lock, flags);
+	}
+}
+#endif