powerpc: Fix bogus it_blocksize in VIO iommu code

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / arch / powerpc / platforms / pseries / xics.c

/*
 * 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/types.h>
#include <linux/threads.h>
#include <linux/kernel.h>
#include <linux/irq.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/radix-tree.h>
#include <linux/cpu.h>
#include <linux/msi.h>
#include <linux/of.h>
#include <linux/percpu.h>

#include <asm/firmware.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 "xics.h"
#include "plpar_wrappers.h"

static struct irq_host *xics_host;

#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 IRQF_DISABLED
 */
#define IPI_PRIORITY            4

/* The least favored priority */
#define LOWEST_PRIORITY         0xFF

/* The number of priorities defined above */
#define MAX_NUM_PRIORITIES      3

static unsigned int default_server = 0xFF;
static unsigned int default_distrib_server = 0;
static unsigned int interrupt_server_size = 8;

/* RTAS service tokens */
static int ibm_get_xive;
static int ibm_set_xive;
static int ibm_int_on;
static int ibm_int_off;

struct xics_cppr {
        unsigned char stack[MAX_NUM_PRIORITIES];
        int index;
};

static DEFINE_PER_CPU(struct xics_cppr, xics_cppr);

/* Direct hardware low level accessors */

/* The part of the interrupt presentation layer that we care about */
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 inline unsigned int direct_xirr_info_get(void)
{
        int cpu = smp_processor_id();

        return in_be32(&xics_per_cpu[cpu]->xirr.word);
}

static inline void direct_xirr_info_set(unsigned int value)
{
        int cpu = smp_processor_id();

        out_be32(&xics_per_cpu[cpu]->xirr.word, value);
}

static inline void direct_cppr_info(u8 value)
{
        int cpu = smp_processor_id();

        out_8(&xics_per_cpu[cpu]->xirr.bytes[0], value);
}

static inline void direct_qirr_info(int n_cpu, u8 value)
{
        out_8(&xics_per_cpu[n_cpu]->qirr.bytes[0], value);
}


/* LPAR low level accessors */

static inline unsigned int lpar_xirr_info_get(unsigned char cppr)
{
        unsigned long lpar_rc;
        unsigned long return_value;

        lpar_rc = plpar_xirr(&return_value, cppr);
        if (lpar_rc != H_SUCCESS)
                panic(" bad return code xirr - rc = %lx\n", lpar_rc);
        return (unsigned int)return_value;
}

static inline void lpar_xirr_info_set(unsigned int value)
{
        unsigned long lpar_rc;

        lpar_rc = plpar_eoi(value);
        if (lpar_rc != H_SUCCESS)
                panic("bad return code EOI - rc = %ld, value=%x\n", lpar_rc,
                      value);
}

static inline void lpar_cppr_info(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 inline void lpar_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);
}


/* Interface to generic irq subsystem */

#ifdef CONFIG_SMP
/*
 * For the moment we only implement delivery to all cpus or one cpu.
 *
 * If the requested affinity is cpu_all_mask, we set global affinity.
 * If not we set it to the first cpu in the mask, even if multiple cpus
 * are set. This is so things like irqbalance (which set core and package
 * wide affinities) do the right thing.
 */
static int get_irq_server(unsigned int virq, const struct cpumask *cpumask,
                          unsigned int strict_check)
{

        if (!distribute_irqs)
                return default_server;

        if (!cpumask_equal(cpumask, cpu_all_mask)) {
                int server = cpumask_first_and(cpu_online_mask, cpumask);

                if (server < nr_cpu_ids)
                        return get_hard_smp_processor_id(server);

                if (strict_check)
                        return -1;
        }

        /*
         * Workaround issue with some versions of JS20 firmware that
         * deliver interrupts to cpus which haven't been started. This
         * happens when using the maxcpus= boot option.
         */
        if (cpumask_equal(cpu_online_mask, cpu_present_mask))
                return default_distrib_server;

        return default_server;
}
#else
#define get_irq_server(virq, cpumask, strict_check) (default_server)
#endif

static void xics_unmask_irq(unsigned int virq)
{
        unsigned int irq;
        int call_status;
        int server;

        pr_devel("xics: unmask virq %d\n", virq);

        irq = (unsigned int)irq_map[virq].hwirq;
        pr_devel(" -> map to hwirq 0x%x\n", irq);
        if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
                return;

        server = get_irq_server(virq, irq_to_desc(virq)->affinity, 0);

        call_status = rtas_call(ibm_set_xive, 3, 1, NULL, irq, server,
                                DEFAULT_PRIORITY);
        if (call_status != 0) {
                printk(KERN_ERR
                        "%s: ibm_set_xive irq %u server %x returned %d\n",
                        __func__, irq, server, call_status);
                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 "%s: ibm_int_on irq=%u returned %d\n",
                        __func__, irq, call_status);
                return;
        }
}

static unsigned int xics_startup(unsigned int virq)
{
        /*
         * The generic MSI code returns with the interrupt disabled on the
         * card, using the MSI mask bits. Firmware doesn't appear to unmask
         * at that level, so we do it here by hand.
         */
        if (irq_to_desc(virq)->msi_desc)
                unmask_msi_irq(virq);

        /* unmask it */
        xics_unmask_irq(virq);
        return 0;
}

static void xics_mask_real_irq(unsigned int irq)
{
        int call_status;

        if (irq == XICS_IPI)
                return;

        call_status = rtas_call(ibm_int_off, 1, 1, NULL, irq);
        if (call_status != 0) {
                printk(KERN_ERR "%s: ibm_int_off irq=%u returned %d\n",
                        __func__, irq, call_status);
                return;
        }

        /* Have to set XIVE to 0xff to be able to remove a slot */
        call_status = rtas_call(ibm_set_xive, 3, 1, NULL, irq,
                                default_server, 0xff);
        if (call_status != 0) {
                printk(KERN_ERR "%s: ibm_set_xive(0xff) irq=%u returned %d\n",
                        __func__, irq, call_status);
                return;
        }
}

static void xics_mask_irq(unsigned int virq)
{
        unsigned int irq;

        pr_devel("xics: mask virq %d\n", virq);

        irq = (unsigned int)irq_map[virq].hwirq;
        if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
                return;
        xics_mask_real_irq(irq);
}

static void xics_mask_unknown_vec(unsigned int vec)
{
        printk(KERN_ERR "Interrupt %u (real) is invalid, disabling it.\n", vec);
        xics_mask_real_irq(vec);
}

static inline unsigned int xics_xirr_vector(unsigned int xirr)
{
        /*
         * The top byte is the old cppr, to be restored on EOI.
         * The remaining 24 bits are the vector.
         */
        return xirr & 0x00ffffff;
}

static void push_cppr(unsigned int vec)
{
        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);

        if (WARN_ON(os_cppr->index >= MAX_NUM_PRIORITIES - 1))
                return;

        if (vec == XICS_IPI)
                os_cppr->stack[++os_cppr->index] = IPI_PRIORITY;
        else
                os_cppr->stack[++os_cppr->index] = DEFAULT_PRIORITY;
}

static unsigned int xics_get_irq_direct(void)
{
        unsigned int xirr = direct_xirr_info_get();
        unsigned int vec = xics_xirr_vector(xirr);
        unsigned int irq;

        if (vec == XICS_IRQ_SPURIOUS)
                return NO_IRQ;

        irq = irq_radix_revmap_lookup(xics_host, vec);
        if (likely(irq != NO_IRQ)) {
                push_cppr(vec);
                return irq;
        }

        /* We don't have a linux mapping, so have rtas mask it. */
        xics_mask_unknown_vec(vec);

        /* We might learn about it later, so EOI it */
        direct_xirr_info_set(xirr);
        return NO_IRQ;
}

static unsigned int xics_get_irq_lpar(void)
{
        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
        unsigned int xirr = lpar_xirr_info_get(os_cppr->stack[os_cppr->index]);
        unsigned int vec = xics_xirr_vector(xirr);
        unsigned int irq;

        if (vec == XICS_IRQ_SPURIOUS)
                return NO_IRQ;

        irq = irq_radix_revmap_lookup(xics_host, vec);
        if (likely(irq != NO_IRQ)) {
                push_cppr(vec);
                return irq;
        }

        /* We don't have a linux mapping, so have RTAS mask it. */
        xics_mask_unknown_vec(vec);

        /* We might learn about it later, so EOI it */
        lpar_xirr_info_set(xirr);
        return NO_IRQ;
}

static unsigned char pop_cppr(void)
{
        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);

        if (WARN_ON(os_cppr->index < 1))
                return LOWEST_PRIORITY;

        return os_cppr->stack[--os_cppr->index];
}

static void xics_eoi_direct(unsigned int virq)
{
        unsigned int irq = (unsigned int)irq_map[virq].hwirq;

        iosync();
        direct_xirr_info_set((pop_cppr() << 24) | irq);
}

static void xics_eoi_lpar(unsigned int virq)
{
        unsigned int irq = (unsigned int)irq_map[virq].hwirq;

        iosync();
        lpar_xirr_info_set((pop_cppr() << 24) | irq);
}

static int xics_set_affinity(unsigned int virq, const struct cpumask *cpumask)
{
        unsigned int irq;
        int status;
        int xics_status[2];
        int irq_server;

        irq = (unsigned int)irq_map[virq].hwirq;
        if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
                return -1;

        status = rtas_call(ibm_get_xive, 1, 3, xics_status, irq);

        if (status) {
                printk(KERN_ERR "%s: ibm,get-xive irq=%u returns %d\n",
                        __func__, irq, status);
                return -1;
        }

        irq_server = get_irq_server(virq, cpumask, 1);
        if (irq_server == -1) {
                char cpulist[128];
                cpumask_scnprintf(cpulist, sizeof(cpulist), cpumask);
                printk(KERN_WARNING
                        "%s: No online cpus in the mask %s for irq %d\n",
                        __func__, cpulist, virq);
                return -1;
        }

        status = rtas_call(ibm_set_xive, 3, 1, NULL,
                                irq, irq_server, xics_status[1]);

        if (status) {
                printk(KERN_ERR "%s: ibm,set-xive irq=%u returns %d\n",
                        __func__, irq, status);
                return -1;
        }

        return 0;
}

static struct irq_chip xics_pic_direct = {
        .name = "XICS",
        .startup = xics_startup,
        .mask = xics_mask_irq,
        .unmask = xics_unmask_irq,
        .eoi = xics_eoi_direct,
        .set_affinity = xics_set_affinity
};

static struct irq_chip xics_pic_lpar = {
        .name = "XICS",
        .startup = xics_startup,
        .mask = xics_mask_irq,
        .unmask = xics_unmask_irq,
        .eoi = xics_eoi_lpar,
        .set_affinity = xics_set_affinity
};


/* Interface to arch irq controller subsystem layer */

/* Points to the irq_chip we're actually using */
static struct irq_chip *xics_irq_chip;

static int xics_host_match(struct irq_host *h, struct device_node *node)
{
        /* IBM machines have interrupt parents of various funky types for things
         * like vdevices, events, etc... The trick we use here is to match
         * everything here except the legacy 8259 which is compatible "chrp,iic"
         */
        return !of_device_is_compatible(node, "chrp,iic");
}

static int xics_host_map(struct irq_host *h, unsigned int virq,
                         irq_hw_number_t hw)
{
        pr_devel("xics: map virq %d, hwirq 0x%lx\n", virq, hw);

        /* Insert the interrupt mapping into the radix tree for fast lookup */
        irq_radix_revmap_insert(xics_host, virq, hw);

        irq_to_desc(virq)->status |= IRQ_LEVEL;
        set_irq_chip_and_handler(virq, xics_irq_chip, handle_fasteoi_irq);
        return 0;
}

static int xics_host_xlate(struct irq_host *h, struct device_node *ct,
                           const u32 *intspec, unsigned int intsize,
                           irq_hw_number_t *out_hwirq, unsigned int *out_flags)

{
        /* Current xics implementation translates everything
         * to level. It is not technically right for MSIs but this
         * is irrelevant at this point. We might get smarter in the future
         */
        *out_hwirq = intspec[0];
        *out_flags = IRQ_TYPE_LEVEL_LOW;

        return 0;
}

static struct irq_host_ops xics_host_ops = {
        .match = xics_host_match,
        .map = xics_host_map,
        .xlate = xics_host_xlate,
};

static void __init xics_init_host(void)
{
        if (firmware_has_feature(FW_FEATURE_LPAR))
                xics_irq_chip = &xics_pic_lpar;
        else
                xics_irq_chip = &xics_pic_direct;

        xics_host = irq_alloc_host(NULL, IRQ_HOST_MAP_TREE, 0, &xics_host_ops,
                                   XICS_IRQ_SPURIOUS);
        BUG_ON(xics_host == NULL);
        irq_set_default_host(xics_host);
}


/* Inter-processor interrupt support */

#ifdef CONFIG_SMP
/*
 * XICS only has a single IPI, so encode the messages per CPU
 */
static DEFINE_PER_CPU_SHARED_ALIGNED(unsigned long, xics_ipi_message);

static inline void smp_xics_do_message(int cpu, int msg)
{
        unsigned long *tgt = &per_cpu(xics_ipi_message, cpu);

        set_bit(msg, tgt);
        mb();
        if (firmware_has_feature(FW_FEATURE_LPAR))
                lpar_qirr_info(cpu, IPI_PRIORITY);
        else
                direct_qirr_info(cpu, IPI_PRIORITY);
}

void smp_xics_message_pass(int target, int msg)
{
        unsigned int i;

        if (target < NR_CPUS) {
                smp_xics_do_message(target, msg);
        } else {
                for_each_online_cpu(i) {
                        if (target == MSG_ALL_BUT_SELF
                            && i == smp_processor_id())
                                continue;
                        smp_xics_do_message(i, msg);
                }
        }
}

static irqreturn_t xics_ipi_dispatch(int cpu)
{
        unsigned long *tgt = &per_cpu(xics_ipi_message, cpu);

        mb();   /* order mmio clearing qirr */
        while (*tgt) {
                if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION, tgt)) {
                        smp_message_recv(PPC_MSG_CALL_FUNCTION);
                }
                if (test_and_clear_bit(PPC_MSG_RESCHEDULE, tgt)) {
                        smp_message_recv(PPC_MSG_RESCHEDULE);
                }
                if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE, tgt)) {
                        smp_message_recv(PPC_MSG_CALL_FUNC_SINGLE);
                }
#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
                if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK, tgt)) {
                        smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
                }
#endif
        }
        return IRQ_HANDLED;
}

static irqreturn_t xics_ipi_action_direct(int irq, void *dev_id)
{
        int cpu = smp_processor_id();

        direct_qirr_info(cpu, 0xff);

        return xics_ipi_dispatch(cpu);
}

static irqreturn_t xics_ipi_action_lpar(int irq, void *dev_id)
{
        int cpu = smp_processor_id();

        lpar_qirr_info(cpu, 0xff);

        return xics_ipi_dispatch(cpu);
}

static void xics_request_ipi(void)
{
        unsigned int ipi;
        int rc;

        ipi = irq_create_mapping(xics_host, XICS_IPI);
        BUG_ON(ipi == NO_IRQ);

        /*
         * IPIs are marked IRQF_DISABLED as they must run with irqs
         * disabled
         */
        set_irq_handler(ipi, handle_percpu_irq);
        if (firmware_has_feature(FW_FEATURE_LPAR))
                rc = request_irq(ipi, xics_ipi_action_lpar,
                                IRQF_DISABLED|IRQF_PERCPU, "IPI", NULL);
        else
                rc = request_irq(ipi, xics_ipi_action_direct,
                                IRQF_DISABLED|IRQF_PERCPU, "IPI", NULL);
        BUG_ON(rc);
}

int __init smp_xics_probe(void)
{
        xics_request_ipi();

        return cpumask_weight(cpu_possible_mask);
}

#endif /* CONFIG_SMP */


/* Initialization */

static void xics_update_irq_servers(void)
{
        int i, j;
        struct device_node *np;
        u32 ilen;
        const u32 *ireg;
        u32 hcpuid;

        /* Find the server numbers for the boot cpu. */
        np = of_get_cpu_node(boot_cpuid, NULL);
        BUG_ON(!np);

        ireg = of_get_property(np, "ibm,ppc-interrupt-gserver#s", &ilen);
        if (!ireg) {
                of_node_put(np);
                return;
        }

        i = ilen / sizeof(int);
        hcpuid = get_hard_smp_processor_id(boot_cpuid);

        /* Global interrupt distribution server is specified in the last
         * entry of "ibm,ppc-interrupt-gserver#s" property. Get the last
         * entry fom this property for current boot cpu id and use it as
         * default distribution server
         */
        for (j = 0; j < i; j += 2) {
                if (ireg[j] == hcpuid) {
                        default_server = hcpuid;
                        default_distrib_server = ireg[j+1];
                }
        }

        of_node_put(np);
}

static void __init xics_map_one_cpu(int hw_id, unsigned long addr,
                                     unsigned long size)
{
        int i;

        /* This may look gross but it's good enough for now, we don't quite
         * have a hard -> linux processor id matching.
         */
        for_each_possible_cpu(i) {
                if (!cpu_present(i))
                        continue;
                if (hw_id == get_hard_smp_processor_id(i)) {
                        xics_per_cpu[i] = ioremap(addr, size);
                        return;
                }
        }
}

static void __init xics_init_one_node(struct device_node *np,
                                      unsigned int *indx)
{
        unsigned int ilen;
        const u32 *ireg;

        /* This code does the theorically broken assumption that the interrupt
         * server numbers are the same as the hard CPU numbers.
         * This happens to be the case so far but we are playing with fire...
         * should be fixed one of these days. -BenH.
         */
        ireg = of_get_property(np, "ibm,interrupt-server-ranges", NULL);

        /* Do that ever happen ? we'll know soon enough... but even good'old
         * f80 does have that property ..
         */
        WARN_ON(ireg == NULL);
        if (ireg) {
                /*
                 * set node starting index for this node
                 */
                *indx = *ireg;
        }
        ireg = of_get_property(np, "reg", &ilen);
        if (!ireg)
                panic("xics_init_IRQ: can't find interrupt reg property");

        while (ilen >= (4 * sizeof(u32))) {
                unsigned long addr, size;

                /* XXX Use proper OF parsing code here !!! */
                addr = (unsigned long)*ireg++ << 32;
                ilen -= sizeof(u32);
                addr |= *ireg++;
                ilen -= sizeof(u32);
                size = (unsigned long)*ireg++ << 32;
                ilen -= sizeof(u32);
                size |= *ireg++;
                ilen -= sizeof(u32);
                xics_map_one_cpu(*indx, addr, size);
                (*indx)++;
        }
}

void __init xics_init_IRQ(void)
{
        struct device_node *np;
        u32 indx = 0;
        int found = 0;
        const u32 *isize;

        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");

        for_each_node_by_type(np, "PowerPC-External-Interrupt-Presentation") {
                found = 1;
                if (firmware_has_feature(FW_FEATURE_LPAR)) {
                        of_node_put(np);
                        break;
                        }
                xics_init_one_node(np, &indx);
        }
        if (found == 0)
                return;

        /* get the bit size of server numbers */
        found = 0;

        for_each_compatible_node(np, NULL, "ibm,ppc-xics") {
                isize = of_get_property(np, "ibm,interrupt-server#-size", NULL);

                if (!isize)
                        continue;

                if (!found) {
                        interrupt_server_size = *isize;
                        found = 1;
                } else if (*isize != interrupt_server_size) {
                        printk(KERN_WARNING "XICS: "
                               "mismatched ibm,interrupt-server#-size\n");
                        interrupt_server_size = max(*isize,
                                                    interrupt_server_size);
                }
        }

        xics_update_irq_servers();
        xics_init_host();

        if (firmware_has_feature(FW_FEATURE_LPAR))
                ppc_md.get_irq = xics_get_irq_lpar;
        else
                ppc_md.get_irq = xics_get_irq_direct;

        xics_setup_cpu();

        ppc64_boot_msg(0x21, "XICS Done");
}

/* Cpu startup, shutdown, and hotplug */

static void xics_set_cpu_priority(unsigned char cppr)
{
        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);

        /*
         * we only really want to set the priority when there's
         * just one cppr value on the stack
         */
        WARN_ON(os_cppr->index != 0);

        os_cppr->stack[0] = cppr;

        if (firmware_has_feature(FW_FEATURE_LPAR))
                lpar_cppr_info(cppr);
        else
                direct_cppr_info(cppr);
        iosync();
}

/* Have the calling processor join or leave the specified global queue */
static void xics_set_cpu_giq(unsigned int gserver, unsigned int join)
{
        int index;
        int status;

        if (!rtas_indicator_present(GLOBAL_INTERRUPT_QUEUE, NULL))
                return;

        index = (1UL << interrupt_server_size) - 1 - gserver;

        status = rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE, index, join);

        WARN(status < 0, "set-indicator(%d, %d, %u) returned %d\n",
             GLOBAL_INTERRUPT_QUEUE, index, join, status);
}

void xics_setup_cpu(void)
{
        xics_set_cpu_priority(LOWEST_PRIORITY);

        xics_set_cpu_giq(default_distrib_server, 1);
}

void xics_teardown_cpu(void)
{
        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
        int cpu = smp_processor_id();

        /*
         * we have to reset the cppr index to 0 because we're
         * not going to return from the IPI
         */
        os_cppr->index = 0;
        xics_set_cpu_priority(0);

        /* Clear any pending IPI request */
        if (firmware_has_feature(FW_FEATURE_LPAR))
                lpar_qirr_info(cpu, 0xff);
        else
                direct_qirr_info(cpu, 0xff);
}

void xics_kexec_teardown_cpu(int secondary)
{
        xics_teardown_cpu();

        /*
         * we take the ipi irq but and never return so we
         * need to EOI the IPI, but want to leave our priority 0
         *
         * should we check all the other interrupts too?
         * should we be flagging idle loop instead?
         * or creating some task to be scheduled?
         */

        if (firmware_has_feature(FW_FEATURE_LPAR))
                lpar_xirr_info_set((0x00 << 24) | XICS_IPI);
        else
                direct_xirr_info_set((0x00 << 24) | XICS_IPI);

        /*
         * Some machines need to have at least one cpu in the GIQ,
         * so leave the master cpu in the group.
         */
        if (secondary)
                xics_set_cpu_giq(default_distrib_server, 0);
}

#ifdef CONFIG_HOTPLUG_CPU

/* Interrupts are disabled. */
void xics_migrate_irqs_away(void)
{
        int cpu = smp_processor_id(), hw_cpu = hard_smp_processor_id();
        unsigned int irq, virq;

        /* If we used to be the default server, move to the new "boot_cpuid" */
        if (hw_cpu == default_server)
                xics_update_irq_servers();

        /* Reject any interrupt that was queued to us... */
        xics_set_cpu_priority(0);

        /* Remove ourselves from the global interrupt queue */
        xics_set_cpu_giq(default_distrib_server, 0);

        /* Allow IPIs again... */
        xics_set_cpu_priority(DEFAULT_PRIORITY);

        for_each_irq(virq) {
                struct irq_desc *desc;
                int xics_status[2];
                int status;
                unsigned long flags;

                /* We cant set affinity on ISA interrupts */
                if (virq < NUM_ISA_INTERRUPTS)
                        continue;
                if (irq_map[virq].host != xics_host)
                        continue;
                irq = (unsigned int)irq_map[virq].hwirq;
                /* We need to get IPIs still. */
                if (irq == XICS_IPI || irq == XICS_IRQ_SPURIOUS)
                        continue;
                desc = irq_to_desc(virq);

                /* We only need to migrate enabled IRQS */
                if (desc == NULL || desc->chip == NULL
                    || desc->action == NULL
                    || desc->chip->set_affinity == NULL)
                        continue;

                raw_spin_lock_irqsave(&desc->lock, flags);

                status = rtas_call(ibm_get_xive, 1, 3, xics_status, irq);
                if (status) {
                        printk(KERN_ERR "%s: ibm,get-xive irq=%u returns %d\n",
                                        __func__, irq, 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] != hw_cpu)
                        goto unlock;

                /* This is expected during cpu offline. */
                if (cpu_online(cpu))
                        printk(KERN_WARNING "IRQ %u affinity broken off cpu %u\n",
                               virq, cpu);

                /* Reset affinity to all cpus */
                cpumask_setall(irq_to_desc(virq)->affinity);
                desc->chip->set_affinity(virq, cpu_all_mask);
unlock:
                raw_spin_unlock_irqrestore(&desc->lock, flags);
        }
}
#endif