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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/signal.h>
#include <linux/init.h>
#include <linux/gfp.h>
#include <linux/radix-tree.h>
#include <linux/cpu.h>

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

#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

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

static struct irq_host *xics_host;

/*
 * 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;


/* Direct HW low level accessors */


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(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(void)
{
      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 (unsigned int)return_value;
}

static inline void lpar_xirr_info_set(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);
}

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);
}


/* High level handlers and init code */

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

                  isize = of_get_property(np,
                              "ibm,interrupt-server#-size", NULL);
                  if (isize)
                        interrupt_server_size = *isize;
            }
      }

      of_node_put(np);
}

#ifdef CONFIG_SMP
static int get_irq_server(unsigned int virq, unsigned int strict_check)
{
      int server;
      /* For the moment only implement delivery to all cpus or one cpu */
      cpumask_t cpumask = irq_desc[virq].affinity;
      cpumask_t tmp = CPU_MASK_NONE;

      if (! cpu_isset(default_server, cpu_online_map))
            xics_update_irq_servers();

      if (!distribute_irqs)
            return default_server;

      if (!cpus_equal(cpumask, CPU_MASK_ALL)) {
            cpus_and(tmp, cpu_online_map, cpumask);

            server = first_cpu(tmp);

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

            if (strict_check)
                  return -1;
      }

      if (cpus_equal(cpu_online_map, cpu_present_map))
            return default_distrib_server;

      return default_server;
}
#else
static int get_irq_server(unsigned int virq, unsigned int strict_check)
{
      return default_server;
}
#endif


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

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

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

      server = get_irq_server(virq, 0);

      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_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 "xics_disable_real_irq: irq=%u: "
                   "ibm_int_off returned %d\n", 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 "xics_disable_irq: irq=%u: ibm_set_xive(0xff)"
                   " returned %d\n", irq, call_status);
            return;
      }
}

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

      pr_debug("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 unsigned int xics_startup(unsigned int virq)
{
      unsigned int irq;

      /* force a reverse mapping of the interrupt so it gets in the cache */
      irq = (unsigned int)irq_map[virq].hwirq;
      irq_radix_revmap(xics_host, irq);

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

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

      iosync();
      direct_xirr_info_set((0xff << 24) | irq);
}


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

      iosync();
      lpar_xirr_info_set((0xff << 24) | irq);
}

static inline unsigned int xics_remap_irq(unsigned int vec)
{
      unsigned int irq;

      vec &= 0x00ffffff;

      if (vec == XICS_IRQ_SPURIOUS)
            return NO_IRQ;
      irq = irq_radix_revmap(xics_host, vec);
      if (likely(irq != NO_IRQ))
            return irq;

      printk(KERN_ERR "Interrupt %u (real) is invalid,"
             " disabling it.\n", vec);
      xics_mask_real_irq(vec);
      return NO_IRQ;
}

static unsigned int xics_get_irq_direct(void)
{
      return xics_remap_irq(direct_xirr_info_get());
}

static unsigned int xics_get_irq_lpar(void)
{
      return xics_remap_irq(lpar_xirr_info_get());
}

#ifdef CONFIG_SMP

static irqreturn_t xics_ipi_dispatch(int cpu)
{
      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);
            }
            if (test_and_clear_bit(PPC_MSG_RESCHEDULE,
                               &xics_ipi_message[cpu].value)) {
                  mb();
                  smp_message_recv(PPC_MSG_RESCHEDULE);
            }
            if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE,
                               &xics_ipi_message[cpu].value)) {
                  mb();
                  smp_message_recv(PPC_MSG_CALL_FUNC_SINGLE);
            }
#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
            if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK,
                               &xics_ipi_message[cpu].value)) {
                  mb();
                  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);
}

void xics_cause_IPI(int cpu)
{
      if (firmware_has_feature(FW_FEATURE_LPAR))
            lpar_qirr_info(cpu, IPI_PRIORITY);
      else
            direct_qirr_info(cpu, IPI_PRIORITY);
}

#endif /* CONFIG_SMP */

static void xics_set_cpu_priority(unsigned char cppr)
{
      if (firmware_has_feature(FW_FEATURE_LPAR))
            lpar_cppr_info(cppr);
      else
            direct_cppr_info(cppr);
      iosync();
}

static void xics_set_affinity(unsigned int virq, cpumask_t 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;

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

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

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

void xics_setup_cpu(void)
{
      xics_set_cpu_priority(0xff);

      /*
       * 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_fast(GLOBAL_INTERRUPT_QUEUE,
            (1UL << interrupt_server_size) - 1 - default_distrib_server, 1);
}


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

/* 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_debug("xics: map virq %d, hwirq 0x%lx\n", virq, hw);

      get_irq_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,
                     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);
}

static void __init xics_map_one_cpu(int hw_id, unsigned long addr,
                             unsigned long size)
{
#ifdef CONFIG_SMP
      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;
            }
      }
#else
      if (hw_id != 0)
            return;
      xics_per_cpu[0] = ioremap(addr, size);
#endif /* CONFIG_SMP */
}

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;

      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))
                  break;
            xics_init_one_node(np, &indx);
      }
      if (found == 0)
            return;

      xics_init_host();
      xics_update_irq_servers();

      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");
}


#ifdef CONFIG_SMP
void xics_request_IPIs(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,
                        "IPI", NULL);
      else
            rc = request_irq(ipi, xics_ipi_action_direct, IRQF_DISABLED,
                        "IPI", NULL);
      BUG_ON(rc);
}
#endif /* CONFIG_SMP */

void xics_teardown_cpu(void)
{
      int cpu = smp_processor_id();

      xics_set_cpu_priority(0);

      /*
       * Clear IPI
       */
      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)
{
      unsigned int ipi;
      struct irq_desc *desc;

      xics_teardown_cpu();

      /*
       * we need to EOI the IPI
       *
       * probably need to check all the other interrupts too
       * should we be flagging idle loop instead?
       * or creating some task to be scheduled?
       */

      ipi = irq_find_mapping(xics_host, XICS_IPI);
      if (ipi == XICS_IRQ_SPURIOUS)
            return;
      desc = get_irq_desc(ipi);
      if (desc->chip && desc->chip->eoi)
            desc->chip->eoi(ipi);

      /*
       * Some machines need to have at least one cpu in the GIQ,
       * so leave the master cpu in the group.
       */
      if (secondary)
            rtas_set_indicator_fast(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;
      int cpu = smp_processor_id(), hw_cpu = hard_smp_processor_id();
      unsigned int irq, virq;

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

      /* remove ourselves from the global interrupt queue */
      status = rtas_set_indicator_fast(GLOBAL_INTERRUPT_QUEUE,
            (1UL << interrupt_server_size) - 1 - default_distrib_server, 0);
      WARN_ON(status < 0);

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

      for_each_irq(virq) {
            struct irq_desc *desc;
            int xics_status[2];
            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 = get_irq_desc(virq);

            /* We only need to migrate enabled IRQS */
            if (desc == NULL || desc->chip == NULL
                || desc->action == NULL
                || desc->chip->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] != hw_cpu)
                  goto unlock;

            printk(KERN_WARNING "IRQ %u affinity broken off cpu %u\n",
                   virq, cpu);

            /* Reset affinity to all cpus */
            irq_desc[virq].affinity = CPU_MASK_ALL;
            desc->chip->set_affinity(virq, CPU_MASK_ALL);
unlock:
            spin_unlock_irqrestore(&desc->lock, flags);
      }
}
#endif

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