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irq.c

/*
 * This module supports the iSeries PCI bus interrupt handling
 * Copyright (C) 20yy  <Robert L Holtorf> <IBM Corp>
 * Copyright (C) 2004-2005 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the:
 * Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330,
 * Boston, MA  02111-1307  USA
 *
 * Change Activity:
 *   Created, December 13, 2000 by Wayne Holm
 * End Change Activity
 */
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/bootmem.h>
#include <linux/irq.h>
#include <linux/spinlock.h>

#include <asm/paca.h>
#include <asm/iseries/hv_types.h>
#include <asm/iseries/hv_lp_event.h>
#include <asm/iseries/hv_call_xm.h>
#include <asm/iseries/it_lp_queue.h>

#include "irq.h"
#include "pci.h"
#include "call_pci.h"
#include "smp.h"

#ifdef CONFIG_PCI

enum pci_event_type {
      pe_bus_created          = 0,  /* PHB has been created */
      pe_bus_error            = 1,  /* PHB has failed */
      pe_bus_failed           = 2,  /* Msg to Secondary, Primary failed bus */
      pe_node_failed          = 4,  /* Multi-adapter bridge has failed */
      pe_node_recovered = 5,  /* Multi-adapter bridge has recovered */
      pe_bus_recovered  = 12, /* PHB has been recovered */
      pe_unquiese_bus         = 18, /* Secondary bus unqiescing */
      pe_bridge_error         = 21, /* Bridge Error */
      pe_slot_interrupt = 22  /* Slot interrupt */
};

struct pci_event {
      struct HvLpEvent event;
      union {
            u64 __align;            /* Align on an 8-byte boundary */
            struct {
                  u32         fisr;
                  HvBusNumber bus_number;
                  HvSubBusNumber    sub_bus_number;
                  HvAgentId   dev_id;
            } slot;
            struct {
                  HvBusNumber bus_number;
                  HvSubBusNumber    sub_bus_number;
            } bus;
            struct {
                  HvBusNumber bus_number;
                  HvSubBusNumber    sub_bus_number;
                  HvAgentId   dev_id;
            } node;
      } data;
};

static DEFINE_SPINLOCK(pending_irqs_lock);
static int num_pending_irqs;
static int pending_irqs[NR_IRQS];

static void int_received(struct pci_event *event)
{
      int irq;

      switch (event->event.xSubtype) {
      case pe_slot_interrupt:
            irq = event->event.xCorrelationToken;
            if (irq < NR_IRQS) {
                  spin_lock(&pending_irqs_lock);
                  pending_irqs[irq]++;
                  num_pending_irqs++;
                  spin_unlock(&pending_irqs_lock);
            } else {
                  printk(KERN_WARNING "int_received: bad irq number %d\n",
                              irq);
                  HvCallPci_eoi(event->data.slot.bus_number,
                              event->data.slot.sub_bus_number,
                              event->data.slot.dev_id);
            }
            break;
            /* Ignore error recovery events for now */
      case pe_bus_created:
            printk(KERN_INFO "int_received: system bus %d created\n",
                  event->data.bus.bus_number);
            break;
      case pe_bus_error:
      case pe_bus_failed:
            printk(KERN_INFO "int_received: system bus %d failed\n",
                  event->data.bus.bus_number);
            break;
      case pe_bus_recovered:
      case pe_unquiese_bus:
            printk(KERN_INFO "int_received: system bus %d recovered\n",
                  event->data.bus.bus_number);
            break;
      case pe_node_failed:
      case pe_bridge_error:
            printk(KERN_INFO
                  "int_received: multi-adapter bridge %d/%d/%d failed\n",
                  event->data.node.bus_number,
                  event->data.node.sub_bus_number,
                  event->data.node.dev_id);
            break;
      case pe_node_recovered:
            printk(KERN_INFO
                  "int_received: multi-adapter bridge %d/%d/%d recovered\n",
                  event->data.node.bus_number,
                  event->data.node.sub_bus_number,
                  event->data.node.dev_id);
            break;
      default:
            printk(KERN_ERR
                  "int_received: unrecognized event subtype 0x%x\n",
                  event->event.xSubtype);
            break;
      }
}

static void pci_event_handler(struct HvLpEvent *event)
{
      if (event && (event->xType == HvLpEvent_Type_PciIo)) {
            if (hvlpevent_is_int(event))
                  int_received((struct pci_event *)event);
            else
                  printk(KERN_ERR
                        "pci_event_handler: unexpected ack received\n");
      } else if (event)
            printk(KERN_ERR
                  "pci_event_handler: Unrecognized PCI event type 0x%x\n",
                  (int)event->xType);
      else
            printk(KERN_ERR "pci_event_handler: NULL event received\n");
}

#define REAL_IRQ_TO_SUBBUS(irq)     (((irq) >> 14) & 0xff)
#define REAL_IRQ_TO_BUS(irq)  ((((irq) >> 6) & 0xff) + 1)
#define REAL_IRQ_TO_IDSEL(irq)      ((((irq) >> 3) & 7) + 1)
#define REAL_IRQ_TO_FUNC(irq) ((irq) & 7)

/*
 * This will be called by device drivers (via enable_IRQ)
 * to enable INTA in the bridge interrupt status register.
 */
static void iseries_enable_IRQ(unsigned int irq)
{
      u32 bus, dev_id, function, mask;
      const u32 sub_bus = 0;
      unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

      /* The IRQ has already been locked by the caller */
      bus = REAL_IRQ_TO_BUS(rirq);
      function = REAL_IRQ_TO_FUNC(rirq);
      dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

      /* Unmask secondary INTA */
      mask = 0x80000000;
      HvCallPci_unmaskInterrupts(bus, sub_bus, dev_id, mask);
}

/* This is called by iseries_activate_IRQs */
static unsigned int iseries_startup_IRQ(unsigned int irq)
{
      u32 bus, dev_id, function, mask;
      const u32 sub_bus = 0;
      unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

      bus = REAL_IRQ_TO_BUS(rirq);
      function = REAL_IRQ_TO_FUNC(rirq);
      dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

      /* Link the IRQ number to the bridge */
      HvCallXm_connectBusUnit(bus, sub_bus, dev_id, irq);

      /* Unmask bridge interrupts in the FISR */
      mask = 0x01010000 << function;
      HvCallPci_unmaskFisr(bus, sub_bus, dev_id, mask);
      iseries_enable_IRQ(irq);
      return 0;
}

/*
 * This is called out of iSeries_fixup to activate interrupt
 * generation for usable slots
 */
void __init iSeries_activate_IRQs()
{
      int irq;
      unsigned long flags;

      for_each_irq (irq) {
            irq_desc_t *desc = get_irq_desc(irq);

            if (desc && desc->chip && desc->chip->startup) {
                  spin_lock_irqsave(&desc->lock, flags);
                  desc->chip->startup(irq);
                  spin_unlock_irqrestore(&desc->lock, flags);
            }
      }
}

/*  this is not called anywhere currently */
static void iseries_shutdown_IRQ(unsigned int irq)
{
      u32 bus, dev_id, function, mask;
      const u32 sub_bus = 0;
      unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

      /* irq should be locked by the caller */
      bus = REAL_IRQ_TO_BUS(rirq);
      function = REAL_IRQ_TO_FUNC(rirq);
      dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

      /* Invalidate the IRQ number in the bridge */
      HvCallXm_connectBusUnit(bus, sub_bus, dev_id, 0);

      /* Mask bridge interrupts in the FISR */
      mask = 0x01010000 << function;
      HvCallPci_maskFisr(bus, sub_bus, dev_id, mask);
}

/*
 * This will be called by device drivers (via disable_IRQ)
 * to disable INTA in the bridge interrupt status register.
 */
static void iseries_disable_IRQ(unsigned int irq)
{
      u32 bus, dev_id, function, mask;
      const u32 sub_bus = 0;
      unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

      /* The IRQ has already been locked by the caller */
      bus = REAL_IRQ_TO_BUS(rirq);
      function = REAL_IRQ_TO_FUNC(rirq);
      dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

      /* Mask secondary INTA   */
      mask = 0x80000000;
      HvCallPci_maskInterrupts(bus, sub_bus, dev_id, mask);
}

static void iseries_end_IRQ(unsigned int irq)
{
      unsigned int rirq = (unsigned int)irq_map[irq].hwirq;

      HvCallPci_eoi(REAL_IRQ_TO_BUS(rirq), REAL_IRQ_TO_SUBBUS(rirq),
            (REAL_IRQ_TO_IDSEL(rirq) << 4) + REAL_IRQ_TO_FUNC(rirq));
}

static struct irq_chip iseries_pic = {
      .typename   = "iSeries irq controller",
      .startup    = iseries_startup_IRQ,
      .shutdown   = iseries_shutdown_IRQ,
      .unmask           = iseries_enable_IRQ,
      .mask       = iseries_disable_IRQ,
      .eoi        = iseries_end_IRQ
};

/*
 * This is called out of iSeries_scan_slot to allocate an IRQ for an EADS slot
 * It calculates the irq value for the slot.
 * Note that sub_bus is always 0 (at the moment at least).
 */
int __init iSeries_allocate_IRQ(HvBusNumber bus,
            HvSubBusNumber sub_bus, u32 bsubbus)
{
      unsigned int realirq;
      u8 idsel = ISERIES_GET_DEVICE_FROM_SUBBUS(bsubbus);
      u8 function = ISERIES_GET_FUNCTION_FROM_SUBBUS(bsubbus);

      realirq = (((((sub_bus << 8) + (bus - 1)) << 3) + (idsel - 1)) << 3)
            + function;

      return irq_create_mapping(NULL, realirq);
}

#endif /* CONFIG_PCI */

/*
 * Get the next pending IRQ.
 */
unsigned int iSeries_get_irq(void)
{
      int irq = NO_IRQ_IGNORE;

#ifdef CONFIG_SMP
      if (get_lppaca()->int_dword.fields.ipi_cnt) {
            get_lppaca()->int_dword.fields.ipi_cnt = 0;
            iSeries_smp_message_recv();
      }
#endif /* CONFIG_SMP */
      if (hvlpevent_is_pending())
            process_hvlpevents();

#ifdef CONFIG_PCI
      if (num_pending_irqs) {
            spin_lock(&pending_irqs_lock);
            for (irq = 0; irq < NR_IRQS; irq++) {
                  if (pending_irqs[irq]) {
                        pending_irqs[irq]--;
                        num_pending_irqs--;
                        break;
                  }
            }
            spin_unlock(&pending_irqs_lock);
            if (irq >= NR_IRQS)
                  irq = NO_IRQ_IGNORE;
      }
#endif

      return irq;
}

#ifdef CONFIG_PCI

static int iseries_irq_host_map(struct irq_host *h, unsigned int virq,
                        irq_hw_number_t hw)
{
      set_irq_chip_and_handler(virq, &iseries_pic, handle_fasteoi_irq);

      return 0;
}

static int iseries_irq_host_match(struct irq_host *h, struct device_node *np)
{
      /* Match all */
      return 1;
}

static struct irq_host_ops iseries_irq_host_ops = {
      .map = iseries_irq_host_map,
      .match = iseries_irq_host_match,
};

/*
 * This is called by init_IRQ.  set in ppc_md.init_IRQ by iSeries_setup.c
 * It must be called before the bus walk.
 */
void __init iSeries_init_IRQ(void)
{
      /* Register PCI event handler and open an event path */
      struct irq_host *host;
      int ret;

      /*
       * The Hypervisor only allows us up to 256 interrupt
       * sources (the irq number is passed in a u8).
       */
      irq_set_virq_count(256);

      /* Create irq host. No need for a revmap since HV will give us
       * back our virtual irq number
       */
      host = irq_alloc_host(NULL, IRQ_HOST_MAP_NOMAP, 0,
                        &iseries_irq_host_ops, 0);
      BUG_ON(host == NULL);
      irq_set_default_host(host);

      ret = HvLpEvent_registerHandler(HvLpEvent_Type_PciIo,
                  &pci_event_handler);
      if (ret == 0) {
            ret = HvLpEvent_openPath(HvLpEvent_Type_PciIo, 0);
            if (ret != 0)
                  printk(KERN_ERR "iseries_init_IRQ: open event path "
                              "failed with rc 0x%x\n", ret);
      } else
            printk(KERN_ERR "iseries_init_IRQ: register handler "
                        "failed with rc 0x%x\n", ret);
}

#endif      /* CONFIG_PCI */

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