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mpic_u3msi.c

/*
 * Copyright 2006, Segher Boessenkool, IBM Corporation.
 * Copyright 2006-2007, Michael Ellerman, 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; version 2 of the
 * License.
 *
 */

#include <linux/irq.h>
#include <linux/bootmem.h>
#include <linux/msi.h>
#include <asm/mpic.h>
#include <asm/prom.h>
#include <asm/hw_irq.h>
#include <asm/ppc-pci.h>

#include "mpic.h"

/* A bit ugly, can we get this from the pci_dev somehow? */
static struct mpic *msi_mpic;

static void mpic_u3msi_mask_irq(unsigned int irq)
{
      mask_msi_irq(irq);
      mpic_mask_irq(irq);
}

static void mpic_u3msi_unmask_irq(unsigned int irq)
{
      mpic_unmask_irq(irq);
      unmask_msi_irq(irq);
}

static struct irq_chip mpic_u3msi_chip = {
      .shutdown   = mpic_u3msi_mask_irq,
      .mask       = mpic_u3msi_mask_irq,
      .unmask           = mpic_u3msi_unmask_irq,
      .eoi        = mpic_end_irq,
      .set_type   = mpic_set_irq_type,
      .set_affinity     = mpic_set_affinity,
      .typename   = "MPIC-U3MSI",
};

static u64 read_ht_magic_addr(struct pci_dev *pdev, unsigned int pos)
{
      u8 flags;
      u32 tmp;
      u64 addr;

      pci_read_config_byte(pdev, pos + HT_MSI_FLAGS, &flags);

      if (flags & HT_MSI_FLAGS_FIXED)
            return HT_MSI_FIXED_ADDR;

      pci_read_config_dword(pdev, pos + HT_MSI_ADDR_LO, &tmp);
      addr = tmp & HT_MSI_ADDR_LO_MASK;
      pci_read_config_dword(pdev, pos + HT_MSI_ADDR_HI, &tmp);
      addr = addr | ((u64)tmp << 32);

      return addr;
}

static u64 find_ht_magic_addr(struct pci_dev *pdev)
{
      struct pci_bus *bus;
      unsigned int pos;

      for (bus = pdev->bus; bus; bus = bus->parent) {
            pos = pci_find_ht_capability(bus->self, HT_CAPTYPE_MSI_MAPPING);
            if (pos)
                  return read_ht_magic_addr(bus->self, pos);
      }

      return 0;
}

static int u3msi_msi_check_device(struct pci_dev *pdev, int nvec, int type)
{
      if (type == PCI_CAP_ID_MSIX)
            pr_debug("u3msi: MSI-X untested, trying anyway.\n");

      /* If we can't find a magic address then MSI ain't gonna work */
      if (find_ht_magic_addr(pdev) == 0) {
            pr_debug("u3msi: no magic address found for %s\n",
                   pci_name(pdev));
            return -ENXIO;
      }

      return 0;
}

static void u3msi_teardown_msi_irqs(struct pci_dev *pdev)
{
      struct msi_desc *entry;

        list_for_each_entry(entry, &pdev->msi_list, list) {
            if (entry->irq == NO_IRQ)
                  continue;

            set_irq_msi(entry->irq, NULL);
            mpic_msi_free_hwirqs(msi_mpic, virq_to_hw(entry->irq), 1);
            irq_dispose_mapping(entry->irq);
      }

      return;
}

static int u3msi_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
{
      irq_hw_number_t hwirq;
      unsigned int virq;
      struct msi_desc *entry;
      struct msi_msg msg;
      u64 addr;

      addr = find_ht_magic_addr(pdev);
      msg.address_lo = addr & 0xFFFFFFFF;
      msg.address_hi = addr >> 32;

      list_for_each_entry(entry, &pdev->msi_list, list) {
            hwirq = mpic_msi_alloc_hwirqs(msi_mpic, 1);
            if (hwirq < 0) {
                  pr_debug("u3msi: failed allocating hwirq\n");
                  return hwirq;
            }

            virq = irq_create_mapping(msi_mpic->irqhost, hwirq);
            if (virq == NO_IRQ) {
                  pr_debug("u3msi: failed mapping hwirq 0x%lx\n", hwirq);
                  mpic_msi_free_hwirqs(msi_mpic, hwirq, 1);
                  return -ENOSPC;
            }

            set_irq_msi(virq, entry);
            set_irq_chip(virq, &mpic_u3msi_chip);
            set_irq_type(virq, IRQ_TYPE_EDGE_RISING);

            pr_debug("u3msi: allocated virq 0x%x (hw 0x%lx) addr 0x%lx\n",
                    virq, hwirq, addr);

            msg.data = hwirq;
            write_msi_msg(virq, &msg);

            hwirq++;
      }

      return 0;
}

int mpic_u3msi_init(struct mpic *mpic)
{
      int rc;

      rc = mpic_msi_init_allocator(mpic);
      if (rc) {
            pr_debug("u3msi: Error allocating bitmap!\n");
            return rc;
      }

      pr_debug("u3msi: Registering MPIC U3 MSI callbacks.\n");

      BUG_ON(msi_mpic);
      msi_mpic = mpic;

      WARN_ON(ppc_md.setup_msi_irqs);
      ppc_md.setup_msi_irqs = u3msi_setup_msi_irqs;
      ppc_md.teardown_msi_irqs = u3msi_teardown_msi_irqs;
      ppc_md.msi_check_device = u3msi_msi_check_device;

      return 0;
}

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