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msi.c

/*
 * arch/arm/mach-iop13xx/msi.c
 *
 * PCI MSI support for the iop13xx processor
 *
 * Copyright (c) 2006, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 *
 */
#include <linux/pci.h>
#include <linux/msi.h>
#include <asm/mach/irq.h>
#include <asm/irq.h>


#define IOP13XX_NUM_MSI_IRQS 128
static DECLARE_BITMAP(msi_irq_in_use, IOP13XX_NUM_MSI_IRQS);

/* IMIPR0 CP6 R8 Page 1
 */
static u32 read_imipr_0(void)
{
      u32 val;
      asm volatile("mrc p6, 0, %0, c8, c1, 0":"=r" (val));
      return val;
}
static void write_imipr_0(u32 val)
{
      asm volatile("mcr p6, 0, %0, c8, c1, 0"::"r" (val));
}

/* IMIPR1 CP6 R9 Page 1
 */
static u32 read_imipr_1(void)
{
      u32 val;
      asm volatile("mrc p6, 0, %0, c9, c1, 0":"=r" (val));
      return val;
}
static void write_imipr_1(u32 val)
{
      asm volatile("mcr p6, 0, %0, c9, c1, 0"::"r" (val));
}

/* IMIPR2 CP6 R10 Page 1
 */
static u32 read_imipr_2(void)
{
      u32 val;
      asm volatile("mrc p6, 0, %0, c10, c1, 0":"=r" (val));
      return val;
}
static void write_imipr_2(u32 val)
{
      asm volatile("mcr p6, 0, %0, c10, c1, 0"::"r" (val));
}

/* IMIPR3 CP6 R11 Page 1
 */
static u32 read_imipr_3(void)
{
      u32 val;
      asm volatile("mrc p6, 0, %0, c11, c1, 0":"=r" (val));
      return val;
}
static void write_imipr_3(u32 val)
{
      asm volatile("mcr p6, 0, %0, c11, c1, 0"::"r" (val));
}

static u32 (*read_imipr[])(void) = {
      read_imipr_0,
      read_imipr_1,
      read_imipr_2,
      read_imipr_3,
};

static void (*write_imipr[])(u32) = {
      write_imipr_0,
      write_imipr_1,
      write_imipr_2,
      write_imipr_3,
};

static void iop13xx_msi_handler(unsigned int irq, struct irq_desc *desc)
{
      int i, j;
      unsigned long status;

      /* read IMIPR registers and find any active interrupts,
       * then call ISR for each active interrupt
       */
      for (i = 0; i < ARRAY_SIZE(read_imipr); i++) {
            status = (read_imipr[i])();
            if (!status)
                  continue;

            do {
                  j = find_first_bit(&status, 32);
                  (write_imipr[i])(1 << j); /* write back to clear bit */
                  desc = irq_desc + IRQ_IOP13XX_MSI_0 + j + (32*i);
                  desc_handle_irq(IRQ_IOP13XX_MSI_0 + j + (32*i), desc);
                  status = (read_imipr[i])();
            } while (status);
      }
}

void __init iop13xx_msi_init(void)
{
      set_irq_chained_handler(IRQ_IOP13XX_INBD_MSI, iop13xx_msi_handler);
}

/*
 * Dynamic irq allocate and deallocation
 */
int create_irq(void)
{
      int irq, pos;

again:
      pos = find_first_zero_bit(msi_irq_in_use, IOP13XX_NUM_MSI_IRQS);
      irq = IRQ_IOP13XX_MSI_0 + pos;
      if (irq > NR_IRQS)
            return -ENOSPC;
      /* test_and_set_bit operates on 32-bits at a time */
      if (test_and_set_bit(pos, msi_irq_in_use))
            goto again;

      dynamic_irq_init(irq);

      return irq;
}

void destroy_irq(unsigned int irq)
{
      int pos = irq - IRQ_IOP13XX_MSI_0;

      dynamic_irq_cleanup(irq);

      clear_bit(pos, msi_irq_in_use);
}

void arch_teardown_msi_irq(unsigned int irq)
{
      destroy_irq(irq);
}

static void iop13xx_msi_nop(unsigned int irq)
{
      return;
}

static struct irq_chip iop13xx_msi_chip = {
      .name = "PCI-MSI",
      .ack = iop13xx_msi_nop,
      .enable = unmask_msi_irq,
      .disable = mask_msi_irq,
      .mask = mask_msi_irq,
      .unmask = unmask_msi_irq,
};

int arch_setup_msi_irq(struct pci_dev *pdev, struct msi_desc *desc)
{
      int id, irq = create_irq();
      struct msi_msg msg;

      if (irq < 0)
            return irq;

      set_irq_msi(irq, desc);

      msg.address_hi = 0x0;
      msg.address_lo = IOP13XX_MU_MIMR_PCI;

      id = iop13xx_cpu_id();
      msg.data = (id << IOP13XX_MU_MIMR_CORE_SELECT) | (irq & 0x7f);

      write_msi_msg(irq, &msg);
      set_irq_chip_and_handler(irq, &iop13xx_msi_chip, handle_simple_irq);

      return 0;
}

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