msi.c

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/*
 * 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 */
            generic_handle_irq(IRQ_IOP13XX_MSI_0 + j + (32*i));
            status = (read_imipr[i])();
        } while (status);
    }
}

void __init iop13xx_msi_init(void)
{
    irq_set_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(struct irq_data *d)
{
    return;
}

static struct irq_chip iop13xx_msi_chip = {
    .name = "PCI-MSI",
    .irq_ack = iop13xx_msi_nop,
    .irq_enable = unmask_msi_irq,
    .irq_disable = mask_msi_irq,
    .irq_mask = mask_msi_irq,
    .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;

    irq_set_msi_desc(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);
    irq_set_chip_and_handler(irq, &iop13xx_msi_chip, handle_simple_irq);

    return 0;
}