LXR linux/arch/arm/mach-iop13xx/msi.c

   1/*
   2 * arch/arm/mach-iop13xx/msi.c
   3 *
   4 * PCI MSI support for the iop13xx processor
   5 *
   6 * Copyright (c) 2006, Intel Corporation.
   7 *
   8 * This program is free software; you can redistribute it and/or modify it
   9 * under the terms and conditions of the GNU General Public License,
  10 * version 2, as published by the Free Software Foundation.
  11 *
  12 * This program is distributed in the hope it will be useful, but WITHOUT
  13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15 * more details.
  16 *
  17 * You should have received a copy of the GNU General Public License along with
  18 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  19 * Place - Suite 330, Boston, MA 02111-1307 USA.
  20 *
  21 */
  22#include <linux/pci.h>
  23#include <linux/msi.h>
  24#include <asm/mach/irq.h>
  25#include <asm/irq.h>
  26
  27
  28#define IOP13XX_NUM_MSI_IRQS 128
  29static DECLARE_BITMAP(msi_irq_in_use, IOP13XX_NUM_MSI_IRQS);
  30
  31/* IMIPR0 CP6 R8 Page 1
  32 */
  33static u32 read_imipr_0(void)
  34{
  35        u32 val;
  36        asm volatile("mrc p6, 0, %0, c8, c1, 0":"=r" (val));
  37        return val;
  38}
  39static void write_imipr_0(u32 val)
  40{
  41        asm volatile("mcr p6, 0, %0, c8, c1, 0"::"r" (val));
  42}
  43
  44/* IMIPR1 CP6 R9 Page 1
  45 */
  46static u32 read_imipr_1(void)
  47{
  48        u32 val;
  49        asm volatile("mrc p6, 0, %0, c9, c1, 0":"=r" (val));
  50        return val;
  51}
  52static void write_imipr_1(u32 val)
  53{
  54        asm volatile("mcr p6, 0, %0, c9, c1, 0"::"r" (val));
  55}
  56
  57/* IMIPR2 CP6 R10 Page 1
  58 */
  59static u32 read_imipr_2(void)
  60{
  61        u32 val;
  62        asm volatile("mrc p6, 0, %0, c10, c1, 0":"=r" (val));
  63        return val;
  64}
  65static void write_imipr_2(u32 val)
  66{
  67        asm volatile("mcr p6, 0, %0, c10, c1, 0"::"r" (val));
  68}
  69
  70/* IMIPR3 CP6 R11 Page 1
  71 */
  72static u32 read_imipr_3(void)
  73{
  74        u32 val;
  75        asm volatile("mrc p6, 0, %0, c11, c1, 0":"=r" (val));
  76        return val;
  77}
  78static void write_imipr_3(u32 val)
  79{
  80        asm volatile("mcr p6, 0, %0, c11, c1, 0"::"r" (val));
  81}
  82
  83static u32 (*read_imipr[])(void) = {
  84        read_imipr_0,
  85        read_imipr_1,
  86        read_imipr_2,
  87        read_imipr_3,
  88};
  89
  90static void (*write_imipr[])(u32) = {
  91        write_imipr_0,
  92        write_imipr_1,
  93        write_imipr_2,
  94        write_imipr_3,
  95};
  96
  97static void iop13xx_msi_handler(unsigned int irq, struct irq_desc *desc)
  98{
  99        int i, j;
 100        unsigned long status;
 101
 102        /* read IMIPR registers and find any active interrupts,
 103         * then call ISR for each active interrupt
 104         */
 105        for (i = 0; i < ARRAY_SIZE(read_imipr); i++) {
 106                status = (read_imipr[i])();
 107                if (!status)
 108                        continue;
 109
 110                do {
 111                        j = find_first_bit(&status, 32);
 112                        (write_imipr[i])(1 << j); /* write back to clear bit */
 113                        generic_handle_irq(IRQ_IOP13XX_MSI_0 + j + (32*i));
 114                        status = (read_imipr[i])();
 115                } while (status);
 116        }
 117}
 118
 119void __init iop13xx_msi_init(void)
 120{
 121        irq_set_chained_handler(IRQ_IOP13XX_INBD_MSI, iop13xx_msi_handler);
 122}
 123
 124/*
 125 * Dynamic irq allocate and deallocation
 126 */
 127int create_irq(void)
 128{
 129        int irq, pos;
 130
 131again:
 132        pos = find_first_zero_bit(msi_irq_in_use, IOP13XX_NUM_MSI_IRQS);
 133        irq = IRQ_IOP13XX_MSI_0 + pos;
 134        if (irq > NR_IRQS)
 135                return -ENOSPC;
 136        /* test_and_set_bit operates on 32-bits at a time */
 137        if (test_and_set_bit(pos, msi_irq_in_use))
 138                goto again;
 139
 140        dynamic_irq_init(irq);
 141
 142        return irq;
 143}
 144
 145void destroy_irq(unsigned int irq)
 146{
 147        int pos = irq - IRQ_IOP13XX_MSI_0;
 148
 149        dynamic_irq_cleanup(irq);
 150
 151        clear_bit(pos, msi_irq_in_use);
 152}
 153
 154void arch_teardown_msi_irq(unsigned int irq)
 155{
 156        destroy_irq(irq);
 157}
 158
 159static void iop13xx_msi_nop(struct irq_data *d)
 160{
 161        return;
 162}
 163
 164static struct irq_chip iop13xx_msi_chip = {
 165        .name = "PCI-MSI",
 166        .irq_ack = iop13xx_msi_nop,
 167        .irq_enable = unmask_msi_irq,
 168        .irq_disable = mask_msi_irq,
 169        .irq_mask = mask_msi_irq,
 170        .irq_unmask = unmask_msi_irq,
 171};
 172
 173int arch_setup_msi_irq(struct pci_dev *pdev, struct msi_desc *desc)
 174{
 175        int id, irq = create_irq();
 176        struct msi_msg msg;
 177
 178        if (irq < 0)
 179                return irq;
 180
 181        irq_set_msi_desc(irq, desc);
 182
 183        msg.address_hi = 0x0;
 184        msg.address_lo = IOP13XX_MU_MIMR_PCI;
 185
 186        id = iop13xx_cpu_id();
 187        msg.data = (id << IOP13XX_MU_MIMR_CORE_SELECT) | (irq & 0x7f);
 188
 189        write_msi_msg(irq, &msg);
 190        irq_set_chip_and_handler(irq, &iop13xx_msi_chip, handle_simple_irq);
 191
 192        return 0;
 193}
 194