LXR linux/arch/powerpc/platforms/512x/mpc5121_ads

   1/*
   2 * Copyright (C) 2008 Freescale Semiconductor, Inc. All rights reserved.
   3 *
   4 * Author: John Rigby, <jrigby@freescale.com>
   5 *
   6 * Description:
   7 * MPC5121ADS CPLD irq handling
   8 *
   9 * This is free software; you can redistribute it and/or modify it
  10 * under the terms of the GNU General Public License as published by
  11 * the Free Software Foundation; either version 2 of the License, or
  12 * (at your option) any later version.
  13 */
  14
  15#undef DEBUG
  16
  17#include <linux/kernel.h>
  18#include <linux/interrupt.h>
  19#include <linux/irq.h>
  20#include <linux/io.h>
  21#include <asm/prom.h>
  22
  23static struct device_node *cpld_pic_node;
  24static struct irq_domain *cpld_pic_host;
  25
  26/*
  27 * Bits to ignore in the misc_status register
  28 * 0x10 touch screen pendown is hard routed to irq1
  29 * 0x02 pci status is read from pci status register
  30 */
  31#define MISC_IGNORE 0x12
  32
  33/*
  34 * Nothing to ignore in pci status register
  35 */
  36#define PCI_IGNORE 0x00
  37
  38struct cpld_pic {
  39        u8 pci_mask;
  40        u8 pci_status;
  41        u8 route;
  42        u8 misc_mask;
  43        u8 misc_status;
  44        u8 misc_control;
  45};
  46
  47static struct cpld_pic __iomem *cpld_regs;
  48
  49static void __iomem *
  50irq_to_pic_mask(unsigned int irq)
  51{
  52        return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask;
  53}
  54
  55static unsigned int
  56irq_to_pic_bit(unsigned int irq)
  57{
  58        return 1 << (irq & 0x7);
  59}
  60
  61static void
  62cpld_mask_irq(struct irq_data *d)
  63{
  64        unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
  65        void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
  66
  67        out_8(pic_mask,
  68              in_8(pic_mask) | irq_to_pic_bit(cpld_irq));
  69}
  70
  71static void
  72cpld_unmask_irq(struct irq_data *d)
  73{
  74        unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
  75        void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
  76
  77        out_8(pic_mask,
  78              in_8(pic_mask) & ~irq_to_pic_bit(cpld_irq));
  79}
  80
  81static struct irq_chip cpld_pic = {
  82        .name = "CPLD PIC",
  83        .irq_mask = cpld_mask_irq,
  84        .irq_ack = cpld_mask_irq,
  85        .irq_unmask = cpld_unmask_irq,
  86};
  87
  88static int
  89cpld_pic_get_irq(int offset, u8 ignore, u8 __iomem *statusp,
  90                            u8 __iomem *maskp)
  91{
  92        int cpld_irq;
  93        u8 status = in_8(statusp);
  94        u8 mask = in_8(maskp);
  95
  96        /* ignore don't cares and masked irqs */
  97        status |= (ignore | mask);
  98
  99        if (status == 0xff)
 100                return 0;
 101
 102        cpld_irq = ffz(status) + offset;
 103
 104        return irq_linear_revmap(cpld_pic_host, cpld_irq);
 105}
 106
 107static void cpld_pic_cascade(struct irq_desc *desc)
 108{
 109        unsigned int irq;
 110
 111        irq = cpld_pic_get_irq(0, PCI_IGNORE, &cpld_regs->pci_status,
 112                &cpld_regs->pci_mask);
 113        if (irq) {
 114                generic_handle_irq(irq);
 115                return;
 116        }
 117
 118        irq = cpld_pic_get_irq(8, MISC_IGNORE, &cpld_regs->misc_status,
 119                &cpld_regs->misc_mask);
 120        if (irq) {
 121                generic_handle_irq(irq);
 122                return;
 123        }
 124}
 125
 126static int
 127cpld_pic_host_match(struct irq_domain *h, struct device_node *node,
 128                    enum irq_domain_bus_token bus_token)
 129{
 130        return cpld_pic_node == node;
 131}
 132
 133static int
 134cpld_pic_host_map(struct irq_domain *h, unsigned int virq,
 135                             irq_hw_number_t hw)
 136{
 137        irq_set_status_flags(virq, IRQ_LEVEL);
 138        irq_set_chip_and_handler(virq, &cpld_pic, handle_level_irq);
 139        return 0;
 140}
 141
 142static const struct irq_domain_ops cpld_pic_host_ops = {
 143        .match = cpld_pic_host_match,
 144        .map = cpld_pic_host_map,
 145};
 146
 147void __init
 148mpc5121_ads_cpld_map(void)
 149{
 150        struct device_node *np = NULL;
 151
 152        np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
 153        if (!np) {
 154                printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
 155                return;
 156        }
 157
 158        cpld_regs = of_iomap(np, 0);
 159        of_node_put(np);
 160}
 161
 162void __init
 163mpc5121_ads_cpld_pic_init(void)
 164{
 165        unsigned int cascade_irq;
 166        struct device_node *np = NULL;
 167
 168        pr_debug("cpld_ic_init\n");
 169
 170        np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
 171        if (!np) {
 172                printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
 173                return;
 174        }
 175
 176        if (!cpld_regs)
 177                goto end;
 178
 179        cascade_irq = irq_of_parse_and_map(np, 0);
 180        if (!cascade_irq)
 181                goto end;
 182
 183        /*
 184         * statically route touch screen pendown through 1
 185         * and ignore it here
 186         * route all others through our cascade irq
 187         */
 188        out_8(&cpld_regs->route, 0xfd);
 189        out_8(&cpld_regs->pci_mask, 0xff);
 190        /* unmask pci ints in misc mask */
 191        out_8(&cpld_regs->misc_mask, ~(MISC_IGNORE));
 192
 193        cpld_pic_node = of_node_get(np);
 194
 195        cpld_pic_host = irq_domain_add_linear(np, 16, &cpld_pic_host_ops, NULL);
 196        if (!cpld_pic_host) {
 197                printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n");
 198                goto end;
 199        }
 200
 201        irq_set_chained_handler(cascade_irq, cpld_pic_cascade);
 202end:
 203        of_node_put(np);
 204}
 205