linux/arch/powerpc/platforms/82xx/pq2ads-pci-pic.c
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   1/*
   2 * PQ2 ADS-style PCI interrupt controller
   3 *
   4 * Copyright 2007 Freescale Semiconductor, Inc.
   5 * Author: Scott Wood <scottwood@freescale.com>
   6 *
   7 * Loosely based on mpc82xx ADS support by Vitaly Bordug <vbordug@ru.mvista.com>
   8 * Copyright (c) 2006 MontaVista Software, Inc.
   9 *
  10 * This program is free software; you can redistribute it and/or modify it
  11 * under the terms of the GNU General Public License version 2 as published
  12 * by the Free Software Foundation.
  13 */
  14
  15#include <linux/init.h>
  16#include <linux/spinlock.h>
  17#include <linux/irq.h>
  18#include <linux/types.h>
  19#include <linux/slab.h>
  20
  21#include <asm/io.h>
  22#include <asm/prom.h>
  23#include <asm/cpm2.h>
  24
  25#include "pq2.h"
  26
  27static DEFINE_RAW_SPINLOCK(pci_pic_lock);
  28
  29struct pq2ads_pci_pic {
  30        struct device_node *node;
  31        struct irq_domain *host;
  32
  33        struct {
  34                u32 stat;
  35                u32 mask;
  36        } __iomem *regs;
  37};
  38
  39#define NUM_IRQS 32
  40
  41static void pq2ads_pci_mask_irq(struct irq_data *d)
  42{
  43        struct pq2ads_pci_pic *priv = irq_data_get_irq_chip_data(d);
  44        int irq = NUM_IRQS - irqd_to_hwirq(d) - 1;
  45
  46        if (irq != -1) {
  47                unsigned long flags;
  48                raw_spin_lock_irqsave(&pci_pic_lock, flags);
  49
  50                setbits32(&priv->regs->mask, 1 << irq);
  51                mb();
  52
  53                raw_spin_unlock_irqrestore(&pci_pic_lock, flags);
  54        }
  55}
  56
  57static void pq2ads_pci_unmask_irq(struct irq_data *d)
  58{
  59        struct pq2ads_pci_pic *priv = irq_data_get_irq_chip_data(d);
  60        int irq = NUM_IRQS - irqd_to_hwirq(d) - 1;
  61
  62        if (irq != -1) {
  63                unsigned long flags;
  64
  65                raw_spin_lock_irqsave(&pci_pic_lock, flags);
  66                clrbits32(&priv->regs->mask, 1 << irq);
  67                raw_spin_unlock_irqrestore(&pci_pic_lock, flags);
  68        }
  69}
  70
  71static struct irq_chip pq2ads_pci_ic = {
  72        .name = "PQ2 ADS PCI",
  73        .irq_mask = pq2ads_pci_mask_irq,
  74        .irq_mask_ack = pq2ads_pci_mask_irq,
  75        .irq_ack = pq2ads_pci_mask_irq,
  76        .irq_unmask = pq2ads_pci_unmask_irq,
  77        .irq_enable = pq2ads_pci_unmask_irq,
  78        .irq_disable = pq2ads_pci_mask_irq
  79};
  80
  81static void pq2ads_pci_irq_demux(struct irq_desc *desc)
  82{
  83        struct pq2ads_pci_pic *priv = irq_desc_get_handler_data(desc);
  84        u32 stat, mask, pend;
  85        int bit;
  86
  87        for (;;) {
  88                stat = in_be32(&priv->regs->stat);
  89                mask = in_be32(&priv->regs->mask);
  90
  91                pend = stat & ~mask;
  92
  93                if (!pend)
  94                        break;
  95
  96                for (bit = 0; pend != 0; ++bit, pend <<= 1) {
  97                        if (pend & 0x80000000) {
  98                                int virq = irq_linear_revmap(priv->host, bit);
  99                                generic_handle_irq(virq);
 100                        }
 101                }
 102        }
 103}
 104
 105static int pci_pic_host_map(struct irq_domain *h, unsigned int virq,
 106                            irq_hw_number_t hw)
 107{
 108        irq_set_status_flags(virq, IRQ_LEVEL);
 109        irq_set_chip_data(virq, h->host_data);
 110        irq_set_chip_and_handler(virq, &pq2ads_pci_ic, handle_level_irq);
 111        return 0;
 112}
 113
 114static const struct irq_domain_ops pci_pic_host_ops = {
 115        .map = pci_pic_host_map,
 116};
 117
 118int __init pq2ads_pci_init_irq(void)
 119{
 120        struct pq2ads_pci_pic *priv;
 121        struct irq_domain *host;
 122        struct device_node *np;
 123        int ret = -ENODEV;
 124        int irq;
 125
 126        np = of_find_compatible_node(NULL, NULL, "fsl,pq2ads-pci-pic");
 127        if (!np) {
 128                printk(KERN_ERR "No pci pic node in device tree.\n");
 129                of_node_put(np);
 130                goto out;
 131        }
 132
 133        irq = irq_of_parse_and_map(np, 0);
 134        if (!irq) {
 135                printk(KERN_ERR "No interrupt in pci pic node.\n");
 136                of_node_put(np);
 137                goto out;
 138        }
 139
 140        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 141        if (!priv) {
 142                of_node_put(np);
 143                ret = -ENOMEM;
 144                goto out_unmap_irq;
 145        }
 146
 147        /* PCI interrupt controller registers: status and mask */
 148        priv->regs = of_iomap(np, 0);
 149        if (!priv->regs) {
 150                printk(KERN_ERR "Cannot map PCI PIC registers.\n");
 151                goto out_free_kmalloc;
 152        }
 153
 154        /* mask all PCI interrupts */
 155        out_be32(&priv->regs->mask, ~0);
 156        mb();
 157
 158        host = irq_domain_add_linear(np, NUM_IRQS, &pci_pic_host_ops, priv);
 159        if (!host) {
 160                ret = -ENOMEM;
 161                goto out_unmap_regs;
 162        }
 163
 164        priv->host = host;
 165        irq_set_handler_data(irq, priv);
 166        irq_set_chained_handler(irq, pq2ads_pci_irq_demux);
 167
 168        of_node_put(np);
 169        return 0;
 170
 171out_unmap_regs:
 172        iounmap(priv->regs);
 173out_free_kmalloc:
 174        kfree(priv);
 175        of_node_put(np);
 176out_unmap_irq:
 177        irq_dispose_mapping(irq);
 178out:
 179        return ret;
 180}
 181