arch/powerpc/platforms/82xx/pq2ads-pci-pic.c

   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/bootmem.h>
  20
  21 #include <asm/io.h>
  22 #include <asm/prom.h>
  23 #include <asm/cpm2.h>
  24
  25 #include "pq2.h"
  26
  27 static DEFINE_SPINLOCK(pci_pic_lock);
  28
  29 struct pq2ads_pci_pic {
  30         struct device_node *node;
  31         struct irq_host *host;
  32
  33         struct {
  34                 u32 stat;
  35                 u32 mask;
  36         } __iomem *regs;
  37 };
  38
  39 #define NUM_IRQS 32
  40
  41 static void pq2ads_pci_mask_irq(unsigned int virq)
  42 {
  43         struct pq2ads_pci_pic *priv = get_irq_chip_data(virq);
  44         int irq = NUM_IRQS - virq_to_hw(virq) - 1;
  45
  46         if (irq != -1) {
  47                 unsigned long flags;
  48                 spin_lock_irqsave(&pci_pic_lock, flags);
  49
  50                 setbits32(&priv->regs->mask, 1 << irq);
  51                 mb();
  52
  53                 spin_unlock_irqrestore(&pci_pic_lock, flags);
  54         }
  55 }
  56
  57 static void pq2ads_pci_unmask_irq(unsigned int virq)
  58 {
  59         struct pq2ads_pci_pic *priv = get_irq_chip_data(virq);
  60         int irq = NUM_IRQS - virq_to_hw(virq) - 1;
  61
  62         if (irq != -1) {
  63                 unsigned long flags;
  64
  65                 spin_lock_irqsave(&pci_pic_lock, flags);
  66                 clrbits32(&priv->regs->mask, 1 << irq);
  67                 spin_unlock_irqrestore(&pci_pic_lock, flags);
  68         }
  69 }
  70
  71 static struct irq_chip pq2ads_pci_ic = {
  72         .name = "PQ2 ADS PCI",
  73         .end = pq2ads_pci_unmask_irq,
  74         .mask = pq2ads_pci_mask_irq,
  75         .mask_ack = pq2ads_pci_mask_irq,
  76         .ack = pq2ads_pci_mask_irq,
  77         .unmask = pq2ads_pci_unmask_irq,
  78         .enable = pq2ads_pci_unmask_irq,
  79         .disable = pq2ads_pci_mask_irq
  80 };
  81
  82 static void pq2ads_pci_irq_demux(unsigned int irq, struct irq_desc *desc)
  83 {
  84         struct pq2ads_pci_pic *priv = desc->handler_data;
  85         u32 stat, mask, pend;
  86         int bit;
  87
  88         for (;;) {
  89                 stat = in_be32(&priv->regs->stat);
  90                 mask = in_be32(&priv->regs->mask);
  91
  92                 pend = stat & ~mask;
  93
  94                 if (!pend)
  95                         break;
  96
  97                 for (bit = 0; pend != 0; ++bit, pend <<= 1) {
  98                         if (pend & 0x80000000) {
  99                                 int virq = irq_linear_revmap(priv->host, bit);
 100                                 generic_handle_irq(virq);
 101                         }
 102                 }
 103         }
 104 }
 105
 106 static int pci_pic_host_map(struct irq_host *h, unsigned int virq,
 107                             irq_hw_number_t hw)
 108 {
 109         irq_to_desc(virq)->status |= IRQ_LEVEL;
 110         set_irq_chip_data(virq, h->host_data);
 111         set_irq_chip_and_handler(virq, &pq2ads_pci_ic, handle_level_irq);
 112         return 0;
 113 }
 114
 115 static void pci_host_unmap(struct irq_host *h, unsigned int virq)
 116 {
 117         /* remove chip and handler */
 118         set_irq_chip_data(virq, NULL);
 119         set_irq_chip(virq, NULL);
 120 }
 121
 122 static struct irq_host_ops pci_pic_host_ops = {
 123         .map = pci_pic_host_map,
 124         .unmap = pci_host_unmap,
 125 };
 126
 127 int __init pq2ads_pci_init_irq(void)
 128 {
 129         struct pq2ads_pci_pic *priv;
 130         struct irq_host *host;
 131         struct device_node *np;
 132         int ret = -ENODEV;
 133         int irq;
 134
 135         np = of_find_compatible_node(NULL, NULL, "fsl,pq2ads-pci-pic");
 136         if (!np) {
 137                 printk(KERN_ERR "No pci pic node in device tree.\n");
 138                 of_node_put(np);
 139                 goto out;
 140         }
 141
 142         irq = irq_of_parse_and_map(np, 0);
 143         if (irq == NO_IRQ) {
 144                 printk(KERN_ERR "No interrupt in pci pic node.\n");
 145                 of_node_put(np);
 146                 goto out;
 147         }
 148
 149         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 150         if (!priv) {
 151                 of_node_put(np);
 152                 ret = -ENOMEM;
 153                 goto out_unmap_irq;
 154         }
 155
 156         /* PCI interrupt controller registers: status and mask */
 157         priv->regs = of_iomap(np, 0);
 158         if (!priv->regs) {
 159                 printk(KERN_ERR "Cannot map PCI PIC registers.\n");
 160                 goto out_free_bootmem;
 161         }
 162
 163         /* mask all PCI interrupts */
 164         out_be32(&priv->regs->mask, ~0);
 165         mb();
 166
 167         host = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, NUM_IRQS,
 168                               &pci_pic_host_ops, NUM_IRQS);
 169         if (!host) {
 170                 ret = -ENOMEM;
 171                 goto out_unmap_regs;
 172         }
 173
 174         host->host_data = priv;
 175
 176         priv->host = host;
 177         host->host_data = priv;
 178         set_irq_data(irq, priv);
 179         set_irq_chained_handler(irq, pq2ads_pci_irq_demux);
 180
 181         of_node_put(np);
 182         return 0;
 183
 184 out_unmap_regs:
 185         iounmap(priv->regs);
 186 out_free_bootmem:
 187         free_bootmem((unsigned long)priv,
 188                      sizeof(struct pq2ads_pci_pic));
 189         of_node_put(np);
 190 out_unmap_irq:
 191         irq_dispose_mapping(irq);
 192 out:
 193         return ret;
 194 }