LXR linux/drivers/pci/htirq.c

   1/*
   2 * File:        htirq.c
   3 * Purpose:     Hypertransport Interrupt Capability
   4 *
   5 * Copyright (C) 2006 Linux Networx
   6 * Copyright (C) Eric Biederman <ebiederman@lnxi.com>
   7 */
   8
   9#include <linux/irq.h>
  10#include <linux/pci.h>
  11#include <linux/spinlock.h>
  12#include <linux/slab.h>
  13#include <linux/gfp.h>
  14#include <linux/htirq.h>
  15
  16/* Global ht irq lock.
  17 *
  18 * This is needed to serialize access to the data port in hypertransport
  19 * irq capability.
  20 *
  21 * With multiple simultaneous hypertransport irq devices it might pay
  22 * to make this more fine grained.  But start with simple, stupid, and correct.
  23 */
  24static DEFINE_SPINLOCK(ht_irq_lock);
  25
  26struct ht_irq_cfg {
  27        struct pci_dev *dev;
  28         /* Update callback used to cope with buggy hardware */
  29        ht_irq_update_t *update;
  30        unsigned pos;
  31        unsigned idx;
  32        struct ht_irq_msg msg;
  33};
  34
  35
  36void write_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
  37{
  38        struct ht_irq_cfg *cfg = get_irq_data(irq);
  39        unsigned long flags;
  40        spin_lock_irqsave(&ht_irq_lock, flags);
  41        if (cfg->msg.address_lo != msg->address_lo) {
  42                pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
  43                pci_write_config_dword(cfg->dev, cfg->pos + 4, msg->address_lo);
  44        }
  45        if (cfg->msg.address_hi != msg->address_hi) {
  46                pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx + 1);
  47                pci_write_config_dword(cfg->dev, cfg->pos + 4, msg->address_hi);
  48        }
  49        if (cfg->update)
  50                cfg->update(cfg->dev, irq, msg);
  51        spin_unlock_irqrestore(&ht_irq_lock, flags);
  52        cfg->msg = *msg;
  53}
  54
  55void fetch_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
  56{
  57        struct ht_irq_cfg *cfg = get_irq_data(irq);
  58        *msg = cfg->msg;
  59}
  60
  61void mask_ht_irq(unsigned int irq)
  62{
  63        struct ht_irq_cfg *cfg;
  64        struct ht_irq_msg msg;
  65
  66        cfg = get_irq_data(irq);
  67
  68        msg = cfg->msg;
  69        msg.address_lo |= 1;
  70        write_ht_irq_msg(irq, &msg);
  71}
  72
  73void unmask_ht_irq(unsigned int irq)
  74{
  75        struct ht_irq_cfg *cfg;
  76        struct ht_irq_msg msg;
  77
  78        cfg = get_irq_data(irq);
  79
  80        msg = cfg->msg;
  81        msg.address_lo &= ~1;
  82        write_ht_irq_msg(irq, &msg);
  83}
  84
  85/**
  86 * __ht_create_irq - create an irq and attach it to a device.
  87 * @dev: The hypertransport device to find the irq capability on.
  88 * @idx: Which of the possible irqs to attach to.
  89 * @update: Function to be called when changing the htirq message
  90 *
  91 * The irq number of the new irq or a negative error value is returned.
  92 */
  93int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update)
  94{
  95        struct ht_irq_cfg *cfg;
  96        unsigned long flags;
  97        u32 data;
  98        int max_irq;
  99        int pos;
 100        int irq;
 101
 102        pos = pci_find_ht_capability(dev, HT_CAPTYPE_IRQ);
 103        if (!pos)
 104                return -EINVAL;
 105
 106        /* Verify the idx I want to use is in range */
 107        spin_lock_irqsave(&ht_irq_lock, flags);
 108        pci_write_config_byte(dev, pos + 2, 1);
 109        pci_read_config_dword(dev, pos + 4, &data);
 110        spin_unlock_irqrestore(&ht_irq_lock, flags);
 111
 112        max_irq = (data >> 16) & 0xff;
 113        if ( idx > max_irq)
 114                return -EINVAL;
 115
 116        cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
 117        if (!cfg)
 118                return -ENOMEM;
 119
 120        cfg->dev = dev;
 121        cfg->update = update;
 122        cfg->pos = pos;
 123        cfg->idx = 0x10 + (idx * 2);
 124        /* Initialize msg to a value that will never match the first write. */
 125        cfg->msg.address_lo = 0xffffffff;
 126        cfg->msg.address_hi = 0xffffffff;
 127
 128        irq = create_irq();
 129
 130        if (irq <= 0) {
 131                kfree(cfg);
 132                return -EBUSY;
 133        }
 134        set_irq_data(irq, cfg);
 135
 136        if (arch_setup_ht_irq(irq, dev) < 0) {
 137                ht_destroy_irq(irq);
 138                return -EBUSY;
 139        }
 140
 141        return irq;
 142}
 143
 144/**
 145 * ht_create_irq - create an irq and attach it to a device.
 146 * @dev: The hypertransport device to find the irq capability on.
 147 * @idx: Which of the possible irqs to attach to.
 148 *
 149 * ht_create_irq needs to be called for all hypertransport devices
 150 * that generate irqs.
 151 *
 152 * The irq number of the new irq or a negative error value is returned.
 153 */
 154int ht_create_irq(struct pci_dev *dev, int idx)
 155{
 156        return __ht_create_irq(dev, idx, NULL);
 157}
 158
 159/**
 160 * ht_destroy_irq - destroy an irq created with ht_create_irq
 161 * @irq: irq to be destroyed
 162 *
 163 * This reverses ht_create_irq removing the specified irq from
 164 * existence.  The irq should be free before this happens.
 165 */
 166void ht_destroy_irq(unsigned int irq)
 167{
 168        struct ht_irq_cfg *cfg;
 169
 170        cfg = get_irq_data(irq);
 171        set_irq_chip(irq, NULL);
 172        set_irq_data(irq, NULL);
 173        destroy_irq(irq);
 174
 175        kfree(cfg);
 176}
 177
 178EXPORT_SYMBOL(__ht_create_irq);
 179EXPORT_SYMBOL(ht_create_irq);
 180EXPORT_SYMBOL(ht_destroy_irq);
 181