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