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/export.h>
  13#include <linux/slab.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 = irq_get_handler_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 = irq_get_handler_data(irq);
  58        *msg = cfg->msg;
  59}
  60
  61void mask_ht_irq(struct irq_data *data)
  62{
  63        struct ht_irq_cfg *cfg = irq_data_get_irq_handler_data(data);
  64        struct ht_irq_msg msg = cfg->msg;
  65
  66        msg.address_lo |= 1;
  67        write_ht_irq_msg(data->irq, &msg);
  68}
  69
  70void unmask_ht_irq(struct irq_data *data)
  71{
  72        struct ht_irq_cfg *cfg = irq_data_get_irq_handler_data(data);
  73        struct ht_irq_msg msg = cfg->msg;
  74
  75        msg.address_lo &= ~1;
  76        write_ht_irq_msg(data->irq, &msg);
  77}
  78
  79/**
  80 * __ht_create_irq - create an irq and attach it to a device.
  81 * @dev: The hypertransport device to find the irq capability on.
  82 * @idx: Which of the possible irqs to attach to.
  83 * @update: Function to be called when changing the htirq message
  84 *
  85 * The irq number of the new irq or a negative error value is returned.
  86 */
  87int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update)
  88{
  89        struct ht_irq_cfg *cfg;
  90        unsigned long flags;
  91        u32 data;
  92        int max_irq;
  93        int pos;
  94        int irq;
  95        int node;
  96
  97        pos = pci_find_ht_capability(dev, HT_CAPTYPE_IRQ);
  98        if (!pos)
  99                return -EINVAL;
 100
 101        /* Verify the idx I want to use is in range */
 102        spin_lock_irqsave(&ht_irq_lock, flags);
 103        pci_write_config_byte(dev, pos + 2, 1);
 104        pci_read_config_dword(dev, pos + 4, &data);
 105        spin_unlock_irqrestore(&ht_irq_lock, flags);
 106
 107        max_irq = (data >> 16) & 0xff;
 108        if ( idx > max_irq)
 109                return -EINVAL;
 110
 111        cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
 112        if (!cfg)
 113                return -ENOMEM;
 114
 115        cfg->dev = dev;
 116        cfg->update = update;
 117        cfg->pos = pos;
 118        cfg->idx = 0x10 + (idx * 2);
 119        /* Initialize msg to a value that will never match the first write. */
 120        cfg->msg.address_lo = 0xffffffff;
 121        cfg->msg.address_hi = 0xffffffff;
 122
 123        node = dev_to_node(&dev->dev);
 124        irq = create_irq_nr(0, node);
 125
 126        if (irq <= 0) {
 127                kfree(cfg);
 128                return -EBUSY;
 129        }
 130        irq_set_handler_data(irq, cfg);
 131
 132        if (arch_setup_ht_irq(irq, dev) < 0) {
 133                ht_destroy_irq(irq);
 134                return -EBUSY;
 135        }
 136
 137        return irq;
 138}
 139
 140/**
 141 * ht_create_irq - create an irq and attach it to a device.
 142 * @dev: The hypertransport device to find the irq capability on.
 143 * @idx: Which of the possible irqs to attach to.
 144 *
 145 * ht_create_irq needs to be called for all hypertransport devices
 146 * that generate irqs.
 147 *
 148 * The irq number of the new irq or a negative error value is returned.
 149 */
 150int ht_create_irq(struct pci_dev *dev, int idx)
 151{
 152        return __ht_create_irq(dev, idx, NULL);
 153}
 154
 155/**
 156 * ht_destroy_irq - destroy an irq created with ht_create_irq
 157 * @irq: irq to be destroyed
 158 *
 159 * This reverses ht_create_irq removing the specified irq from
 160 * existence.  The irq should be free before this happens.
 161 */
 162void ht_destroy_irq(unsigned int irq)
 163{
 164        struct ht_irq_cfg *cfg;
 165
 166        cfg = irq_get_handler_data(irq);
 167        irq_set_chip(irq, NULL);
 168        irq_set_handler_data(irq, NULL);
 169        destroy_irq(irq);
 170
 171        kfree(cfg);
 172}
 173
 174EXPORT_SYMBOL(__ht_create_irq);
 175EXPORT_SYMBOL(ht_create_irq);
 176EXPORT_SYMBOL(ht_destroy_irq);
 177
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