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/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  */
  24 static DEFINE_SPINLOCK(ht_irq_lock);
  25
  26 struct 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
  36 void 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
  55 void 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
  61 void 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
  70 void 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  */
  87 int __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  */
 150 int 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  */
 162 void 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
 174 EXPORT_SYMBOL(__ht_create_irq);
 175 EXPORT_SYMBOL(ht_create_irq);
 176 EXPORT_SYMBOL(ht_destroy_irq);