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         int max_irq, pos, irq;
  91         unsigned long flags;
  92         u32 data;
  93
  94         pos = pci_find_ht_capability(dev, HT_CAPTYPE_IRQ);
  95         if (!pos)
  96                 return -EINVAL;
  97
  98         /* Verify the idx I want to use is in range */
  99         spin_lock_irqsave(&ht_irq_lock, flags);
 100         pci_write_config_byte(dev, pos + 2, 1);
 101         pci_read_config_dword(dev, pos + 4, &data);
 102         spin_unlock_irqrestore(&ht_irq_lock, flags);
 103
 104         max_irq = (data >> 16) & 0xff;
 105         if (idx > max_irq)
 106                 return -EINVAL;
 107
 108         cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
 109         if (!cfg)
 110                 return -ENOMEM;
 111
 112         cfg->dev = dev;
 113         cfg->update = update;
 114         cfg->pos = pos;
 115         cfg->idx = 0x10 + (idx * 2);
 116         /* Initialize msg to a value that will never match the first write. */
 117         cfg->msg.address_lo = 0xffffffff;
 118         cfg->msg.address_hi = 0xffffffff;
 119
 120         irq = irq_alloc_hwirq(dev_to_node(&dev->dev));
 121         if (!irq) {
 122                 kfree(cfg);
 123                 return -EBUSY;
 124         }
 125         irq_set_handler_data(irq, cfg);
 126
 127         if (arch_setup_ht_irq(irq, dev) < 0) {
 128                 ht_destroy_irq(irq);
 129                 return -EBUSY;
 130         }
 131
 132         return irq;
 133 }
 134 EXPORT_SYMBOL(__ht_create_irq);
 135
 136 /**
 137  * ht_create_irq - create an irq and attach it to a device.
 138  * @dev: The hypertransport device to find the irq capability on.
 139  * @idx: Which of the possible irqs to attach to.
 140  *
 141  * ht_create_irq needs to be called for all hypertransport devices
 142  * that generate irqs.
 143  *
 144  * The irq number of the new irq or a negative error value is returned.
 145  */
 146 int ht_create_irq(struct pci_dev *dev, int idx)
 147 {
 148         return __ht_create_irq(dev, idx, NULL);
 149 }
 150 EXPORT_SYMBOL(ht_create_irq);
 151
 152 /**
 153  * ht_destroy_irq - destroy an irq created with ht_create_irq
 154  * @irq: irq to be destroyed
 155  *
 156  * This reverses ht_create_irq removing the specified irq from
 157  * existence.  The irq should be free before this happens.
 158  */
 159 void ht_destroy_irq(unsigned int irq)
 160 {
 161         struct ht_irq_cfg *cfg;
 162
 163         cfg = irq_get_handler_data(irq);
 164         irq_set_chip(irq, NULL);
 165         irq_set_handler_data(irq, NULL);
 166         irq_free_hwirq(irq);
 167
 168         kfree(cfg);
 169 }
 170 EXPORT_SYMBOL(ht_destroy_irq);