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/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  */
  23 static DEFINE_SPINLOCK(ht_irq_lock);
  24
  25 struct 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
  35 void write_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
  36 {
  37         struct ht_irq_cfg *cfg = get_irq_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
  54 void fetch_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
  55 {
  56         struct ht_irq_cfg *cfg = get_irq_data(irq);
  57         *msg = cfg->msg;
  58 }
  59
  60 void mask_ht_irq(unsigned int irq)
  61 {
  62         struct ht_irq_cfg *cfg;
  63         struct ht_irq_msg msg;
  64
  65         cfg = get_irq_data(irq);
  66
  67         msg = cfg->msg;
  68         msg.address_lo |= 1;
  69         write_ht_irq_msg(irq, &msg);
  70 }
  71
  72 void unmask_ht_irq(unsigned int irq)
  73 {
  74         struct ht_irq_cfg *cfg;
  75         struct ht_irq_msg msg;
  76
  77         cfg = get_irq_data(irq);
  78
  79         msg = cfg->msg;
  80         msg.address_lo &= ~1;
  81         write_ht_irq_msg(irq, &msg);
  82 }
  83
  84 /**
  85  * __ht_create_irq - create an irq and attach it to a device.
  86  * @dev: The hypertransport device to find the irq capability on.
  87  * @idx: Which of the possible irqs to attach to.
  88  * @update: Function to be called when changing the htirq message
  89  *
  90  * The irq number of the new irq or a negative error value is returned.
  91  */
  92 int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update)
  93 {
  94         struct ht_irq_cfg *cfg;
  95         unsigned long flags;
  96         u32 data;
  97         int max_irq;
  98         int pos;
  99         int irq;
 100         int node;
 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         node = dev_to_node(&dev->dev);
 129         irq = create_irq_nr(0, node);
 130
 131         if (irq <= 0) {
 132                 kfree(cfg);
 133                 return -EBUSY;
 134         }
 135         set_irq_data(irq, cfg);
 136
 137         if (arch_setup_ht_irq(irq, dev) < 0) {
 138                 ht_destroy_irq(irq);
 139                 return -EBUSY;
 140         }
 141
 142         return irq;
 143 }
 144
 145 /**
 146  * ht_create_irq - create an irq and attach it to a device.
 147  * @dev: The hypertransport device to find the irq capability on.
 148  * @idx: Which of the possible irqs to attach to.
 149  *
 150  * ht_create_irq needs to be called for all hypertransport devices
 151  * that generate irqs.
 152  *
 153  * The irq number of the new irq or a negative error value is returned.
 154  */
 155 int ht_create_irq(struct pci_dev *dev, int idx)
 156 {
 157         return __ht_create_irq(dev, idx, NULL);
 158 }
 159
 160 /**
 161  * ht_destroy_irq - destroy an irq created with ht_create_irq
 162  * @irq: irq to be destroyed
 163  *
 164  * This reverses ht_create_irq removing the specified irq from
 165  * existence.  The irq should be free before this happens.
 166  */
 167 void ht_destroy_irq(unsigned int irq)
 168 {
 169         struct ht_irq_cfg *cfg;
 170
 171         cfg = get_irq_data(irq);
 172         set_irq_chip(irq, NULL);
 173         set_irq_data(irq, NULL);
 174         destroy_irq(irq);
 175
 176         kfree(cfg);
 177 }
 178
 179 EXPORT_SYMBOL(__ht_create_irq);
 180 EXPORT_SYMBOL(ht_create_irq);
 181 EXPORT_SYMBOL(ht_destroy_irq);