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 = 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
  54 void 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
  60 void 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
  69 void 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  */
  86 int __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  */
 149 int 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  */
 161 void 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
 173 EXPORT_SYMBOL(__ht_create_irq);
 174 EXPORT_SYMBOL(ht_create_irq);
 175 EXPORT_SYMBOL(ht_destroy_irq);