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 void write_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
  27 {
  28         struct ht_irq_cfg *cfg = irq_get_handler_data(irq);
  29         unsigned long flags;
  30
  31         spin_lock_irqsave(&ht_irq_lock, flags);
  32         if (cfg->msg.address_lo != msg->address_lo) {
  33                 pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
  34                 pci_write_config_dword(cfg->dev, cfg->pos + 4, msg->address_lo);
  35         }
  36         if (cfg->msg.address_hi != msg->address_hi) {
  37                 pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx + 1);
  38                 pci_write_config_dword(cfg->dev, cfg->pos + 4, msg->address_hi);
  39         }
  40         if (cfg->update)
  41                 cfg->update(cfg->dev, irq, msg);
  42         spin_unlock_irqrestore(&ht_irq_lock, flags);
  43         cfg->msg = *msg;
  44 }
  45
  46 void fetch_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
  47 {
  48         struct ht_irq_cfg *cfg = irq_get_handler_data(irq);
  49
  50         *msg = cfg->msg;
  51 }
  52
  53 void mask_ht_irq(struct irq_data *data)
  54 {
  55         struct ht_irq_cfg *cfg = irq_data_get_irq_handler_data(data);
  56         struct ht_irq_msg msg = cfg->msg;
  57
  58         msg.address_lo |= 1;
  59         write_ht_irq_msg(data->irq, &msg);
  60 }
  61
  62 void unmask_ht_irq(struct irq_data *data)
  63 {
  64         struct ht_irq_cfg *cfg = irq_data_get_irq_handler_data(data);
  65         struct ht_irq_msg msg = cfg->msg;
  66
  67         msg.address_lo &= ~1;
  68         write_ht_irq_msg(data->irq, &msg);
  69 }
  70
  71 /**
  72  * __ht_create_irq - create an irq and attach it to a device.
  73  * @dev: The hypertransport device to find the irq capability on.
  74  * @idx: Which of the possible irqs to attach to.
  75  * @update: Function to be called when changing the htirq message
  76  *
  77  * The irq number of the new irq or a negative error value is returned.
  78  */
  79 int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update)
  80 {
  81         int max_irq, pos, irq;
  82         unsigned long flags;
  83         u32 data;
  84
  85         pos = pci_find_ht_capability(dev, HT_CAPTYPE_IRQ);
  86         if (!pos)
  87                 return -EINVAL;
  88
  89         /* Verify the idx I want to use is in range */
  90         spin_lock_irqsave(&ht_irq_lock, flags);
  91         pci_write_config_byte(dev, pos + 2, 1);
  92         pci_read_config_dword(dev, pos + 4, &data);
  93         spin_unlock_irqrestore(&ht_irq_lock, flags);
  94
  95         max_irq = (data >> 16) & 0xff;
  96         if (idx > max_irq)
  97                 return -EINVAL;
  98
  99         irq = arch_setup_ht_irq(idx, pos, dev, update);
 100         if (irq > 0)
 101                 dev_dbg(&dev->dev, "irq %d for HT\n", irq);
 102
 103         return irq;
 104 }
 105 EXPORT_SYMBOL(__ht_create_irq);
 106
 107 /**
 108  * ht_create_irq - create an irq and attach it to a device.
 109  * @dev: The hypertransport device to find the irq capability on.
 110  * @idx: Which of the possible irqs to attach to.
 111  *
 112  * ht_create_irq needs to be called for all hypertransport devices
 113  * that generate irqs.
 114  *
 115  * The irq number of the new irq or a negative error value is returned.
 116  */
 117 int ht_create_irq(struct pci_dev *dev, int idx)
 118 {
 119         return __ht_create_irq(dev, idx, NULL);
 120 }
 121 EXPORT_SYMBOL(ht_create_irq);
 122
 123 /**
 124  * ht_destroy_irq - destroy an irq created with ht_create_irq
 125  * @irq: irq to be destroyed
 126  *
 127  * This reverses ht_create_irq removing the specified irq from
 128  * existence.  The irq should be free before this happens.
 129  */
 130 void ht_destroy_irq(unsigned int irq)
 131 {
 132         arch_teardown_ht_irq(irq);
 133 }
 134 EXPORT_SYMBOL(ht_destroy_irq);