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/gfp.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 = get_irq_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 = get_irq_data(irq);
  58         *msg = cfg->msg;
  59 }
  60
  61 void mask_ht_irq(unsigned int irq)
  62 {
  63         struct ht_irq_cfg *cfg;
  64         struct ht_irq_msg msg;
  65
  66         cfg = get_irq_data(irq);
  67
  68         msg = cfg->msg;
  69         msg.address_lo |= 1;
  70         write_ht_irq_msg(irq, &msg);
  71 }
  72
  73 void unmask_ht_irq(unsigned int irq)
  74 {
  75         struct ht_irq_cfg *cfg;
  76         struct ht_irq_msg msg;
  77
  78         cfg = get_irq_data(irq);
  79
  80         msg = cfg->msg;
  81         msg.address_lo &= ~1;
  82         write_ht_irq_msg(irq, &msg);
  83 }
  84
  85 static unsigned int build_irq_for_pci_dev(struct pci_dev *dev)
  86 {
  87         unsigned int irq;
  88
  89         irq = dev->bus->number;
  90         irq <<= 8;
  91         irq |= dev->devfn;
  92         irq <<= 12;
  93
  94         return irq;
  95 }
  96
  97 /**
  98  * __ht_create_irq - create an irq and attach it to a device.
  99  * @dev: The hypertransport device to find the irq capability on.
 100  * @idx: Which of the possible irqs to attach to.
 101  * @update: Function to be called when changing the htirq message
 102  *
 103  * The irq number of the new irq or a negative error value is returned.
 104  */
 105 int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update)
 106 {
 107         struct ht_irq_cfg *cfg;
 108         unsigned long flags;
 109         u32 data;
 110         int max_irq;
 111         int pos;
 112         int irq;
 113         unsigned int irq_want;
 114
 115         pos = pci_find_ht_capability(dev, HT_CAPTYPE_IRQ);
 116         if (!pos)
 117                 return -EINVAL;
 118
 119         /* Verify the idx I want to use is in range */
 120         spin_lock_irqsave(&ht_irq_lock, flags);
 121         pci_write_config_byte(dev, pos + 2, 1);
 122         pci_read_config_dword(dev, pos + 4, &data);
 123         spin_unlock_irqrestore(&ht_irq_lock, flags);
 124
 125         max_irq = (data >> 16) & 0xff;
 126         if ( idx > max_irq)
 127                 return -EINVAL;
 128
 129         cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
 130         if (!cfg)
 131                 return -ENOMEM;
 132
 133         cfg->dev = dev;
 134         cfg->update = update;
 135         cfg->pos = pos;
 136         cfg->idx = 0x10 + (idx * 2);
 137         /* Initialize msg to a value that will never match the first write. */
 138         cfg->msg.address_lo = 0xffffffff;
 139         cfg->msg.address_hi = 0xffffffff;
 140
 141         irq_want= build_irq_for_pci_dev(dev);
 142 #ifdef CONFIG_HAVE_SPARSE_IRQ
 143         irq = create_irq_nr(irq_want + idx);
 144 #else
 145         irq = create_irq();
 146 #endif
 147         if (irq <= 0) {
 148                 kfree(cfg);
 149                 return -EBUSY;
 150         }
 151         set_irq_data(irq, cfg);
 152
 153         if (arch_setup_ht_irq(irq, dev) < 0) {
 154                 ht_destroy_irq(irq);
 155                 return -EBUSY;
 156         }
 157
 158         return irq;
 159 }
 160
 161 /**
 162  * ht_create_irq - create an irq and attach it to a device.
 163  * @dev: The hypertransport device to find the irq capability on.
 164  * @idx: Which of the possible irqs to attach to.
 165  *
 166  * ht_create_irq needs to be called for all hypertransport devices
 167  * that generate irqs.
 168  *
 169  * The irq number of the new irq or a negative error value is returned.
 170  */
 171 int ht_create_irq(struct pci_dev *dev, int idx)
 172 {
 173         return __ht_create_irq(dev, idx, NULL);
 174 }
 175
 176 /**
 177  * ht_destroy_irq - destroy an irq created with ht_create_irq
 178  *
 179  * This reverses ht_create_irq removing the specified irq from
 180  * existence.  The irq should be free before this happens.
 181  */
 182 void ht_destroy_irq(unsigned int irq)
 183 {
 184         struct ht_irq_cfg *cfg;
 185
 186         cfg = get_irq_data(irq);
 187         set_irq_chip(irq, NULL);
 188         set_irq_data(irq, NULL);
 189         destroy_irq(irq);
 190
 191         kfree(cfg);
 192 }
 193
 194 EXPORT_SYMBOL(__ht_create_irq);
 195 EXPORT_SYMBOL(ht_create_irq);
 196 EXPORT_SYMBOL(ht_destroy_irq);