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 */
 24static DEFINE_SPINLOCK(ht_irq_lock);
 25
 26void 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
 46void 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
 53void 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
 62void 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 */
 79int __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}
105EXPORT_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 */
117int ht_create_irq(struct pci_dev *dev, int idx)
118{
119	return __ht_create_irq(dev, idx, NULL);
120}
121EXPORT_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 */
130void ht_destroy_irq(unsigned int irq)
131{
132	arch_teardown_ht_irq(irq);
133}
134EXPORT_SYMBOL(ht_destroy_irq);