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
 26struct 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
 36void write_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
 37{
 38	struct ht_irq_cfg *cfg = irq_get_handler_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
 55void fetch_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
 56{
 57	struct ht_irq_cfg *cfg = irq_get_handler_data(irq);
 58	*msg = cfg->msg;
 59}
 60
 61void mask_ht_irq(struct irq_data *data)
 62{
 63	struct ht_irq_cfg *cfg = irq_data_get_irq_handler_data(data);
 64	struct ht_irq_msg msg = cfg->msg;
 65
 66	msg.address_lo |= 1;
 67	write_ht_irq_msg(data->irq, &msg);
 68}
 69
 70void unmask_ht_irq(struct irq_data *data)
 71{
 72	struct ht_irq_cfg *cfg = irq_data_get_irq_handler_data(data);
 73	struct ht_irq_msg msg = cfg->msg;
 74
 75	msg.address_lo &= ~1;
 76	write_ht_irq_msg(data->irq, &msg);
 77}
 78
 79/**
 80 * __ht_create_irq - create an irq and attach it to a device.
 81 * @dev: The hypertransport device to find the irq capability on.
 82 * @idx: Which of the possible irqs to attach to.
 83 * @update: Function to be called when changing the htirq message
 84 *
 85 * The irq number of the new irq or a negative error value is returned.
 86 */
 87int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update)
 88{
 89	struct ht_irq_cfg *cfg;
 90	unsigned long flags;
 91	u32 data;
 92	int max_irq;
 93	int pos;
 94	int irq;
 95	int node;
 96
 97	pos = pci_find_ht_capability(dev, HT_CAPTYPE_IRQ);
 98	if (!pos)
 99		return -EINVAL;
100
101	/* Verify the idx I want to use is in range */
102	spin_lock_irqsave(&ht_irq_lock, flags);
103	pci_write_config_byte(dev, pos + 2, 1);
104	pci_read_config_dword(dev, pos + 4, &data);
105	spin_unlock_irqrestore(&ht_irq_lock, flags);
106
107	max_irq = (data >> 16) & 0xff;
108	if ( idx > max_irq)
109		return -EINVAL;
110
111	cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
112	if (!cfg)
113		return -ENOMEM;
114
115	cfg->dev = dev;
116	cfg->update = update;
117	cfg->pos = pos;
118	cfg->idx = 0x10 + (idx * 2);
119	/* Initialize msg to a value that will never match the first write. */
120	cfg->msg.address_lo = 0xffffffff;
121	cfg->msg.address_hi = 0xffffffff;
122
123	node = dev_to_node(&dev->dev);
124	irq = create_irq_nr(0, node);
125
126	if (irq <= 0) {
127		kfree(cfg);
128		return -EBUSY;
129	}
130	irq_set_handler_data(irq, cfg);
131
132	if (arch_setup_ht_irq(irq, dev) < 0) {
133		ht_destroy_irq(irq);
134		return -EBUSY;
135	}
136
137	return irq;
138}
139
140/**
141 * ht_create_irq - create an irq and attach it to a device.
142 * @dev: The hypertransport device to find the irq capability on.
143 * @idx: Which of the possible irqs to attach to.
144 *
145 * ht_create_irq needs to be called for all hypertransport devices
146 * that generate irqs.
147 *
148 * The irq number of the new irq or a negative error value is returned.
149 */
150int ht_create_irq(struct pci_dev *dev, int idx)
151{
152	return __ht_create_irq(dev, idx, NULL);
153}
154
155/**
156 * ht_destroy_irq - destroy an irq created with ht_create_irq
157 * @irq: irq to be destroyed
158 *
159 * This reverses ht_create_irq removing the specified irq from
160 * existence.  The irq should be free before this happens.
161 */
162void ht_destroy_irq(unsigned int irq)
163{
164	struct ht_irq_cfg *cfg;
165
166	cfg = irq_get_handler_data(irq);
167	irq_set_chip(irq, NULL);
168	irq_set_handler_data(irq, NULL);
169	destroy_irq(irq);
170
171	kfree(cfg);
172}
173
174EXPORT_SYMBOL(__ht_create_irq);
175EXPORT_SYMBOL(ht_create_irq);
176EXPORT_SYMBOL(ht_destroy_irq);