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 */
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 = 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
55void 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
61void 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
73void 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/**
86 * __ht_create_irq - create an irq and attach it to a device.
87 * @dev: The hypertransport device to find the irq capability on.
88 * @idx: Which of the possible irqs to attach to.
89 * @update: Function to be called when changing the htirq message
90 *
91 * The irq number of the new irq or a negative error value is returned.
92 */
93int __ht_create_irq(struct pci_dev *dev, int idx, ht_irq_update_t *update)
94{
95	struct ht_irq_cfg *cfg;
96	unsigned long flags;
97	u32 data;
98	int max_irq;
99	int pos;
100	int irq;
101
102	pos = pci_find_ht_capability(dev, HT_CAPTYPE_IRQ);
103	if (!pos)
104		return -EINVAL;
105
106	/* Verify the idx I want to use is in range */
107	spin_lock_irqsave(&ht_irq_lock, flags);
108	pci_write_config_byte(dev, pos + 2, 1);
109	pci_read_config_dword(dev, pos + 4, &data);
110	spin_unlock_irqrestore(&ht_irq_lock, flags);
111
112	max_irq = (data >> 16) & 0xff;
113	if ( idx > max_irq)
114		return -EINVAL;
115
116	cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
117	if (!cfg)
118		return -ENOMEM;
119
120	cfg->dev = dev;
121	cfg->update = update;
122	cfg->pos = pos;
123	cfg->idx = 0x10 + (idx * 2);
124	/* Initialize msg to a value that will never match the first write. */
125	cfg->msg.address_lo = 0xffffffff;
126	cfg->msg.address_hi = 0xffffffff;
127
128	irq = create_irq();
129	if (irq < 0) {
130		kfree(cfg);
131		return -EBUSY;
132	}
133	set_irq_data(irq, cfg);
134
135	if (arch_setup_ht_irq(irq, dev) < 0) {
136		ht_destroy_irq(irq);
137		return -EBUSY;
138	}
139
140	return irq;
141}
142
143/**
144 * ht_create_irq - create an irq and attach it to a device.
145 * @dev: The hypertransport device to find the irq capability on.
146 * @idx: Which of the possible irqs to attach to.
147 *
148 * ht_create_irq needs to be called for all hypertransport devices
149 * that generate irqs.
150 *
151 * The irq number of the new irq or a negative error value is returned.
152 */
153int ht_create_irq(struct pci_dev *dev, int idx)
154{
155	return __ht_create_irq(dev, idx, NULL);
156}
157
158/**
159 * ht_destroy_irq - destroy an irq created with ht_create_irq
160 *
161 * This reverses ht_create_irq removing the specified irq from
162 * existence.  The irq should be free before this happens.
163 */
164void ht_destroy_irq(unsigned int irq)
165{
166	struct ht_irq_cfg *cfg;
167
168	cfg = get_irq_data(irq);
169	set_irq_chip(irq, NULL);
170	set_irq_data(irq, NULL);
171	destroy_irq(irq);
172
173	kfree(cfg);
174}
175
176EXPORT_SYMBOL(__ht_create_irq);
177EXPORT_SYMBOL(ht_create_irq);
178EXPORT_SYMBOL(ht_destroy_irq);
179