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 /**
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 */
93 int __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 */
153 int 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 */
164 void 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
176 EXPORT_SYMBOL(__ht_create_irq);
177 EXPORT_SYMBOL(ht_create_irq);
178 EXPORT_SYMBOL(ht_destroy_irq);
179
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