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