tjh.dev
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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);