Root/drivers/pci/htirq.c

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);
177

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