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13b54a50 HS |
1 | /* |
2 | * Copyright (C) 2007 Atmel Corporation | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | */ | |
8 | #include <linux/init.h> | |
9 | #include <linux/sched.h> | |
10 | #include <linux/spinlock.h> | |
11 | ||
12 | #include <asm/ocd.h> | |
13 | ||
14 | static long ocd_count; | |
15 | static spinlock_t ocd_lock; | |
16 | ||
17 | /** | |
18 | * ocd_enable - enable on-chip debugging | |
19 | * @child: task to be debugged | |
20 | * | |
21 | * If @child is non-NULL, ocd_enable() first checks if debugging has | |
22 | * already been enabled for @child, and if it has, does nothing. | |
23 | * | |
24 | * If @child is NULL (e.g. when debugging the kernel), or debugging | |
25 | * has not already been enabled for it, ocd_enable() increments the | |
26 | * reference count and enables the debugging hardware. | |
27 | */ | |
28 | void ocd_enable(struct task_struct *child) | |
29 | { | |
30 | u32 dc; | |
31 | ||
32 | if (child) | |
33 | pr_debug("ocd_enable: child=%s [%u]\n", | |
34 | child->comm, child->pid); | |
35 | else | |
36 | pr_debug("ocd_enable (no child)\n"); | |
37 | ||
38 | if (!child || !test_and_set_tsk_thread_flag(child, TIF_DEBUG)) { | |
39 | spin_lock(&ocd_lock); | |
40 | ocd_count++; | |
41 | dc = ocd_read(DC); | |
42 | dc |= (1 << OCD_DC_MM_BIT) | (1 << OCD_DC_DBE_BIT); | |
43 | ocd_write(DC, dc); | |
44 | spin_unlock(&ocd_lock); | |
45 | } | |
46 | } | |
47 | ||
48 | /** | |
49 | * ocd_disable - disable on-chip debugging | |
50 | * @child: task that was being debugged, but isn't anymore | |
51 | * | |
52 | * If @child is non-NULL, ocd_disable() checks if debugging is enabled | |
53 | * for @child, and if it isn't, does nothing. | |
54 | * | |
55 | * If @child is NULL (e.g. when debugging the kernel), or debugging is | |
56 | * enabled, ocd_disable() decrements the reference count, and if it | |
57 | * reaches zero, disables the debugging hardware. | |
58 | */ | |
59 | void ocd_disable(struct task_struct *child) | |
60 | { | |
61 | u32 dc; | |
62 | ||
63 | if (!child) | |
64 | pr_debug("ocd_disable (no child)\n"); | |
65 | else if (test_tsk_thread_flag(child, TIF_DEBUG)) | |
66 | pr_debug("ocd_disable: child=%s [%u]\n", | |
67 | child->comm, child->pid); | |
68 | ||
69 | if (!child || test_and_clear_tsk_thread_flag(child, TIF_DEBUG)) { | |
70 | spin_lock(&ocd_lock); | |
71 | ocd_count--; | |
72 | ||
73 | WARN_ON(ocd_count < 0); | |
74 | ||
75 | if (ocd_count <= 0) { | |
76 | dc = ocd_read(DC); | |
77 | dc &= ~((1 << OCD_DC_MM_BIT) | (1 << OCD_DC_DBE_BIT)); | |
78 | ocd_write(DC, dc); | |
79 | } | |
80 | spin_unlock(&ocd_lock); | |
81 | } | |
82 | } | |
83 | ||
84 | #ifdef CONFIG_DEBUG_FS | |
85 | #include <linux/debugfs.h> | |
86 | #include <linux/module.h> | |
87 | ||
88 | static struct dentry *ocd_debugfs_root; | |
89 | static struct dentry *ocd_debugfs_DC; | |
90 | static struct dentry *ocd_debugfs_DS; | |
91 | static struct dentry *ocd_debugfs_count; | |
92 | ||
93 | static u64 ocd_DC_get(void *data) | |
94 | { | |
95 | return ocd_read(DC); | |
96 | } | |
97 | static void ocd_DC_set(void *data, u64 val) | |
98 | { | |
99 | ocd_write(DC, val); | |
100 | } | |
101 | DEFINE_SIMPLE_ATTRIBUTE(fops_DC, ocd_DC_get, ocd_DC_set, "0x%08llx\n"); | |
102 | ||
103 | static u64 ocd_DS_get(void *data) | |
104 | { | |
105 | return ocd_read(DS); | |
106 | } | |
107 | DEFINE_SIMPLE_ATTRIBUTE(fops_DS, ocd_DS_get, NULL, "0x%08llx\n"); | |
108 | ||
109 | static u64 ocd_count_get(void *data) | |
110 | { | |
111 | return ocd_count; | |
112 | } | |
113 | DEFINE_SIMPLE_ATTRIBUTE(fops_count, ocd_count_get, NULL, "%lld\n"); | |
114 | ||
115 | static void ocd_debugfs_init(void) | |
116 | { | |
117 | struct dentry *root; | |
118 | ||
119 | root = debugfs_create_dir("ocd", NULL); | |
120 | if (IS_ERR(root) || !root) | |
121 | goto err_root; | |
122 | ocd_debugfs_root = root; | |
123 | ||
124 | ocd_debugfs_DC = debugfs_create_file("DC", S_IRUSR | S_IWUSR, | |
125 | root, NULL, &fops_DC); | |
126 | if (!ocd_debugfs_DC) | |
127 | goto err_DC; | |
128 | ||
129 | ocd_debugfs_DS = debugfs_create_file("DS", S_IRUSR, root, | |
130 | NULL, &fops_DS); | |
131 | if (!ocd_debugfs_DS) | |
132 | goto err_DS; | |
133 | ||
134 | ocd_debugfs_count = debugfs_create_file("count", S_IRUSR, root, | |
135 | NULL, &fops_count); | |
136 | if (!ocd_debugfs_count) | |
137 | goto err_count; | |
138 | ||
139 | return; | |
140 | ||
141 | err_count: | |
142 | debugfs_remove(ocd_debugfs_DS); | |
143 | err_DS: | |
144 | debugfs_remove(ocd_debugfs_DC); | |
145 | err_DC: | |
146 | debugfs_remove(ocd_debugfs_root); | |
147 | err_root: | |
148 | printk(KERN_WARNING "OCD: Failed to create debugfs entries\n"); | |
149 | } | |
150 | #else | |
151 | static inline void ocd_debugfs_init(void) | |
152 | { | |
153 | ||
154 | } | |
155 | #endif | |
156 | ||
157 | static int __init ocd_init(void) | |
158 | { | |
159 | spin_lock_init(&ocd_lock); | |
160 | ocd_debugfs_init(); | |
161 | return 0; | |
162 | } | |
163 | arch_initcall(ocd_init); |