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1da177e4 LT |
1 | /* |
2 | * Sky CPU State Driver | |
3 | * | |
4 | * Copyright (C) 2002 Brian Waite | |
5 | * | |
6 | * This driver allows use of the CPU state bits | |
7 | * It exports the /dev/sky_cpustate and also | |
8 | * /proc/sky_cpustate pseudo-file for status information. | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License | |
12 | * as published by the Free Software Foundation; either version | |
13 | * 2 of the License, or (at your option) any later version. | |
14 | * | |
15 | */ | |
16 | ||
1da177e4 LT |
17 | #include <linux/module.h> |
18 | #include <linux/kernel.h> | |
19 | #include <linux/spinlock.h> | |
4a7e79a7 | 20 | #include <linux/smp_lock.h> |
1da177e4 | 21 | #include <linux/miscdevice.h> |
1da177e4 | 22 | #include <linux/proc_fs.h> |
3049ea7e | 23 | #include <linux/hdpu_features.h> |
d052d1be | 24 | #include <linux/platform_device.h> |
1da177e4 | 25 | #include <asm/uaccess.h> |
3049ea7e | 26 | #include <linux/seq_file.h> |
d2ceb47a | 27 | #include <asm/io.h> |
1da177e4 LT |
28 | |
29 | #define SKY_CPUSTATE_VERSION "1.1" | |
30 | ||
3ae5eaec RK |
31 | static int hdpu_cpustate_probe(struct platform_device *pdev); |
32 | static int hdpu_cpustate_remove(struct platform_device *pdev); | |
1da177e4 | 33 | |
3049ea7e CG |
34 | static unsigned char cpustate_get_state(void); |
35 | static int cpustate_proc_open(struct inode *inode, struct file *file); | |
36 | static int cpustate_proc_read(struct seq_file *seq, void *offset); | |
37 | ||
38 | static struct cpustate_t cpustate; | |
39 | ||
40 | static const struct file_operations proc_cpustate = { | |
41 | .open = cpustate_proc_open, | |
42 | .read = seq_read, | |
43 | .llseek = seq_lseek, | |
44 | .release = single_release, | |
45 | .owner = THIS_MODULE, | |
46 | }; | |
47 | ||
48 | static int cpustate_proc_open(struct inode *inode, struct file *file) | |
49 | { | |
50 | return single_open(file, cpustate_proc_read, NULL); | |
51 | } | |
52 | ||
53 | static int cpustate_proc_read(struct seq_file *seq, void *offset) | |
54 | { | |
55 | seq_printf(seq, "CPU State: %04x\n", cpustate_get_state()); | |
56 | return 0; | |
57 | } | |
1da177e4 LT |
58 | |
59 | static int cpustate_get_ref(int excl) | |
60 | { | |
61 | ||
62 | int retval = -EBUSY; | |
63 | ||
64 | spin_lock(&cpustate.lock); | |
65 | ||
66 | if (cpustate.excl) | |
67 | goto out_busy; | |
68 | ||
69 | if (excl) { | |
70 | if (cpustate.open_count) | |
71 | goto out_busy; | |
72 | cpustate.excl = 1; | |
73 | } | |
74 | ||
75 | cpustate.open_count++; | |
76 | retval = 0; | |
77 | ||
78 | out_busy: | |
79 | spin_unlock(&cpustate.lock); | |
80 | return retval; | |
81 | } | |
82 | ||
83 | static int cpustate_free_ref(void) | |
84 | { | |
85 | ||
86 | spin_lock(&cpustate.lock); | |
87 | ||
88 | cpustate.excl = 0; | |
89 | cpustate.open_count--; | |
90 | ||
91 | spin_unlock(&cpustate.lock); | |
92 | return 0; | |
93 | } | |
94 | ||
3049ea7e | 95 | static unsigned char cpustate_get_state(void) |
1da177e4 LT |
96 | { |
97 | ||
98 | return cpustate.cached_val; | |
99 | } | |
100 | ||
3049ea7e | 101 | static void cpustate_set_state(unsigned char new_state) |
1da177e4 LT |
102 | { |
103 | unsigned int state = (new_state << 21); | |
104 | ||
105 | #ifdef DEBUG_CPUSTATE | |
106 | printk("CPUSTATE -> 0x%x\n", new_state); | |
107 | #endif | |
108 | spin_lock(&cpustate.lock); | |
109 | cpustate.cached_val = new_state; | |
110 | writel((0xff << 21), cpustate.clr_addr); | |
111 | writel(state, cpustate.set_addr); | |
112 | spin_unlock(&cpustate.lock); | |
113 | } | |
114 | ||
115 | /* | |
116 | * Now all the various file operations that we export. | |
117 | */ | |
118 | ||
119 | static ssize_t cpustate_read(struct file *file, char *buf, | |
120 | size_t count, loff_t * ppos) | |
121 | { | |
122 | unsigned char data; | |
123 | ||
124 | if (count < 0) | |
125 | return -EFAULT; | |
126 | if (count == 0) | |
127 | return 0; | |
128 | ||
129 | data = cpustate_get_state(); | |
130 | if (copy_to_user(buf, &data, sizeof(unsigned char))) | |
131 | return -EFAULT; | |
132 | return sizeof(unsigned char); | |
133 | } | |
134 | ||
135 | static ssize_t cpustate_write(struct file *file, const char *buf, | |
136 | size_t count, loff_t * ppos) | |
137 | { | |
138 | unsigned char data; | |
139 | ||
140 | if (count < 0) | |
141 | return -EFAULT; | |
142 | ||
143 | if (count == 0) | |
144 | return 0; | |
145 | ||
146 | if (copy_from_user((unsigned char *)&data, buf, sizeof(unsigned char))) | |
147 | return -EFAULT; | |
148 | ||
149 | cpustate_set_state(data); | |
150 | return sizeof(unsigned char); | |
151 | } | |
152 | ||
153 | static int cpustate_open(struct inode *inode, struct file *file) | |
154 | { | |
4a7e79a7 AB |
155 | int ret; |
156 | ||
157 | lock_kernel(); | |
158 | ret = cpustate_get_ref((file->f_flags & O_EXCL)); | |
159 | unlock_kernel(); | |
160 | ||
161 | return ret; | |
1da177e4 LT |
162 | } |
163 | ||
164 | static int cpustate_release(struct inode *inode, struct file *file) | |
165 | { | |
166 | return cpustate_free_ref(); | |
167 | } | |
168 | ||
3ae5eaec | 169 | static struct platform_driver hdpu_cpustate_driver = { |
1da177e4 LT |
170 | .probe = hdpu_cpustate_probe, |
171 | .remove = hdpu_cpustate_remove, | |
3ae5eaec RK |
172 | .driver = { |
173 | .name = HDPU_CPUSTATE_NAME, | |
d6c23850 | 174 | .owner = THIS_MODULE, |
3ae5eaec | 175 | }, |
1da177e4 LT |
176 | }; |
177 | ||
178 | /* | |
179 | * The various file operations we support. | |
180 | */ | |
d54b1fdb | 181 | static const struct file_operations cpustate_fops = { |
8b70da1a CG |
182 | .owner = THIS_MODULE, |
183 | .open = cpustate_open, | |
184 | .release = cpustate_release, | |
185 | .read = cpustate_read, | |
186 | .write = cpustate_write, | |
187 | .llseek = no_llseek, | |
1da177e4 LT |
188 | }; |
189 | ||
190 | static struct miscdevice cpustate_dev = { | |
8b70da1a CG |
191 | .minor = MISC_DYNAMIC_MINOR, |
192 | .name = "sky_cpustate", | |
193 | .fops = &cpustate_fops, | |
1da177e4 LT |
194 | }; |
195 | ||
3ae5eaec | 196 | static int hdpu_cpustate_probe(struct platform_device *pdev) |
1da177e4 | 197 | { |
1da177e4 | 198 | struct resource *res; |
1ac19f4c CL |
199 | struct proc_dir_entry *proc_de; |
200 | int ret; | |
1da177e4 LT |
201 | |
202 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
7472fd36 CG |
203 | if (!res) { |
204 | printk(KERN_ERR "sky_cpustate: " | |
205 | "Invalid memory resource.\n"); | |
206 | return -EINVAL; | |
207 | } | |
1da177e4 LT |
208 | cpustate.set_addr = (unsigned long *)res->start; |
209 | cpustate.clr_addr = (unsigned long *)res->end - 1; | |
210 | ||
1ac19f4c CL |
211 | ret = misc_register(&cpustate_dev); |
212 | if (ret) { | |
a4e32b5f CG |
213 | printk(KERN_WARNING "sky_cpustate: " |
214 | "Unable to register misc device.\n"); | |
1ac19f4c CL |
215 | cpustate.set_addr = NULL; |
216 | cpustate.clr_addr = NULL; | |
217 | return ret; | |
218 | } | |
219 | ||
c7705f34 | 220 | proc_de = proc_create("sky_cpustate", 0666, NULL, &proc_cpustate); |
3049ea7e | 221 | if (!proc_de) { |
a4e32b5f | 222 | printk(KERN_WARNING "sky_cpustate: " |
3049ea7e | 223 | "Unable to create proc entry\n"); |
3049ea7e | 224 | } |
1da177e4 LT |
225 | |
226 | printk(KERN_INFO "Sky CPU State Driver v" SKY_CPUSTATE_VERSION "\n"); | |
227 | return 0; | |
228 | } | |
1ac19f4c | 229 | |
3ae5eaec | 230 | static int hdpu_cpustate_remove(struct platform_device *pdev) |
1da177e4 | 231 | { |
1ac19f4c CL |
232 | cpustate.set_addr = NULL; |
233 | cpustate.clr_addr = NULL; | |
1da177e4 LT |
234 | |
235 | remove_proc_entry("sky_cpustate", NULL); | |
236 | misc_deregister(&cpustate_dev); | |
1da177e4 | 237 | |
a4e32b5f | 238 | return 0; |
1da177e4 LT |
239 | } |
240 | ||
241 | static int __init cpustate_init(void) | |
242 | { | |
a4e32b5f | 243 | return platform_driver_register(&hdpu_cpustate_driver); |
1da177e4 LT |
244 | } |
245 | ||
246 | static void __exit cpustate_exit(void) | |
247 | { | |
3ae5eaec | 248 | platform_driver_unregister(&hdpu_cpustate_driver); |
1da177e4 LT |
249 | } |
250 | ||
251 | module_init(cpustate_init); | |
252 | module_exit(cpustate_exit); | |
253 | ||
254 | MODULE_AUTHOR("Brian Waite"); | |
255 | MODULE_LICENSE("GPL"); | |
d6c23850 | 256 | MODULE_ALIAS("platform:" HDPU_CPUSTATE_NAME); |