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