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