Merge branch 'topic/lola' into for-linus
[pandora-kernel.git] / Documentation / laptops / hpfall.c
1 /* Disk protection for HP machines.
2  *
3  * Copyright 2008 Eric Piel
4  * Copyright 2009 Pavel Machek <pavel@ucw.cz>
5  *
6  * GPLv2.
7  */
8
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <unistd.h>
12 #include <fcntl.h>
13 #include <sys/stat.h>
14 #include <sys/types.h>
15 #include <string.h>
16 #include <stdint.h>
17 #include <errno.h>
18 #include <signal.h>
19 #include <sys/mman.h>
20 #include <sched.h>
21
22 char unload_heads_path[64];
23
24 int set_unload_heads_path(char *device)
25 {
26         char devname[64];
27
28         if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
29                 return -EINVAL;
30         strncpy(devname, device + 5, sizeof(devname));
31
32         snprintf(unload_heads_path, sizeof(unload_heads_path),
33                                 "/sys/block/%s/device/unload_heads", devname);
34         return 0;
35 }
36 int valid_disk(void)
37 {
38         int fd = open(unload_heads_path, O_RDONLY);
39         if (fd < 0) {
40                 perror(unload_heads_path);
41                 return 0;
42         }
43
44         close(fd);
45         return 1;
46 }
47
48 void write_int(char *path, int i)
49 {
50         char buf[1024];
51         int fd = open(path, O_RDWR);
52         if (fd < 0) {
53                 perror("open");
54                 exit(1);
55         }
56         sprintf(buf, "%d", i);
57         if (write(fd, buf, strlen(buf)) != strlen(buf)) {
58                 perror("write");
59                 exit(1);
60         }
61         close(fd);
62 }
63
64 void set_led(int on)
65 {
66         write_int("/sys/class/leds/hp::hddprotect/brightness", on);
67 }
68
69 void protect(int seconds)
70 {
71         write_int(unload_heads_path, seconds*1000);
72 }
73
74 int on_ac(void)
75 {
76 //      /sys/class/power_supply/AC0/online
77 }
78
79 int lid_open(void)
80 {
81 //      /proc/acpi/button/lid/LID/state
82 }
83
84 void ignore_me(void)
85 {
86         protect(0);
87         set_led(0);
88 }
89
90 int main(int argc, char **argv)
91 {
92         int fd, ret;
93         struct sched_param param;
94
95         if (argc == 1)
96                 ret = set_unload_heads_path("/dev/sda");
97         else if (argc == 2)
98                 ret = set_unload_heads_path(argv[1]);
99         else
100                 ret = -EINVAL;
101
102         if (ret || !valid_disk()) {
103                 fprintf(stderr, "usage: %s <device> (default: /dev/sda)\n",
104                                 argv[0]);
105                 exit(1);
106         }
107
108         fd = open("/dev/freefall", O_RDONLY);
109         if (fd < 0) {
110                 perror("/dev/freefall");
111                 return EXIT_FAILURE;
112         }
113
114         daemon(0, 0);
115         param.sched_priority = sched_get_priority_max(SCHED_FIFO);
116         sched_setscheduler(0, SCHED_FIFO, &param);
117         mlockall(MCL_CURRENT|MCL_FUTURE);
118
119         signal(SIGALRM, ignore_me);
120
121         for (;;) {
122                 unsigned char count;
123
124                 ret = read(fd, &count, sizeof(count));
125                 alarm(0);
126                 if ((ret == -1) && (errno == EINTR)) {
127                         /* Alarm expired, time to unpark the heads */
128                         continue;
129                 }
130
131                 if (ret != sizeof(count)) {
132                         perror("read");
133                         break;
134                 }
135
136                 protect(21);
137                 set_led(1);
138                 if (1 || on_ac() || lid_open())
139                         alarm(2);
140                 else
141                         alarm(20);
142         }
143
144         close(fd);
145         return EXIT_SUCCESS;
146 }