1 files changed, 146 insertions, 0 deletions
diff --git a/Documentation/laptops/hpfall.c b/Documentation/laptops/hpfall.c
new file mode 100644
index 000000000000..a4a8fc5d05d4
--- /dev/null
+++ b/Documentation/laptops/hpfall.c
@@ -0,0 +1,146 @@
+/* Disk protection for HP machines.
+ *
+ * Copyright 2008 Eric Piel
+ * Copyright 2009 Pavel Machek <pavel@ucw.cz>
+ *
+ * GPLv2.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <string.h>
+#include <stdint.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include <sched.h>
+
+char unload_heads_path[64];
+
+int set_unload_heads_path(char *device)
+{
+	char devname[64];
+
+	if (strlen(device) <= 5 || strncmp(device, "/dev/", 5) != 0)
+		return -EINVAL;
+	strncpy(devname, device + 5, sizeof(devname));
+
+	snprintf(unload_heads_path, sizeof(unload_heads_path),
+				"/sys/block/%s/device/unload_heads", devname);
+	return 0;
+}
+int valid_disk(void)
+{
+	int fd = open(unload_heads_path, O_RDONLY);
+	if (fd < 0) {
+		perror(unload_heads_path);
+		return 0;
+	}
+
+	close(fd);
+	return 1;
+}
+
+void write_int(char *path, int i)
+{
+	char buf[1024];
+	int fd = open(path, O_RDWR);
+	if (fd < 0) {
+		perror("open");
+		exit(1);
+	}
+	sprintf(buf, "%d", i);
+	if (write(fd, buf, strlen(buf)) != strlen(buf)) {
+		perror("write");
+		exit(1);
+	}
+	close(fd);
+}
+
+void set_led(int on)
+{
+	write_int("/sys/class/leds/hp::hddprotect/brightness", on);
+}
+
+void protect(int seconds)
+{
+	write_int(unload_heads_path, seconds*1000);
+}
+
+int on_ac(void)
+{
+//	/sys/class/power_supply/AC0/online
+}
+
+int lid_open(void)
+{
+//	/proc/acpi/button/lid/LID/state
+}
+
+void ignore_me(void)
+{
+	protect(0);
+	set_led(0);
+}
+
+int main(int argc, char **argv)
+{
+	int fd, ret;
+	struct sched_param param;
+
+	if (argc == 1)
+		ret = set_unload_heads_path("/dev/sda");
+	else if (argc == 2)
+		ret = set_unload_heads_path(argv[1]);
+	else
+		ret = -EINVAL;
+
+	if (ret || !valid_disk()) {
+		fprintf(stderr, "usage: %s <device> (default: /dev/sda)\n",
+				argv[0]);
+		exit(1);
+	}
+
+	fd = open("/dev/freefall", O_RDONLY);
+	if (fd < 0) {
+		perror("/dev/freefall");
+		return EXIT_FAILURE;
+	}
+
+	daemon(0, 0);
+	param.sched_priority = sched_get_priority_max(SCHED_FIFO);
+	sched_setscheduler(0, SCHED_FIFO, &param);
+	mlockall(MCL_CURRENT|MCL_FUTURE);
+
+	signal(SIGALRM, ignore_me);
+
+	for (;;) {
+		unsigned char count;
+
+		ret = read(fd, &count, sizeof(count));
+		alarm(0);
+		if ((ret == -1) && (errno == EINTR)) {
+			/* Alarm expired, time to unpark the heads */
+			continue;
+		}
+
+		if (ret != sizeof(count)) {
+			perror("read");
+			break;
+		}
+
+		protect(21);
+		set_led(1);
+		if (1 || on_ac() || lid_open())
+			alarm(2);
+		else
+			alarm(20);
+	}
+
+	close(fd);
+	return EXIT_SUCCESS;
+}