1 /*
2 * linux/drivers/parisc/power.c
3 * HP PARISC soft power switch support driver
4 *
5 * Copyright (c) 2001-2007 Helge Deller <deller@gmx.de>
6 * All rights reserved.
7 *
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions, and the following disclaimer,
14 * without modification.
15 * 2. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * Alternatively, this software may be distributed under the terms of the
19 * GNU General Public License ("GPL").
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
25 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 *
31 *
32 * HINT:
33 * Support of the soft power switch button may be enabled or disabled at
34 * runtime through the "/proc/sys/kernel/power" procfs entry.
35 */
36
37 #include <linux/module.h>
38 #include <linux/init.h>
39 #include <linux/kernel.h>
40 #include <linux/notifier.h>
41 #include <linux/reboot.h>
42 #include <linux/sched.h>
43 #include <linux/kthread.h>
44 #include <linux/pm.h>
45
46 #include <asm/pdc.h>
47 #include <asm/io.h>
48 #include <asm/led.h>
49
50 #define DRIVER_NAME "powersw"
51 #define KTHREAD_NAME "kpowerswd"
52
53 /* how often should the power button be polled ? */
54 #define POWERSWITCH_POLL_PER_SEC 2
55
56 /* how long does the power button needs to be down until we react ? */
57 #define POWERSWITCH_DOWN_SEC 2
58
59 /* assembly code to access special registers */
60 /* taken from PCXL ERS page 82 */
61 #define DIAG_CODE(code) (0x14000000 + ((code)<<5))
62
63 #define MFCPU_X(rDiagReg, t_ch, t_th, code) \
64 (DIAG_CODE(code) + ((rDiagReg)<<21) + ((t_ch)<<16) + ((t_th)<<0) )
65
66 #define MTCPU(dr, gr) MFCPU_X(dr, gr, 0, 0x12) /* move value of gr to dr[dr] */
67 #define MFCPU_C(dr, gr) MFCPU_X(dr, gr, 0, 0x30) /* for dr0 and dr8 only ! */
68 #define MFCPU_T(dr, gr) MFCPU_X(dr, 0, gr, 0xa0) /* all dr except dr0 and dr8 */
69
70 #define __getDIAG(dr) ( { \
71 register unsigned long __res asm("r28");\
72 __asm__ __volatile__ ( \
73 ".word %1" : "=&r" (__res) : "i" (MFCPU_T(dr,28) ) \
74 ); \
75 __res; \
76 } )
77
78 /* local shutdown counter */
79 static int shutdown_timer __read_mostly;
80
81 /* check, give feedback and start shutdown after one second */
82 static void process_shutdown(void)
83 {
84 if (shutdown_timer == 0)
85 printk(KERN_ALERT KTHREAD_NAME ": Shutdown requested...\n");
86
87 shutdown_timer++;
88
89 /* wait until the button was pressed for 1 second */
90 if (shutdown_timer == (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC)) {
91 static const char msg[] = "Shutting down...";
92 printk(KERN_INFO KTHREAD_NAME ": %s\n", msg);
93 lcd_print(msg);
94
95 /* send kill signal */
96 if (kill_cad_pid(SIGINT, 1)) {
97 /* just in case killing init process failed */
98 if (pm_power_off)
99 pm_power_off();
100 }
101 }
102 }
103
104
105 /* main power switch task struct */
106 static struct task_struct *power_task;
107
108 /* filename in /proc which can be used to enable/disable the power switch */
109 #define SYSCTL_FILENAME "sys/kernel/power"
110
111 /* soft power switch enabled/disabled */
112 int pwrsw_enabled __read_mostly = 1;
113
114 /* main kernel thread worker. It polls the button state */
115 static int kpowerswd(void *param)
116 {
117 __set_current_state(TASK_RUNNING);
118
119 do {
120 int button_not_pressed;
121 unsigned long soft_power_reg = (unsigned long) param;
122
123 schedule_timeout_interruptible(pwrsw_enabled ? HZ : HZ/POWERSWITCH_POLL_PER_SEC);
124 __set_current_state(TASK_RUNNING);
125
126 if (unlikely(!pwrsw_enabled))
127 continue;
128
129 if (soft_power_reg) {
130 /*
131 * Non-Gecko-style machines:
132 * Check the power switch status which is read from the
133 * real I/O location at soft_power_reg.
134 * Bit 31 ("the lowest bit) is the status of the power switch.
135 * This bit is "1" if the button is NOT pressed.
136 */
137 button_not_pressed = (gsc_readl(soft_power_reg) & 0x1);
138 } else {
139 /*
140 * On gecko style machines (e.g. 712/xx and 715/xx)
141 * the power switch status is stored in Bit 0 ("the highest bit")
142 * of CPU diagnose register 25.
143 * Warning: Some machines never reset the DIAG flag, even if
144 * the button has been released again.
145 */
146 button_not_pressed = (__getDIAG(25) & 0x80000000);
147 }
148
149 if (likely(button_not_pressed)) {
150 if (unlikely(shutdown_timer && /* avoid writing if not necessary */
151 shutdown_timer < (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC))) {
152 shutdown_timer = 0;
153 printk(KERN_INFO KTHREAD_NAME ": Shutdown request aborted.\n");
154 }
155 } else
156 process_shutdown();
157
158
159 } while (!kthread_should_stop());
160
161 return 0;
162 }
163
164
165 /*
166 * powerfail interruption handler (irq IRQ_FROM_REGION(CPU_IRQ_REGION)+2)
167 */
168 #if 0
169 static void powerfail_interrupt(int code, void *x)
170 {
171 printk(KERN_CRIT "POWERFAIL INTERRUPTION !\n");
172 poweroff();
173 }
174 #endif
175
176
177
178
179 /* parisc_panic_event() is called by the panic handler.
180 * As soon as a panic occurs, our tasklets above will not be
181 * executed any longer. This function then re-enables the
182 * soft-power switch and allows the user to switch off the system
183 */
184 static int parisc_panic_event(struct notifier_block *this,
185 unsigned long event, void *ptr)
186 {
187 /* re-enable the soft-power switch */
188 pdc_soft_power_button(0);
189 return NOTIFY_DONE;
190 }
191
192 static struct notifier_block parisc_panic_block = {
193 .notifier_call = parisc_panic_event,
194 .priority = INT_MAX,
195 };
196
197
198 static int __init power_init(void)
199 {
200 unsigned long ret;
201 unsigned long soft_power_reg;
202
203 #if 0
204 request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt,
205 0, "powerfail", NULL);
206 #endif
207
208 /* enable the soft power switch if possible */
209 ret = pdc_soft_power_info(&soft_power_reg);
210 if (ret == PDC_OK)
211 ret = pdc_soft_power_button(1);
212 if (ret != PDC_OK)
213 soft_power_reg = -1UL;
214
215 switch (soft_power_reg) {
216 case 0: printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n");
217 break;
218
219 case -1UL: printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n");
220 return -ENODEV;
221
222 default: printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n",
223 soft_power_reg);
224 }
225
226 power_task = kthread_run(kpowerswd, (void*)soft_power_reg, KTHREAD_NAME);
227 if (IS_ERR(power_task)) {
228 printk(KERN_ERR DRIVER_NAME ": thread creation failed. Driver not loaded.\n");
229 pdc_soft_power_button(0);
230 return -EIO;
231 }
232
233 /* Register a call for panic conditions. */
234 atomic_notifier_chain_register(&panic_notifier_list,
235 &parisc_panic_block);
236
237 return 0;
238 }
239
240 static void __exit power_exit(void)
241 {
242 kthread_stop(power_task);
243
244 atomic_notifier_chain_unregister(&panic_notifier_list,
245 &parisc_panic_block);
246
247 pdc_soft_power_button(0);
248 }
249
250 arch_initcall(power_init);
251 module_exit(power_exit);
252
253
254 MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
255 MODULE_DESCRIPTION("Soft power switch driver");
256 MODULE_LICENSE("Dual BSD/GPL");
257
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