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/panic_notifier.h>
41 #include <linux/reboot.h>
42 #include <linux/sched/signal.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 */
process_shutdown(void)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 machine_power_off();
99 }
100 }
101 }
102
103
104 /* main power switch task struct */
105 static struct task_struct *power_task;
106
107 /* filename in /proc which can be used to enable/disable the power switch */
108 #define SYSCTL_FILENAME "sys/kernel/power"
109
110 /* soft power switch enabled/disabled */
111 int pwrsw_enabled __read_mostly = 1;
112
113 /* main kernel thread worker. It polls the button state */
kpowerswd(void * param)114 static int kpowerswd(void *param)
115 {
116 __set_current_state(TASK_RUNNING);
117
118 do {
119 int button_not_pressed;
120 unsigned long soft_power_reg = (unsigned long) param;
121
122 schedule_timeout_interruptible(pwrsw_enabled ? HZ : HZ/POWERSWITCH_POLL_PER_SEC);
123
124 if (unlikely(!pwrsw_enabled))
125 continue;
126
127 if (soft_power_reg) {
128 /*
129 * Non-Gecko-style machines:
130 * Check the power switch status which is read from the
131 * real I/O location at soft_power_reg.
132 * Bit 31 ("the lowest bit) is the status of the power switch.
133 * This bit is "1" if the button is NOT pressed.
134 */
135 button_not_pressed = (gsc_readl(soft_power_reg) & 0x1);
136 } else {
137 /*
138 * On gecko style machines (e.g. 712/xx and 715/xx)
139 * the power switch status is stored in Bit 0 ("the highest bit")
140 * of CPU diagnose register 25.
141 * Warning: Some machines never reset the DIAG flag, even if
142 * the button has been released again.
143 */
144 button_not_pressed = (__getDIAG(25) & 0x80000000);
145 }
146
147 if (likely(button_not_pressed)) {
148 if (unlikely(shutdown_timer && /* avoid writing if not necessary */
149 shutdown_timer < (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC))) {
150 shutdown_timer = 0;
151 printk(KERN_INFO KTHREAD_NAME ": Shutdown request aborted.\n");
152 }
153 } else
154 process_shutdown();
155
156
157 } while (!kthread_should_stop());
158
159 return 0;
160 }
161
162
163 /*
164 * powerfail interruption handler (irq IRQ_FROM_REGION(CPU_IRQ_REGION)+2)
165 */
166 #if 0
167 static void powerfail_interrupt(int code, void *x)
168 {
169 printk(KERN_CRIT "POWERFAIL INTERRUPTION !\n");
170 poweroff();
171 }
172 #endif
173
174
175
176
177 /*
178 * parisc_panic_event() is called by the panic handler.
179 *
180 * As soon as a panic occurs, our tasklets above will not
181 * be executed any longer. This function then re-enables
182 * the soft-power switch and allows the user to switch off
183 * the system. We rely in pdc_soft_power_button_panic()
184 * since this version spin_trylocks (instead of regular
185 * spinlock), preventing deadlocks on panic path.
186 */
parisc_panic_event(struct notifier_block * this,unsigned long event,void * ptr)187 static int parisc_panic_event(struct notifier_block *this,
188 unsigned long event, void *ptr)
189 {
190 /* re-enable the soft-power switch */
191 pdc_soft_power_button_panic(0);
192 return NOTIFY_DONE;
193 }
194
195 static struct notifier_block parisc_panic_block = {
196 .notifier_call = parisc_panic_event,
197 .priority = INT_MAX,
198 };
199
200 /* qemu soft power-off function */
qemu_power_off(struct sys_off_data * data)201 static int qemu_power_off(struct sys_off_data *data)
202 {
203 /* this turns the system off via SeaBIOS */
204 gsc_writel(0, (unsigned long) data->cb_data);
205 pdc_soft_power_button(1);
206 return NOTIFY_DONE;
207 }
208
power_init(void)209 static int __init power_init(void)
210 {
211 unsigned long ret;
212 unsigned long soft_power_reg;
213
214 #if 0
215 request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt,
216 0, "powerfail", NULL);
217 #endif
218
219 /* enable the soft power switch if possible */
220 ret = pdc_soft_power_info(&soft_power_reg);
221 if (ret == PDC_OK)
222 ret = pdc_soft_power_button(1);
223 if (ret != PDC_OK)
224 soft_power_reg = -1UL;
225
226 switch (soft_power_reg) {
227 case 0: printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n");
228 break;
229
230 case -1UL: printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n");
231 return -ENODEV;
232
233 default: printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n",
234 soft_power_reg);
235 }
236
237 power_task = NULL;
238 if (running_on_qemu && soft_power_reg)
239 register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_DEFAULT,
240 qemu_power_off, (void *)soft_power_reg);
241 if (!running_on_qemu || soft_power_reg)
242 power_task = kthread_run(kpowerswd, (void*)soft_power_reg,
243 KTHREAD_NAME);
244 if (IS_ERR(power_task)) {
245 printk(KERN_ERR DRIVER_NAME ": thread creation failed. Driver not loaded.\n");
246 pdc_soft_power_button(0);
247 return -EIO;
248 }
249
250 /* Register a call for panic conditions. */
251 atomic_notifier_chain_register(&panic_notifier_list,
252 &parisc_panic_block);
253
254 return 0;
255 }
256
power_exit(void)257 static void __exit power_exit(void)
258 {
259 kthread_stop(power_task);
260
261 atomic_notifier_chain_unregister(&panic_notifier_list,
262 &parisc_panic_block);
263
264 pdc_soft_power_button(0);
265 }
266
267 arch_initcall(power_init);
268 module_exit(power_exit);
269
270
271 MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
272 MODULE_DESCRIPTION("Soft power switch driver");
273 MODULE_LICENSE("Dual BSD/GPL");
274