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 */
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 			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 */
kpowerswd(void * param)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  */
parisc_panic_event(struct notifier_block * this,unsigned long event,void * ptr)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 
power_init(void)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 
power_exit(void)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