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 */
79static int shutdown_timer __read_mostly;
80
81/* check, give feedback and start shutdown after one second */
82static 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 */
106static 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 */
112int pwrsw_enabled __read_mostly = 1;
113
114/* main kernel thread worker. It polls the button state */
115static 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
169
170
171
172/* parisc_panic_event() is called by the panic handler.
173 * As soon as a panic occurs, our tasklets above will not be
174 * executed any longer. This function then re-enables the
175 * soft-power switch and allows the user to switch off the system
176 */
177static int parisc_panic_event(struct notifier_block *this,
178		unsigned long event, void *ptr)
179{
180	/* re-enable the soft-power switch */
181	pdc_soft_power_button(0);
182	return NOTIFY_DONE;
183}
184
185static struct notifier_block parisc_panic_block = {
186	.notifier_call	= parisc_panic_event,
187	.priority	= INT_MAX,
188};
189
190
191static int __init power_init(void)
192{
193	unsigned long ret;
194	unsigned long soft_power_reg;
195
196
197	/* enable the soft power switch if possible */
198	ret = pdc_soft_power_info(&soft_power_reg);
199	if (ret == PDC_OK)
200		ret = pdc_soft_power_button(1);
201	if (ret != PDC_OK)
202		soft_power_reg = -1UL;
203
204	switch (soft_power_reg) {
205	case 0:		printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n");
206			break;
207
208	case -1UL:	printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n");
209			return -ENODEV;
210
211	default:	printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n",
212				soft_power_reg);
213	}
214
215	power_task = kthread_run(kpowerswd, (void*)soft_power_reg, KTHREAD_NAME);
216	if (IS_ERR(power_task)) {
217		printk(KERN_ERR DRIVER_NAME ": thread creation failed.  Driver not loaded.\n");
218		pdc_soft_power_button(0);
219		return -EIO;
220	}
221
222	/* Register a call for panic conditions. */
223	atomic_notifier_chain_register(&panic_notifier_list,
224			&parisc_panic_block);
225
226	return 0;
227}
228
229static void __exit power_exit(void)
230{
231	kthread_stop(power_task);
232
233	atomic_notifier_chain_unregister(&panic_notifier_list,
234			&parisc_panic_block);
235
236	pdc_soft_power_button(0);
237}
238
239arch_initcall(power_init);
240module_exit(power_exit);
241
242
243MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
244MODULE_DESCRIPTION("Soft power switch driver");
245MODULE_LICENSE("Dual BSD/GPL");
246