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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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