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 */ 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 */ 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 */ 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 */ 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 } 208 209 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 else 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 } 256 257 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