drivers/parisc/power.c

   1 /*
   2  * linux/arch/parisc/kernel/power.c
   3  * HP PARISC soft power switch support driver
   4  *
   5  * Copyright (c) 2001-2005 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  *
  33  *  HINT:
  34  *  Support of the soft power switch button may be enabled or disabled at
  35  *  runtime through the "/proc/sys/kernel/power" procfs entry.
  36  */
  37
  38 #include <linux/module.h>
  39 #include <linux/init.h>
  40 #include <linux/kernel.h>
  41 #include <linux/string.h>
  42 #include <linux/notifier.h>
  43 #include <linux/reboot.h>
  44 #include <linux/sched.h>
  45 #include <linux/interrupt.h>
  46 #include <linux/workqueue.h>
  47
  48 #include <asm/pdc.h>
  49 #include <asm/io.h>
  50 #include <asm/led.h>
  51 #include <asm/uaccess.h>
  52
  53
  54 #ifdef DEBUG
  55 # define DPRINTK(x...) printk(x)
  56 #else
  57 # define DPRINTK(x...)
  58 #endif
  59
  60
  61 /* filename in /proc which can be used to enable/disable the power switch */
  62 #define SYSCTL_FILENAME         "sys/kernel/power"
  63
  64
  65 #define DIAG_CODE(code)         (0x14000000 + ((code)<<5))
  66
  67 /* this will go to processor.h or any other place... */
  68 /* taken from PCXL ERS page 82 */
  69 #define MFCPU_X(rDiagReg, t_ch, t_th, code) \
  70         (DIAG_CODE(code) + ((rDiagReg)<<21) + ((t_ch)<<16) + ((t_th)<<0) )
  71
  72 #define MTCPU(dr, gr)           MFCPU_X(dr, gr,  0, 0x12)       /* move value of gr to dr[dr] */
  73 #define MFCPU_C(dr, gr)         MFCPU_X(dr, gr,  0, 0x30)       /* for dr0 and dr8 only ! */
  74 #define MFCPU_T(dr, gr)         MFCPU_X(dr,  0, gr, 0xa0)       /* all dr except dr0 and dr8 */
  75
  76 #define __getDIAG(dr) ( {                       \
  77         register unsigned long __res asm("r28");\
  78          __asm__ __volatile__ (                 \
  79                 ".word %1\n nop\n" : "=&r" (__res) : "i" (MFCPU_T(dr,28)) \
  80         );                                      \
  81         __res;                                  \
  82 } )
  83
  84
  85 static void deferred_poweroff(void *dummy)
  86 {
  87         extern int cad_pid;     /* from kernel/sys.c */
  88         if (kill_proc(cad_pid, SIGINT, 1)) {
  89                 /* just in case killing init process failed */
  90                 machine_power_off();
  91         }
  92 }
  93
  94 /*
  95  * This function gets called from interrupt context.
  96  * As it's called within an interrupt, it wouldn't sync if we don't
  97  * use schedule_work().
  98  */
  99
 100 static DECLARE_WORK(poweroff_work, deferred_poweroff, NULL);
 101
 102 static void poweroff(void)
 103 {
 104         static int powering_off __read_mostly;
 105
 106         if (powering_off)
 107                 return;
 108
 109         powering_off++;
 110         schedule_work(&poweroff_work);
 111 }
 112
 113
 114 /* local time-counter for shutdown */
 115 static int shutdown_timer __read_mostly;
 116
 117 /* check, give feedback and start shutdown after one second */
 118 static void process_shutdown(void)
 119 {
 120         if (shutdown_timer == 0)
 121                 DPRINTK(KERN_INFO "Shutdown requested...\n");
 122
 123         shutdown_timer++;
 124
 125         /* wait until the button was pressed for 1 second */
 126         if (shutdown_timer == HZ) {
 127 #if defined (DEBUG) || defined(CONFIG_CHASSIS_LCD_LED)
 128                 static char msg[] = "Shutting down...";
 129 #endif
 130                 DPRINTK(KERN_INFO "%s\n", msg);
 131                 lcd_print(msg);
 132                 poweroff();
 133         }
 134 }
 135
 136
 137 /* main power switch tasklet struct (scheduled from time.c) */
 138 DECLARE_TASKLET_DISABLED(power_tasklet, NULL, 0);
 139
 140 /* soft power switch enabled/disabled */
 141 int pwrsw_enabled __read_mostly = 1;
 142
 143 /*
 144  * On gecko style machines (e.g. 712/xx and 715/xx)
 145  * the power switch status is stored in Bit 0 ("the highest bit")
 146  * of CPU diagnose register 25.
 147  *
 148  */
 149 static void gecko_tasklet_func(unsigned long unused)
 150 {
 151         if (unlikely(!pwrsw_enabled))
 152                 return;
 153
 154         if (__getDIAG(25) & 0x80000000) {
 155                 /* power switch button not pressed or released again */
 156                 /* Warning: Some machines do never reset this DIAG flag! */
 157                 shutdown_timer = 0;
 158         } else {
 159                 process_shutdown();
 160         }
 161 }
 162
 163
 164
 165 /*
 166  * Check the power switch status which is read from the
 167  * real I/O location at soft_power_reg.
 168  * Bit 31 ("the lowest bit) is the status of the power switch.
 169  */
 170
 171 static void polling_tasklet_func(unsigned long soft_power_reg)
 172 {
 173         unsigned long current_status;
 174
 175         if (unlikely(!pwrsw_enabled))
 176                 return;
 177
 178         current_status = gsc_readl(soft_power_reg);
 179         if (current_status & 0x1) {
 180                 /* power switch button not pressed */
 181                 shutdown_timer = 0;
 182         } else {
 183                 process_shutdown();
 184         }
 185 }
 186
 187
 188 /*
 189  * powerfail interruption handler (irq IRQ_FROM_REGION(CPU_IRQ_REGION)+2)
 190  */
 191 #if 0
 192 static void powerfail_interrupt(int code, void *x, struct pt_regs *regs)
 193 {
 194         printk(KERN_CRIT "POWERFAIL INTERRUPTION !\n");
 195         poweroff();
 196 }
 197 #endif
 198
 199
 200
 201
 202 /* parisc_panic_event() is called by the panic handler.
 203  * As soon as a panic occurs, our tasklets above will not be
 204  * executed any longer. This function then re-enables the
 205  * soft-power switch and allows the user to switch off the system
 206  */
 207 static int parisc_panic_event(struct notifier_block *this,
 208                 unsigned long event, void *ptr)
 209 {
 210         /* re-enable the soft-power switch */
 211         pdc_soft_power_button(0);
 212         return NOTIFY_DONE;
 213 }
 214
 215 static struct notifier_block parisc_panic_block = {
 216         .notifier_call  = parisc_panic_event,
 217         .priority       = INT_MAX,
 218 };
 219
 220
 221 static int __init power_init(void)
 222 {
 223         unsigned long ret;
 224         unsigned long soft_power_reg = 0;
 225
 226 #if 0
 227         request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt,
 228                 0, "powerfail", NULL);
 229 #endif
 230
 231         /* enable the soft power switch if possible */
 232         ret = pdc_soft_power_info(&soft_power_reg);
 233         if (ret == PDC_OK)
 234                 ret = pdc_soft_power_button(1);
 235         if (ret != PDC_OK)
 236                 soft_power_reg = -1UL;
 237
 238         switch (soft_power_reg) {
 239         case 0:         printk(KERN_INFO "Gecko-style soft power switch enabled.\n");
 240                         power_tasklet.func = gecko_tasklet_func;
 241                         break;
 242
 243         case -1UL:      printk(KERN_INFO "Soft power switch support not available.\n");
 244                         return -ENODEV;
 245
 246         default:        printk(KERN_INFO "Soft power switch enabled, polling @ 0x%08lx.\n",
 247                                 soft_power_reg);
 248                         power_tasklet.data = soft_power_reg;
 249                         power_tasklet.func = polling_tasklet_func;
 250         }
 251
 252         /* Register a call for panic conditions. */
 253         atomic_notifier_chain_register(&panic_notifier_list,
 254                         &parisc_panic_block);
 255
 256         tasklet_enable(&power_tasklet);
 257
 258         return 0;
 259 }
 260
 261 static void __exit power_exit(void)
 262 {
 263         if (!power_tasklet.func)
 264                 return;
 265
 266         tasklet_disable(&power_tasklet);
 267         atomic_notifier_chain_unregister(&panic_notifier_list,
 268                         &parisc_panic_block);
 269         power_tasklet.func = NULL;
 270         pdc_soft_power_button(0);
 271 }
 272
 273 module_init(power_init);
 274 module_exit(power_exit);
 275
 276
 277 MODULE_AUTHOR("Helge Deller");
 278 MODULE_DESCRIPTION("Soft power switch driver");
 279 MODULE_LICENSE("Dual BSD/GPL");