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