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         if (kill_cad_pid(SIGINT, 1)) {
  88                 /* just in case killing init process failed */
  89                 machine_power_off();
  90         }
  91 }
  92
  93 /*
  94  * This function gets called from interrupt context.
  95  * As it's called within an interrupt, it wouldn't sync if we don't
  96  * use schedule_work().
  97  */
  98
  99 static DECLARE_WORK(poweroff_work, deferred_poweroff, NULL);
 100
 101 static void poweroff(void)
 102 {
 103         static int powering_off __read_mostly;
 104
 105         if (powering_off)
 106                 return;
 107
 108         powering_off++;
 109         schedule_work(&poweroff_work);
 110 }
 111
 112
 113 /* local time-counter for shutdown */
 114 static int shutdown_timer __read_mostly;
 115
 116 /* check, give feedback and start shutdown after one second */
 117 static void process_shutdown(void)
 118 {
 119         if (shutdown_timer == 0)
 120                 DPRINTK(KERN_INFO "Shutdown requested...\n");
 121
 122         shutdown_timer++;
 123
 124         /* wait until the button was pressed for 1 second */
 125         if (shutdown_timer == HZ) {
 126 #if defined (DEBUG) || defined(CONFIG_CHASSIS_LCD_LED)
 127                 static char msg[] = "Shutting down...";
 128 #endif
 129                 DPRINTK(KERN_INFO "%s\n", msg);
 130                 lcd_print(msg);
 131                 poweroff();
 132         }
 133 }
 134
 135
 136 /* main power switch tasklet struct (scheduled from time.c) */
 137 DECLARE_TASKLET_DISABLED(power_tasklet, NULL, 0);
 138
 139 /* soft power switch enabled/disabled */
 140 int pwrsw_enabled __read_mostly = 1;
 141
 142 /*
 143  * On gecko style machines (e.g. 712/xx and 715/xx)
 144  * the power switch status is stored in Bit 0 ("the highest bit")
 145  * of CPU diagnose register 25.
 146  *
 147  */
 148 static void gecko_tasklet_func(unsigned long unused)
 149 {
 150         if (unlikely(!pwrsw_enabled))
 151                 return;
 152
 153         if (__getDIAG(25) & 0x80000000) {
 154                 /* power switch button not pressed or released again */
 155                 /* Warning: Some machines do never reset this DIAG flag! */
 156                 shutdown_timer = 0;
 157         } else {
 158                 process_shutdown();
 159         }
 160 }
 161
 162
 163
 164 /*
 165  * Check the power switch status which is read from the
 166  * real I/O location at soft_power_reg.
 167  * Bit 31 ("the lowest bit) is the status of the power switch.
 168  */
 169
 170 static void polling_tasklet_func(unsigned long soft_power_reg)
 171 {
 172         unsigned long current_status;
 173
 174         if (unlikely(!pwrsw_enabled))
 175                 return;
 176
 177         current_status = gsc_readl(soft_power_reg);
 178         if (current_status & 0x1) {
 179                 /* power switch button not pressed */
 180                 shutdown_timer = 0;
 181         } else {
 182                 process_shutdown();
 183         }
 184 }
 185
 186
 187 /*
 188  * powerfail interruption handler (irq IRQ_FROM_REGION(CPU_IRQ_REGION)+2)
 189  */
 190 #if 0
 191 static void powerfail_interrupt(int code, void *x, struct pt_regs *regs)
 192 {
 193         printk(KERN_CRIT "POWERFAIL INTERRUPTION !\n");
 194         poweroff();
 195 }
 196 #endif
 197
 198
 199
 200
 201 /* parisc_panic_event() is called by the panic handler.
 202  * As soon as a panic occurs, our tasklets above will not be
 203  * executed any longer. This function then re-enables the
 204  * soft-power switch and allows the user to switch off the system
 205  */
 206 static int parisc_panic_event(struct notifier_block *this,
 207                 unsigned long event, void *ptr)
 208 {
 209         /* re-enable the soft-power switch */
 210         pdc_soft_power_button(0);
 211         return NOTIFY_DONE;
 212 }
 213
 214 static struct notifier_block parisc_panic_block = {
 215         .notifier_call  = parisc_panic_event,
 216         .priority       = INT_MAX,
 217 };
 218
 219
 220 static int __init power_init(void)
 221 {
 222         unsigned long ret;
 223         unsigned long soft_power_reg = 0;
 224
 225 #if 0
 226         request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt,
 227                 0, "powerfail", NULL);
 228 #endif
 229
 230         /* enable the soft power switch if possible */
 231         ret = pdc_soft_power_info(&soft_power_reg);
 232         if (ret == PDC_OK)
 233                 ret = pdc_soft_power_button(1);
 234         if (ret != PDC_OK)
 235                 soft_power_reg = -1UL;
 236
 237         switch (soft_power_reg) {
 238         case 0:         printk(KERN_INFO "Gecko-style soft power switch enabled.\n");
 239                         power_tasklet.func = gecko_tasklet_func;
 240                         break;
 241
 242         case -1UL:      printk(KERN_INFO "Soft power switch support not available.\n");
 243                         return -ENODEV;
 244
 245         default:        printk(KERN_INFO "Soft power switch enabled, polling @ 0x%08lx.\n",
 246                                 soft_power_reg);
 247                         power_tasklet.data = soft_power_reg;
 248                         power_tasklet.func = polling_tasklet_func;
 249         }
 250
 251         /* Register a call for panic conditions. */
 252         atomic_notifier_chain_register(&panic_notifier_list,
 253                         &parisc_panic_block);
 254
 255         tasklet_enable(&power_tasklet);
 256
 257         return 0;
 258 }
 259
 260 static void __exit power_exit(void)
 261 {
 262         if (!power_tasklet.func)
 263                 return;
 264
 265         tasklet_disable(&power_tasklet);
 266         atomic_notifier_chain_unregister(&panic_notifier_list,
 267                         &parisc_panic_block);
 268         power_tasklet.func = NULL;
 269         pdc_soft_power_button(0);
 270 }
 271
 272 module_init(power_init);
 273 module_exit(power_exit);
 274
 275
 276 MODULE_AUTHOR("Helge Deller");
 277 MODULE_DESCRIPTION("Soft power switch driver");
 278 MODULE_LICENSE("Dual BSD/GPL");