drivers/parisc/power.c

   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/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 /* parisc_panic_event() is called by the panic handler.
 178  * As soon as a panic occurs, our tasklets above will not be
 179  * executed any longer. This function then re-enables the
 180  * soft-power switch and allows the user to switch off the system
 181  */
 182 static int parisc_panic_event(struct notifier_block *this,
 183                 unsigned long event, void *ptr)
 184 {
 185         /* re-enable the soft-power switch */
 186         pdc_soft_power_button(0);
 187         return NOTIFY_DONE;
 188 }
 189
 190 static struct notifier_block parisc_panic_block = {
 191         .notifier_call  = parisc_panic_event,
 192         .priority       = INT_MAX,
 193 };
 194
 195
 196 static int __init power_init(void)
 197 {
 198         unsigned long ret;
 199         unsigned long soft_power_reg;
 200
 201 #if 0
 202         request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt,
 203                 0, "powerfail", NULL);
 204 #endif
 205
 206         /* enable the soft power switch if possible */
 207         ret = pdc_soft_power_info(&soft_power_reg);
 208         if (ret == PDC_OK)
 209                 ret = pdc_soft_power_button(1);
 210         if (ret != PDC_OK)
 211                 soft_power_reg = -1UL;
 212
 213         switch (soft_power_reg) {
 214         case 0:         printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n");
 215                         break;
 216
 217         case -1UL:      printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n");
 218                         return -ENODEV;
 219
 220         default:        printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n",
 221                                 soft_power_reg);
 222         }
 223
 224         power_task = kthread_run(kpowerswd, (void*)soft_power_reg, KTHREAD_NAME);
 225         if (IS_ERR(power_task)) {
 226                 printk(KERN_ERR DRIVER_NAME ": thread creation failed.  Driver not loaded.\n");
 227                 pdc_soft_power_button(0);
 228                 return -EIO;
 229         }
 230
 231         /* Register a call for panic conditions. */
 232         atomic_notifier_chain_register(&panic_notifier_list,
 233                         &parisc_panic_block);
 234
 235         return 0;
 236 }
 237
 238 static void __exit power_exit(void)
 239 {
 240         kthread_stop(power_task);
 241
 242         atomic_notifier_chain_unregister(&panic_notifier_list,
 243                         &parisc_panic_block);
 244
 245         pdc_soft_power_button(0);
 246 }
 247
 248 arch_initcall(power_init);
 249 module_exit(power_exit);
 250
 251
 252 MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
 253 MODULE_DESCRIPTION("Soft power switch driver");
 254 MODULE_LICENSE("Dual BSD/GPL");