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.h>
  43 #include <linux/kthread.h>
  44
  45 #include <asm/pdc.h>
  46 #include <asm/io.h>
  47 #include <asm/led.h>
  48
  49 #define DRIVER_NAME  "powersw"
  50 #define KTHREAD_NAME "kpowerswd"
  51
  52 /* how often should the power button be polled ? */
  53 #define POWERSWITCH_POLL_PER_SEC 2
  54
  55 /* how long does the power button needs to be down until we react ? */
  56 #define POWERSWITCH_DOWN_SEC 2
  57
  58 /* assembly code to access special registers */
  59 /* taken from PCXL ERS page 82 */
  60 #define DIAG_CODE(code)         (0x14000000 + ((code)<<5))
  61
  62 #define MFCPU_X(rDiagReg, t_ch, t_th, code) \
  63         (DIAG_CODE(code) + ((rDiagReg)<<21) + ((t_ch)<<16) + ((t_th)<<0) )
  64
  65 #define MTCPU(dr, gr)           MFCPU_X(dr, gr,  0, 0x12)       /* move value of gr to dr[dr] */
  66 #define MFCPU_C(dr, gr)         MFCPU_X(dr, gr,  0, 0x30)       /* for dr0 and dr8 only ! */
  67 #define MFCPU_T(dr, gr)         MFCPU_X(dr,  0, gr, 0xa0)       /* all dr except dr0 and dr8 */
  68
  69 #define __getDIAG(dr) ( {                       \
  70         register unsigned long __res asm("r28");\
  71          __asm__ __volatile__ (                 \
  72                 ".word %1" : "=&r" (__res) : "i" (MFCPU_T(dr,28) ) \
  73         );                                      \
  74         __res;                                  \
  75 } )
  76
  77 /* local shutdown counter */
  78 static int shutdown_timer __read_mostly;
  79
  80 /* check, give feedback and start shutdown after one second */
  81 static void process_shutdown(void)
  82 {
  83         if (shutdown_timer == 0)
  84                 printk(KERN_ALERT KTHREAD_NAME ": Shutdown requested...\n");
  85
  86         shutdown_timer++;
  87
  88         /* wait until the button was pressed for 1 second */
  89         if (shutdown_timer == (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC)) {
  90                 static const char msg[] = "Shutting down...";
  91                 printk(KERN_INFO KTHREAD_NAME ": %s\n", msg);
  92                 lcd_print(msg);
  93
  94                 /* send kill signal */
  95                 if (kill_cad_pid(SIGINT, 1)) {
  96                         /* just in case killing init process failed */
  97                         if (pm_power_off)
  98                                 pm_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                 __set_current_state(TASK_RUNNING);
 124
 125                 if (unlikely(!pwrsw_enabled))
 126                         continue;
 127
 128                 if (soft_power_reg) {
 129                         /*
 130                          * Non-Gecko-style machines:
 131                          * Check the power switch status which is read from the
 132                          * real I/O location at soft_power_reg.
 133                          * Bit 31 ("the lowest bit) is the status of the power switch.
 134                          * This bit is "1" if the button is NOT pressed.
 135                          */
 136                         button_not_pressed = (gsc_readl(soft_power_reg) & 0x1);
 137                 } else {
 138                         /*
 139                          * On gecko style machines (e.g. 712/xx and 715/xx)
 140                          * the power switch status is stored in Bit 0 ("the highest bit")
 141                          * of CPU diagnose register 25.
 142                          * Warning: Some machines never reset the DIAG flag, even if
 143                          * the button has been released again.
 144                          */
 145                         button_not_pressed = (__getDIAG(25) & 0x80000000);
 146                 }
 147
 148                 if (likely(button_not_pressed)) {
 149                         if (unlikely(shutdown_timer && /* avoid writing if not necessary */
 150                                 shutdown_timer < (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC))) {
 151                                 shutdown_timer = 0;
 152                                 printk(KERN_INFO KTHREAD_NAME ": Shutdown request aborted.\n");
 153                         }
 154                 } else
 155                         process_shutdown();
 156
 157
 158         } while (!kthread_should_stop());
 159
 160         return 0;
 161 }
 162
 163
 164 /*
 165  * powerfail interruption handler (irq IRQ_FROM_REGION(CPU_IRQ_REGION)+2)
 166  */
 167 #if 0
 168 static void powerfail_interrupt(int code, void *x)
 169 {
 170         printk(KERN_CRIT "POWERFAIL INTERRUPTION !\n");
 171         poweroff();
 172 }
 173 #endif
 174
 175
 176
 177
 178 /* parisc_panic_event() is called by the panic handler.
 179  * As soon as a panic occurs, our tasklets above will not be
 180  * executed any longer. This function then re-enables the
 181  * soft-power switch and allows the user to switch off the system
 182  */
 183 static int parisc_panic_event(struct notifier_block *this,
 184                 unsigned long event, void *ptr)
 185 {
 186         /* re-enable the soft-power switch */
 187         pdc_soft_power_button(0);
 188         return NOTIFY_DONE;
 189 }
 190
 191 static struct notifier_block parisc_panic_block = {
 192         .notifier_call  = parisc_panic_event,
 193         .priority       = INT_MAX,
 194 };
 195
 196
 197 static int __init power_init(void)
 198 {
 199         unsigned long ret;
 200         unsigned long soft_power_reg;
 201
 202 #if 0
 203         request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt,
 204                 0, "powerfail", NULL);
 205 #endif
 206
 207         /* enable the soft power switch if possible */
 208         ret = pdc_soft_power_info(&soft_power_reg);
 209         if (ret == PDC_OK)
 210                 ret = pdc_soft_power_button(1);
 211         if (ret != PDC_OK)
 212                 soft_power_reg = -1UL;
 213
 214         switch (soft_power_reg) {
 215         case 0:         printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n");
 216                         break;
 217
 218         case -1UL:      printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n");
 219                         return -ENODEV;
 220
 221         default:        printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n",
 222                                 soft_power_reg);
 223         }
 224
 225         power_task = kthread_run(kpowerswd, (void*)soft_power_reg, KTHREAD_NAME);
 226         if (IS_ERR(power_task)) {
 227                 printk(KERN_ERR DRIVER_NAME ": thread creation failed.  Driver not loaded.\n");
 228                 pdc_soft_power_button(0);
 229                 return -EIO;
 230         }
 231
 232         /* Register a call for panic conditions. */
 233         atomic_notifier_chain_register(&panic_notifier_list,
 234                         &parisc_panic_block);
 235
 236         return 0;
 237 }
 238
 239 static void __exit power_exit(void)
 240 {
 241         kthread_stop(power_task);
 242
 243         atomic_notifier_chain_unregister(&panic_notifier_list,
 244                         &parisc_panic_block);
 245
 246         pdc_soft_power_button(0);
 247 }
 248
 249 arch_initcall(power_init);
 250 module_exit(power_exit);
 251
 252
 253 MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
 254 MODULE_DESCRIPTION("Soft power switch driver");
 255 MODULE_LICENSE("Dual BSD/GPL");