release/src-rt-6.x.4708/linux/linux-2.6.36/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 #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                         if (pm_power_off)
  99                                 pm_power_off();
 100                 }
 101         }
 102 }
 103
 104
 105 /* main power switch task struct */
 106 static struct task_struct *power_task;
 107
 108 /* filename in /proc which can be used to enable/disable the power switch */
 109 #define SYSCTL_FILENAME "sys/kernel/power"
 110
 111 /* soft power switch enabled/disabled */
 112 int pwrsw_enabled __read_mostly = 1;
 113
 114 /* main kernel thread worker. It polls the button state */
 115 static int kpowerswd(void *param)
 116 {
 117         __set_current_state(TASK_RUNNING);
 118
 119         do {
 120                 int button_not_pressed;
 121                 unsigned long soft_power_reg = (unsigned long) param;
 122
 123                 schedule_timeout_interruptible(pwrsw_enabled ? HZ : HZ/POWERSWITCH_POLL_PER_SEC);
 124                 __set_current_state(TASK_RUNNING);
 125
 126                 if (unlikely(!pwrsw_enabled))
 127                         continue;
 128
 129                 if (soft_power_reg) {
 130                         /*
 131                          * Non-Gecko-style machines:
 132                          * Check the power switch status which is read from the
 133                          * real I/O location at soft_power_reg.
 134                          * Bit 31 ("the lowest bit) is the status of the power switch.
 135                          * This bit is "1" if the button is NOT pressed.
 136                          */
 137                         button_not_pressed = (gsc_readl(soft_power_reg) & 0x1);
 138                 } else {
 139                         /*
 140                          * On gecko style machines (e.g. 712/xx and 715/xx)
 141                          * the power switch status is stored in Bit 0 ("the highest bit")
 142                          * of CPU diagnose register 25.
 143                          * Warning: Some machines never reset the DIAG flag, even if
 144                          * the button has been released again.
 145                          */
 146                         button_not_pressed = (__getDIAG(25) & 0x80000000);
 147                 }
 148
 149                 if (likely(button_not_pressed)) {
 150                         if (unlikely(shutdown_timer && /* avoid writing if not necessary */
 151                                 shutdown_timer < (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC))) {
 152                                 shutdown_timer = 0;
 153                                 printk(KERN_INFO KTHREAD_NAME ": Shutdown request aborted.\n");
 154                         }
 155                 } else
 156                         process_shutdown();
 157
 158
 159         } while (!kthread_should_stop());
 160
 161         return 0;
 162 }
 163
 164
 165 /*
 166  * powerfail interruption handler (irq IRQ_FROM_REGION(CPU_IRQ_REGION)+2)
 167  */
 168
 169
 170
 171
 172 /* parisc_panic_event() is called by the panic handler.
 173  * As soon as a panic occurs, our tasklets above will not be
 174  * executed any longer. This function then re-enables the
 175  * soft-power switch and allows the user to switch off the system
 176  */
 177 static int parisc_panic_event(struct notifier_block *this,
 178                 unsigned long event, void *ptr)
 179 {
 180         /* re-enable the soft-power switch */
 181         pdc_soft_power_button(0);
 182         return NOTIFY_DONE;
 183 }
 184
 185 static struct notifier_block parisc_panic_block = {
 186         .notifier_call  = parisc_panic_event,
 187         .priority       = INT_MAX,
 188 };
 189
 190
 191 static int __init power_init(void)
 192 {
 193         unsigned long ret;
 194         unsigned long soft_power_reg;
 195
 196
 197         /* enable the soft power switch if possible */
 198         ret = pdc_soft_power_info(&soft_power_reg);
 199         if (ret == PDC_OK)
 200                 ret = pdc_soft_power_button(1);
 201         if (ret != PDC_OK)
 202                 soft_power_reg = -1UL;
 203
 204         switch (soft_power_reg) {
 205         case 0:         printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n");
 206                         break;
 207
 208         case -1UL:      printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n");
 209                         return -ENODEV;
 210
 211         default:        printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n",
 212                                 soft_power_reg);
 213         }
 214
 215         power_task = kthread_run(kpowerswd, (void*)soft_power_reg, KTHREAD_NAME);
 216         if (IS_ERR(power_task)) {
 217                 printk(KERN_ERR DRIVER_NAME ": thread creation failed.  Driver not loaded.\n");
 218                 pdc_soft_power_button(0);
 219                 return -EIO;
 220         }
 221
 222         /* Register a call for panic conditions. */
 223         atomic_notifier_chain_register(&panic_notifier_list,
 224                         &parisc_panic_block);
 225
 226         return 0;
 227 }
 228
 229 static void __exit power_exit(void)
 230 {
 231         kthread_stop(power_task);
 232
 233         atomic_notifier_chain_unregister(&panic_notifier_list,
 234                         &parisc_panic_block);
 235
 236         pdc_soft_power_button(0);
 237 }
 238
 239 arch_initcall(power_init);
 240 module_exit(power_exit);
 241
 242
 243 MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
 244 MODULE_DESCRIPTION("Soft power switch driver");
 245 MODULE_LICENSE("Dual BSD/GPL");