1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * HP PARISC soft power switch driver 4 * 5 * Copyright (c) 2001-2023 Helge Deller <deller@gmx.de> 6 * 7 * HINT: 8 * Support of the soft power switch button may be enabled or disabled at 9 * runtime through the "/proc/sys/kernel/power" procfs entry. 10 */ 11 12 #include <linux/module.h> 13 #include <linux/init.h> 14 #include <linux/kernel.h> 15 #include <linux/panic_notifier.h> 16 #include <linux/reboot.h> 17 #include <linux/sched/signal.h> 18 #include <linux/kthread.h> 19 #include <linux/pm.h> 20 21 #include <asm/pdc.h> 22 #include <asm/io.h> 23 #include <asm/led.h> 24 25 #define DRIVER_NAME "powersw" 26 #define KTHREAD_NAME "kpowerswd" 27 28 /* how often should the power button be polled ? */ 29 #define POWERSWITCH_POLL_PER_SEC 2 30 31 /* how long does the power button needs to be down until we react ? */ 32 #define POWERSWITCH_DOWN_SEC 2 33 34 /* assembly code to access special registers */ 35 /* taken from PCXL ERS page 82 */ 36 #define DIAG_CODE(code) (0x14000000 + ((code)<<5)) 37 38 #define MFCPU_X(rDiagReg, t_ch, t_th, code) \ 39 (DIAG_CODE(code) + ((rDiagReg)<<21) + ((t_ch)<<16) + ((t_th)<<0) ) 40 41 #define MTCPU(dr, gr) MFCPU_X(dr, gr, 0, 0x12) /* move value of gr to dr[dr] */ 42 #define MFCPU_C(dr, gr) MFCPU_X(dr, gr, 0, 0x30) /* for dr0 and dr8 only ! */ 43 #define MFCPU_T(dr, gr) MFCPU_X(dr, 0, gr, 0xa0) /* all dr except dr0 and dr8 */ 44 45 #define __getDIAG(dr) ( { \ 46 register unsigned long __res asm("r28");\ 47 __asm__ __volatile__ ( \ 48 ".word %1" : "=&r" (__res) : "i" (MFCPU_T(dr,28) ) \ 49 ); \ 50 __res; \ 51 } ) 52 53 /* local shutdown counter */ 54 static int shutdown_timer __read_mostly; 55 56 /* check, give feedback and start shutdown after one second */ 57 static void process_shutdown(void) 58 { 59 if (shutdown_timer == 0) 60 printk(KERN_ALERT KTHREAD_NAME ": Shutdown requested...\n"); 61 62 shutdown_timer++; 63 64 /* wait until the button was pressed for 1 second */ 65 if (shutdown_timer == (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC)) { 66 static const char msg[] = "Shutting down..."; 67 printk(KERN_INFO KTHREAD_NAME ": %s\n", msg); 68 lcd_print(msg); 69 70 /* send kill signal */ 71 if (kill_cad_pid(SIGINT, 1)) { 72 /* just in case killing init process failed */ 73 machine_power_off(); 74 } 75 } 76 } 77 78 79 /* main power switch task struct */ 80 static struct task_struct *power_task; 81 82 /* filename in /proc which can be used to enable/disable the power switch */ 83 #define SYSCTL_FILENAME "sys/kernel/power" 84 85 /* soft power switch enabled/disabled */ 86 static int pwrsw_enabled __read_mostly = 1; 87 88 static const struct ctl_table power_sysctl_table[] = { 89 { 90 .procname = "soft-power", 91 .data = &pwrsw_enabled, 92 .maxlen = sizeof(int), 93 .mode = 0644, 94 .proc_handler = proc_dointvec, 95 }, 96 }; 97 98 static int __init init_power_sysctl(void) 99 { 100 register_sysctl_init("kernel", power_sysctl_table); 101 return 0; 102 } 103 104 arch_initcall(init_power_sysctl); 105 106 /* main kernel thread worker. It polls the button state */ 107 static int kpowerswd(void *param) 108 { 109 __set_current_state(TASK_RUNNING); 110 111 do { 112 int button_not_pressed; 113 unsigned long soft_power_reg = (unsigned long) param; 114 115 schedule_timeout_interruptible(pwrsw_enabled ? HZ : HZ/POWERSWITCH_POLL_PER_SEC); 116 117 if (unlikely(!pwrsw_enabled)) 118 continue; 119 120 if (soft_power_reg) { 121 /* 122 * Non-Gecko-style machines: 123 * Check the power switch status which is read from the 124 * real I/O location at soft_power_reg. 125 * Bit 31 ("the lowest bit) is the status of the power switch. 126 * This bit is "1" if the button is NOT pressed. 127 */ 128 button_not_pressed = (gsc_readl(soft_power_reg) & 0x1); 129 } else { 130 /* 131 * On gecko style machines (e.g. 712/xx and 715/xx) 132 * the power switch status is stored in Bit 0 ("the highest bit") 133 * of CPU diagnose register 25. 134 * Warning: Some machines never reset the DIAG flag, even if 135 * the button has been released again. 136 */ 137 button_not_pressed = (__getDIAG(25) & 0x80000000); 138 } 139 140 if (likely(button_not_pressed)) { 141 if (unlikely(shutdown_timer && /* avoid writing if not necessary */ 142 shutdown_timer < (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC))) { 143 shutdown_timer = 0; 144 printk(KERN_INFO KTHREAD_NAME ": Shutdown request aborted.\n"); 145 } 146 } else 147 process_shutdown(); 148 149 150 } while (!kthread_should_stop()); 151 152 return 0; 153 } 154 155 156 /* 157 * powerfail interruption handler (irq IRQ_FROM_REGION(CPU_IRQ_REGION)+2) 158 */ 159 #if 0 160 static void powerfail_interrupt(int code, void *x) 161 { 162 printk(KERN_CRIT "POWERFAIL INTERRUPTION !\n"); 163 poweroff(); 164 } 165 #endif 166 167 168 169 170 /* 171 * parisc_panic_event() is called by the panic handler. 172 * 173 * As soon as a panic occurs, our tasklets above will not 174 * be executed any longer. This function then re-enables 175 * the soft-power switch and allows the user to switch off 176 * the system. We rely in pdc_soft_power_button_panic() 177 * since this version spin_trylocks (instead of regular 178 * spinlock), preventing deadlocks on panic path. 179 */ 180 static int parisc_panic_event(struct notifier_block *this, 181 unsigned long event, void *ptr) 182 { 183 /* re-enable the soft-power switch */ 184 pdc_soft_power_button_panic(0); 185 return NOTIFY_DONE; 186 } 187 188 static struct notifier_block parisc_panic_block = { 189 .notifier_call = parisc_panic_event, 190 .priority = INT_MAX, 191 }; 192 193 /* qemu soft power-off function */ 194 static int qemu_power_off(struct sys_off_data *data) 195 { 196 /* this turns the system off via SeaBIOS */ 197 gsc_writel(0, (unsigned long) data->cb_data); 198 pdc_soft_power_button(1); 199 return NOTIFY_DONE; 200 } 201 202 static int __init power_init(void) 203 { 204 unsigned long ret; 205 unsigned long soft_power_reg; 206 207 #if 0 208 request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt, 209 0, "powerfail", NULL); 210 #endif 211 212 /* enable the soft power switch if possible */ 213 ret = pdc_soft_power_info(&soft_power_reg); 214 if (ret == PDC_OK) 215 ret = pdc_soft_power_button(1); 216 if (ret != PDC_OK) 217 soft_power_reg = -1UL; 218 219 switch (soft_power_reg) { 220 case 0: printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n"); 221 break; 222 223 case -1UL: printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n"); 224 return -ENODEV; 225 226 default: printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n", 227 soft_power_reg); 228 } 229 230 power_task = NULL; 231 if (running_on_qemu && soft_power_reg) 232 register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_DEFAULT, 233 qemu_power_off, (void *)soft_power_reg); 234 if (!running_on_qemu || soft_power_reg) 235 power_task = kthread_run(kpowerswd, (void*)soft_power_reg, 236 KTHREAD_NAME); 237 if (IS_ERR(power_task)) { 238 printk(KERN_ERR DRIVER_NAME ": thread creation failed. Driver not loaded.\n"); 239 pdc_soft_power_button(0); 240 return -EIO; 241 } 242 243 /* Register a call for panic conditions. */ 244 atomic_notifier_chain_register(&panic_notifier_list, 245 &parisc_panic_block); 246 247 return 0; 248 } 249 250 static void __exit power_exit(void) 251 { 252 kthread_stop(power_task); 253 254 atomic_notifier_chain_unregister(&panic_notifier_list, 255 &parisc_panic_block); 256 257 pdc_soft_power_button(0); 258 } 259 260 arch_initcall(power_init); 261 module_exit(power_exit); 262 263 264 MODULE_AUTHOR("Helge Deller <deller@gmx.de>"); 265 MODULE_DESCRIPTION("Soft power switch driver"); 266 MODULE_LICENSE("Dual BSD/GPL"); 267