/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * HP PARISC soft power switch driver * * Copyright (c) 2001-2023 Helge Deller * * HINT: * Support of the soft power switch button may be enabled or disabled at * runtime through the "/proc/sys/kernel/power" procfs entry. */ #include #include #include #include #include #include #include #include #include #include #include #define DRIVER_NAME "powersw" #define KTHREAD_NAME "kpowerswd" /* how often should the power button be polled ? */ #define POWERSWITCH_POLL_PER_SEC 2 /* how long does the power button needs to be down until we react ? */ #define POWERSWITCH_DOWN_SEC 2 /* assembly code to access special registers */ /* taken from PCXL ERS page 82 */ #define DIAG_CODE(code) (0x14000000 + ((code)<<5)) #define MFCPU_X(rDiagReg, t_ch, t_th, code) \ (DIAG_CODE(code) + ((rDiagReg)<<21) + ((t_ch)<<16) + ((t_th)<<0) ) #define MTCPU(dr, gr) MFCPU_X(dr, gr, 0, 0x12) /* move value of gr to dr[dr] */ #define MFCPU_C(dr, gr) MFCPU_X(dr, gr, 0, 0x30) /* for dr0 and dr8 only ! */ #define MFCPU_T(dr, gr) MFCPU_X(dr, 0, gr, 0xa0) /* all dr except dr0 and dr8 */ #define __getDIAG(dr) ( { \ register unsigned long __res asm("r28");\ __asm__ __volatile__ ( \ ".word %1" : "=&r" (__res) : "i" (MFCPU_T(dr,28) ) \ ); \ __res; \ } ) /* local shutdown counter */ static int shutdown_timer __read_mostly; /* check, give feedback and start shutdown after one second */ static void process_shutdown(void) { if (shutdown_timer == 0) printk(KERN_ALERT KTHREAD_NAME ": Shutdown requested...\n"); shutdown_timer++; /* wait until the button was pressed for 1 second */ if (shutdown_timer == (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC)) { static const char msg[] = "Shutting down..."; printk(KERN_INFO KTHREAD_NAME ": %s\n", msg); lcd_print(msg); /* send kill signal */ if (kill_cad_pid(SIGINT, 1)) { /* just in case killing init process failed */ machine_power_off(); } } } /* main power switch task struct */ static struct task_struct *power_task; /* filename in /proc which can be used to enable/disable the power switch */ #define SYSCTL_FILENAME "sys/kernel/power" /* soft power switch enabled/disabled */ int pwrsw_enabled __read_mostly = 1; /* main kernel thread worker. It polls the button state */ static int kpowerswd(void *param) { __set_current_state(TASK_RUNNING); do { int button_not_pressed; unsigned long soft_power_reg = (unsigned long) param; schedule_timeout_interruptible(pwrsw_enabled ? HZ : HZ/POWERSWITCH_POLL_PER_SEC); if (unlikely(!pwrsw_enabled)) continue; if (soft_power_reg) { /* * Non-Gecko-style machines: * Check the power switch status which is read from the * real I/O location at soft_power_reg. * Bit 31 ("the lowest bit) is the status of the power switch. * This bit is "1" if the button is NOT pressed. */ button_not_pressed = (gsc_readl(soft_power_reg) & 0x1); } else { /* * On gecko style machines (e.g. 712/xx and 715/xx) * the power switch status is stored in Bit 0 ("the highest bit") * of CPU diagnose register 25. * Warning: Some machines never reset the DIAG flag, even if * the button has been released again. */ button_not_pressed = (__getDIAG(25) & 0x80000000); } if (likely(button_not_pressed)) { if (unlikely(shutdown_timer && /* avoid writing if not necessary */ shutdown_timer < (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC))) { shutdown_timer = 0; printk(KERN_INFO KTHREAD_NAME ": Shutdown request aborted.\n"); } } else process_shutdown(); } while (!kthread_should_stop()); return 0; } /* * powerfail interruption handler (irq IRQ_FROM_REGION(CPU_IRQ_REGION)+2) */ #if 0 static void powerfail_interrupt(int code, void *x) { printk(KERN_CRIT "POWERFAIL INTERRUPTION !\n"); poweroff(); } #endif /* * parisc_panic_event() is called by the panic handler. * * As soon as a panic occurs, our tasklets above will not * be executed any longer. This function then re-enables * the soft-power switch and allows the user to switch off * the system. We rely in pdc_soft_power_button_panic() * since this version spin_trylocks (instead of regular * spinlock), preventing deadlocks on panic path. */ static int parisc_panic_event(struct notifier_block *this, unsigned long event, void *ptr) { /* re-enable the soft-power switch */ pdc_soft_power_button_panic(0); return NOTIFY_DONE; } static struct notifier_block parisc_panic_block = { .notifier_call = parisc_panic_event, .priority = INT_MAX, }; /* qemu soft power-off function */ static int qemu_power_off(struct sys_off_data *data) { /* this turns the system off via SeaBIOS */ gsc_writel(0, (unsigned long) data->cb_data); pdc_soft_power_button(1); return NOTIFY_DONE; } static int __init power_init(void) { unsigned long ret; unsigned long soft_power_reg; #if 0 request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt, 0, "powerfail", NULL); #endif /* enable the soft power switch if possible */ ret = pdc_soft_power_info(&soft_power_reg); if (ret == PDC_OK) ret = pdc_soft_power_button(1); if (ret != PDC_OK) soft_power_reg = -1UL; switch (soft_power_reg) { case 0: printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n"); break; case -1UL: printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n"); return -ENODEV; default: printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n", soft_power_reg); } power_task = NULL; if (running_on_qemu && soft_power_reg) register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_DEFAULT, qemu_power_off, (void *)soft_power_reg); if (!running_on_qemu || soft_power_reg) power_task = kthread_run(kpowerswd, (void*)soft_power_reg, KTHREAD_NAME); if (IS_ERR(power_task)) { printk(KERN_ERR DRIVER_NAME ": thread creation failed. Driver not loaded.\n"); pdc_soft_power_button(0); return -EIO; } /* Register a call for panic conditions. */ atomic_notifier_chain_register(&panic_notifier_list, &parisc_panic_block); return 0; } static void __exit power_exit(void) { kthread_stop(power_task); atomic_notifier_chain_unregister(&panic_notifier_list, &parisc_panic_block); pdc_soft_power_button(0); } arch_initcall(power_init); module_exit(power_exit); MODULE_AUTHOR("Helge Deller "); MODULE_DESCRIPTION("Soft power switch driver"); MODULE_LICENSE("Dual BSD/GPL");