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, priv: 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 | int pwrsw_enabled __read_mostly = 1; |
87 | |
88 | /* main kernel thread worker. It polls the button state */ |
89 | static int kpowerswd(void *param) |
90 | { |
91 | __set_current_state(TASK_RUNNING); |
92 | |
93 | do { |
94 | int button_not_pressed; |
95 | unsigned long soft_power_reg = (unsigned long) param; |
96 | |
97 | schedule_timeout_interruptible(timeout: pwrsw_enabled ? HZ : HZ/POWERSWITCH_POLL_PER_SEC); |
98 | |
99 | if (unlikely(!pwrsw_enabled)) |
100 | continue; |
101 | |
102 | if (soft_power_reg) { |
103 | /* |
104 | * Non-Gecko-style machines: |
105 | * Check the power switch status which is read from the |
106 | * real I/O location at soft_power_reg. |
107 | * Bit 31 ("the lowest bit) is the status of the power switch. |
108 | * This bit is "1" if the button is NOT pressed. |
109 | */ |
110 | button_not_pressed = (gsc_readl(soft_power_reg) & 0x1); |
111 | } else { |
112 | /* |
113 | * On gecko style machines (e.g. 712/xx and 715/xx) |
114 | * the power switch status is stored in Bit 0 ("the highest bit") |
115 | * of CPU diagnose register 25. |
116 | * Warning: Some machines never reset the DIAG flag, even if |
117 | * the button has been released again. |
118 | */ |
119 | button_not_pressed = (__getDIAG(25) & 0x80000000); |
120 | } |
121 | |
122 | if (likely(button_not_pressed)) { |
123 | if (unlikely(shutdown_timer && /* avoid writing if not necessary */ |
124 | shutdown_timer < (POWERSWITCH_DOWN_SEC*POWERSWITCH_POLL_PER_SEC))) { |
125 | shutdown_timer = 0; |
126 | printk(KERN_INFO KTHREAD_NAME ": Shutdown request aborted.\n" ); |
127 | } |
128 | } else |
129 | process_shutdown(); |
130 | |
131 | |
132 | } while (!kthread_should_stop()); |
133 | |
134 | return 0; |
135 | } |
136 | |
137 | |
138 | /* |
139 | * powerfail interruption handler (irq IRQ_FROM_REGION(CPU_IRQ_REGION)+2) |
140 | */ |
141 | #if 0 |
142 | static void powerfail_interrupt(int code, void *x) |
143 | { |
144 | printk(KERN_CRIT "POWERFAIL INTERRUPTION !\n" ); |
145 | poweroff(); |
146 | } |
147 | #endif |
148 | |
149 | |
150 | |
151 | |
152 | /* |
153 | * parisc_panic_event() is called by the panic handler. |
154 | * |
155 | * As soon as a panic occurs, our tasklets above will not |
156 | * be executed any longer. This function then re-enables |
157 | * the soft-power switch and allows the user to switch off |
158 | * the system. We rely in pdc_soft_power_button_panic() |
159 | * since this version spin_trylocks (instead of regular |
160 | * spinlock), preventing deadlocks on panic path. |
161 | */ |
162 | static int parisc_panic_event(struct notifier_block *this, |
163 | unsigned long event, void *ptr) |
164 | { |
165 | /* re-enable the soft-power switch */ |
166 | pdc_soft_power_button_panic(0); |
167 | return NOTIFY_DONE; |
168 | } |
169 | |
170 | static struct notifier_block parisc_panic_block = { |
171 | .notifier_call = parisc_panic_event, |
172 | .priority = INT_MAX, |
173 | }; |
174 | |
175 | /* qemu soft power-off function */ |
176 | static int qemu_power_off(struct sys_off_data *data) |
177 | { |
178 | /* this turns the system off via SeaBIOS */ |
179 | *(int *)data->cb_data = 0; |
180 | pdc_soft_power_button(1); |
181 | return NOTIFY_DONE; |
182 | } |
183 | |
184 | static int __init power_init(void) |
185 | { |
186 | unsigned long ret; |
187 | unsigned long soft_power_reg; |
188 | |
189 | #if 0 |
190 | request_irq( IRQ_FROM_REGION(CPU_IRQ_REGION)+2, &powerfail_interrupt, |
191 | 0, "powerfail" , NULL); |
192 | #endif |
193 | |
194 | /* enable the soft power switch if possible */ |
195 | ret = pdc_soft_power_info(&soft_power_reg); |
196 | if (ret == PDC_OK) |
197 | ret = pdc_soft_power_button(1); |
198 | if (ret != PDC_OK) |
199 | soft_power_reg = -1UL; |
200 | |
201 | switch (soft_power_reg) { |
202 | case 0: printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n" ); |
203 | break; |
204 | |
205 | case -1UL: printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n" ); |
206 | return -ENODEV; |
207 | |
208 | default: printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n" , |
209 | soft_power_reg); |
210 | } |
211 | |
212 | power_task = NULL; |
213 | if (running_on_qemu && soft_power_reg) |
214 | register_sys_off_handler(mode: SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_DEFAULT, |
215 | callback: qemu_power_off, cb_data: (void *)soft_power_reg); |
216 | else |
217 | power_task = kthread_run(kpowerswd, (void*)soft_power_reg, |
218 | KTHREAD_NAME); |
219 | if (IS_ERR(ptr: power_task)) { |
220 | printk(KERN_ERR DRIVER_NAME ": thread creation failed. Driver not loaded.\n" ); |
221 | pdc_soft_power_button(0); |
222 | return -EIO; |
223 | } |
224 | |
225 | /* Register a call for panic conditions. */ |
226 | atomic_notifier_chain_register(nh: &panic_notifier_list, |
227 | nb: &parisc_panic_block); |
228 | |
229 | return 0; |
230 | } |
231 | |
232 | static void __exit power_exit(void) |
233 | { |
234 | kthread_stop(k: power_task); |
235 | |
236 | atomic_notifier_chain_unregister(nh: &panic_notifier_list, |
237 | nb: &parisc_panic_block); |
238 | |
239 | pdc_soft_power_button(0); |
240 | } |
241 | |
242 | arch_initcall(power_init); |
243 | module_exit(power_exit); |
244 | |
245 | |
246 | MODULE_AUTHOR("Helge Deller <deller@gmx.de>" ); |
247 | MODULE_DESCRIPTION("Soft power switch driver" ); |
248 | MODULE_LICENSE("Dual BSD/GPL" ); |
249 | |