1 /*
2  * PowerNV OPAL power control for graceful shutdown handling
3  *
4  * Copyright 2015 IBM Corp.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 #define pr_fmt(fmt)	"opal-power: "	fmt
13 
14 #include <linux/kernel.h>
15 #include <linux/reboot.h>
16 #include <linux/notifier.h>
17 #include <linux/of.h>
18 
19 #include <asm/opal.h>
20 #include <asm/machdep.h>
21 
22 #define SOFT_OFF 0x00
23 #define SOFT_REBOOT 0x01
24 
25 /* Detect EPOW event */
26 static bool detect_epow(void)
27 {
28 	u16 epow;
29 	int i, rc;
30 	__be16 epow_classes;
31 	__be16 opal_epow_status[OPAL_SYSEPOW_MAX] = {0};
32 
33 	/*
34 	* Check for EPOW event. Kernel sends supported EPOW classes info
35 	* to OPAL. OPAL returns EPOW info along with classes present.
36 	*/
37 	epow_classes = cpu_to_be16(OPAL_SYSEPOW_MAX);
38 	rc = opal_get_epow_status(opal_epow_status, &epow_classes);
39 	if (rc != OPAL_SUCCESS) {
40 		pr_err("Failed to get EPOW event information\n");
41 		return false;
42 	}
43 
44 	/* Look for EPOW events present */
45 	for (i = 0; i < be16_to_cpu(epow_classes); i++) {
46 		epow = be16_to_cpu(opal_epow_status[i]);
47 
48 		/* Filter events which do not need shutdown. */
49 		if (i == OPAL_SYSEPOW_POWER)
50 			epow &= ~(OPAL_SYSPOWER_CHNG | OPAL_SYSPOWER_FAIL |
51 					OPAL_SYSPOWER_INCL);
52 		if (epow)
53 			return true;
54 	}
55 
56 	return false;
57 }
58 
59 /* Check for existing EPOW, DPO events */
60 static bool poweroff_pending(void)
61 {
62 	int rc;
63 	__be64 opal_dpo_timeout;
64 
65 	/* Check for DPO event */
66 	rc = opal_get_dpo_status(&opal_dpo_timeout);
67 	if (rc == OPAL_SUCCESS) {
68 		pr_info("Existing DPO event detected.\n");
69 		return true;
70 	}
71 
72 	/* Check for EPOW event */
73 	if (detect_epow()) {
74 		pr_info("Existing EPOW event detected.\n");
75 		return true;
76 	}
77 
78 	return false;
79 }
80 
81 /* OPAL power-control events notifier */
82 static int opal_power_control_event(struct notifier_block *nb,
83 					unsigned long msg_type, void *msg)
84 {
85 	uint64_t type;
86 
87 	switch (msg_type) {
88 	case OPAL_MSG_EPOW:
89 		if (detect_epow()) {
90 			pr_info("EPOW msg received. Powering off system\n");
91 			orderly_poweroff(true);
92 		}
93 		break;
94 	case OPAL_MSG_DPO:
95 		pr_info("DPO msg received. Powering off system\n");
96 		orderly_poweroff(true);
97 		break;
98 	case OPAL_MSG_SHUTDOWN:
99 		type = be64_to_cpu(((struct opal_msg *)msg)->params[0]);
100 		switch (type) {
101 		case SOFT_REBOOT:
102 			pr_info("Reboot requested\n");
103 			orderly_reboot();
104 			break;
105 		case SOFT_OFF:
106 			pr_info("Poweroff requested\n");
107 			orderly_poweroff(true);
108 			break;
109 		default:
110 			pr_err("Unknown power-control type %llu\n", type);
111 		}
112 		break;
113 	default:
114 		pr_err("Unknown OPAL message type %lu\n", msg_type);
115 	}
116 
117 	return 0;
118 }
119 
120 /* OPAL EPOW event notifier block */
121 static struct notifier_block opal_epow_nb = {
122 	.notifier_call	= opal_power_control_event,
123 	.next		= NULL,
124 	.priority	= 0,
125 };
126 
127 /* OPAL DPO event notifier block */
128 static struct notifier_block opal_dpo_nb = {
129 	.notifier_call	= opal_power_control_event,
130 	.next		= NULL,
131 	.priority	= 0,
132 };
133 
134 /* OPAL power-control event notifier block */
135 static struct notifier_block opal_power_control_nb = {
136 	.notifier_call	= opal_power_control_event,
137 	.next		= NULL,
138 	.priority	= 0,
139 };
140 
141 int __init opal_power_control_init(void)
142 {
143 	int ret, supported = 0;
144 	struct device_node *np;
145 
146 	/* Register OPAL power-control events notifier */
147 	ret = opal_message_notifier_register(OPAL_MSG_SHUTDOWN,
148 						&opal_power_control_nb);
149 	if (ret)
150 		pr_err("Failed to register SHUTDOWN notifier, ret = %d\n", ret);
151 
152 	/* Determine OPAL EPOW, DPO support */
153 	np = of_find_node_by_path("/ibm,opal/epow");
154 	if (np) {
155 		supported = of_device_is_compatible(np, "ibm,opal-v3-epow");
156 		of_node_put(np);
157 	}
158 
159 	if (!supported)
160 		return 0;
161 	pr_info("OPAL EPOW, DPO support detected.\n");
162 
163 	/* Register EPOW event notifier */
164 	ret = opal_message_notifier_register(OPAL_MSG_EPOW, &opal_epow_nb);
165 	if (ret)
166 		pr_err("Failed to register EPOW notifier, ret = %d\n", ret);
167 
168 	/* Register DPO event notifier */
169 	ret = opal_message_notifier_register(OPAL_MSG_DPO, &opal_dpo_nb);
170 	if (ret)
171 		pr_err("Failed to register DPO notifier, ret = %d\n", ret);
172 
173 	/* Check for any pending EPOW or DPO events. */
174 	if (poweroff_pending())
175 		orderly_poweroff(true);
176 
177 	return 0;
178 }
179