1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PowerNV OPAL power control for graceful shutdown handling
4  *
5  * Copyright 2015 IBM Corp.
6  */
7 
8 #define pr_fmt(fmt)	"opal-power: "	fmt
9 
10 #include <linux/kernel.h>
11 #include <linux/reboot.h>
12 #include <linux/notifier.h>
13 #include <linux/of.h>
14 
15 #include <asm/opal.h>
16 #include <asm/machdep.h>
17 
18 #define SOFT_OFF 0x00
19 #define SOFT_REBOOT 0x01
20 
21 /* Detect EPOW event */
22 static bool detect_epow(void)
23 {
24 	u16 epow;
25 	int i, rc;
26 	__be16 epow_classes;
27 	__be16 opal_epow_status[OPAL_SYSEPOW_MAX] = {0};
28 
29 	/*
30 	* Check for EPOW event. Kernel sends supported EPOW classes info
31 	* to OPAL. OPAL returns EPOW info along with classes present.
32 	*/
33 	epow_classes = cpu_to_be16(OPAL_SYSEPOW_MAX);
34 	rc = opal_get_epow_status(opal_epow_status, &epow_classes);
35 	if (rc != OPAL_SUCCESS) {
36 		pr_err("Failed to get EPOW event information\n");
37 		return false;
38 	}
39 
40 	/* Look for EPOW events present */
41 	for (i = 0; i < be16_to_cpu(epow_classes); i++) {
42 		epow = be16_to_cpu(opal_epow_status[i]);
43 
44 		/* Filter events which do not need shutdown. */
45 		if (i == OPAL_SYSEPOW_POWER)
46 			epow &= ~(OPAL_SYSPOWER_CHNG | OPAL_SYSPOWER_FAIL |
47 					OPAL_SYSPOWER_INCL);
48 		if (epow)
49 			return true;
50 	}
51 
52 	return false;
53 }
54 
55 /* Check for existing EPOW, DPO events */
56 static bool poweroff_pending(void)
57 {
58 	int rc;
59 	__be64 opal_dpo_timeout;
60 
61 	/* Check for DPO event */
62 	rc = opal_get_dpo_status(&opal_dpo_timeout);
63 	if (rc == OPAL_SUCCESS) {
64 		pr_info("Existing DPO event detected.\n");
65 		return true;
66 	}
67 
68 	/* Check for EPOW event */
69 	if (detect_epow()) {
70 		pr_info("Existing EPOW event detected.\n");
71 		return true;
72 	}
73 
74 	return false;
75 }
76 
77 /* OPAL power-control events notifier */
78 static int opal_power_control_event(struct notifier_block *nb,
79 					unsigned long msg_type, void *msg)
80 {
81 	uint64_t type;
82 
83 	switch (msg_type) {
84 	case OPAL_MSG_EPOW:
85 		if (detect_epow()) {
86 			pr_info("EPOW msg received. Powering off system\n");
87 			orderly_poweroff(true);
88 		}
89 		break;
90 	case OPAL_MSG_DPO:
91 		pr_info("DPO msg received. Powering off system\n");
92 		orderly_poweroff(true);
93 		break;
94 	case OPAL_MSG_SHUTDOWN:
95 		type = be64_to_cpu(((struct opal_msg *)msg)->params[0]);
96 		switch (type) {
97 		case SOFT_REBOOT:
98 			pr_info("Reboot requested\n");
99 			orderly_reboot();
100 			break;
101 		case SOFT_OFF:
102 			pr_info("Poweroff requested\n");
103 			orderly_poweroff(true);
104 			break;
105 		default:
106 			pr_err("Unknown power-control type %llu\n", type);
107 		}
108 		break;
109 	default:
110 		pr_err("Unknown OPAL message type %lu\n", msg_type);
111 	}
112 
113 	return 0;
114 }
115 
116 /* OPAL EPOW event notifier block */
117 static struct notifier_block opal_epow_nb = {
118 	.notifier_call	= opal_power_control_event,
119 	.next		= NULL,
120 	.priority	= 0,
121 };
122 
123 /* OPAL DPO event notifier block */
124 static struct notifier_block opal_dpo_nb = {
125 	.notifier_call	= opal_power_control_event,
126 	.next		= NULL,
127 	.priority	= 0,
128 };
129 
130 /* OPAL power-control event notifier block */
131 static struct notifier_block opal_power_control_nb = {
132 	.notifier_call	= opal_power_control_event,
133 	.next		= NULL,
134 	.priority	= 0,
135 };
136 
137 int __init opal_power_control_init(void)
138 {
139 	int ret, supported = 0;
140 	struct device_node *np;
141 
142 	/* Register OPAL power-control events notifier */
143 	ret = opal_message_notifier_register(OPAL_MSG_SHUTDOWN,
144 						&opal_power_control_nb);
145 	if (ret)
146 		pr_err("Failed to register SHUTDOWN notifier, ret = %d\n", ret);
147 
148 	/* Determine OPAL EPOW, DPO support */
149 	np = of_find_node_by_path("/ibm,opal/epow");
150 	if (np) {
151 		supported = of_device_is_compatible(np, "ibm,opal-v3-epow");
152 		of_node_put(np);
153 	}
154 
155 	if (!supported)
156 		return 0;
157 	pr_info("OPAL EPOW, DPO support detected.\n");
158 
159 	/* Register EPOW event notifier */
160 	ret = opal_message_notifier_register(OPAL_MSG_EPOW, &opal_epow_nb);
161 	if (ret)
162 		pr_err("Failed to register EPOW notifier, ret = %d\n", ret);
163 
164 	/* Register DPO event notifier */
165 	ret = opal_message_notifier_register(OPAL_MSG_DPO, &opal_dpo_nb);
166 	if (ret)
167 		pr_err("Failed to register DPO notifier, ret = %d\n", ret);
168 
169 	/* Check for any pending EPOW or DPO events. */
170 	if (poweroff_pending())
171 		orderly_poweroff(true);
172 
173 	return 0;
174 }
175