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 */
22static 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 */
56static 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 */
78static 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 */
117static 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 */
124static 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 */
131static struct notifier_block opal_power_control_nb = {
132	.notifier_call	= opal_power_control_event,
133	.next		= NULL,
134	.priority	= 0,
135};
136
137int __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