root/arch/powerpc/platforms/powernv/opal-power.c

DEFINITIONS

1. detect_epow
2. poweroff_pending
3. opal_power_control_event
4. opal_power_control_init

   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 }