arch/arm/kernel/psci.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2012 ARM Limited
  12  *
  13  * Author: Will Deacon <will.deacon@arm.com>
  14  */
  15
  16 #define pr_fmt(fmt) "psci: " fmt
  17
  18 #include <linux/init.h>
  19 #include <linux/of.h>
  20 #include <linux/reboot.h>
  21 #include <linux/pm.h>
  22 #include <uapi/linux/psci.h>
  23
  24 #include <asm/compiler.h>
  25 #include <asm/errno.h>
  26 #include <asm/opcodes-sec.h>
  27 #include <asm/opcodes-virt.h>
  28 #include <asm/psci.h>
  29 #include <asm/system_misc.h>
  30
  31 struct psci_operations psci_ops;
  32
  33 static int (*invoke_psci_fn)(u32, u32, u32, u32);
  34 typedef int (*psci_initcall_t)(const struct device_node *);
  35
  36 enum psci_function {
  37         PSCI_FN_CPU_SUSPEND,
  38         PSCI_FN_CPU_ON,
  39         PSCI_FN_CPU_OFF,
  40         PSCI_FN_MIGRATE,
  41         PSCI_FN_AFFINITY_INFO,
  42         PSCI_FN_MIGRATE_INFO_TYPE,
  43         PSCI_FN_MAX,
  44 };
  45
  46 static u32 psci_function_id[PSCI_FN_MAX];
  47
  48 static int psci_to_linux_errno(int errno)
  49 {
  50         switch (errno) {
  51         case PSCI_RET_SUCCESS:
  52                 return 0;
  53         case PSCI_RET_NOT_SUPPORTED:
  54                 return -EOPNOTSUPP;
  55         case PSCI_RET_INVALID_PARAMS:
  56                 return -EINVAL;
  57         case PSCI_RET_DENIED:
  58                 return -EPERM;
  59         };
  60
  61         return -EINVAL;
  62 }
  63
  64 static u32 psci_power_state_pack(struct psci_power_state state)
  65 {
  66         return ((state.id << PSCI_0_2_POWER_STATE_ID_SHIFT)
  67                         & PSCI_0_2_POWER_STATE_ID_MASK) |
  68                 ((state.type << PSCI_0_2_POWER_STATE_TYPE_SHIFT)
  69                  & PSCI_0_2_POWER_STATE_TYPE_MASK) |
  70                 ((state.affinity_level << PSCI_0_2_POWER_STATE_AFFL_SHIFT)
  71                  & PSCI_0_2_POWER_STATE_AFFL_MASK);
  72 }
  73
  74 /*
  75  * The following two functions are invoked via the invoke_psci_fn pointer
  76  * and will not be inlined, allowing us to piggyback on the AAPCS.
  77  */
  78 static noinline int __invoke_psci_fn_hvc(u32 function_id, u32 arg0, u32 arg1,
  79                                          u32 arg2)
  80 {
  81         asm volatile(
  82                         __asmeq("%0", "r0")
  83                         __asmeq("%1", "r1")
  84                         __asmeq("%2", "r2")
  85                         __asmeq("%3", "r3")
  86                         __HVC(0)
  87                 : "+r" (function_id)
  88                 : "r" (arg0), "r" (arg1), "r" (arg2));
  89
  90         return function_id;
  91 }
  92
  93 static noinline int __invoke_psci_fn_smc(u32 function_id, u32 arg0, u32 arg1,
  94                                          u32 arg2)
  95 {
  96         asm volatile(
  97                         __asmeq("%0", "r0")
  98                         __asmeq("%1", "r1")
  99                         __asmeq("%2", "r2")
 100                         __asmeq("%3", "r3")
 101                         __SMC(0)
 102                 : "+r" (function_id)
 103                 : "r" (arg0), "r" (arg1), "r" (arg2));
 104
 105         return function_id;
 106 }
 107
 108 static int psci_get_version(void)
 109 {
 110         int err;
 111
 112         err = invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
 113         return err;
 114 }
 115
 116 static int psci_cpu_suspend(struct psci_power_state state,
 117                             unsigned long entry_point)
 118 {
 119         int err;
 120         u32 fn, power_state;
 121
 122         fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
 123         power_state = psci_power_state_pack(state);
 124         err = invoke_psci_fn(fn, power_state, entry_point, 0);
 125         return psci_to_linux_errno(err);
 126 }
 127
 128 static int psci_cpu_off(struct psci_power_state state)
 129 {
 130         int err;
 131         u32 fn, power_state;
 132
 133         fn = psci_function_id[PSCI_FN_CPU_OFF];
 134         power_state = psci_power_state_pack(state);
 135         err = invoke_psci_fn(fn, power_state, 0, 0);
 136         return psci_to_linux_errno(err);
 137 }
 138
 139 static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
 140 {
 141         int err;
 142         u32 fn;
 143
 144         fn = psci_function_id[PSCI_FN_CPU_ON];
 145         err = invoke_psci_fn(fn, cpuid, entry_point, 0);
 146         return psci_to_linux_errno(err);
 147 }
 148
 149 static int psci_migrate(unsigned long cpuid)
 150 {
 151         int err;
 152         u32 fn;
 153
 154         fn = psci_function_id[PSCI_FN_MIGRATE];
 155         err = invoke_psci_fn(fn, cpuid, 0, 0);
 156         return psci_to_linux_errno(err);
 157 }
 158
 159 static int psci_affinity_info(unsigned long target_affinity,
 160                 unsigned long lowest_affinity_level)
 161 {
 162         int err;
 163         u32 fn;
 164
 165         fn = psci_function_id[PSCI_FN_AFFINITY_INFO];
 166         err = invoke_psci_fn(fn, target_affinity, lowest_affinity_level, 0);
 167         return err;
 168 }
 169
 170 static int psci_migrate_info_type(void)
 171 {
 172         int err;
 173         u32 fn;
 174
 175         fn = psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE];
 176         err = invoke_psci_fn(fn, 0, 0, 0);
 177         return err;
 178 }
 179
 180 static int get_set_conduit_method(struct device_node *np)
 181 {
 182         const char *method;
 183
 184         pr_info("probing for conduit method from DT.\n");
 185
 186         if (of_property_read_string(np, "method", &method)) {
 187                 pr_warn("missing \"method\" property\n");
 188                 return -ENXIO;
 189         }
 190
 191         if (!strcmp("hvc", method)) {
 192                 invoke_psci_fn = __invoke_psci_fn_hvc;
 193         } else if (!strcmp("smc", method)) {
 194                 invoke_psci_fn = __invoke_psci_fn_smc;
 195         } else {
 196                 pr_warn("invalid \"method\" property: %s\n", method);
 197                 return -EINVAL;
 198         }
 199         return 0;
 200 }
 201
 202 static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
 203 {
 204         invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
 205 }
 206
 207 static void psci_sys_poweroff(void)
 208 {
 209         invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
 210 }
 211
 212 /*
 213  * PSCI Function IDs for v0.2+ are well defined so use
 214  * standard values.
 215  */
 216 static int psci_0_2_init(struct device_node *np)
 217 {
 218         int err, ver;
 219
 220         err = get_set_conduit_method(np);
 221
 222         if (err)
 223                 goto out_put_node;
 224
 225         ver = psci_get_version();
 226
 227         if (ver == PSCI_RET_NOT_SUPPORTED) {
 228                 /* PSCI v0.2 mandates implementation of PSCI_ID_VERSION. */
 229                 pr_err("PSCI firmware does not comply with the v0.2 spec.\n");
 230                 err = -EOPNOTSUPP;
 231                 goto out_put_node;
 232         } else {
 233                 pr_info("PSCIv%d.%d detected in firmware.\n",
 234                                 PSCI_VERSION_MAJOR(ver),
 235                                 PSCI_VERSION_MINOR(ver));
 236
 237                 if (PSCI_VERSION_MAJOR(ver) == 0 &&
 238                                 PSCI_VERSION_MINOR(ver) < 2) {
 239                         err = -EINVAL;
 240                         pr_err("Conflicting PSCI version detected.\n");
 241                         goto out_put_node;
 242                 }
 243         }
 244
 245         pr_info("Using standard PSCI v0.2 function IDs\n");
 246         psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN_CPU_SUSPEND;
 247         psci_ops.cpu_suspend = psci_cpu_suspend;
 248
 249         psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
 250         psci_ops.cpu_off = psci_cpu_off;
 251
 252         psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN_CPU_ON;
 253         psci_ops.cpu_on = psci_cpu_on;
 254
 255         psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN_MIGRATE;
 256         psci_ops.migrate = psci_migrate;
 257
 258         psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN_AFFINITY_INFO;
 259         psci_ops.affinity_info = psci_affinity_info;
 260
 261         psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] =
 262                 PSCI_0_2_FN_MIGRATE_INFO_TYPE;
 263         psci_ops.migrate_info_type = psci_migrate_info_type;
 264
 265         arm_pm_restart = psci_sys_reset;
 266
 267         pm_power_off = psci_sys_poweroff;
 268
 269 out_put_node:
 270         of_node_put(np);
 271         return err;
 272 }
 273
 274 /*
 275  * PSCI < v0.2 get PSCI Function IDs via DT.
 276  */
 277 static int psci_0_1_init(struct device_node *np)
 278 {
 279         u32 id;
 280         int err;
 281
 282         err = get_set_conduit_method(np);
 283
 284         if (err)
 285                 goto out_put_node;
 286
 287         pr_info("Using PSCI v0.1 Function IDs from DT\n");
 288
 289         if (!of_property_read_u32(np, "cpu_suspend", &id)) {
 290                 psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
 291                 psci_ops.cpu_suspend = psci_cpu_suspend;
 292         }
 293
 294         if (!of_property_read_u32(np, "cpu_off", &id)) {
 295                 psci_function_id[PSCI_FN_CPU_OFF] = id;
 296                 psci_ops.cpu_off = psci_cpu_off;
 297         }
 298
 299         if (!of_property_read_u32(np, "cpu_on", &id)) {
 300                 psci_function_id[PSCI_FN_CPU_ON] = id;
 301                 psci_ops.cpu_on = psci_cpu_on;
 302         }
 303
 304         if (!of_property_read_u32(np, "migrate", &id)) {
 305                 psci_function_id[PSCI_FN_MIGRATE] = id;
 306                 psci_ops.migrate = psci_migrate;
 307         }
 308
 309 out_put_node:
 310         of_node_put(np);
 311         return err;
 312 }
 313
 314 static const struct of_device_id psci_of_match[] __initconst = {
 315         { .compatible = "arm,psci", .data = psci_0_1_init},
 316         { .compatible = "arm,psci-0.2", .data = psci_0_2_init},
 317         {},
 318 };
 319
 320 int __init psci_init(void)
 321 {
 322         struct device_node *np;
 323         const struct of_device_id *matched_np;
 324         psci_initcall_t init_fn;
 325
 326         np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
 327         if (!np)
 328                 return -ENODEV;
 329
 330         init_fn = (psci_initcall_t)matched_np->data;
 331         return init_fn(np);
 332 }