drivers/firmware/smccc/smccc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2020 Arm Limited
   4  */
   5
   6 #define pr_fmt(fmt) "smccc: " fmt
   7
   8 #include <linux/cache.h>
   9 #include <linux/init.h>
  10 #include <linux/arm-smccc.h>
  11 #include <linux/kernel.h>
  12 #include <linux/platform_device.h>
  13 #include <asm/archrandom.h>
  14
  15 static u32 smccc_version = ARM_SMCCC_VERSION_1_0;
  16 static enum arm_smccc_conduit smccc_conduit = SMCCC_CONDUIT_NONE;
  17
  18 bool __ro_after_init smccc_trng_available = false;
  19 s32 __ro_after_init smccc_soc_id_version = SMCCC_RET_NOT_SUPPORTED;
  20 s32 __ro_after_init smccc_soc_id_revision = SMCCC_RET_NOT_SUPPORTED;
  21
  22 void __init arm_smccc_version_init(u32 version, enum arm_smccc_conduit conduit)
  23 {
  24         struct arm_smccc_res res;
  25
  26         smccc_version = version;
  27         smccc_conduit = conduit;
  28
  29         smccc_trng_available = smccc_probe_trng();
  30
  31         if ((smccc_version >= ARM_SMCCC_VERSION_1_2) &&
  32             (smccc_conduit != SMCCC_CONDUIT_NONE)) {
  33                 arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
  34                                      ARM_SMCCC_ARCH_SOC_ID, &res);
  35                 if ((s32)res.a0 >= 0) {
  36                         arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 0, &res);
  37                         smccc_soc_id_version = (s32)res.a0;
  38                         arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 1, &res);
  39                         smccc_soc_id_revision = (s32)res.a0;
  40                 }
  41         }
  42 }
  43
  44 enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
  45 {
  46         if (smccc_version < ARM_SMCCC_VERSION_1_1)
  47                 return SMCCC_CONDUIT_NONE;
  48
  49         return smccc_conduit;
  50 }
  51 EXPORT_SYMBOL_GPL(arm_smccc_1_1_get_conduit);
  52
  53 u32 arm_smccc_get_version(void)
  54 {
  55         return smccc_version;
  56 }
  57 EXPORT_SYMBOL_GPL(arm_smccc_get_version);
  58
  59 s32 arm_smccc_get_soc_id_version(void)
  60 {
  61         return smccc_soc_id_version;
  62 }
  63
  64 s32 arm_smccc_get_soc_id_revision(void)
  65 {
  66         return smccc_soc_id_revision;
  67 }
  68 EXPORT_SYMBOL_GPL(arm_smccc_get_soc_id_revision);
  69
  70 static int __init smccc_devices_init(void)
  71 {
  72         struct platform_device *pdev;
  73
  74         if (smccc_trng_available) {
  75                 pdev = platform_device_register_simple("smccc_trng", -1,
  76                                                        NULL, 0);
  77                 if (IS_ERR(pdev))
  78                         pr_err("smccc_trng: could not register device: %ld\n",
  79                                PTR_ERR(pdev));
  80         }
  81
  82         return 0;
  83 }
  84 device_initcall(smccc_devices_init);