drivers/firmware/smccc/soc_id.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2020 Arm Limited
   4  */
   5
   6 #define pr_fmt(fmt) "SMCCC: SOC_ID: " fmt
   7
   8 #include <linux/arm-smccc.h>
   9 #include <linux/bitfield.h>
  10 #include <linux/device.h>
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/sys_soc.h>
  15
  16 #define SMCCC_SOC_ID_JEP106_BANK_IDX_MASK       GENMASK(30, 24)
  17 /*
  18  * As per the SMC Calling Convention specification v1.2 (ARM DEN 0028C)
  19  * Section 7.4 SMCCC_ARCH_SOC_ID bits[23:16] are JEP-106 identification
  20  * code with parity bit for the SiP. We can drop the parity bit.
  21  */
  22 #define SMCCC_SOC_ID_JEP106_ID_CODE_MASK        GENMASK(22, 16)
  23 #define SMCCC_SOC_ID_IMP_DEF_SOC_ID_MASK        GENMASK(15, 0)
  24
  25 #define JEP106_BANK_CONT_CODE(x)        \
  26         (u8)(FIELD_GET(SMCCC_SOC_ID_JEP106_BANK_IDX_MASK, (x)))
  27 #define JEP106_ID_CODE(x)       \
  28         (u8)(FIELD_GET(SMCCC_SOC_ID_JEP106_ID_CODE_MASK, (x)))
  29 #define IMP_DEF_SOC_ID(x)       \
  30         (u16)(FIELD_GET(SMCCC_SOC_ID_IMP_DEF_SOC_ID_MASK, (x)))
  31
  32 static struct soc_device *soc_dev;
  33 static struct soc_device_attribute *soc_dev_attr;
  34
  35 static int __init smccc_soc_init(void)
  36 {
  37         struct arm_smccc_res res;
  38         int soc_id_rev, soc_id_version;
  39         static char soc_id_str[20], soc_id_rev_str[12];
  40         static char soc_id_jep106_id_str[12];
  41
  42         if (arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2)
  43                 return 0;
  44
  45         if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) {
  46                 pr_err("%s: invalid SMCCC conduit\n", __func__);
  47                 return -EOPNOTSUPP;
  48         }
  49
  50         arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
  51                              ARM_SMCCC_ARCH_SOC_ID, &res);
  52
  53         if (res.a0 == SMCCC_RET_NOT_SUPPORTED) {
  54                 pr_info("ARCH_SOC_ID not implemented, skipping ....\n");
  55                 return 0;
  56         }
  57
  58         if ((int)res.a0 < 0) {
  59                 pr_info("ARCH_FEATURES(ARCH_SOC_ID) returned error: %lx\n",
  60                         res.a0);
  61                 return -EINVAL;
  62         }
  63
  64         arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 0, &res);
  65         if ((int)res.a0 < 0) {
  66                 pr_err("ARCH_SOC_ID(0) returned error: %lx\n", res.a0);
  67                 return -EINVAL;
  68         }
  69
  70         soc_id_version = res.a0;
  71
  72         arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 1, &res);
  73         if ((int)res.a0 < 0) {
  74                 pr_err("ARCH_SOC_ID(1) returned error: %lx\n", res.a0);
  75                 return -EINVAL;
  76         }
  77
  78         soc_id_rev = res.a0;
  79
  80         soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
  81         if (!soc_dev_attr)
  82                 return -ENOMEM;
  83
  84         sprintf(soc_id_rev_str, "0x%08x", soc_id_rev);
  85         sprintf(soc_id_jep106_id_str, "jep106:%02x%02x",
  86                 JEP106_BANK_CONT_CODE(soc_id_version),
  87                 JEP106_ID_CODE(soc_id_version));
  88         sprintf(soc_id_str, "%s:%04x", soc_id_jep106_id_str,
  89                 IMP_DEF_SOC_ID(soc_id_version));
  90
  91         soc_dev_attr->soc_id = soc_id_str;
  92         soc_dev_attr->revision = soc_id_rev_str;
  93         soc_dev_attr->family = soc_id_jep106_id_str;
  94
  95         soc_dev = soc_device_register(soc_dev_attr);
  96         if (IS_ERR(soc_dev)) {
  97                 kfree(soc_dev_attr);
  98                 return PTR_ERR(soc_dev);
  99         }
 100
 101         pr_info("ID = %s Revision = %s\n", soc_dev_attr->soc_id,
 102                 soc_dev_attr->revision);
 103
 104         return 0;
 105 }
 106 module_init(smccc_soc_init);
 107
 108 static void __exit smccc_soc_exit(void)
 109 {
 110         if (soc_dev)
 111                 soc_device_unregister(soc_dev);
 112         kfree(soc_dev_attr);
 113 }
 114 module_exit(smccc_soc_exit);