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
32static struct soc_device *soc_dev;
33static struct soc_device_attribute *soc_dev_attr;
34
35static int __init smccc_soc_init(void)
36{
37	int soc_id_rev, soc_id_version;
38	static char soc_id_str[20], soc_id_rev_str[12];
39	static char soc_id_jep106_id_str[12];
40
41	if (arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2)
42		return 0;
43
44	soc_id_version = arm_smccc_get_soc_id_version();
45	if (soc_id_version == SMCCC_RET_NOT_SUPPORTED) {
46		pr_info("ARCH_SOC_ID not implemented, skipping ....\n");
47		return 0;
48	}
49
50	if (soc_id_version < 0) {
51		pr_err("Invalid SoC Version: %x\n", soc_id_version);
52		return -EINVAL;
53	}
54
55	soc_id_rev = arm_smccc_get_soc_id_revision();
56	if (soc_id_rev < 0) {
57		pr_err("Invalid SoC Revision: %x\n", soc_id_rev);
58		return -EINVAL;
59	}
60
61	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
62	if (!soc_dev_attr)
63		return -ENOMEM;
64
65	sprintf(soc_id_rev_str, "0x%08x", soc_id_rev);
66	sprintf(soc_id_jep106_id_str, "jep106:%02x%02x",
67		JEP106_BANK_CONT_CODE(soc_id_version),
68		JEP106_ID_CODE(soc_id_version));
69	sprintf(soc_id_str, "%s:%04x", soc_id_jep106_id_str,
70		IMP_DEF_SOC_ID(soc_id_version));
71
72	soc_dev_attr->soc_id = soc_id_str;
73	soc_dev_attr->revision = soc_id_rev_str;
74	soc_dev_attr->family = soc_id_jep106_id_str;
75
76	soc_dev = soc_device_register(soc_dev_attr);
77	if (IS_ERR(soc_dev)) {
78		kfree(soc_dev_attr);
79		return PTR_ERR(soc_dev);
80	}
81
82	pr_info("ID = %s Revision = %s\n", soc_dev_attr->soc_id,
83		soc_dev_attr->revision);
84
85	return 0;
86}
87module_init(smccc_soc_init);
88
89static void __exit smccc_soc_exit(void)
90{
91	if (soc_dev)
92		soc_device_unregister(soc_dev);
93	kfree(soc_dev_attr);
94}
95module_exit(smccc_soc_exit);