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	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 ((int)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}
106module_init(smccc_soc_init);
107
108static void __exit smccc_soc_exit(void)
109{
110	if (soc_dev)
111		soc_device_unregister(soc_dev);
112	kfree(soc_dev_attr);
113}
114module_exit(smccc_soc_exit);
115