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 #ifdef CONFIG_ARM64
36
37 static char __ro_after_init smccc_soc_id_name[136] = "";
38
str_fragment_from_reg(char * dst,unsigned long reg)39 static inline void str_fragment_from_reg(char *dst, unsigned long reg)
40 {
41 dst[0] = (reg >> 0) & 0xff;
42 dst[1] = (reg >> 8) & 0xff;
43 dst[2] = (reg >> 16) & 0xff;
44 dst[3] = (reg >> 24) & 0xff;
45 dst[4] = (reg >> 32) & 0xff;
46 dst[5] = (reg >> 40) & 0xff;
47 dst[6] = (reg >> 48) & 0xff;
48 dst[7] = (reg >> 56) & 0xff;
49 }
50
smccc_soc_name_init(void)51 static char __init *smccc_soc_name_init(void)
52 {
53 struct arm_smccc_1_2_regs args;
54 struct arm_smccc_1_2_regs res;
55 size_t len;
56
57 /*
58 * Issue Number 1.6 of the Arm SMC Calling Convention
59 * specification introduces an optional "name" string
60 * to the ARM_SMCCC_ARCH_SOC_ID function. Fetch it if
61 * available.
62 */
63 args.a0 = ARM_SMCCC_ARCH_SOC_ID;
64 args.a1 = 2; /* SOC_ID name */
65 arm_smccc_1_2_invoke(&args, &res);
66
67 if ((u32)res.a0 == 0) {
68 /*
69 * Copy res.a1..res.a17 to the smccc_soc_id_name string
70 * 8 bytes at a time. As per Issue 1.6 of the Arm SMC
71 * Calling Convention, the string will be NUL terminated
72 * and padded, from the end of the string to the end of the
73 * 136 byte buffer, with NULs.
74 */
75 str_fragment_from_reg(smccc_soc_id_name + 8 * 0, res.a1);
76 str_fragment_from_reg(smccc_soc_id_name + 8 * 1, res.a2);
77 str_fragment_from_reg(smccc_soc_id_name + 8 * 2, res.a3);
78 str_fragment_from_reg(smccc_soc_id_name + 8 * 3, res.a4);
79 str_fragment_from_reg(smccc_soc_id_name + 8 * 4, res.a5);
80 str_fragment_from_reg(smccc_soc_id_name + 8 * 5, res.a6);
81 str_fragment_from_reg(smccc_soc_id_name + 8 * 6, res.a7);
82 str_fragment_from_reg(smccc_soc_id_name + 8 * 7, res.a8);
83 str_fragment_from_reg(smccc_soc_id_name + 8 * 8, res.a9);
84 str_fragment_from_reg(smccc_soc_id_name + 8 * 9, res.a10);
85 str_fragment_from_reg(smccc_soc_id_name + 8 * 10, res.a11);
86 str_fragment_from_reg(smccc_soc_id_name + 8 * 11, res.a12);
87 str_fragment_from_reg(smccc_soc_id_name + 8 * 12, res.a13);
88 str_fragment_from_reg(smccc_soc_id_name + 8 * 13, res.a14);
89 str_fragment_from_reg(smccc_soc_id_name + 8 * 14, res.a15);
90 str_fragment_from_reg(smccc_soc_id_name + 8 * 15, res.a16);
91 str_fragment_from_reg(smccc_soc_id_name + 8 * 16, res.a17);
92
93 len = strnlen(smccc_soc_id_name, sizeof(smccc_soc_id_name));
94 if (len) {
95 if (len == sizeof(smccc_soc_id_name))
96 pr_warn(FW_BUG "Ignoring improperly formatted name\n");
97 else
98 return smccc_soc_id_name;
99 }
100 }
101
102 return NULL;
103 }
104
105 #else
106
smccc_soc_name_init(void)107 static char __init *smccc_soc_name_init(void)
108 {
109 return NULL;
110 }
111
112 #endif
113
smccc_soc_init(void)114 static int __init smccc_soc_init(void)
115 {
116 int soc_id_rev, soc_id_version;
117 static char soc_id_str[20], soc_id_rev_str[12];
118 static char soc_id_jep106_id_str[12];
119
120 if (arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2)
121 return 0;
122
123 soc_id_version = arm_smccc_get_soc_id_version();
124 if (soc_id_version == SMCCC_RET_NOT_SUPPORTED) {
125 pr_info("ARCH_SOC_ID not implemented, skipping ....\n");
126 return 0;
127 }
128
129 if (soc_id_version < 0) {
130 pr_err("Invalid SoC Version: %x\n", soc_id_version);
131 return -EINVAL;
132 }
133
134 soc_id_rev = arm_smccc_get_soc_id_revision();
135 if (soc_id_rev < 0) {
136 pr_err("Invalid SoC Revision: %x\n", soc_id_rev);
137 return -EINVAL;
138 }
139
140 soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
141 if (!soc_dev_attr)
142 return -ENOMEM;
143
144 sprintf(soc_id_rev_str, "0x%08x", soc_id_rev);
145 sprintf(soc_id_jep106_id_str, "jep106:%02x%02x",
146 JEP106_BANK_CONT_CODE(soc_id_version),
147 JEP106_ID_CODE(soc_id_version));
148 sprintf(soc_id_str, "%s:%04x", soc_id_jep106_id_str,
149 IMP_DEF_SOC_ID(soc_id_version));
150
151 soc_dev_attr->soc_id = soc_id_str;
152 soc_dev_attr->revision = soc_id_rev_str;
153 soc_dev_attr->family = soc_id_jep106_id_str;
154 soc_dev_attr->machine = smccc_soc_name_init();
155
156 soc_dev = soc_device_register(soc_dev_attr);
157 if (IS_ERR(soc_dev)) {
158 kfree(soc_dev_attr);
159 return PTR_ERR(soc_dev);
160 }
161
162 pr_info("ID = %s Revision = %s\n", soc_dev_attr->soc_id,
163 soc_dev_attr->revision);
164
165 return 0;
166 }
167 module_init(smccc_soc_init);
168
smccc_soc_exit(void)169 static void __exit smccc_soc_exit(void)
170 {
171 if (soc_dev)
172 soc_device_unregister(soc_dev);
173 kfree(soc_dev_attr);
174 }
175 module_exit(smccc_soc_exit);
176