1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Author: Yinbo Zhu <zhuyinbo@loongson.cn>
4  * Copyright (C) 2022-2023 Loongson Technology Corporation Limited
5  */
6 
7 #include <linux/io.h>
8 #include <linux/slab.h>
9 #include <linux/module.h>
10 #include <linux/of_fdt.h>
11 #include <linux/sys_soc.h>
12 #include <linux/of_address.h>
13 #include <linux/platform_device.h>
14 
15 static struct soc_device_attribute soc_dev_attr;
16 static struct soc_device *soc_dev;
17 
18 /*
19  * Global Utility Registers.
20  *
21  * Not all registers defined in this structure are available on all chips, so
22  * you are expected to know whether a given register actually exists on your
23  * chip before you access it.
24  *
25  * Also, some registers are similar on different chips but have slightly
26  * different names.  In these cases, one name is chosen to avoid extraneous
27  * #ifdefs.
28  */
29 struct scfg_guts {
30 	u32     svr;            /* Version Register */
31 	u8      res0[4];
32 	u16     feature;        /* Feature Register */
33 	u32     vendor;         /* Vendor Register */
34 	u8      res1[6];
35 	u32     id;
36 	u8      res2[0x3ff8 - 0x18];
37 	u32     chip;
38 };
39 
40 static struct guts {
41 	struct scfg_guts __iomem *regs;
42 	bool little_endian;
43 } *guts;
44 
45 struct loongson2_soc_die_attr {
46 	char	*die;
47 	u32	svr;
48 	u32	mask;
49 };
50 
51 /* SoC die attribute definition for Loongson-2 platform */
52 static const struct loongson2_soc_die_attr loongson2_soc_die[] = {
53 
54 	/*
55 	 * LoongArch-based SoCs Loongson-2 Series
56 	 */
57 
58 	/* Die: 2k1000, SoC: 2k1000 */
59 	{ .die		= "2K1000",
60 	  .svr		= 0x00000013,
61 	  .mask		= 0x000000ff,
62 	},
63 	{ },
64 };
65 
loongson2_soc_die_match(u32 svr,const struct loongson2_soc_die_attr * matches)66 static const struct loongson2_soc_die_attr *loongson2_soc_die_match(
67 	u32 svr, const struct loongson2_soc_die_attr *matches)
68 {
69 	while (matches->svr) {
70 		if (matches->svr == (svr & matches->mask))
71 			return matches;
72 		matches++;
73 	}
74 
75 	return NULL;
76 }
77 
loongson2_guts_get_svr(void)78 static u32 loongson2_guts_get_svr(void)
79 {
80 	u32 svr = 0;
81 
82 	if (!guts || !guts->regs)
83 		return svr;
84 
85 	if (guts->little_endian)
86 		svr = ioread32(&guts->regs->svr);
87 	else
88 		svr = ioread32be(&guts->regs->svr);
89 
90 	return svr;
91 }
92 
loongson2_guts_probe(struct platform_device * pdev)93 static int loongson2_guts_probe(struct platform_device *pdev)
94 {
95 	struct device_node *root, *np = pdev->dev.of_node;
96 	struct device *dev = &pdev->dev;
97 	const struct loongson2_soc_die_attr *soc_die;
98 	const char *machine;
99 	u32 svr;
100 
101 	/* Initialize guts */
102 	guts = devm_kzalloc(dev, sizeof(*guts), GFP_KERNEL);
103 	if (!guts)
104 		return -ENOMEM;
105 
106 	guts->little_endian = of_property_read_bool(np, "little-endian");
107 
108 	guts->regs = devm_platform_ioremap_resource(pdev, 0);
109 	if (IS_ERR(guts->regs))
110 		return PTR_ERR(guts->regs);
111 
112 	/* Register soc device */
113 	root = of_find_node_by_path("/");
114 	if (of_property_read_string(root, "model", &machine))
115 		of_property_read_string_index(root, "compatible", 0, &machine);
116 	of_node_put(root);
117 	if (machine)
118 		soc_dev_attr.machine = devm_kstrdup(dev, machine, GFP_KERNEL);
119 
120 	svr = loongson2_guts_get_svr();
121 	soc_die = loongson2_soc_die_match(svr, loongson2_soc_die);
122 	if (soc_die) {
123 		soc_dev_attr.family = devm_kasprintf(dev, GFP_KERNEL,
124 						     "Loongson %s", soc_die->die);
125 	} else {
126 		soc_dev_attr.family = devm_kasprintf(dev, GFP_KERNEL, "Loongson");
127 	}
128 	if (!soc_dev_attr.family)
129 		return -ENOMEM;
130 	soc_dev_attr.soc_id = devm_kasprintf(dev, GFP_KERNEL,
131 					     "svr:0x%08x", svr);
132 	if (!soc_dev_attr.soc_id)
133 		return -ENOMEM;
134 	soc_dev_attr.revision = devm_kasprintf(dev, GFP_KERNEL, "%d.%d",
135 					       (svr >>  4) & 0xf, svr & 0xf);
136 	if (!soc_dev_attr.revision)
137 		return -ENOMEM;
138 
139 	soc_dev = soc_device_register(&soc_dev_attr);
140 	if (IS_ERR(soc_dev))
141 		return PTR_ERR(soc_dev);
142 
143 	pr_info("Machine: %s\n", soc_dev_attr.machine);
144 	pr_info("SoC family: %s\n", soc_dev_attr.family);
145 	pr_info("SoC ID: %s, Revision: %s\n",
146 		soc_dev_attr.soc_id, soc_dev_attr.revision);
147 
148 	return 0;
149 }
150 
loongson2_guts_remove(struct platform_device * dev)151 static int loongson2_guts_remove(struct platform_device *dev)
152 {
153 	soc_device_unregister(soc_dev);
154 
155 	return 0;
156 }
157 
158 /*
159  * Table for matching compatible strings, for device tree
160  * guts node, for Loongson-2 SoCs.
161  */
162 static const struct of_device_id loongson2_guts_of_match[] = {
163 	{ .compatible = "loongson,ls2k-chipid", },
164 	{}
165 };
166 MODULE_DEVICE_TABLE(of, loongson2_guts_of_match);
167 
168 static struct platform_driver loongson2_guts_driver = {
169 	.driver = {
170 		.name = "loongson2-guts",
171 		.of_match_table = loongson2_guts_of_match,
172 	},
173 	.probe = loongson2_guts_probe,
174 	.remove = loongson2_guts_remove,
175 };
176 
loongson2_guts_init(void)177 static int __init loongson2_guts_init(void)
178 {
179 	return platform_driver_register(&loongson2_guts_driver);
180 }
181 core_initcall(loongson2_guts_init);
182 
loongson2_guts_exit(void)183 static void __exit loongson2_guts_exit(void)
184 {
185 	platform_driver_unregister(&loongson2_guts_driver);
186 }
187 module_exit(loongson2_guts_exit);
188 
189 MODULE_DESCRIPTION("Loongson2 GUTS driver");
190 MODULE_LICENSE("GPL");
191