xref: /linux/drivers/nvmem/sec-qfprom.c (revision df34ecc52526480a1a4bb78bc75bfb009c6076a4)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
4  */
5 
6 #include <linux/firmware/qcom/qcom_scm.h>
7 #include <linux/nvmem-provider.h>
8 #include <linux/platform_device.h>
9 #include <linux/pm_runtime.h>
10 
11 /**
12  * struct sec_qfprom - structure holding secure qfprom attributes
13  *
14  * @base: starting physical address for secure qfprom corrected address space.
15  * @dev: qfprom device structure.
16  */
17 struct sec_qfprom {
18 	phys_addr_t base;
19 	struct device *dev;
20 };
21 
22 static int sec_qfprom_reg_read(void *context, unsigned int reg, void *_val, size_t bytes)
23 {
24 	struct sec_qfprom *priv = context;
25 	unsigned int i;
26 	u8 *val = _val;
27 	u32 read_val;
28 	u8 *tmp;
29 
30 	for (i = 0; i < bytes; i++, reg++) {
31 		if (i == 0 || reg % 4 == 0) {
32 			if (qcom_scm_io_readl(priv->base + (reg & ~3), &read_val)) {
33 				dev_err(priv->dev, "Couldn't access fuse register\n");
34 				return -EINVAL;
35 			}
36 			tmp = (u8 *)&read_val;
37 		}
38 
39 		val[i] = tmp[reg & 3];
40 	}
41 
42 	return 0;
43 }
44 
45 static int sec_qfprom_probe(struct platform_device *pdev)
46 {
47 	struct nvmem_config econfig = {
48 		.name = "sec-qfprom",
49 		.add_legacy_fixed_of_cells = true,
50 		.stride = 1,
51 		.word_size = 1,
52 		.id = NVMEM_DEVID_AUTO,
53 		.reg_read = sec_qfprom_reg_read,
54 	};
55 	struct device *dev = &pdev->dev;
56 	struct nvmem_device *nvmem;
57 	struct sec_qfprom *priv;
58 	struct resource *res;
59 
60 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
61 	if (!priv)
62 		return -ENOMEM;
63 
64 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
65 	if (!res)
66 		return -EINVAL;
67 
68 	priv->base = res->start;
69 
70 	econfig.size = resource_size(res);
71 	econfig.dev = dev;
72 	econfig.priv = priv;
73 
74 	priv->dev = dev;
75 
76 	nvmem = devm_nvmem_register(dev, &econfig);
77 
78 	return PTR_ERR_OR_ZERO(nvmem);
79 }
80 
81 static const struct of_device_id sec_qfprom_of_match[] = {
82 	{ .compatible = "qcom,sec-qfprom" },
83 	{/* sentinel */},
84 };
85 MODULE_DEVICE_TABLE(of, sec_qfprom_of_match);
86 
87 static struct platform_driver qfprom_driver = {
88 	.probe = sec_qfprom_probe,
89 	.driver = {
90 		.name = "qcom_sec_qfprom",
91 		.of_match_table = sec_qfprom_of_match,
92 	},
93 };
94 module_platform_driver(qfprom_driver);
95 MODULE_DESCRIPTION("Qualcomm Secure QFPROM driver");
96 MODULE_LICENSE("GPL");
97