xref: /openbmc/linux/drivers/nvmem/sec-qfprom.c (revision 6fa24b41)
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/mod_devicetable.h>
8 #include <linux/nvmem-provider.h>
9 #include <linux/platform_device.h>
10 #include <linux/pm_runtime.h>
11 
12 /**
13  * struct sec_qfprom - structure holding secure qfprom attributes
14  *
15  * @base: starting physical address for secure qfprom corrected address space.
16  * @dev: qfprom device structure.
17  */
18 struct sec_qfprom {
19 	phys_addr_t base;
20 	struct device *dev;
21 };
22 
23 static int sec_qfprom_reg_read(void *context, unsigned int reg, void *_val, size_t bytes)
24 {
25 	struct sec_qfprom *priv = context;
26 	unsigned int i;
27 	u8 *val = _val;
28 	u32 read_val;
29 	u8 *tmp;
30 
31 	for (i = 0; i < bytes; i++, reg++) {
32 		if (i == 0 || reg % 4 == 0) {
33 			if (qcom_scm_io_readl(priv->base + (reg & ~3), &read_val)) {
34 				dev_err(priv->dev, "Couldn't access fuse register\n");
35 				return -EINVAL;
36 			}
37 			tmp = (u8 *)&read_val;
38 		}
39 
40 		val[i] = tmp[reg & 3];
41 	}
42 
43 	return 0;
44 }
45 
46 static int sec_qfprom_probe(struct platform_device *pdev)
47 {
48 	struct nvmem_config econfig = {
49 		.name = "sec-qfprom",
50 		.add_legacy_fixed_of_cells = true,
51 		.stride = 1,
52 		.word_size = 1,
53 		.id = NVMEM_DEVID_AUTO,
54 		.reg_read = sec_qfprom_reg_read,
55 	};
56 	struct device *dev = &pdev->dev;
57 	struct nvmem_device *nvmem;
58 	struct sec_qfprom *priv;
59 	struct resource *res;
60 
61 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
62 	if (!priv)
63 		return -ENOMEM;
64 
65 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
66 	if (!res)
67 		return -EINVAL;
68 
69 	priv->base = res->start;
70 
71 	econfig.size = resource_size(res);
72 	econfig.dev = dev;
73 	econfig.priv = priv;
74 
75 	priv->dev = dev;
76 
77 	nvmem = devm_nvmem_register(dev, &econfig);
78 
79 	return PTR_ERR_OR_ZERO(nvmem);
80 }
81 
82 static const struct of_device_id sec_qfprom_of_match[] = {
83 	{ .compatible = "qcom,sec-qfprom" },
84 	{/* sentinel */},
85 };
86 MODULE_DEVICE_TABLE(of, sec_qfprom_of_match);
87 
88 static struct platform_driver qfprom_driver = {
89 	.probe = sec_qfprom_probe,
90 	.driver = {
91 		.name = "qcom_sec_qfprom",
92 		.of_match_table = sec_qfprom_of_match,
93 	},
94 };
95 module_platform_driver(qfprom_driver);
96 MODULE_DESCRIPTION("Qualcomm Secure QFPROM driver");
97 MODULE_LICENSE("GPL");
98