1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2019-2020 Linaro Ltd.
4  */
5 #include <linux/kernel.h>
6 #include <linux/module.h>
7 #include <linux/mutex.h>
8 #include <linux/of_address.h>
9 #include "qcom_pil_info.h"
10 
11 /*
12  * The PIL relocation information region is used to communicate memory regions
13  * occupied by co-processor firmware for post mortem crash analysis.
14  *
15  * It consists of an array of entries with an 8 byte textual identifier of the
16  * region followed by a 64 bit base address and 32 bit size, both little
17  * endian.
18  */
19 #define PIL_RELOC_NAME_LEN	8
20 #define PIL_RELOC_ENTRY_SIZE	(PIL_RELOC_NAME_LEN + sizeof(__le64) + sizeof(__le32))
21 
22 struct pil_reloc {
23 	void __iomem *base;
24 	size_t num_entries;
25 };
26 
27 static struct pil_reloc _reloc __read_mostly;
28 static DEFINE_MUTEX(pil_reloc_lock);
29 
30 static int qcom_pil_info_init(void)
31 {
32 	struct device_node *np;
33 	struct resource imem;
34 	void __iomem *base;
35 	int ret;
36 
37 	/* Already initialized? */
38 	if (_reloc.base)
39 		return 0;
40 
41 	np = of_find_compatible_node(NULL, NULL, "qcom,pil-reloc-info");
42 	if (!np)
43 		return -ENOENT;
44 
45 	ret = of_address_to_resource(np, 0, &imem);
46 	of_node_put(np);
47 	if (ret < 0)
48 		return ret;
49 
50 	base = ioremap(imem.start, resource_size(&imem));
51 	if (!base) {
52 		pr_err("failed to map PIL relocation info region\n");
53 		return -ENOMEM;
54 	}
55 
56 	memset_io(base, 0, resource_size(&imem));
57 
58 	_reloc.base = base;
59 	_reloc.num_entries = resource_size(&imem) / PIL_RELOC_ENTRY_SIZE;
60 
61 	return 0;
62 }
63 
64 /**
65  * qcom_pil_info_store() - store PIL information of image in IMEM
66  * @image:	name of the image
67  * @base:	base address of the loaded image
68  * @size:	size of the loaded image
69  *
70  * Return: 0 on success, negative errno on failure
71  */
72 int qcom_pil_info_store(const char *image, phys_addr_t base, size_t size)
73 {
74 	char buf[PIL_RELOC_NAME_LEN];
75 	void __iomem *entry;
76 	int ret;
77 	int i;
78 
79 	mutex_lock(&pil_reloc_lock);
80 	ret = qcom_pil_info_init();
81 	if (ret < 0) {
82 		mutex_unlock(&pil_reloc_lock);
83 		return ret;
84 	}
85 
86 	for (i = 0; i < _reloc.num_entries; i++) {
87 		entry = _reloc.base + i * PIL_RELOC_ENTRY_SIZE;
88 
89 		memcpy_fromio(buf, entry, PIL_RELOC_NAME_LEN);
90 
91 		/*
92 		 * An empty record means we didn't find it, given that the
93 		 * records are packed.
94 		 */
95 		if (!buf[0])
96 			goto found_unused;
97 
98 		if (!strncmp(buf, image, PIL_RELOC_NAME_LEN))
99 			goto found_existing;
100 	}
101 
102 	pr_warn("insufficient PIL info slots\n");
103 	mutex_unlock(&pil_reloc_lock);
104 	return -ENOMEM;
105 
106 found_unused:
107 	memcpy_toio(entry, image, PIL_RELOC_NAME_LEN);
108 found_existing:
109 	/* Use two writel() as base is only aligned to 4 bytes on odd entries */
110 	writel(base, entry + PIL_RELOC_NAME_LEN);
111 	writel((u64)base >> 32, entry + PIL_RELOC_NAME_LEN + 4);
112 	writel(size, entry + PIL_RELOC_NAME_LEN + sizeof(__le64));
113 	mutex_unlock(&pil_reloc_lock);
114 
115 	return 0;
116 }
117 EXPORT_SYMBOL_GPL(qcom_pil_info_store);
118 
119 static void __exit pil_reloc_exit(void)
120 {
121 	mutex_lock(&pil_reloc_lock);
122 	iounmap(_reloc.base);
123 	_reloc.base = NULL;
124 	mutex_unlock(&pil_reloc_lock);
125 }
126 module_exit(pil_reloc_exit);
127 
128 MODULE_DESCRIPTION("Qualcomm PIL relocation info");
129 MODULE_LICENSE("GPL v2");
130