1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Driver for Xilinx TMR Inject IP.
4  *
5  * Copyright (C) 2022 Advanced Micro Devices, Inc.
6  *
7  * Description:
8  * This driver is developed for TMR Inject IP,The Triple Modular Redundancy(TMR)
9  * Inject provides fault injection.
10  */
11 
12 #include <asm/xilinx_mb_manager.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/fault-inject.h>
17 
18 /* TMR Inject Register offsets */
19 #define XTMR_INJECT_CR_OFFSET		0x0
20 #define XTMR_INJECT_AIR_OFFSET		0x4
21 #define XTMR_INJECT_IIR_OFFSET		0xC
22 #define XTMR_INJECT_EAIR_OFFSET		0x10
23 #define XTMR_INJECT_ERR_OFFSET		0x204
24 
25 /* Register Bitmasks/shifts */
26 #define XTMR_INJECT_CR_CPUID_SHIFT	8
27 #define XTMR_INJECT_CR_IE_SHIFT		10
28 #define XTMR_INJECT_IIR_ADDR_MASK	GENMASK(31, 16)
29 
30 #define XTMR_INJECT_MAGIC_MAX_VAL	255
31 
32 /**
33  * struct xtmr_inject_dev - Driver data for TMR Inject
34  * @regs: device physical base address
35  * @magic: Magic hardware configuration value
36  */
37 struct xtmr_inject_dev {
38 	void __iomem *regs;
39 	u32 magic;
40 };
41 
42 static DECLARE_FAULT_ATTR(inject_fault);
43 static char *inject_request;
44 module_param(inject_request, charp, 0);
45 MODULE_PARM_DESC(inject_request, "default fault injection attributes");
46 static struct dentry *dbgfs_root;
47 
48 /* IO accessors */
49 static inline void xtmr_inject_write(struct xtmr_inject_dev *xtmr_inject,
50 				     u32 addr, u32 value)
51 {
52 	iowrite32(value, xtmr_inject->regs + addr);
53 }
54 
55 static inline u32 xtmr_inject_read(struct xtmr_inject_dev *xtmr_inject,
56 				   u32 addr)
57 {
58 	return ioread32(xtmr_inject->regs + addr);
59 }
60 
61 static int xtmr_inject_set(void *data, u64 val)
62 {
63 	if (val != 1)
64 		return -EINVAL;
65 
66 	xmb_inject_err();
67 	return 0;
68 }
69 DEFINE_DEBUGFS_ATTRIBUTE(xtmr_inject_fops, NULL, xtmr_inject_set, "%llu\n");
70 
71 static void xtmr_init_debugfs(struct xtmr_inject_dev *xtmr_inject)
72 {
73 	struct dentry *dir;
74 
75 	dbgfs_root = debugfs_create_dir("xtmr_inject", NULL);
76 	dir = fault_create_debugfs_attr("inject_fault", dbgfs_root,
77 					&inject_fault);
78 	debugfs_create_file("inject_fault", 0200, dir, NULL,
79 			    &xtmr_inject_fops);
80 }
81 
82 static void xtmr_inject_init(struct xtmr_inject_dev *xtmr_inject)
83 {
84 	u32 cr_val;
85 
86 	if (inject_request)
87 		setup_fault_attr(&inject_fault, inject_request);
88 	/* Allow fault injection */
89 	cr_val = xtmr_inject->magic |
90 		 (1 << XTMR_INJECT_CR_IE_SHIFT) |
91 		 (1 << XTMR_INJECT_CR_CPUID_SHIFT);
92 	xtmr_inject_write(xtmr_inject, XTMR_INJECT_CR_OFFSET,
93 			  cr_val);
94 	/* Initialize the address inject and instruction inject registers */
95 	xtmr_inject_write(xtmr_inject, XTMR_INJECT_AIR_OFFSET,
96 			  XMB_INJECT_ERR_OFFSET);
97 	xtmr_inject_write(xtmr_inject, XTMR_INJECT_IIR_OFFSET,
98 			  XMB_INJECT_ERR_OFFSET & XTMR_INJECT_IIR_ADDR_MASK);
99 }
100 
101 /**
102  * xtmr_inject_probe - Driver probe function
103  * @pdev: Pointer to the platform_device structure
104  *
105  * This is the driver probe routine. It does all the memory
106  * allocation for the device.
107  *
108  * Return: 0 on success and failure value on error
109  */
110 static int xtmr_inject_probe(struct platform_device *pdev)
111 {
112 	struct xtmr_inject_dev *xtmr_inject;
113 	int err;
114 
115 	xtmr_inject = devm_kzalloc(&pdev->dev, sizeof(*xtmr_inject),
116 				   GFP_KERNEL);
117 	if (!xtmr_inject)
118 		return -ENOMEM;
119 
120 	xtmr_inject->regs = devm_platform_ioremap_resource(pdev, 0);
121 	if (IS_ERR(xtmr_inject->regs))
122 		return PTR_ERR(xtmr_inject->regs);
123 
124 	err = of_property_read_u32(pdev->dev.of_node, "xlnx,magic",
125 				   &xtmr_inject->magic);
126 	if (err < 0) {
127 		dev_err(&pdev->dev, "unable to read xlnx,magic property");
128 		return err;
129 	}
130 
131 	if (xtmr_inject->magic > XTMR_INJECT_MAGIC_MAX_VAL) {
132 		dev_err(&pdev->dev, "invalid xlnx,magic property value");
133 		return -EINVAL;
134 	}
135 
136 	/* Initialize TMR Inject */
137 	xtmr_inject_init(xtmr_inject);
138 
139 	xtmr_init_debugfs(xtmr_inject);
140 
141 	platform_set_drvdata(pdev, xtmr_inject);
142 
143 	return 0;
144 }
145 
146 static int xtmr_inject_remove(struct platform_device *pdev)
147 {
148 	debugfs_remove_recursive(dbgfs_root);
149 	dbgfs_root = NULL;
150 	return 0;
151 }
152 
153 static const struct of_device_id xtmr_inject_of_match[] = {
154 	{
155 		.compatible = "xlnx,tmr-inject-1.0",
156 	},
157 	{ /* end of table */ }
158 };
159 MODULE_DEVICE_TABLE(of, xtmr_inject_of_match);
160 
161 static struct platform_driver xtmr_inject_driver = {
162 	.driver = {
163 		.name = "xilinx-tmr_inject",
164 		.of_match_table = xtmr_inject_of_match,
165 	},
166 	.probe = xtmr_inject_probe,
167 	.remove = xtmr_inject_remove,
168 };
169 module_platform_driver(xtmr_inject_driver);
170 MODULE_AUTHOR("Advanced Micro Devices, Inc");
171 MODULE_DESCRIPTION("Xilinx TMR Inject Driver");
172 MODULE_LICENSE("GPL");
173