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