drivers/misc/xilinx_tmr_inject.c

   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  */
  38 struct xtmr_inject_dev {
  39         void __iomem *regs;
  40         u32 magic;
  41 };
  42
  43 static DECLARE_FAULT_ATTR(inject_fault);
  44 static char *inject_request;
  45 module_param(inject_request, charp, 0);
  46 MODULE_PARM_DESC(inject_request, "default fault injection attributes");
  47 static struct dentry *dbgfs_root;
  48
  49 /* IO accessors */
  50 static 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
  56 static inline u32 xtmr_inject_read(struct xtmr_inject_dev *xtmr_inject,
  57                                    u32 addr)
  58 {
  59         return ioread32(xtmr_inject->regs + addr);
  60 }
  61
  62 static 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 }
  70 DEFINE_DEBUGFS_ATTRIBUTE(xtmr_inject_fops, NULL, xtmr_inject_set, "%llu\n");
  71
  72 static 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
  83 static 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  */
 111 static 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
 147 static void xtmr_inject_remove(struct platform_device *pdev)
 148 {
 149         debugfs_remove_recursive(dbgfs_root);
 150         dbgfs_root = NULL;
 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");