reset/brcmstb-reboot.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 // Copyright (C) 2013 Broadcom Corporation
   3
   4 #include <linux/bitops.h>
   5 #include <linux/device.h>
   6 #include <linux/errno.h>
   7 #include <linux/init.h>
   8 #include <linux/io.h>
   9 #include <linux/jiffies.h>
  10 #include <linux/notifier.h>
  11 #include <linux/of_address.h>
  12 #include <linux/of_irq.h>
  13 #include <linux/of_platform.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/printk.h>
  16 #include <linux/reboot.h>
  17 #include <linux/regmap.h>
  18 #include <linux/smp.h>
  19 #include <linux/mfd/syscon.h>
  20
  21 #define RESET_SOURCE_ENABLE_REG 1
  22 #define SW_MASTER_RESET_REG 2
  23
  24 static struct regmap *regmap;
  25 static u32 rst_src_en;
  26 static u32 sw_mstr_rst;
  27
  28 struct reset_reg_mask {
  29         u32 rst_src_en_mask;
  30         u32 sw_mstr_rst_mask;
  31 };
  32
  33 static const struct reset_reg_mask *reset_masks;
  34
  35 static int brcmstb_restart_handler(struct notifier_block *this,
  36                                    unsigned long mode, void *cmd)
  37 {
  38         int rc;
  39         u32 tmp;
  40
  41         rc = regmap_write(regmap, rst_src_en, reset_masks->rst_src_en_mask);
  42         if (rc) {
  43                 pr_err("failed to write rst_src_en (%d)\n", rc);
  44                 return NOTIFY_DONE;
  45         }
  46
  47         rc = regmap_read(regmap, rst_src_en, &tmp);
  48         if (rc) {
  49                 pr_err("failed to read rst_src_en (%d)\n", rc);
  50                 return NOTIFY_DONE;
  51         }
  52
  53         rc = regmap_write(regmap, sw_mstr_rst, reset_masks->sw_mstr_rst_mask);
  54         if (rc) {
  55                 pr_err("failed to write sw_mstr_rst (%d)\n", rc);
  56                 return NOTIFY_DONE;
  57         }
  58
  59         rc = regmap_read(regmap, sw_mstr_rst, &tmp);
  60         if (rc) {
  61                 pr_err("failed to read sw_mstr_rst (%d)\n", rc);
  62                 return NOTIFY_DONE;
  63         }
  64
  65         while (1)
  66                 ;
  67
  68         return NOTIFY_DONE;
  69 }
  70
  71 static struct notifier_block brcmstb_restart_nb = {
  72         .notifier_call = brcmstb_restart_handler,
  73         .priority = 128,
  74 };
  75
  76 static const struct reset_reg_mask reset_bits_40nm = {
  77         .rst_src_en_mask = BIT(0),
  78         .sw_mstr_rst_mask = BIT(0),
  79 };
  80
  81 static const struct reset_reg_mask reset_bits_65nm = {
  82         .rst_src_en_mask = BIT(3),
  83         .sw_mstr_rst_mask = BIT(31),
  84 };
  85
  86 static const struct of_device_id of_match[] = {
  87         { .compatible = "brcm,brcmstb-reboot", .data = &reset_bits_40nm },
  88         { .compatible = "brcm,bcm7038-reboot", .data = &reset_bits_65nm },
  89         {},
  90 };
  91
  92 static int brcmstb_reboot_probe(struct platform_device *pdev)
  93 {
  94         int rc;
  95         struct device_node *np = pdev->dev.of_node;
  96         const struct of_device_id *of_id;
  97
  98         of_id = of_match_node(of_match, np);
  99         if (!of_id) {
 100                 pr_err("failed to look up compatible string\n");
 101                 return -EINVAL;
 102         }
 103         reset_masks = of_id->data;
 104
 105         regmap = syscon_regmap_lookup_by_phandle(np, "syscon");
 106         if (IS_ERR(regmap)) {
 107                 pr_err("failed to get syscon phandle\n");
 108                 return -EINVAL;
 109         }
 110
 111         rc = of_property_read_u32_index(np, "syscon", RESET_SOURCE_ENABLE_REG,
 112                                         &rst_src_en);
 113         if (rc) {
 114                 pr_err("can't get rst_src_en offset (%d)\n", rc);
 115                 return -EINVAL;
 116         }
 117
 118         rc = of_property_read_u32_index(np, "syscon", SW_MASTER_RESET_REG,
 119                                         &sw_mstr_rst);
 120         if (rc) {
 121                 pr_err("can't get sw_mstr_rst offset (%d)\n", rc);
 122                 return -EINVAL;
 123         }
 124
 125         rc = register_restart_handler(&brcmstb_restart_nb);
 126         if (rc)
 127                 dev_err(&pdev->dev,
 128                         "cannot register restart handler (err=%d)\n", rc);
 129
 130         return rc;
 131 }
 132
 133 static struct platform_driver brcmstb_reboot_driver = {
 134         .probe = brcmstb_reboot_probe,
 135         .driver = {
 136                 .name = "brcmstb-reboot",
 137                 .of_match_table = of_match,
 138         },
 139 };
 140
 141 static int __init brcmstb_reboot_init(void)
 142 {
 143         return platform_driver_probe(&brcmstb_reboot_driver,
 144                                         brcmstb_reboot_probe);
 145 }
 146 subsys_initcall(brcmstb_reboot_init);