linux/drivers/power/reset/brcmstb-reboot.c
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   1/*
   2 * Copyright (C) 2013 Broadcom Corporation
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public License as
   6 * published by the Free Software Foundation version 2.
   7 *
   8 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9 * kind, whether express or implied; without even the implied warranty
  10 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 */
  13
  14#include <linux/device.h>
  15#include <linux/errno.h>
  16#include <linux/init.h>
  17#include <linux/io.h>
  18#include <linux/jiffies.h>
  19#include <linux/notifier.h>
  20#include <linux/of_address.h>
  21#include <linux/of_irq.h>
  22#include <linux/of_platform.h>
  23#include <linux/platform_device.h>
  24#include <linux/printk.h>
  25#include <linux/reboot.h>
  26#include <linux/regmap.h>
  27#include <linux/smp.h>
  28#include <linux/mfd/syscon.h>
  29
  30#define RESET_SOURCE_ENABLE_REG 1
  31#define SW_MASTER_RESET_REG 2
  32
  33static struct regmap *regmap;
  34static u32 rst_src_en;
  35static u32 sw_mstr_rst;
  36
  37static int brcmstb_restart_handler(struct notifier_block *this,
  38                                   unsigned long mode, void *cmd)
  39{
  40        int rc;
  41        u32 tmp;
  42
  43        rc = regmap_write(regmap, rst_src_en, 1);
  44        if (rc) {
  45                pr_err("failed to write rst_src_en (%d)\n", rc);
  46                return NOTIFY_DONE;
  47        }
  48
  49        rc = regmap_read(regmap, rst_src_en, &tmp);
  50        if (rc) {
  51                pr_err("failed to read rst_src_en (%d)\n", rc);
  52                return NOTIFY_DONE;
  53        }
  54
  55        rc = regmap_write(regmap, sw_mstr_rst, 1);
  56        if (rc) {
  57                pr_err("failed to write sw_mstr_rst (%d)\n", rc);
  58                return NOTIFY_DONE;
  59        }
  60
  61        rc = regmap_read(regmap, sw_mstr_rst, &tmp);
  62        if (rc) {
  63                pr_err("failed to read sw_mstr_rst (%d)\n", rc);
  64                return NOTIFY_DONE;
  65        }
  66
  67        while (1)
  68                ;
  69
  70        return NOTIFY_DONE;
  71}
  72
  73static struct notifier_block brcmstb_restart_nb = {
  74        .notifier_call = brcmstb_restart_handler,
  75        .priority = 128,
  76};
  77
  78static int brcmstb_reboot_probe(struct platform_device *pdev)
  79{
  80        int rc;
  81        struct device_node *np = pdev->dev.of_node;
  82
  83        regmap = syscon_regmap_lookup_by_phandle(np, "syscon");
  84        if (IS_ERR(regmap)) {
  85                pr_err("failed to get syscon phandle\n");
  86                return -EINVAL;
  87        }
  88
  89        rc = of_property_read_u32_index(np, "syscon", RESET_SOURCE_ENABLE_REG,
  90                                        &rst_src_en);
  91        if (rc) {
  92                pr_err("can't get rst_src_en offset (%d)\n", rc);
  93                return -EINVAL;
  94        }
  95
  96        rc = of_property_read_u32_index(np, "syscon", SW_MASTER_RESET_REG,
  97                                        &sw_mstr_rst);
  98        if (rc) {
  99                pr_err("can't get sw_mstr_rst offset (%d)\n", rc);
 100                return -EINVAL;
 101        }
 102
 103        rc = register_restart_handler(&brcmstb_restart_nb);
 104        if (rc)
 105                dev_err(&pdev->dev,
 106                        "cannot register restart handler (err=%d)\n", rc);
 107
 108        return rc;
 109}
 110
 111static const struct of_device_id of_match[] = {
 112        { .compatible = "brcm,brcmstb-reboot", },
 113        {},
 114};
 115
 116static struct platform_driver brcmstb_reboot_driver = {
 117        .probe = brcmstb_reboot_probe,
 118        .driver = {
 119                .name = "brcmstb-reboot",
 120                .of_match_table = of_match,
 121        },
 122};
 123
 124static int __init brcmstb_reboot_init(void)
 125{
 126        return platform_driver_probe(&brcmstb_reboot_driver,
 127                                        brcmstb_reboot_probe);
 128}
 129subsys_initcall(brcmstb_reboot_init);
 130
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