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/bitops.h>
  15#include <linux/device.h>
  16#include <linux/errno.h>
  17#include <linux/init.h>
  18#include <linux/io.h>
  19#include <linux/jiffies.h>
  20#include <linux/notifier.h>
  21#include <linux/of_address.h>
  22#include <linux/of_irq.h>
  23#include <linux/of_platform.h>
  24#include <linux/platform_device.h>
  25#include <linux/printk.h>
  26#include <linux/reboot.h>
  27#include <linux/regmap.h>
  28#include <linux/smp.h>
  29#include <linux/mfd/syscon.h>
  30
  31#define RESET_SOURCE_ENABLE_REG 1
  32#define SW_MASTER_RESET_REG 2
  33
  34static struct regmap *regmap;
  35static u32 rst_src_en;
  36static u32 sw_mstr_rst;
  37
  38struct reset_reg_mask {
  39        u32 rst_src_en_mask;
  40        u32 sw_mstr_rst_mask;
  41};
  42
  43static const struct reset_reg_mask *reset_masks;
  44
  45static int brcmstb_restart_handler(struct notifier_block *this,
  46                                   unsigned long mode, void *cmd)
  47{
  48        int rc;
  49        u32 tmp;
  50
  51        rc = regmap_write(regmap, rst_src_en, reset_masks->rst_src_en_mask);
  52        if (rc) {
  53                pr_err("failed to write rst_src_en (%d)\n", rc);
  54                return NOTIFY_DONE;
  55        }
  56
  57        rc = regmap_read(regmap, rst_src_en, &tmp);
  58        if (rc) {
  59                pr_err("failed to read rst_src_en (%d)\n", rc);
  60                return NOTIFY_DONE;
  61        }
  62
  63        rc = regmap_write(regmap, sw_mstr_rst, reset_masks->sw_mstr_rst_mask);
  64        if (rc) {
  65                pr_err("failed to write sw_mstr_rst (%d)\n", rc);
  66                return NOTIFY_DONE;
  67        }
  68
  69        rc = regmap_read(regmap, sw_mstr_rst, &tmp);
  70        if (rc) {
  71                pr_err("failed to read sw_mstr_rst (%d)\n", rc);
  72                return NOTIFY_DONE;
  73        }
  74
  75        while (1)
  76                ;
  77
  78        return NOTIFY_DONE;
  79}
  80
  81static struct notifier_block brcmstb_restart_nb = {
  82        .notifier_call = brcmstb_restart_handler,
  83        .priority = 128,
  84};
  85
  86static const struct reset_reg_mask reset_bits_40nm = {
  87        .rst_src_en_mask = BIT(0),
  88        .sw_mstr_rst_mask = BIT(0),
  89};
  90
  91static const struct reset_reg_mask reset_bits_65nm = {
  92        .rst_src_en_mask = BIT(3),
  93        .sw_mstr_rst_mask = BIT(31),
  94};
  95
  96static const struct of_device_id of_match[] = {
  97        { .compatible = "brcm,brcmstb-reboot", .data = &reset_bits_40nm },
  98        { .compatible = "brcm,bcm7038-reboot", .data = &reset_bits_65nm },
  99        {},
 100};
 101
 102static int brcmstb_reboot_probe(struct platform_device *pdev)
 103{
 104        int rc;
 105        struct device_node *np = pdev->dev.of_node;
 106        const struct of_device_id *of_id;
 107
 108        of_id = of_match_node(of_match, np);
 109        if (!of_id) {
 110                pr_err("failed to look up compatible string\n");
 111                return -EINVAL;
 112        }
 113        reset_masks = of_id->data;
 114
 115        regmap = syscon_regmap_lookup_by_phandle(np, "syscon");
 116        if (IS_ERR(regmap)) {
 117                pr_err("failed to get syscon phandle\n");
 118                return -EINVAL;
 119        }
 120
 121        rc = of_property_read_u32_index(np, "syscon", RESET_SOURCE_ENABLE_REG,
 122                                        &rst_src_en);
 123        if (rc) {
 124                pr_err("can't get rst_src_en offset (%d)\n", rc);
 125                return -EINVAL;
 126        }
 127
 128        rc = of_property_read_u32_index(np, "syscon", SW_MASTER_RESET_REG,
 129                                        &sw_mstr_rst);
 130        if (rc) {
 131                pr_err("can't get sw_mstr_rst offset (%d)\n", rc);
 132                return -EINVAL;
 133        }
 134
 135        rc = register_restart_handler(&brcmstb_restart_nb);
 136        if (rc)
 137                dev_err(&pdev->dev,
 138                        "cannot register restart handler (err=%d)\n", rc);
 139
 140        return rc;
 141}
 142
 143static struct platform_driver brcmstb_reboot_driver = {
 144        .probe = brcmstb_reboot_probe,
 145        .driver = {
 146                .name = "brcmstb-reboot",
 147                .of_match_table = of_match,
 148        },
 149};
 150
 151static int __init brcmstb_reboot_init(void)
 152{
 153        return platform_driver_probe(&brcmstb_reboot_driver,
 154                                        brcmstb_reboot_probe);
 155}
 156subsys_initcall(brcmstb_reboot_init);
 157
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