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kernel/linux-rt-4.4.41/drivers/power/reset/axxia-reset.c 2.63 KB
5113f6f70   김현기   kernel add
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  /*
   * Reset driver for Axxia devices
   *
   * Copyright (C) 2014 LSI
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 and
   * only version 2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   */
  #include <linux/init.h>
  #include <linux/err.h>
  #include <linux/io.h>
  #include <linux/kernel.h>
  #include <linux/mfd/syscon.h>
  #include <linux/module.h>
  #include <linux/notifier.h>
  #include <linux/of.h>
  #include <linux/platform_device.h>
  #include <linux/reboot.h>
  #include <linux/regmap.h>
  
  #define SC_CRIT_WRITE_KEY	0x1000
  #define SC_LATCH_ON_RESET	0x1004
  #define SC_RESET_CONTROL	0x1008
  #define   RSTCTL_RST_ZERO	(1<<3)
  #define   RSTCTL_RST_FAB	(1<<2)
  #define   RSTCTL_RST_CHIP	(1<<1)
  #define   RSTCTL_RST_SYS	(1<<0)
  #define SC_EFUSE_INT_STATUS	0x180c
  #define   EFUSE_READ_DONE	(1<<31)
  
  static struct regmap *syscon;
  
  static int axxia_restart_handler(struct notifier_block *this,
  				 unsigned long mode, void *cmd)
  {
  	/* Access Key (0xab) */
  	regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);
  	/* Select internal boot from 0xffff0000 */
  	regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);
  	/* Assert ResetReadDone (to avoid hanging in boot ROM) */
  	regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);
  	/* Assert chip reset */
  	regmap_update_bits(syscon, SC_RESET_CONTROL,
  			   RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);
  
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block axxia_restart_nb = {
  	.notifier_call = axxia_restart_handler,
  	.priority = 128,
  };
  
  static int axxia_reset_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	int err;
  
  	syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
  	if (IS_ERR(syscon)) {
  		pr_err("%s: syscon lookup failed
  ", dev->of_node->name);
  		return PTR_ERR(syscon);
  	}
  
  	err = register_restart_handler(&axxia_restart_nb);
  	if (err)
  		dev_err(dev, "cannot register restart handler (err=%d)
  ", err);
  
  	return err;
  }
  
  static const struct of_device_id of_axxia_reset_match[] = {
  	{ .compatible = "lsi,axm55xx-reset", },
  	{},
  };
  MODULE_DEVICE_TABLE(of, of_axxia_reset_match);
  
  static struct platform_driver axxia_reset_driver = {
  	.probe = axxia_reset_probe,
  	.driver = {
  		.name = "axxia-reset",
  		.of_match_table = of_match_ptr(of_axxia_reset_match),
  	},
  };
  
  static int __init axxia_reset_init(void)
  {
  	return platform_driver_register(&axxia_reset_driver);
  }
  device_initcall(axxia_reset_init);