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kernel/linux-rt-4.4.41/drivers/soc/mediatek/mtk-infracfg.c 2.18 KB
5113f6f70   김현기   kernel add
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  /*
   * Copyright (c) 2015 Pengutronix, Sascha Hauer <kernel@pengutronix.de>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License 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/export.h>
  #include <linux/jiffies.h>
  #include <linux/regmap.h>
  #include <linux/soc/mediatek/infracfg.h>
  #include <asm/processor.h>
  
  #define INFRA_TOPAXI_PROTECTEN		0x0220
  #define INFRA_TOPAXI_PROTECTSTA1	0x0228
  
  /**
   * mtk_infracfg_set_bus_protection - enable bus protection
   * @regmap: The infracfg regmap
   * @mask: The mask containing the protection bits to be enabled.
   *
   * This function enables the bus protection bits for disabled power
   * domains so that the system does not hang when some unit accesses the
   * bus while in power down.
   */
  int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask)
  {
  	unsigned long expired;
  	u32 val;
  	int ret;
  
  	regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, mask);
  
  	expired = jiffies + HZ;
  
  	while (1) {
  		ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
  		if (ret)
  			return ret;
  
  		if ((val & mask) == mask)
  			break;
  
  		cpu_relax();
  		if (time_after(jiffies, expired))
  			return -EIO;
  	}
  
  	return 0;
  }
  
  /**
   * mtk_infracfg_clear_bus_protection - disable bus protection
   * @regmap: The infracfg regmap
   * @mask: The mask containing the protection bits to be disabled.
   *
   * This function disables the bus protection bits previously enabled with
   * mtk_infracfg_set_bus_protection.
   */
  int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask)
  {
  	unsigned long expired;
  	int ret;
  
  	regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, 0);
  
  	expired = jiffies + HZ;
  
  	while (1) {
  		u32 val;
  
  		ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
  		if (ret)
  			return ret;
  
  		if (!(val & mask))
  			break;
  
  		cpu_relax();
  		if (time_after(jiffies, expired))
  			return -EIO;
  	}
  
  	return 0;
  }