text: // SPDX-License-Identifier: GPL-2.0
  /*
   * Copyright 2017 Google, Inc
   */
  
  #include <common.h>
  #include <dm.h>
  #include <misc.h>
  #include <reset.h>
  #include <reset-uclass.h>
  #include <wdt.h>
  #include <asm/io.h>
  #include <asm/arch/scu_ast2500.h>
  #include <asm/arch/wdt.h>
  
  struct ast2500_reset_priv {
  	/* WDT used to perform resets. */
  	struct udevice *wdt;
  	struct ast2500_scu *scu;
  };
  
  static int ast2500_ofdata_to_platdata(struct udevice *dev)
  {
  	struct ast2500_reset_priv *priv = dev_get_priv(dev);
  	int ret;
  
  	ret = uclass_get_device_by_phandle(UCLASS_WDT, dev, "aspeed,wdt",
  					   &priv->wdt);
  	if (ret) {
  		debug("%s: can't find WDT for reset controller", __func__);
  		return ret;
  	}
  
  	return 0;
  }
  
  static int ast2500_reset_assert(struct reset_ctl *reset_ctl)
  {
  	struct ast2500_reset_priv *priv = dev_get_priv(reset_ctl->dev);
  	u32 reset_mode, reset_mask;
  	bool reset_sdram;
  	int ret;
  
  	/*
  	 * To reset SDRAM, a specifal flag in SYSRESET register
  	 * needs to be enabled first
  	 */
  	reset_mode = ast_reset_mode_from_flags(reset_ctl->id);
  	reset_mask = ast_reset_mask_from_flags(reset_ctl->id);
  	reset_sdram = reset_mode == WDT_CTRL_RESET_SOC &&
  		(reset_mask & WDT_RESET_SDRAM);
  
  	if (reset_sdram) {
  		ast_scu_unlock(priv->scu);
  		setbits_le32(&priv->scu->sysreset_ctrl1,
  			     SCU_SYSRESET_SDRAM_WDT);
  		ret = wdt_expire_now(priv->wdt, reset_ctl->id);
  		clrbits_le32(&priv->scu->sysreset_ctrl1,
  			     SCU_SYSRESET_SDRAM_WDT);
  		ast_scu_lock(priv->scu);
  	} else {
  		ret = wdt_expire_now(priv->wdt, reset_ctl->id);
  	}
  
  	return ret;
  }
  
  static int ast2500_reset_request(struct reset_ctl *reset_ctl)
  {
  	debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
  	      reset_ctl->dev, reset_ctl->id);
  
  	return 0;
  }
  
  static int ast2500_reset_probe(struct udevice *dev)
  {
  	struct ast2500_reset_priv *priv = dev_get_priv(dev);
  
  	priv->scu = ast_get_scu();
  
  	return 0;
  }
  
  static const struct udevice_id ast2500_reset_ids[] = {
  	{ .compatible = "aspeed,ast2500-reset" },
  	{ }
  };
  
  struct reset_ops ast2500_reset_ops = {
  	.rst_assert = ast2500_reset_assert,
  	.request = ast2500_reset_request,
  };
  
  U_BOOT_DRIVER(ast2500_reset) = {
  	.name		= "ast2500_reset",
  	.id		= UCLASS_RESET,
  	.of_match = ast2500_reset_ids,
  	.probe = ast2500_reset_probe,
  	.ops = &ast2500_reset_ops,
  	.ofdata_to_platdata = ast2500_ofdata_to_platdata,
  	.priv_auto_alloc_size = sizeof(struct ast2500_reset_priv),
  };
  