text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * CPU idle for DaVinci SoCs
   *
   * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/
   *
   * Derived from Marvell Kirkwood CPU idle code
   * (arch/arm/mach-kirkwood/cpuidle.c)
   */
  
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/cpuidle.h>
  #include <linux/io.h>
  #include <linux/export.h>
  #include <asm/cpuidle.h>
  
  #include "cpuidle.h"
  #include "ddr2.h"
  
  #define DAVINCI_CPUIDLE_MAX_STATES	2
  
  static void __iomem *ddr2_reg_base;
  static bool ddr2_pdown;
  
  static void davinci_save_ddr_power(int enter, bool pdown)
  {
  	u32 val;
  
  	val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET);
  
  	if (enter) {
  		if (pdown)
  			val |= DDR2_SRPD_BIT;
  		else
  			val &= ~DDR2_SRPD_BIT;
  		val |= DDR2_LPMODEN_BIT;
  	} else {
  		val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT);
  	}
  
  	__raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET);
  }
  
  /* Actual code that puts the SoC in different idle states */
  static int davinci_enter_idle(struct cpuidle_device *dev,
  			      struct cpuidle_driver *drv, int index)
  {
  	davinci_save_ddr_power(1, ddr2_pdown);
  	cpu_do_idle();
  	davinci_save_ddr_power(0, ddr2_pdown);
  
  	return index;
  }
  
  static struct cpuidle_driver davinci_idle_driver = {
  	.name			= "cpuidle-davinci",
  	.owner			= THIS_MODULE,
  	.states[0]		= ARM_CPUIDLE_WFI_STATE,
  	.states[1]		= {
  		.enter			= davinci_enter_idle,
  		.exit_latency		= 10,
  		.target_residency	= 10000,
  		.name			= "DDR SR",
  		.desc			= "WFI and DDR Self Refresh",
  	},
  	.state_count = DAVINCI_CPUIDLE_MAX_STATES,
  };
  
  static int __init davinci_cpuidle_probe(struct platform_device *pdev)
  {
  	struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
  
  	if (!pdata) {
  		dev_err(&pdev->dev, "cannot get platform data\n");
  		return -ENOENT;
  	}
  
  	ddr2_reg_base = pdata->ddr2_ctlr_base;
  
  	ddr2_pdown = pdata->ddr2_pdown;
  
  	return cpuidle_register(&davinci_idle_driver, NULL);
  }
  
  static struct platform_driver davinci_cpuidle_driver = {
  	.driver = {
  		.name	= "cpuidle-davinci",
  	},
  };
  
  static int __init davinci_cpuidle_init(void)
  {
  	return platform_driver_probe(&davinci_cpuidle_driver,
  						davinci_cpuidle_probe);
  }
  device_initcall(davinci_cpuidle_init);
  
  