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kernel/linux-imx6_3.14.28/arch/arm/mach-picoxcell/common.c 2.22 KB
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  /*
   * Copyright (c) 2011 Picochip Ltd., Jamie Iles
   *
   * 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.
   *
   * All enquiries to support@picochip.com
   */
  #include <linux/delay.h>
  #include <linux/of.h>
  #include <linux/of_address.h>
  #include <linux/of_platform.h>
  #include <linux/reboot.h>
  
  #include <asm/mach/arch.h>
  #include <asm/mach/map.h>
  
  #define PHYS_TO_IO(x)			(((x) & 0x00ffffff) | 0xfe000000)
  #define PICOXCELL_PERIPH_BASE		0x80000000
  #define PICOXCELL_PERIPH_LENGTH		SZ_4M
  
  #define WDT_CTRL_REG_EN_MASK		(1 << 0)
  #define WDT_CTRL_REG_OFFS		(0x00)
  #define WDT_TIMEOUT_REG_OFFS		(0x04)
  static void __iomem *wdt_regs;
  
  /*
   * The machine restart method can be called from an atomic context so we won't
   * be able to ioremap the regs then.
   */
  static void picoxcell_setup_restart(void)
  {
  	struct device_node *np = of_find_compatible_node(NULL, NULL,
  							 "snps,dw-apb-wdg");
  	if (WARN(!np, "unable to setup watchdog restart"))
  		return;
  
  	wdt_regs = of_iomap(np, 0);
  	WARN(!wdt_regs, "failed to remap watchdog regs");
  }
  
  static struct map_desc io_map __initdata = {
  	.virtual	= PHYS_TO_IO(PICOXCELL_PERIPH_BASE),
  	.pfn		= __phys_to_pfn(PICOXCELL_PERIPH_BASE),
  	.length		= PICOXCELL_PERIPH_LENGTH,
  	.type		= MT_DEVICE,
  };
  
  static void __init picoxcell_map_io(void)
  {
  	iotable_init(&io_map, 1);
  }
  
  static void __init picoxcell_init_machine(void)
  {
  	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
  	picoxcell_setup_restart();
  }
  
  static const char *picoxcell_dt_match[] = {
  	"picochip,pc3x2",
  	"picochip,pc3x3",
  	NULL
  };
  
  static void picoxcell_wdt_restart(enum reboot_mode mode, const char *cmd)
  {
  	/*
  	 * Configure the watchdog to reset with the shortest possible timeout
  	 * and give it chance to do the reset.
  	 */
  	if (wdt_regs) {
  		writel_relaxed(WDT_CTRL_REG_EN_MASK, wdt_regs + WDT_CTRL_REG_OFFS);
  		writel_relaxed(0, wdt_regs + WDT_TIMEOUT_REG_OFFS);
  		/* No sleeping, possibly atomic. */
  		mdelay(500);
  	}
  }
  
  DT_MACHINE_START(PICOXCELL, "Picochip picoXcell")
  	.map_io		= picoxcell_map_io,
  	.init_machine	= picoxcell_init_machine,
  	.dt_compat	= picoxcell_dt_match,
  	.restart	= picoxcell_wdt_restart,
  MACHINE_END