/*
   * Copyright (C) 1999 ARM Limited
   * Copyright (C) 2000 Deep Blue Solutions Ltd
   * Copyright 2006-2007,2010 Freescale Semiconductor, Inc. All Rights Reserved.
   * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
   * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com
   * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   */
  
  #include <linux/io.h>
  #include <linux/errno.h>
  #include <linux/delay.h>
  #include <linux/module.h>
  #include <linux/stmp_device.h>
  
  #define STMP_MODULE_CLKGATE	(1 << 30)
  #define STMP_MODULE_SFTRST	(1 << 31)
  
  /*
   * Clear the bit and poll it cleared.  This is usually called with
   * a reset address and mask being either SFTRST(bit 31) or CLKGATE
   * (bit 30).
   */
  static int stmp_clear_poll_bit(void __iomem *addr, u32 mask)
  {
  	int timeout = 0x400;
  
  	writel(mask, addr + STMP_OFFSET_REG_CLR);
  	udelay(1);
  	while ((readl(addr) & mask) && --timeout)
  		/* nothing */;
  
  	return !timeout;
  }
  
  int stmp_reset_block(void __iomem *reset_addr)
  {
  	int ret;
  	int timeout = 0x400;
  
  	/* clear and poll SFTRST */
  	ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
  	if (unlikely(ret))
  		goto error;
  
  	/* clear CLKGATE */
  	writel(STMP_MODULE_CLKGATE, reset_addr + STMP_OFFSET_REG_CLR);
  
  	/* set SFTRST to reset the block */
  	writel(STMP_MODULE_SFTRST, reset_addr + STMP_OFFSET_REG_SET);
  	udelay(1);
  
  	/* poll CLKGATE becoming set */
  	while ((!(readl(reset_addr) & STMP_MODULE_CLKGATE)) && --timeout)
  		/* nothing */;
  	if (unlikely(!timeout))
  		goto error;
  
  	/* clear and poll SFTRST */
  	ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
  	if (unlikely(ret))
  		goto error;
  
  	/* clear and poll CLKGATE */
  	ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_CLKGATE);
  	if (unlikely(ret))
  		goto error;
  
  	return 0;
  
  error:
  	pr_err("%s(%p): module reset timeout
  ", __func__, reset_addr);
  	return -ETIMEDOUT;
  }
  EXPORT_SYMBOL(stmp_reset_block);