[linux.git] / lib / stmp_device.c

/*
 * 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, [email protected]
 * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, [email protected]
 * 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/compiler.h>
#include <linux/export.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\n", __func__, reset_addr);
	return -ETIMEDOUT;
}
EXPORT_SYMBOL(stmp_reset_block);
Commit	Line	Data
4ccf4bea WS	1	/*
	2	* Copyright (C) 1999 ARM Limited
	3	* Copyright (C) 2000 Deep Blue Solutions Ltd
	4	* Copyright 2006-2007,2010 Freescale Semiconductor, Inc. All Rights Reserved.
	5	* Copyright 2008 Juergen Beisert, [email protected]
	6	* Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, [email protected]
	7	* Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation; either version 2 of the License, or
	12	* (at your option) any later version.
	13	*/
	14
	15	#include <linux/io.h>
	16	#include <linux/errno.h>
	17	#include <linux/delay.h>
b6d4f322 RV	18	#include <linux/compiler.h>
b6d4f322 RV	19	#include <linux/export.h>
4ccf4bea WS	20	#include <linux/stmp_device.h>
	21
	22	#define STMP_MODULE_CLKGATE (1 << 30)
	23	#define STMP_MODULE_SFTRST (1 << 31)
	24
	25	/*
	26	* Clear the bit and poll it cleared. This is usually called with
	27	* a reset address and mask being either SFTRST(bit 31) or CLKGATE
	28	* (bit 30).
	29	*/
	30	static int stmp_clear_poll_bit(void __iomem *addr, u32 mask)
	31	{
	32	int timeout = 0x400;
	33
	34	writel(mask, addr + STMP_OFFSET_REG_CLR);
	35	udelay(1);
	36	while ((readl(addr) & mask) && --timeout)
	37	/* nothing */;
	38
	39	return !timeout;
	40	}
	41
	42	int stmp_reset_block(void __iomem *reset_addr)
	43	{
	44	int ret;
	45	int timeout = 0x400;
	46
	47	/* clear and poll SFTRST */
	48	ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
	49	if (unlikely(ret))
	50	goto error;
	51
	52	/* clear CLKGATE */
	53	writel(STMP_MODULE_CLKGATE, reset_addr + STMP_OFFSET_REG_CLR);
	54
	55	/* set SFTRST to reset the block */
	56	writel(STMP_MODULE_SFTRST, reset_addr + STMP_OFFSET_REG_SET);
	57	udelay(1);
	58
	59	/* poll CLKGATE becoming set */
	60	while ((!(readl(reset_addr) & STMP_MODULE_CLKGATE)) && --timeout)
	61	/* nothing */;
	62	if (unlikely(!timeout))
	63	goto error;
	64
	65	/* clear and poll SFTRST */
	66	ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
	67	if (unlikely(ret))
	68	goto error;
	69
	70	/* clear and poll CLKGATE */
	71	ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_CLKGATE);
	72	if (unlikely(ret))
	73	goto error;
	74
	75	return 0;
	76
	77	error:
	78	pr_err("%s(%p): module reset timeout\n", __func__, reset_addr);
	79	return -ETIMEDOUT;
	80	}
	81	EXPORT_SYMBOL(stmp_reset_block);