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/*
* 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
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/module.h>
#include <asm/proc-fns.h>
#include <asm/system.h>
#include <mach/mxs.h>
#include <mach/common.h>
#define MX23_CLKCTRL_RESET_OFFSET 0x120
#define MX28_CLKCTRL_RESET_OFFSET 0x1e0
#define MXS_CLKCTRL_RESET_CHIP (1 << 1)
#define MXS_MODULE_CLKGATE (1 << 30)
#define MXS_MODULE_SFTRST (1 << 31)
static void __iomem *mxs_clkctrl_reset_addr;
/*
* Reset the system. It is called by machine_restart().
*/
void arch_reset(char mode, const char *cmd)
{
/* reset the chip */
__mxs_setl(MXS_CLKCTRL_RESET_CHIP, mxs_clkctrl_reset_addr);
pr_err("Failed to assert the chip reset\n");
/* Delay to allow the serial port to show the message */
mdelay(50);
/* We'll take a jump through zero as a poor second */
cpu_reset(0);
}
static int __init mxs_arch_reset_init(void)
{
struct clk *clk;
mxs_clkctrl_reset_addr = MXS_IO_ADDRESS(MXS_CLKCTRL_BASE_ADDR) +
(cpu_is_mx23() ? MX23_CLKCTRL_RESET_OFFSET :
MX28_CLKCTRL_RESET_OFFSET);
clk = clk_get_sys("rtc", NULL);
if (!IS_ERR(clk))
clk_prepare_enable(clk);
return 0;
}
core_initcall(mxs_arch_reset_init);
/*
* 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 clear_poll_bit(void __iomem *addr, u32 mask)
{
int timeout = 0x400;
/* clear the bit */
__mxs_clrl(mask, addr);
/*
* SFTRST needs 3 GPMI clocks to settle, the reference manual
* recommends to wait 1us.
*/
udelay(1);
/* poll the bit becoming clear */
while ((__raw_readl(addr) & mask) && --timeout)
/* nothing */;
return !timeout;
}
int mxs_reset_block(void __iomem *reset_addr)
{
int ret;
int timeout = 0x400;
/* clear and poll SFTRST */
ret = clear_poll_bit(reset_addr, MXS_MODULE_SFTRST);
if (unlikely(ret))
goto error;
/* clear CLKGATE */
__mxs_clrl(MXS_MODULE_CLKGATE, reset_addr);
/* set SFTRST to reset the block */
__mxs_setl(MXS_MODULE_SFTRST, reset_addr);
udelay(1);
/* poll CLKGATE becoming set */
while ((!(__raw_readl(reset_addr) & MXS_MODULE_CLKGATE)) && --timeout)
/* nothing */;
if (unlikely(!timeout))
goto error;
/* clear and poll SFTRST */
ret = clear_poll_bit(reset_addr, MXS_MODULE_SFTRST);
if (unlikely(ret))
goto error;
/* clear and poll CLKGATE */
ret = clear_poll_bit(reset_addr, MXS_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(mxs_reset_block);
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