From 65d7d94405dcc1845ad2680eeb6af43ced74fdc4 Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Sat, 18 Dec 2010 21:39:27 +0800 Subject: ARM: mxs: Add reset routines MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - The mxs wdog is implemented in RTC block. - There is a generic software reset routine for most modules on mxs. Signed-off-by: Shawn Guo Signed-off-by: Uwe Kleine-König --- arch/arm/mach-mxs/system.c | 137 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) create mode 100644 arch/arm/mach-mxs/system.c (limited to 'arch/arm/mach-mxs/system.c') diff --git a/arch/arm/mach-mxs/system.c b/arch/arm/mach-mxs/system.c new file mode 100644 index 00000000000..9343d7edd4f --- /dev/null +++ b/arch/arm/mach-mxs/system.c @@ -0,0 +1,137 @@ +/* + * 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 +#include +#include +#include +#include +#include + +#include +#include + +#include +#include + +#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_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; +} -- cgit v1.2.3