ARM: mxs: Add reset routines

 - 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 <shawn.guo@freescale.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

2 files changed, 164 insertions, 0 deletions

diff --git a/arch/arm/mach-mxs/include/mach/system.h b/arch/arm/mach-mxs/include/mach/system.h
new file mode 100644
index 000000000000..0e428239b433
--- /dev/null
+++ b/arch/arm/mach-mxs/include/mach/system.h
@@ -0,0 +1,27 @@
+/*
+ *  Copyright (C) 1999 ARM Limited
+ *  Copyright (C) 2000 Deep Blue Solutions Ltd
+ *  Copyright 2004-2008 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * 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.
+ */
+
+#ifndef __MACH_MXS_SYSTEM_H__
+#define __MACH_MXS_SYSTEM_H__
+
+static inline void arch_idle(void)
+{
+        cpu_do_idle();
+}
+
+void arch_reset(char mode, const char *cmd);
+
+#endif /* __MACH_MXS_SYSTEM_H__ */
diff --git a/arch/arm/mach-mxs/system.c b/arch/arm/mach-mxs/system.c
new file mode 100644
index 000000000000..9343d7edd4f6
--- /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 <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/init.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_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;
+}