Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mv-sheeva.git] / 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 (file)
index 0000000..9343d7e
--- /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;
+}