arch/arm/mach-imx/system.c

   1 /*
   2  * Copyright (C) 1999 ARM Limited
   3  * Copyright (C) 2000 Deep Blue Solutions Ltd
   4  * Copyright 2006-2007 Freescale Semiconductor, Inc. All Rights Reserved.
   5  * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
   6  * Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/clk.h>
  21 #include <linux/io.h>
  22 #include <linux/err.h>
  23 #include <linux/delay.h>
  24 #include <linux/of.h>
  25 #include <linux/of_address.h>
  26
  27 #include <asm/system_misc.h>
  28 #include <asm/proc-fns.h>
  29 #include <asm/mach-types.h>
  30 #include <asm/hardware/cache-l2x0.h>
  31
  32 #include "common.h"
  33 #include "hardware.h"
  34
  35 static void __iomem *wdog_base;
  36 static struct clk *wdog_clk;
  37
  38 /*
  39  * Reset the system. It is called by machine_restart().
  40  */
  41 void mxc_restart(enum reboot_mode mode, const char *cmd)
  42 {
  43         unsigned int wcr_enable;
  44
  45         if (!wdog_base)
  46                 goto reset_fallback;
  47
  48         if (!IS_ERR(wdog_clk))
  49                 clk_enable(wdog_clk);
  50
  51         if (cpu_is_mx1())
  52                 wcr_enable = (1 << 0);
  53         else
  54                 wcr_enable = (1 << 2);
  55
  56         /* Assert SRS signal */
  57         imx_writew(wcr_enable, wdog_base);
  58         /*
  59          * Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be
  60          * written twice), we add another two writes to ensure there must be at
  61          * least two writes happen in the same one 32kHz clock period.  We save
  62          * the target check here, since the writes shouldn't be a huge burden
  63          * for other platforms.
  64          */
  65         imx_writew(wcr_enable, wdog_base);
  66         imx_writew(wcr_enable, wdog_base);
  67
  68         /* wait for reset to assert... */
  69         mdelay(500);
  70
  71         pr_err("%s: Watchdog reset failed to assert reset\n", __func__);
  72
  73         /* delay to allow the serial port to show the message */
  74         mdelay(50);
  75
  76 reset_fallback:
  77         /* we'll take a jump through zero as a poor second */
  78         soft_restart(0);
  79 }
  80
  81 void __init mxc_arch_reset_init(void __iomem *base)
  82 {
  83         wdog_base = base;
  84
  85         wdog_clk = clk_get_sys("imx2-wdt.0", NULL);
  86         if (IS_ERR(wdog_clk))
  87                 pr_warn("%s: failed to get wdog clock\n", __func__);
  88         else
  89                 clk_prepare(wdog_clk);
  90 }
  91
  92 #ifdef CONFIG_CACHE_L2X0
  93 void __init imx_init_l2cache(void)
  94 {
  95         void __iomem *l2x0_base;
  96         struct device_node *np;
  97         unsigned int val;
  98
  99         np = of_find_compatible_node(NULL, NULL, "arm,pl310-cache");
 100         if (!np)
 101                 goto out;
 102
 103         l2x0_base = of_iomap(np, 0);
 104         if (!l2x0_base) {
 105                 of_node_put(np);
 106                 goto out;
 107         }
 108
 109         if (readl_relaxed(l2x0_base + L2X0_CTRL) & L2X0_CTRL_EN)
 110                 goto skip_if_enabled;
 111
 112         /* Configure the L2 PREFETCH and POWER registers */
 113         val = readl_relaxed(l2x0_base + L310_PREFETCH_CTRL);
 114         val |= 0x70800000;
 115         /*
 116          * The L2 cache controller(PL310) version on the i.MX6D/Q is r3p1-50rel0
 117          * The L2 cache controller(PL310) version on the i.MX6DL/SOLO/SL is r3p2
 118          * But according to ARM PL310 errata: 752271
 119          * ID: 752271: Double linefill feature can cause data corruption
 120          * Fault Status: Present in: r3p0, r3p1, r3p1-50rel0. Fixed in r3p2
 121          * Workaround: The only workaround to this erratum is to disable the
 122          * double linefill feature. This is the default behavior.
 123          */
 124         if (cpu_is_imx6q())
 125                 val &= ~(1 << 30 | 1 << 23);
 126         writel_relaxed(val, l2x0_base + L310_PREFETCH_CTRL);
 127
 128 skip_if_enabled:
 129         iounmap(l2x0_base);
 130         of_node_put(np);
 131
 132 out:
 133         l2x0_of_init(0, ~0);
 134 }
 135 #endif