arch/arm/mach-keystone/keystone.c

   1 /*
   2  * Keystone2 based boards and SOC related code.
   3  *
   4  * Copyright 2013 Texas Instruments, Inc.
   5  *      Cyril Chemparathy <cyril@ti.com>
   6  *      Santosh Shilimkar <santosh.shillimkar@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  */
  12 #include <linux/io.h>
  13 #include <linux/of.h>
  14 #include <linux/init.h>
  15 #include <linux/of_platform.h>
  16 #include <linux/of_address.h>
  17
  18 #include <asm/setup.h>
  19 #include <asm/mach/map.h>
  20 #include <asm/mach/arch.h>
  21 #include <asm/mach/time.h>
  22 #include <asm/smp_plat.h>
  23
  24 #include "keystone.h"
  25
  26 #define PLL_RESET_WRITE_KEY_MASK                0xffff0000
  27 #define PLL_RESET_WRITE_KEY                     0x5a69
  28 #define PLL_RESET                               BIT(16)
  29
  30 static void __iomem *keystone_rstctrl;
  31
  32 static void __init keystone_init(void)
  33 {
  34         struct device_node *node;
  35
  36         node = of_find_compatible_node(NULL, NULL, "ti,keystone-reset");
  37         if (WARN_ON(!node))
  38                 pr_warn("ti,keystone-reset node undefined\n");
  39
  40         keystone_rstctrl = of_iomap(node, 0);
  41         if (WARN_ON(!keystone_rstctrl))
  42                 pr_warn("ti,keystone-reset iomap error\n");
  43
  44         of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
  45 }
  46
  47 static const char *keystone_match[] __initconst = {
  48         "ti,keystone-evm",
  49         NULL,
  50 };
  51
  52 void keystone_restart(enum reboot_mode mode, const char *cmd)
  53 {
  54         u32 val;
  55
  56         BUG_ON(!keystone_rstctrl);
  57
  58         /* Enable write access to RSTCTRL */
  59         val = readl(keystone_rstctrl);
  60         val &= PLL_RESET_WRITE_KEY_MASK;
  61         val |= PLL_RESET_WRITE_KEY;
  62         writel(val, keystone_rstctrl);
  63
  64         /* Reset the SOC */
  65         val = readl(keystone_rstctrl);
  66         val &= ~PLL_RESET;
  67         writel(val, keystone_rstctrl);
  68 }
  69
  70 DT_MACHINE_START(KEYSTONE, "Keystone")
  71         .smp            = smp_ops(keystone_smp_ops),
  72         .init_machine   = keystone_init,
  73         .dt_compat      = keystone_match,
  74         .restart        = keystone_restart,
  75 MACHINE_END