arch/arm/mach-bcm/board_bcm21664.c

   1 /*
   2  * Copyright (C) 2014 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation version 2.
   7  *
   8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9  * kind, whether express or implied; without even the implied warranty
  10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/of_address.h>
  15 #include <linux/of_platform.h>
  16 #include <linux/io.h>
  17
  18 #include <asm/mach/arch.h>
  19
  20 #include "kona_l2_cache.h"
  21
  22 #define RSTMGR_DT_STRING                "brcm,bcm21664-resetmgr"
  23
  24 #define RSTMGR_REG_WR_ACCESS_OFFSET     0
  25 #define RSTMGR_REG_CHIP_SOFT_RST_OFFSET 4
  26
  27 #define RSTMGR_WR_PASSWORD              0xa5a5
  28 #define RSTMGR_WR_PASSWORD_SHIFT        8
  29 #define RSTMGR_WR_ACCESS_ENABLE         1
  30
  31 static void bcm21664_restart(enum reboot_mode mode, const char *cmd)
  32 {
  33         void __iomem *base;
  34         struct device_node *resetmgr;
  35
  36         resetmgr = of_find_compatible_node(NULL, NULL, RSTMGR_DT_STRING);
  37         if (!resetmgr) {
  38                 pr_emerg("Couldn't find " RSTMGR_DT_STRING "\n");
  39                 return;
  40         }
  41         base = of_iomap(resetmgr, 0);
  42         if (!base) {
  43                 pr_emerg("Couldn't map " RSTMGR_DT_STRING "\n");
  44                 return;
  45         }
  46
  47         /*
  48          * A soft reset is triggered by writing a 0 to bit 0 of the soft reset
  49          * register. To write to that register we must first write the password
  50          * and the enable bit in the write access enable register.
  51          */
  52         writel((RSTMGR_WR_PASSWORD << RSTMGR_WR_PASSWORD_SHIFT) |
  53                 RSTMGR_WR_ACCESS_ENABLE,
  54                 base + RSTMGR_REG_WR_ACCESS_OFFSET);
  55         writel(0, base + RSTMGR_REG_CHIP_SOFT_RST_OFFSET);
  56
  57         /* Wait for reset */
  58         while (1);
  59 }
  60
  61 static void __init bcm21664_init(void)
  62 {
  63         of_platform_populate(NULL, of_default_bus_match_table, NULL,
  64                 &platform_bus);
  65         kona_l2_cache_init();
  66 }
  67
  68 static const char * const bcm21664_dt_compat[] = {
  69         "brcm,bcm21664",
  70         NULL,
  71 };
  72
  73 DT_MACHINE_START(BCM21664_DT, "BCM21664 Broadcom Application Processor")
  74         .init_machine = bcm21664_init,
  75         .restart = bcm21664_restart,
  76         .dt_compat = bcm21664_dt_compat,
  77 MACHINE_END