arch/arm/mach-sunxi/sunxi.c

   1 /*
   2  * Device Tree support for Allwinner A1X SoCs
   3  *
   4  * Copyright (C) 2012 Maxime Ripard
   5  *
   6  * Maxime Ripard <maxime.ripard@free-electrons.com>
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2.  This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/of_address.h>
  17 #include <linux/of_irq.h>
  18 #include <linux/of_platform.h>
  19 #include <linux/io.h>
  20 #include <linux/sunxi_timer.h>
  21
  22 #include <linux/irqchip/sunxi.h>
  23
  24 #include <asm/mach/arch.h>
  25 #include <asm/mach/map.h>
  26
  27 #include "sunxi.h"
  28
  29 #define WATCHDOG_CTRL_REG       0x00
  30 #define WATCHDOG_CTRL_RESTART           (1 << 0)
  31 #define WATCHDOG_MODE_REG       0x04
  32 #define WATCHDOG_MODE_ENABLE            (1 << 0)
  33 #define WATCHDOG_MODE_RESET_ENABLE      (1 << 1)
  34
  35 static void __iomem *wdt_base;
  36
  37 static void sunxi_setup_restart(void)
  38 {
  39         struct device_node *np = of_find_compatible_node(NULL, NULL,
  40                                                 "allwinner,sunxi-wdt");
  41         if (WARN(!np, "unable to setup watchdog restart"))
  42                 return;
  43
  44         wdt_base = of_iomap(np, 0);
  45         WARN(!wdt_base, "failed to map watchdog base address");
  46 }
  47
  48 static void sunxi_restart(char mode, const char *cmd)
  49 {
  50         if (!wdt_base)
  51                 return;
  52
  53         /* Enable timer and set reset bit in the watchdog */
  54         writel(WATCHDOG_MODE_ENABLE | WATCHDOG_MODE_RESET_ENABLE,
  55                 wdt_base + WATCHDOG_MODE_REG);
  56
  57         /*
  58          * Restart the watchdog. The default (and lowest) interval
  59          * value for the watchdog is 0.5s.
  60          */
  61         writel(WATCHDOG_CTRL_RESTART, wdt_base + WATCHDOG_CTRL_REG);
  62
  63         while (1) {
  64                 mdelay(5);
  65                 writel(WATCHDOG_MODE_ENABLE | WATCHDOG_MODE_RESET_ENABLE,
  66                         wdt_base + WATCHDOG_MODE_REG);
  67         }
  68 }
  69
  70 static struct map_desc sunxi_io_desc[] __initdata = {
  71         {
  72                 .virtual        = (unsigned long) SUNXI_REGS_VIRT_BASE,
  73                 .pfn            = __phys_to_pfn(SUNXI_REGS_PHYS_BASE),
  74                 .length         = SUNXI_REGS_SIZE,
  75                 .type           = MT_DEVICE,
  76         },
  77 };
  78
  79 void __init sunxi_map_io(void)
  80 {
  81         iotable_init(sunxi_io_desc, ARRAY_SIZE(sunxi_io_desc));
  82 }
  83
  84 static void __init sunxi_dt_init(void)
  85 {
  86         sunxi_setup_restart();
  87
  88         of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
  89 }
  90
  91 static const char * const sunxi_board_dt_compat[] = {
  92         "allwinner,sun4i-a10",
  93         "allwinner,sun5i-a13",
  94         NULL,
  95 };
  96
  97 DT_MACHINE_START(SUNXI_DT, "Allwinner A1X (Device Tree)")
  98         .init_machine   = sunxi_dt_init,
  99         .map_io         = sunxi_map_io,
 100         .init_irq       = sunxi_init_irq,
 101         .handle_irq     = sunxi_handle_irq,
 102         .restart        = sunxi_restart,
 103         .init_time      = &sunxi_timer_init,
 104         .dt_compat      = sunxi_board_dt_compat,
 105 MACHINE_END