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_MODE_REG       0x04
  31
  32 static void __iomem *wdt_base;
  33
  34 static void sunxi_setup_restart(void)
  35 {
  36         struct device_node *np = of_find_compatible_node(NULL, NULL,
  37                                                 "allwinner,sunxi-wdt");
  38         if (WARN(!np, "unable to setup watchdog restart"))
  39                 return;
  40
  41         wdt_base = of_iomap(np, 0);
  42         WARN(!wdt_base, "failed to map watchdog base address");
  43 }
  44
  45 static void sunxi_restart(char mode, const char *cmd)
  46 {
  47         if (!wdt_base)
  48                 return;
  49
  50         /* Enable timer and set reset bit in the watchdog */
  51         writel(3, wdt_base + WATCHDOG_MODE_REG);
  52         writel(0xa57 << 1 | 1, wdt_base + WATCHDOG_CTRL_REG);
  53         while(1) {
  54                 mdelay(5);
  55                 writel(3, wdt_base + WATCHDOG_MODE_REG);
  56         }
  57 }
  58
  59 static struct map_desc sunxi_io_desc[] __initdata = {
  60         {
  61                 .virtual        = (unsigned long) SUNXI_REGS_VIRT_BASE,
  62                 .pfn            = __phys_to_pfn(SUNXI_REGS_PHYS_BASE),
  63                 .length         = SUNXI_REGS_SIZE,
  64                 .type           = MT_DEVICE,
  65         },
  66 };
  67
  68 void __init sunxi_map_io(void)
  69 {
  70         iotable_init(sunxi_io_desc, ARRAY_SIZE(sunxi_io_desc));
  71 }
  72
  73 static void __init sunxi_dt_init(void)
  74 {
  75         sunxi_setup_restart();
  76
  77         of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
  78 }
  79
  80 static const char * const sunxi_board_dt_compat[] = {
  81         "allwinner,sun4i-a10",
  82         "allwinner,sun5i-a13",
  83         NULL,
  84 };
  85
  86 DT_MACHINE_START(SUNXI_DT, "Allwinner A1X (Device Tree)")
  87         .init_machine   = sunxi_dt_init,
  88         .map_io         = sunxi_map_io,
  89         .init_irq       = sunxi_init_irq,
  90         .handle_irq     = sunxi_handle_irq,
  91         .restart        = sunxi_restart,
  92         .timer          = &sunxi_timer,
  93         .dt_compat      = sunxi_board_dt_compat,
  94 MACHINE_END