arch/arm/mach-picoxcell/common.c

   1 /*
   2  * Copyright (c) 2011 Picochip Ltd., Jamie Iles
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * All enquiries to support@picochip.com
   9  */
  10 #include <linux/delay.h>
  11 #include <linux/irq.h>
  12 #include <linux/irqdomain.h>
  13 #include <linux/of.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/of_platform.h>
  17 #include <linux/dw_apb_timer.h>
  18
  19 #include <asm/mach/arch.h>
  20 #include <asm/hardware/vic.h>
  21 #include <asm/mach/map.h>
  22
  23 #include <mach/map.h>
  24 #include <mach/picoxcell_soc.h>
  25
  26 #include "common.h"
  27
  28 #define WDT_CTRL_REG_EN_MASK    (1 << 0)
  29 #define WDT_CTRL_REG_OFFS       (0x00)
  30 #define WDT_TIMEOUT_REG_OFFS    (0x04)
  31 static void __iomem *wdt_regs;
  32
  33 /*
  34  * The machine restart method can be called from an atomic context so we won't
  35  * be able to ioremap the regs then.
  36  */
  37 static void picoxcell_setup_restart(void)
  38 {
  39         struct device_node *np = of_find_compatible_node(NULL, NULL,
  40                                                          "snps,dw-apb-wdg");
  41         if (WARN(!np, "unable to setup watchdog restart"))
  42                 return;
  43
  44         wdt_regs = of_iomap(np, 0);
  45         WARN(!wdt_regs, "failed to remap watchdog regs");
  46 }
  47
  48 static struct map_desc io_map __initdata = {
  49         .virtual        = PHYS_TO_IO(PICOXCELL_PERIPH_BASE),
  50         .pfn            = __phys_to_pfn(PICOXCELL_PERIPH_BASE),
  51         .length         = PICOXCELL_PERIPH_LENGTH,
  52         .type           = MT_DEVICE,
  53 };
  54
  55 static void __init picoxcell_map_io(void)
  56 {
  57         iotable_init(&io_map, 1);
  58 }
  59
  60 static void __init picoxcell_init_machine(void)
  61 {
  62         of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
  63         picoxcell_setup_restart();
  64 }
  65
  66 static const char *picoxcell_dt_match[] = {
  67         "picochip,pc3x2",
  68         "picochip,pc3x3",
  69         NULL
  70 };
  71
  72 static const struct of_device_id vic_of_match[] __initconst = {
  73         { .compatible = "arm,pl192-vic", .data = vic_of_init, },
  74         { /* Sentinel */ }
  75 };
  76
  77 static void __init picoxcell_init_irq(void)
  78 {
  79         of_irq_init(vic_of_match);
  80 }
  81
  82 static void picoxcell_wdt_restart(char mode, const char *cmd)
  83 {
  84         /*
  85          * Configure the watchdog to reset with the shortest possible timeout
  86          * and give it chance to do the reset.
  87          */
  88         if (wdt_regs) {
  89                 writel_relaxed(WDT_CTRL_REG_EN_MASK, wdt_regs + WDT_CTRL_REG_OFFS);
  90                 writel_relaxed(0, wdt_regs + WDT_TIMEOUT_REG_OFFS);
  91                 /* No sleeping, possibly atomic. */
  92                 mdelay(500);
  93         }
  94 }
  95
  96 DT_MACHINE_START(PICOXCELL, "Picochip picoXcell")
  97         .map_io         = picoxcell_map_io,
  98         .nr_irqs        = NR_IRQS_LEGACY,
  99         .init_irq       = picoxcell_init_irq,
 100         .handle_irq     = vic_handle_irq,
 101         .timer          = &dw_apb_timer,
 102         .init_machine   = picoxcell_init_machine,
 103         .dt_compat      = picoxcell_dt_match,
 104         .restart        = picoxcell_wdt_restart,
 105 MACHINE_END