2 * Copyright (c) 2011 Picochip Ltd., Jamie Iles
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.
8 * All enquiries to support@picochip.com
10 #include <linux/delay.h>
12 #include <linux/of_address.h>
13 #include <linux/of_platform.h>
15 #include <asm/mach/arch.h>
16 #include <asm/mach/map.h>
18 #define PHYS_TO_IO(x) (((x) & 0x00ffffff) | 0xfe000000)
19 #define PICOXCELL_PERIPH_BASE 0x80000000
20 #define PICOXCELL_PERIPH_LENGTH SZ_4M
22 #define WDT_CTRL_REG_EN_MASK (1 << 0)
23 #define WDT_CTRL_REG_OFFS (0x00)
24 #define WDT_TIMEOUT_REG_OFFS (0x04)
25 static void __iomem *wdt_regs;
28 * The machine restart method can be called from an atomic context so we won't
29 * be able to ioremap the regs then.
31 static void picoxcell_setup_restart(void)
33 struct device_node *np = of_find_compatible_node(NULL, NULL,
35 if (WARN(!np, "unable to setup watchdog restart"))
38 wdt_regs = of_iomap(np, 0);
39 WARN(!wdt_regs, "failed to remap watchdog regs");
42 static struct map_desc io_map __initdata = {
43 .virtual = PHYS_TO_IO(PICOXCELL_PERIPH_BASE),
44 .pfn = __phys_to_pfn(PICOXCELL_PERIPH_BASE),
45 .length = PICOXCELL_PERIPH_LENGTH,
49 static void __init picoxcell_map_io(void)
51 iotable_init(&io_map, 1);
54 static void __init picoxcell_init_machine(void)
56 of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
57 picoxcell_setup_restart();
60 static const char *picoxcell_dt_match[] = {
66 static void picoxcell_wdt_restart(char mode, const char *cmd)
69 * Configure the watchdog to reset with the shortest possible timeout
70 * and give it chance to do the reset.
73 writel_relaxed(WDT_CTRL_REG_EN_MASK, wdt_regs + WDT_CTRL_REG_OFFS);
74 writel_relaxed(0, wdt_regs + WDT_TIMEOUT_REG_OFFS);
75 /* No sleeping, possibly atomic. */
80 DT_MACHINE_START(PICOXCELL, "Picochip picoXcell")
81 .map_io = picoxcell_map_io,
82 .init_machine = picoxcell_init_machine,
83 .dt_compat = picoxcell_dt_match,
84 .restart = picoxcell_wdt_restart,