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/of.h>
12#include <linux/of_address.h>
13#include <linux/reboot.h>
14
15#include <asm/mach/arch.h>
16#include <asm/mach/map.h>
17
18#define PHYS_TO_IO(x)			(((x) & 0x00ffffff) | 0xfe000000)
19#define PICOXCELL_PERIPH_BASE		0x80000000
20#define PICOXCELL_PERIPH_LENGTH		SZ_4M
21
22#define WDT_CTRL_REG_EN_MASK		(1 << 0)
23#define WDT_CTRL_REG_OFFS		(0x00)
24#define WDT_TIMEOUT_REG_OFFS		(0x04)
25static void __iomem *wdt_regs;
26
27/*
28 * The machine restart method can be called from an atomic context so we won't
29 * be able to ioremap the regs then.
30 */
31static void picoxcell_setup_restart(void)
32{
33	struct device_node *np = of_find_compatible_node(NULL, NULL,
34							 "snps,dw-apb-wdg");
35	if (WARN(!np, "unable to setup watchdog restart"))
36		return;
37
38	wdt_regs = of_iomap(np, 0);
39	WARN(!wdt_regs, "failed to remap watchdog regs");
40}
41
42static 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,
46	.type		= MT_DEVICE,
47};
48
49static void __init picoxcell_map_io(void)
50{
51	iotable_init(&io_map, 1);
52}
53
54static void __init picoxcell_init_machine(void)
55{
56	picoxcell_setup_restart();
57}
58
59static const char *picoxcell_dt_match[] = {
60	"picochip,pc3x2",
61	"picochip,pc3x3",
62	NULL
63};
64
65static void picoxcell_wdt_restart(enum reboot_mode mode, const char *cmd)
66{
67	/*
68	 * Configure the watchdog to reset with the shortest possible timeout
69	 * and give it chance to do the reset.
70	 */
71	if (wdt_regs) {
72		writel_relaxed(WDT_CTRL_REG_EN_MASK, wdt_regs + WDT_CTRL_REG_OFFS);
73		writel_relaxed(0, wdt_regs + WDT_TIMEOUT_REG_OFFS);
74		/* No sleeping, possibly atomic. */
75		mdelay(500);
76	}
77}
78
79DT_MACHINE_START(PICOXCELL, "Picochip picoXcell")
80	.map_io		= picoxcell_map_io,
81	.init_machine	= picoxcell_init_machine,
82	.dt_compat	= picoxcell_dt_match,
83	.restart	= picoxcell_wdt_restart,
84MACHINE_END