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)
25 static 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 */
picoxcell_setup_restart(void)31 static 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
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,
46 .type = MT_DEVICE,
47 };
48
picoxcell_map_io(void)49 static void __init picoxcell_map_io(void)
50 {
51 iotable_init(&io_map, 1);
52 }
53
picoxcell_init_machine(void)54 static void __init picoxcell_init_machine(void)
55 {
56 picoxcell_setup_restart();
57 }
58
59 static const char *picoxcell_dt_match[] = {
60 "picochip,pc3x2",
61 "picochip,pc3x3",
62 NULL
63 };
64
picoxcell_wdt_restart(enum reboot_mode mode,const char * cmd)65 static 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
79 DT_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,
84 MACHINE_END
85
