2 * Copyright (C) 2010 Broadcom
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
15 #include <linux/delay.h>
16 #include <linux/init.h>
17 #include <linux/irqchip.h>
18 #include <linux/of_address.h>
19 #include <linux/of_platform.h>
20 #include <linux/clk/bcm2835.h>
22 #include <asm/mach/arch.h>
23 #include <asm/mach/map.h>
29 #define PM_PASSWORD 0x5a000000
30 #define PM_RSTC_WRCFG_MASK 0x00000030
31 #define PM_RSTC_WRCFG_FULL_RESET 0x00000020
32 #define PM_RSTS_HADWRH_SET 0x00000040
34 static void __iomem *wdt_regs;
37 * The machine restart method can be called from an atomic context so we won't
38 * be able to ioremap the regs then.
40 static void bcm2835_setup_restart(void)
42 struct device_node *np = of_find_compatible_node(NULL, NULL,
43 "brcm,bcm2835-pm-wdt");
44 if (WARN(!np, "unable to setup watchdog restart"))
47 wdt_regs = of_iomap(np, 0);
48 WARN(!wdt_regs, "failed to remap watchdog regs");
51 static void bcm2835_restart(enum reboot_mode mode, const char *cmd)
58 /* use a timeout of 10 ticks (~150us) */
59 writel_relaxed(10 | PM_PASSWORD, wdt_regs + PM_WDOG);
60 val = readl_relaxed(wdt_regs + PM_RSTC);
61 val &= ~PM_RSTC_WRCFG_MASK;
62 val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
63 writel_relaxed(val, wdt_regs + PM_RSTC);
65 /* No sleeping, possibly atomic. */
70 * We can't really power off, but if we do the normal reset scheme, and
71 * indicate to bootcode.bin not to reboot, then most of the chip will be
74 static void bcm2835_power_off(void)
79 * We set the watchdog hard reset bit here to distinguish this reset
80 * from the normal (full) reset. bootcode.bin will not reboot after a
83 val = readl_relaxed(wdt_regs + PM_RSTS);
84 val &= ~PM_RSTC_WRCFG_MASK;
85 val |= PM_PASSWORD | PM_RSTS_HADWRH_SET;
86 writel_relaxed(val, wdt_regs + PM_RSTS);
88 /* Continue with normal reset mechanism */
89 bcm2835_restart(REBOOT_HARD, "");
92 static void __init bcm2835_init(void)
96 bcm2835_setup_restart();
98 pm_power_off = bcm2835_power_off;
100 bcm2835_init_clocks();
102 ret = of_platform_populate(NULL, of_default_bus_match_table, NULL,
105 pr_err("of_platform_populate failed: %d\n", ret);
110 static const char * const bcm2835_compat[] = {
115 DT_MACHINE_START(BCM2835, "BCM2835")
116 .init_irq = irqchip_init,
117 .init_machine = bcm2835_init,
118 .restart = bcm2835_restart,
119 .dt_compat = bcm2835_compat