bcm2835.c
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/*
* Copyright (C) 2010 Broadcom
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/irqchip.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/clk/bcm2835.h>
#include <asm/mach/arch.h>
#include <asm/mach/map.h>
#define PM_RSTC 0x1c
#define PM_RSTS 0x20
#define PM_WDOG 0x24
#define PM_PASSWORD 0x5a000000
#define PM_RSTC_WRCFG_MASK 0x00000030
#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
#define PM_RSTS_HADWRH_SET 0x00000040
#define BCM2835_PERIPH_PHYS 0x20000000
#define BCM2835_PERIPH_VIRT 0xf0000000
#define BCM2835_PERIPH_SIZE SZ_16M
static void __iomem *wdt_regs;
/*
* The machine restart method can be called from an atomic context so we won't
* be able to ioremap the regs then.
*/
static void bcm2835_setup_restart(void)
{
struct device_node *np = of_find_compatible_node(NULL, NULL,
"brcm,bcm2835-pm-wdt");
if (WARN(!np, "unable to setup watchdog restart"))
return;
wdt_regs = of_iomap(np, 0);
WARN(!wdt_regs, "failed to remap watchdog regs");
}
static void bcm2835_restart(enum reboot_mode mode, const char *cmd)
{
u32 val;
if (!wdt_regs)
return;
/* use a timeout of 10 ticks (~150us) */
writel_relaxed(10 | PM_PASSWORD, wdt_regs + PM_WDOG);
val = readl_relaxed(wdt_regs + PM_RSTC);
val &= ~PM_RSTC_WRCFG_MASK;
val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
writel_relaxed(val, wdt_regs + PM_RSTC);
/* No sleeping, possibly atomic. */
mdelay(1);
}
/*
* We can't really power off, but if we do the normal reset scheme, and
* indicate to bootcode.bin not to reboot, then most of the chip will be
* powered off.
*/
static void bcm2835_power_off(void)
{
u32 val;
/*
* We set the watchdog hard reset bit here to distinguish this reset
* from the normal (full) reset. bootcode.bin will not reboot after a
* hard reset.
*/
val = readl_relaxed(wdt_regs + PM_RSTS);
val &= ~PM_RSTC_WRCFG_MASK;
val |= PM_PASSWORD | PM_RSTS_HADWRH_SET;
writel_relaxed(val, wdt_regs + PM_RSTS);
/* Continue with normal reset mechanism */
bcm2835_restart(REBOOT_HARD, "");
}
static struct map_desc io_map __initdata = {
.virtual = BCM2835_PERIPH_VIRT,
.pfn = __phys_to_pfn(BCM2835_PERIPH_PHYS),
.length = BCM2835_PERIPH_SIZE,
.type = MT_DEVICE
};
static void __init bcm2835_map_io(void)
{
iotable_init(&io_map, 1);
}
static void __init bcm2835_init(void)
{
int ret;
bcm2835_setup_restart();
if (wdt_regs)
pm_power_off = bcm2835_power_off;
bcm2835_init_clocks();
ret = of_platform_populate(NULL, of_default_bus_match_table, NULL,
NULL);
if (ret) {
pr_err("of_platform_populate failed: %d\n", ret);
BUG();
}
}
static const char * const bcm2835_compat[] = {
"brcm,bcm2835",
NULL
};
DT_MACHINE_START(BCM2835, "BCM2835")
.map_io = bcm2835_map_io,
.init_irq = irqchip_init,
.init_machine = bcm2835_init,
.restart = bcm2835_restart,
.dt_compat = bcm2835_compat
MACHINE_END