141 lines
3.4 KiB
C
141 lines
3.4 KiB
C
/*
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* Copyright (C) 2010 Broadcom
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/irqchip/bcm2835.h>
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#include <linux/of_address.h>
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#include <linux/of_platform.h>
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#include <linux/clk/bcm2835.h>
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#include <linux/clocksource.h>
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#include <asm/mach/arch.h>
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#include <asm/mach/map.h>
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#define PM_RSTC 0x1c
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#define PM_RSTS 0x20
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#define PM_WDOG 0x24
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#define PM_PASSWORD 0x5a000000
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#define PM_RSTC_WRCFG_MASK 0x00000030
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#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
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#define PM_RSTS_HADWRH_SET 0x00000040
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#define BCM2835_PERIPH_PHYS 0x20000000
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#define BCM2835_PERIPH_VIRT 0xf0000000
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#define BCM2835_PERIPH_SIZE SZ_16M
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static void __iomem *wdt_regs;
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/*
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* The machine restart method can be called from an atomic context so we won't
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* be able to ioremap the regs then.
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*/
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static void bcm2835_setup_restart(void)
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{
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struct device_node *np = of_find_compatible_node(NULL, NULL,
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"brcm,bcm2835-pm-wdt");
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if (WARN(!np, "unable to setup watchdog restart"))
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return;
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wdt_regs = of_iomap(np, 0);
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WARN(!wdt_regs, "failed to remap watchdog regs");
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}
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static void bcm2835_restart(char mode, const char *cmd)
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{
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u32 val;
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if (!wdt_regs)
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return;
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/* use a timeout of 10 ticks (~150us) */
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writel_relaxed(10 | PM_PASSWORD, wdt_regs + PM_WDOG);
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val = readl_relaxed(wdt_regs + PM_RSTC);
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val &= ~PM_RSTC_WRCFG_MASK;
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val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
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writel_relaxed(val, wdt_regs + PM_RSTC);
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/* No sleeping, possibly atomic. */
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mdelay(1);
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}
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/*
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* We can't really power off, but if we do the normal reset scheme, and
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* indicate to bootcode.bin not to reboot, then most of the chip will be
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* powered off.
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*/
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static void bcm2835_power_off(void)
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{
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u32 val;
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/*
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* We set the watchdog hard reset bit here to distinguish this reset
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* from the normal (full) reset. bootcode.bin will not reboot after a
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* hard reset.
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*/
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val = readl_relaxed(wdt_regs + PM_RSTS);
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val &= ~PM_RSTC_WRCFG_MASK;
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val |= PM_PASSWORD | PM_RSTS_HADWRH_SET;
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writel_relaxed(val, wdt_regs + PM_RSTS);
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/* Continue with normal reset mechanism */
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bcm2835_restart(0, "");
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}
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static struct map_desc io_map __initdata = {
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.virtual = BCM2835_PERIPH_VIRT,
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.pfn = __phys_to_pfn(BCM2835_PERIPH_PHYS),
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.length = BCM2835_PERIPH_SIZE,
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.type = MT_DEVICE
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};
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static void __init bcm2835_map_io(void)
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{
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iotable_init(&io_map, 1);
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}
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static void __init bcm2835_init(void)
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{
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int ret;
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bcm2835_setup_restart();
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if (wdt_regs)
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pm_power_off = bcm2835_power_off;
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bcm2835_init_clocks();
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ret = of_platform_populate(NULL, of_default_bus_match_table, NULL,
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NULL);
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if (ret) {
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pr_err("of_platform_populate failed: %d\n", ret);
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BUG();
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}
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}
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static const char * const bcm2835_compat[] = {
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"brcm,bcm2835",
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NULL
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};
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DT_MACHINE_START(BCM2835, "BCM2835")
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.map_io = bcm2835_map_io,
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.init_irq = bcm2835_init_irq,
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.handle_irq = bcm2835_handle_irq,
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.init_machine = bcm2835_init,
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.init_time = clocksource_of_init,
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.restart = bcm2835_restart,
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.dt_compat = bcm2835_compat
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MACHINE_END
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