diff options
Diffstat (limited to 'arch/arm/mach-bcm/board_bcm2835.c')
-rw-r--r-- | arch/arm/mach-bcm/board_bcm2835.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/arch/arm/mach-bcm/board_bcm2835.c b/arch/arm/mach-bcm/board_bcm2835.c new file mode 100644 index 000000000..70f2f3925 --- /dev/null +++ b/arch/arm/mach-bcm/board_bcm2835.c @@ -0,0 +1,137 @@ +/* + * 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 |