| 1 | /* |
| 2 | * Copyright (C) 2010 Broadcom |
| 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 as published by |
| 6 | * the Free Software Foundation; either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 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. |
| 13 | */ |
| 14 | |
| 15 | #include <linux/delay.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/irqchip/bcm2835.h> |
| 18 | #include <linux/of_address.h> |
| 19 | #include <linux/of_platform.h> |
| 20 | #include <linux/clk/bcm2835.h> |
| 21 | #include <linux/clocksource.h> |
| 22 | |
| 23 | #include <asm/mach/arch.h> |
| 24 | #include <asm/mach/map.h> |
| 25 | |
| 26 | #include <mach/bcm2835_soc.h> |
| 27 | |
| 28 | #define PM_RSTC 0x1c |
| 29 | #define PM_RSTS 0x20 |
| 30 | #define PM_WDOG 0x24 |
| 31 | |
| 32 | #define PM_PASSWORD 0x5a000000 |
| 33 | #define PM_RSTC_WRCFG_MASK 0x00000030 |
| 34 | #define PM_RSTC_WRCFG_FULL_RESET 0x00000020 |
| 35 | #define PM_RSTS_HADWRH_SET 0x00000040 |
| 36 | |
| 37 | static void __iomem *wdt_regs; |
| 38 | |
| 39 | /* |
| 40 | * The machine restart method can be called from an atomic context so we won't |
| 41 | * be able to ioremap the regs then. |
| 42 | */ |
| 43 | static void bcm2835_setup_restart(void) |
| 44 | { |
| 45 | struct device_node *np = of_find_compatible_node(NULL, NULL, |
| 46 | "brcm,bcm2835-pm-wdt"); |
| 47 | if (WARN(!np, "unable to setup watchdog restart")) |
| 48 | return; |
| 49 | |
| 50 | wdt_regs = of_iomap(np, 0); |
| 51 | WARN(!wdt_regs, "failed to remap watchdog regs"); |
| 52 | } |
| 53 | |
| 54 | static void bcm2835_restart(char mode, const char *cmd) |
| 55 | { |
| 56 | u32 val; |
| 57 | |
| 58 | if (!wdt_regs) |
| 59 | return; |
| 60 | |
| 61 | /* use a timeout of 10 ticks (~150us) */ |
| 62 | writel_relaxed(10 | PM_PASSWORD, wdt_regs + PM_WDOG); |
| 63 | val = readl_relaxed(wdt_regs + PM_RSTC); |
| 64 | val &= ~PM_RSTC_WRCFG_MASK; |
| 65 | val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET; |
| 66 | writel_relaxed(val, wdt_regs + PM_RSTC); |
| 67 | |
| 68 | /* No sleeping, possibly atomic. */ |
| 69 | mdelay(1); |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * We can't really power off, but if we do the normal reset scheme, and |
| 74 | * indicate to bootcode.bin not to reboot, then most of the chip will be |
| 75 | * powered off. |
| 76 | */ |
| 77 | static void bcm2835_power_off(void) |
| 78 | { |
| 79 | u32 val; |
| 80 | |
| 81 | /* |
| 82 | * We set the watchdog hard reset bit here to distinguish this reset |
| 83 | * from the normal (full) reset. bootcode.bin will not reboot after a |
| 84 | * hard reset. |
| 85 | */ |
| 86 | val = readl_relaxed(wdt_regs + PM_RSTS); |
| 87 | val &= ~PM_RSTC_WRCFG_MASK; |
| 88 | val |= PM_PASSWORD | PM_RSTS_HADWRH_SET; |
| 89 | writel_relaxed(val, wdt_regs + PM_RSTS); |
| 90 | |
| 91 | /* Continue with normal reset mechanism */ |
| 92 | bcm2835_restart(0, ""); |
| 93 | } |
| 94 | |
| 95 | static struct map_desc io_map __initdata = { |
| 96 | .virtual = BCM2835_PERIPH_VIRT, |
| 97 | .pfn = __phys_to_pfn(BCM2835_PERIPH_PHYS), |
| 98 | .length = BCM2835_PERIPH_SIZE, |
| 99 | .type = MT_DEVICE |
| 100 | }; |
| 101 | |
| 102 | static void __init bcm2835_map_io(void) |
| 103 | { |
| 104 | iotable_init(&io_map, 1); |
| 105 | } |
| 106 | |
| 107 | static void __init bcm2835_init(void) |
| 108 | { |
| 109 | int ret; |
| 110 | |
| 111 | bcm2835_setup_restart(); |
| 112 | if (wdt_regs) |
| 113 | pm_power_off = bcm2835_power_off; |
| 114 | |
| 115 | bcm2835_init_clocks(); |
| 116 | |
| 117 | ret = of_platform_populate(NULL, of_default_bus_match_table, NULL, |
| 118 | NULL); |
| 119 | if (ret) { |
| 120 | pr_err("of_platform_populate failed: %d\n", ret); |
| 121 | BUG(); |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | static const char * const bcm2835_compat[] = { |
| 126 | "brcm,bcm2835", |
| 127 | NULL |
| 128 | }; |
| 129 | |
| 130 | DT_MACHINE_START(BCM2835, "BCM2835") |
| 131 | .map_io = bcm2835_map_io, |
| 132 | .init_irq = bcm2835_init_irq, |
| 133 | .handle_irq = bcm2835_handle_irq, |
| 134 | .init_machine = bcm2835_init, |
| 135 | .init_time = clocksource_of_init, |
| 136 | .restart = bcm2835_restart, |
| 137 | .dt_compat = bcm2835_compat |
| 138 | MACHINE_END |