Russell King | 045ab94 | 2015-04-01 17:02:45 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 1996-2000 Russell King - Converted to ARM. |
| 3 | * Original Copyright (C) 1995 Linus Torvalds |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | */ |
| 9 | #include <linux/cpu.h> |
| 10 | #include <linux/delay.h> |
| 11 | #include <linux/reboot.h> |
| 12 | |
| 13 | #include <asm/cacheflush.h> |
| 14 | #include <asm/idmap.h> |
| 15 | |
| 16 | #include "reboot.h" |
| 17 | |
| 18 | typedef void (*phys_reset_t)(unsigned long); |
| 19 | |
| 20 | /* |
| 21 | * Function pointers to optional machine specific functions |
| 22 | */ |
| 23 | void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); |
| 24 | void (*pm_power_off)(void); |
| 25 | EXPORT_SYMBOL(pm_power_off); |
| 26 | |
| 27 | /* |
| 28 | * A temporary stack to use for CPU reset. This is static so that we |
| 29 | * don't clobber it with the identity mapping. When running with this |
| 30 | * stack, any references to the current task *will not work* so you |
| 31 | * should really do as little as possible before jumping to your reset |
| 32 | * code. |
| 33 | */ |
| 34 | static u64 soft_restart_stack[16]; |
| 35 | |
| 36 | static void __soft_restart(void *addr) |
| 37 | { |
| 38 | phys_reset_t phys_reset; |
| 39 | |
| 40 | /* Take out a flat memory mapping. */ |
| 41 | setup_mm_for_reboot(); |
| 42 | |
| 43 | /* Clean and invalidate caches */ |
| 44 | flush_cache_all(); |
| 45 | |
| 46 | /* Turn off caching */ |
| 47 | cpu_proc_fin(); |
| 48 | |
| 49 | /* Push out any further dirty data, and ensure cache is empty */ |
| 50 | flush_cache_all(); |
| 51 | |
| 52 | /* Switch to the identity mapping. */ |
Russell King | 2841029 | 2016-01-11 17:15:58 +0000 | [diff] [blame] | 53 | phys_reset = (phys_reset_t)virt_to_idmap(cpu_reset); |
Russell King | 045ab94 | 2015-04-01 17:02:45 +0100 | [diff] [blame] | 54 | phys_reset((unsigned long)addr); |
| 55 | |
| 56 | /* Should never get here. */ |
| 57 | BUG(); |
| 58 | } |
| 59 | |
| 60 | void _soft_restart(unsigned long addr, bool disable_l2) |
| 61 | { |
| 62 | u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); |
| 63 | |
| 64 | /* Disable interrupts first */ |
| 65 | raw_local_irq_disable(); |
| 66 | local_fiq_disable(); |
| 67 | |
| 68 | /* Disable the L2 if we're the last man standing. */ |
| 69 | if (disable_l2) |
| 70 | outer_disable(); |
| 71 | |
| 72 | /* Change to the new stack and continue with the reset. */ |
| 73 | call_with_stack(__soft_restart, (void *)addr, (void *)stack); |
| 74 | |
| 75 | /* Should never get here. */ |
| 76 | BUG(); |
| 77 | } |
| 78 | |
| 79 | void soft_restart(unsigned long addr) |
| 80 | { |
| 81 | _soft_restart(addr, num_online_cpus() == 1); |
| 82 | } |
| 83 | |
| 84 | /* |
| 85 | * Called by kexec, immediately prior to machine_kexec(). |
| 86 | * |
| 87 | * This must completely disable all secondary CPUs; simply causing those CPUs |
| 88 | * to execute e.g. a RAM-based pin loop is not sufficient. This allows the |
| 89 | * kexec'd kernel to use any and all RAM as it sees fit, without having to |
| 90 | * avoid any code or data used by any SW CPU pin loop. The CPU hotplug |
| 91 | * functionality embodied in disable_nonboot_cpus() to achieve this. |
| 92 | */ |
| 93 | void machine_shutdown(void) |
| 94 | { |
| 95 | disable_nonboot_cpus(); |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * Halting simply requires that the secondary CPUs stop performing any |
| 100 | * activity (executing tasks, handling interrupts). smp_send_stop() |
| 101 | * achieves this. |
| 102 | */ |
| 103 | void machine_halt(void) |
| 104 | { |
| 105 | local_irq_disable(); |
| 106 | smp_send_stop(); |
Russell King | 045ab94 | 2015-04-01 17:02:45 +0100 | [diff] [blame] | 107 | while (1); |
| 108 | } |
| 109 | |
| 110 | /* |
| 111 | * Power-off simply requires that the secondary CPUs stop performing any |
| 112 | * activity (executing tasks, handling interrupts). smp_send_stop() |
| 113 | * achieves this. When the system power is turned off, it will take all CPUs |
| 114 | * with it. |
| 115 | */ |
| 116 | void machine_power_off(void) |
| 117 | { |
| 118 | local_irq_disable(); |
| 119 | smp_send_stop(); |
| 120 | |
| 121 | if (pm_power_off) |
| 122 | pm_power_off(); |
| 123 | } |
| 124 | |
| 125 | /* |
| 126 | * Restart requires that the secondary CPUs stop performing any activity |
| 127 | * while the primary CPU resets the system. Systems with a single CPU can |
| 128 | * use soft_restart() as their machine descriptor's .restart hook, since that |
| 129 | * will cause the only available CPU to reset. Systems with multiple CPUs must |
| 130 | * provide a HW restart implementation, to ensure that all CPUs reset at once. |
| 131 | * This is required so that any code running after reset on the primary CPU |
| 132 | * doesn't have to co-ordinate with other CPUs to ensure they aren't still |
| 133 | * executing pre-reset code, and using RAM that the primary CPU's code wishes |
| 134 | * to use. Implementing such co-ordination would be essentially impossible. |
| 135 | */ |
| 136 | void machine_restart(char *cmd) |
| 137 | { |
| 138 | local_irq_disable(); |
| 139 | smp_send_stop(); |
| 140 | |
| 141 | if (arm_pm_restart) |
| 142 | arm_pm_restart(reboot_mode, cmd); |
| 143 | else |
| 144 | do_kernel_restart(cmd); |
| 145 | |
| 146 | /* Give a grace period for failure to restart of 1s */ |
| 147 | mdelay(1000); |
| 148 | |
| 149 | /* Whoops - the platform was unable to reboot. Tell the user! */ |
| 150 | printk("Reboot failed -- System halted\n"); |
Russell King | 045ab94 | 2015-04-01 17:02:45 +0100 | [diff] [blame] | 151 | while (1); |
| 152 | } |