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100 lines
1.9 KiB
100 lines
1.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* linux/arch/arm/mach-spear13xx/hotplug.c |
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* |
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* Copyright (C) 2012 ST Microelectronics Ltd. |
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* Deepak Sikri <[email protected]> |
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* |
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* based upon linux/arch/arm/mach-realview/hotplug.c |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/errno.h> |
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#include <linux/smp.h> |
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#include <asm/cp15.h> |
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#include <asm/smp_plat.h> |
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#include "generic.h" |
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static inline void cpu_enter_lowpower(void) |
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{ |
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unsigned int v; |
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asm volatile( |
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" mcr p15, 0, %1, c7, c5, 0\n" |
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" dsb\n" |
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/* |
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* Turn off coherency |
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*/ |
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" mrc p15, 0, %0, c1, c0, 1\n" |
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" bic %0, %0, #0x20\n" |
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" mcr p15, 0, %0, c1, c0, 1\n" |
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" mrc p15, 0, %0, c1, c0, 0\n" |
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" bic %0, %0, %2\n" |
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" mcr p15, 0, %0, c1, c0, 0\n" |
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: "=&r" (v) |
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: "r" (0), "Ir" (CR_C) |
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: "cc", "memory"); |
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} |
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static inline void cpu_leave_lowpower(void) |
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{ |
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unsigned int v; |
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asm volatile("mrc p15, 0, %0, c1, c0, 0\n" |
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" orr %0, %0, %1\n" |
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" mcr p15, 0, %0, c1, c0, 0\n" |
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" mrc p15, 0, %0, c1, c0, 1\n" |
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" orr %0, %0, #0x20\n" |
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" mcr p15, 0, %0, c1, c0, 1\n" |
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: "=&r" (v) |
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: "Ir" (CR_C) |
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: "cc"); |
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} |
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static inline void spear13xx_do_lowpower(unsigned int cpu, int *spurious) |
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{ |
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for (;;) { |
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wfi(); |
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if (spear_pen_release == cpu) { |
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/* |
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* OK, proper wakeup, we're done |
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*/ |
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break; |
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} |
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/* |
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* Getting here, means that we have come out of WFI without |
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* having been woken up - this shouldn't happen |
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* |
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* Just note it happening - when we're woken, we can report |
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* its occurrence. |
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*/ |
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(*spurious)++; |
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} |
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} |
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/* |
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* platform-specific code to shutdown a CPU |
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* |
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* Called with IRQs disabled |
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*/ |
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void spear13xx_cpu_die(unsigned int cpu) |
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{ |
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int spurious = 0; |
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/* |
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* we're ready for shutdown now, so do it |
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*/ |
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cpu_enter_lowpower(); |
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spear13xx_do_lowpower(cpu, &spurious); |
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/* |
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* bring this CPU back into the world of cache |
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* coherency, and then restore interrupts |
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*/ |
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cpu_leave_lowpower(); |
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if (spurious) |
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pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); |
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}
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