1 /* 2 * OMAP4 SMP cpu-hotplug support 3 * 4 * Copyright (C) 2010 Texas Instruments, Inc. 5 * Author: 6 * Santosh Shilimkar <santosh.shilimkar@ti.com> 7 * 8 * Platform file needed for the OMAP4 SMP. This file is based on arm 9 * realview smp platform. 10 * Copyright (c) 2002 ARM Limited. 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 as 14 * published by the Free Software Foundation. 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/errno.h> 19 #include <linux/smp.h> 20 21 #include <asm/cacheflush.h> 22 23 #include "common.h" 24 25 #include "powerdomain.h" 26 27 int platform_cpu_kill(unsigned int cpu) 28 { 29 return 1; 30 } 31 32 /* 33 * platform-specific code to shutdown a CPU 34 * Called with IRQs disabled 35 */ 36 void platform_cpu_die(unsigned int cpu) 37 { 38 unsigned int this_cpu; 39 40 flush_cache_all(); 41 dsb(); 42 43 /* 44 * we're ready for shutdown now, so do it 45 */ 46 if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0) 47 pr_err("Secure clear status failed\n"); 48 49 for (;;) { 50 /* 51 * Enter into low power state 52 */ 53 omap4_hotplug_cpu(cpu, PWRDM_POWER_OFF); 54 this_cpu = smp_processor_id(); 55 if (omap_read_auxcoreboot0() == this_cpu) { 56 /* 57 * OK, proper wakeup, we're done 58 */ 59 break; 60 } 61 pr_debug("CPU%u: spurious wakeup call\n", cpu); 62 } 63 } 64 65 int platform_cpu_disable(unsigned int cpu) 66 { 67 /* 68 * we don't allow CPU 0 to be shutdown (it is still too special 69 * e.g. clock tick interrupts) 70 */ 71 return cpu == 0 ? -EPERM : 0; 72 } 73