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 #include <linux/io.h> 21 22 #include <asm/cacheflush.h> 23 #include <mach/omap-wakeupgen.h> 24 25 #include "common.h" 26 27 #include "powerdomain.h" 28 29 int platform_cpu_kill(unsigned int cpu) 30 { 31 return 1; 32 } 33 34 /* 35 * platform-specific code to shutdown a CPU 36 * Called with IRQs disabled 37 */ 38 void __ref platform_cpu_die(unsigned int cpu) 39 { 40 unsigned int boot_cpu = 0; 41 void __iomem *base = omap_get_wakeupgen_base(); 42 43 flush_cache_all(); 44 dsb(); 45 46 /* 47 * we're ready for shutdown now, so do it 48 */ 49 if (omap_secure_apis_support()) { 50 if (omap_modify_auxcoreboot0(0x0, 0x200) != 0x0) 51 pr_err("Secure clear status failed\n"); 52 } else { 53 __raw_writel(0, base + OMAP_AUX_CORE_BOOT_0); 54 } 55 56 57 for (;;) { 58 /* 59 * Enter into low power state 60 */ 61 omap4_hotplug_cpu(cpu, PWRDM_POWER_OFF); 62 63 if (omap_secure_apis_support()) 64 boot_cpu = omap_read_auxcoreboot0(); 65 else 66 boot_cpu = 67 __raw_readl(base + OMAP_AUX_CORE_BOOT_0) >> 5; 68 69 if (boot_cpu == smp_processor_id()) { 70 /* 71 * OK, proper wakeup, we're done 72 */ 73 break; 74 } 75 pr_debug("CPU%u: spurious wakeup call\n", cpu); 76 } 77 } 78 79 int platform_cpu_disable(unsigned int cpu) 80 { 81 /* 82 * we don't allow CPU 0 to be shutdown (it is still too special 83 * e.g. clock tick interrupts) 84 */ 85 return cpu == 0 ? -EPERM : 0; 86 } 87