1 /* 2 * Copyright 2011 Freescale Semiconductor, Inc. 3 * Copyright 2011 Linaro Ltd. 4 * 5 * The code contained herein is licensed under the GNU General Public 6 * License. You may obtain a copy of the GNU General Public License 7 * Version 2 or later at the following locations: 8 * 9 * http://www.opensource.org/licenses/gpl-license.html 10 * http://www.gnu.org/copyleft/gpl.html 11 */ 12 13 #include <linux/errno.h> 14 #include <asm/cacheflush.h> 15 #include <asm/cp15.h> 16 #include <mach/common.h> 17 18 int platform_cpu_kill(unsigned int cpu) 19 { 20 return 1; 21 } 22 23 static inline void cpu_enter_lowpower(void) 24 { 25 unsigned int v; 26 27 flush_cache_all(); 28 asm volatile( 29 "mcr p15, 0, %1, c7, c5, 0\n" 30 " mcr p15, 0, %1, c7, c10, 4\n" 31 /* 32 * Turn off coherency 33 */ 34 " mrc p15, 0, %0, c1, c0, 1\n" 35 " bic %0, %0, %3\n" 36 " mcr p15, 0, %0, c1, c0, 1\n" 37 " mrc p15, 0, %0, c1, c0, 0\n" 38 " bic %0, %0, %2\n" 39 " mcr p15, 0, %0, c1, c0, 0\n" 40 : "=&r" (v) 41 : "r" (0), "Ir" (CR_C), "Ir" (0x40) 42 : "cc"); 43 } 44 45 /* 46 * platform-specific code to shutdown a CPU 47 * 48 * Called with IRQs disabled 49 */ 50 void platform_cpu_die(unsigned int cpu) 51 { 52 cpu_enter_lowpower(); 53 imx_enable_cpu(cpu, false); 54 55 /* spin here until hardware takes it down */ 56 while (1) 57 ; 58 } 59 60 int platform_cpu_disable(unsigned int cpu) 61 { 62 /* 63 * we don't allow CPU 0 to be shutdown (it is still too special 64 * e.g. clock tick interrupts) 65 */ 66 return cpu == 0 ? -EPERM : 0; 67 } 68