• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 <linux/jiffies.h>
15 #include <asm/cp15.h>
16 #include <asm/proc-fns.h>
17 
18 #include "common.h"
19 
cpu_enter_lowpower(void)20 static inline void cpu_enter_lowpower(void)
21 {
22 	unsigned int v;
23 
24 	asm volatile(
25 		"mcr	p15, 0, %1, c7, c5, 0\n"
26 	"	mcr	p15, 0, %1, c7, c10, 4\n"
27 	/*
28 	 * Turn off coherency
29 	 */
30 	"	mrc	p15, 0, %0, c1, c0, 1\n"
31 	"	bic	%0, %0, %3\n"
32 	"	mcr	p15, 0, %0, c1, c0, 1\n"
33 	"	mrc	p15, 0, %0, c1, c0, 0\n"
34 	"	bic	%0, %0, %2\n"
35 	"	mcr	p15, 0, %0, c1, c0, 0\n"
36 	  : "=&r" (v)
37 	  : "r" (0), "Ir" (CR_C), "Ir" (0x40)
38 	  : "cc");
39 }
40 
41 /*
42  * platform-specific code to shutdown a CPU
43  *
44  * Called with IRQs disabled
45  */
imx_cpu_die(unsigned int cpu)46 void imx_cpu_die(unsigned int cpu)
47 {
48 	cpu_enter_lowpower();
49 	/*
50 	 * We use the cpu jumping argument register to sync with
51 	 * imx_cpu_kill() which is running on cpu0 and waiting for
52 	 * the register being cleared to kill the cpu.
53 	 */
54 	imx_set_cpu_arg(cpu, ~0);
55 
56 	while (1)
57 		cpu_do_idle();
58 }
59 
imx_cpu_kill(unsigned int cpu)60 int imx_cpu_kill(unsigned int cpu)
61 {
62 	unsigned long timeout = jiffies + msecs_to_jiffies(50);
63 
64 	while (imx_get_cpu_arg(cpu) == 0)
65 		if (time_after(jiffies, timeout))
66 			return 0;
67 	imx_enable_cpu(cpu, false);
68 	imx_set_cpu_arg(cpu, 0);
69 	return 1;
70 }
71