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
20static 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 */
46void 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
60int 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