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