1/*
 2 * Copyright 2012 Calxeda, Inc.
 3 *
 4 * This program is free software; you can redistribute it and/or modify it
 5 * under the terms and conditions of the GNU General Public License,
 6 * version 2, as published by the Free Software Foundation.
 7 *
 8 * This program is distributed in the hope it will be useful, but WITHOUT
 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program.  If not, see <http://www.gnu.org/licenses/>.
15 */
16#ifndef _ASM_ARM_PERCPU_H_
17#define _ASM_ARM_PERCPU_H_
18
19/*
20 * Same as asm-generic/percpu.h, except that we store the per cpu offset
21 * in the TPIDRPRW. TPIDRPRW only exists on V6K and V7
22 */
23#if defined(CONFIG_SMP) && !defined(CONFIG_CPU_V6)
24static inline void set_my_cpu_offset(unsigned long off)
25{
26	/* Set TPIDRPRW */
27	asm volatile("mcr p15, 0, %0, c13, c0, 4" : : "r" (off) : "memory");
28}
29
30static inline unsigned long __my_cpu_offset(void)
31{
32	unsigned long off;
33	register unsigned long *sp asm ("sp");
34
35	/*
36	 * Read TPIDRPRW.
37	 * We want to allow caching the value, so avoid using volatile and
38	 * instead use a fake stack read to hazard against barrier().
39	 */
40	asm("mrc p15, 0, %0, c13, c0, 4" : "=r" (off) : "Q" (*sp));
41
42	return off;
43}
44#define __my_cpu_offset __my_cpu_offset()
45#else
46#define set_my_cpu_offset(x)	do {} while(0)
47
48#endif /* CONFIG_SMP */
49
50#include <asm-generic/percpu.h>
51
52#endif /* _ASM_ARM_PERCPU_H_ */