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)
set_my_cpu_offset(unsigned long off)24 static 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
__my_cpu_offset(void)30 static 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_ */
53