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author | David Howells <dhowells@redhat.com> | 2012-03-28 17:30:02 (GMT) |
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committer | David Howells <dhowells@redhat.com> | 2012-03-28 17:30:02 (GMT) |
commit | 8335896bed16d8b86a28ec5b1e0f723d1cf75aa8 (patch) | |
tree | ce95f070b734d4ad67ee4b2c3a7b04f433012c5d /arch/hexagon/include/asm/cmpxchg.h | |
parent | a5401ee3da720d29bcce90ed352738c85a71f6cf (diff) | |
download | linux-8335896bed16d8b86a28ec5b1e0f723d1cf75aa8.tar.xz |
Disintegrate asm/system.h for Hexagon
Disintegrate asm/system.h for Hexagon. Not compiled.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Richard Kuo <rkuo@codeaurora.org>
cc: linux-hexagon@vger.kernel.org
Diffstat (limited to 'arch/hexagon/include/asm/cmpxchg.h')
-rw-r--r-- | arch/hexagon/include/asm/cmpxchg.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/arch/hexagon/include/asm/cmpxchg.h b/arch/hexagon/include/asm/cmpxchg.h new file mode 100644 index 0000000..c5f9527 --- /dev/null +++ b/arch/hexagon/include/asm/cmpxchg.h @@ -0,0 +1,90 @@ +/* + * xchg/cmpxchg operations for the Hexagon architecture + * + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. + * + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#ifndef _ASM_CMPXCHG_H +#define _ASM_CMPXCHG_H + +/* + * __xchg - atomically exchange a register and a memory location + * @x: value to swap + * @ptr: pointer to memory + * @size: size of the value + * + * Only 4 bytes supported currently. + * + * Note: there was an errata for V2 about .new's and memw_locked. + * + */ +static inline unsigned long __xchg(unsigned long x, volatile void *ptr, + int size) +{ + unsigned long retval; + + /* Can't seem to use printk or panic here, so just stop */ + if (size != 4) do { asm volatile("brkpt;\n"); } while (1); + + __asm__ __volatile__ ( + "1: %0 = memw_locked(%1);\n" /* load into retval */ + " memw_locked(%1,P0) = %2;\n" /* store into memory */ + " if !P0 jump 1b;\n" + : "=&r" (retval) + : "r" (ptr), "r" (x) + : "memory", "p0" + ); + return retval; +} + +/* + * Atomically swap the contents of a register with memory. Should be atomic + * between multiple CPU's and within interrupts on the same CPU. + */ +#define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), \ + sizeof(*(ptr)))) + +/* + * see rt-mutex-design.txt; cmpxchg supposedly checks if *ptr == A and swaps. + * looks just like atomic_cmpxchg on our arch currently with a bunch of + * variable casting. + */ +#define __HAVE_ARCH_CMPXCHG 1 + +#define cmpxchg(ptr, old, new) \ +({ \ + __typeof__(ptr) __ptr = (ptr); \ + __typeof__(*(ptr)) __old = (old); \ + __typeof__(*(ptr)) __new = (new); \ + __typeof__(*(ptr)) __oldval = 0; \ + \ + asm volatile( \ + "1: %0 = memw_locked(%1);\n" \ + " { P0 = cmp.eq(%0,%2);\n" \ + " if (!P0.new) jump:nt 2f; }\n" \ + " memw_locked(%1,p0) = %3;\n" \ + " if (!P0) jump 1b;\n" \ + "2:\n" \ + : "=&r" (__oldval) \ + : "r" (__ptr), "r" (__old), "r" (__new) \ + : "memory", "p0" \ + ); \ + __oldval; \ +}) + +#endif /* _ASM_CMPXCHG_H */ |