From 1a16f67a28c6e8b9875b07e15c7c379cfc147e69 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Mon, 19 Oct 2015 20:01:19 +0100 Subject: [arm] Add support for 32-bit ARM Signed-off-by: Michael Brown --- src/arch/arm/include/bits/bitops.h | 100 +++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 src/arch/arm/include/bits/bitops.h (limited to 'src/arch/arm/include/bits/bitops.h') diff --git a/src/arch/arm/include/bits/bitops.h b/src/arch/arm/include/bits/bitops.h new file mode 100644 index 000000000..9a5fe14c2 --- /dev/null +++ b/src/arch/arm/include/bits/bitops.h @@ -0,0 +1,100 @@ +#ifndef _BITS_BITOPS_H +#define _BITS_BITOPS_H + +/** @file + * + * ARM bit operations + * + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +#include + +/** + * Test and set bit atomically + * + * @v bit Bit to set + * @v bits Bit field + * @ret old Old value of bit (zero or non-zero) + */ +static inline __attribute__ (( always_inline )) int +test_and_set_bit ( unsigned int bit, volatile void *bits ) { + unsigned int index = ( bit / 32 ); + unsigned int offset = ( bit % 32 ); + volatile uint32_t *dword = ( ( ( volatile uint32_t * ) bits ) + index ); + uint32_t mask = ( 1UL << offset ); + uint32_t old; + uint32_t new; + uint32_t flag; + + __asm__ __volatile__ ( "\n1:\n\t" + "ldrex %0, %3\n\t" + "orr %1, %0, %4\n\t" + "strex %2, %1, %3\n\t" + "tst %2, %2\n\t" + "bne 1b\n\t" + : "=&r" ( old ), "=&r" ( new ), "=&l" ( flag ), + "+Q" ( *dword ) + : "r" ( mask ) + : "cc" ); + + return ( old & mask ); +} + +/** + * Test and clear bit atomically + * + * @v bit Bit to set + * @v bits Bit field + * @ret old Old value of bit (zero or non-zero) + */ +static inline __attribute__ (( always_inline )) int +test_and_clear_bit ( unsigned int bit, volatile void *bits ) { + unsigned int index = ( bit / 32 ); + unsigned int offset = ( bit % 32 ); + volatile uint32_t *dword = ( ( ( volatile uint32_t * ) bits ) + index ); + uint32_t mask = ( 1UL << offset ); + uint32_t old; + uint32_t new; + uint32_t flag; + + __asm__ __volatile__ ( "\n1:\n\t" + "ldrex %0, %3\n\t" + "bic %1, %0, %4\n\t" + "strex %2, %1, %3\n\t" + "tst %2, %2\n\t" + "bne 1b\n\t" + : "=&r" ( old ), "=&r" ( new ), "=&l" ( flag ), + "+Q" ( *dword ) + : "r" ( mask ) + : "cc" ); + + return ( old & mask ); +} + +/** + * Set bit atomically + * + * @v bit Bit to set + * @v bits Bit field + */ +static inline __attribute__ (( always_inline )) void +set_bit ( unsigned int bit, volatile void *bits ) { + + test_and_set_bit ( bit, bits ); +} + +/** + * Clear bit atomically + * + * @v bit Bit to set + * @v bits Bit field + */ +static inline __attribute__ (( always_inline )) void +clear_bit ( unsigned int bit, volatile void *bits ) { + + test_and_clear_bit ( bit, bits ); +} + +#endif /* _BITS_BITOPS_H */ -- cgit v1.2.3-55-g7522