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Diffstat (limited to 'drivers/gpu/mali400/r3p2/mali/common/mali_osk_bitops.h')
| -rw-r--r-- | drivers/gpu/mali400/r3p2/mali/common/mali_osk_bitops.h | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/drivers/gpu/mali400/r3p2/mali/common/mali_osk_bitops.h b/drivers/gpu/mali400/r3p2/mali/common/mali_osk_bitops.h new file mode 100644 index 0000000..f262f7d --- /dev/null +++ b/drivers/gpu/mali400/r3p2/mali/common/mali_osk_bitops.h @@ -0,0 +1,166 @@ +/* + * Copyright (C) 2010 ARM Limited. All rights reserved. + * + * This program is free software and is provided to you under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation, and any use by you of this program is subject to the terms of such GNU licence. + * + * A copy of the licence is included with the program, and can also be obtained from Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +/** + * @file mali_osk_bitops.h + * Implementation of the OS abstraction layer for the kernel device driver + */ + +#ifndef __MALI_OSK_BITOPS_H__ +#define __MALI_OSK_BITOPS_H__ + +#ifdef __cplusplus +extern "C" +{ +#endif + +MALI_STATIC_INLINE void _mali_internal_clear_bit( u32 bit, u32 *addr ) +{ + MALI_DEBUG_ASSERT( bit < 32 ); + MALI_DEBUG_ASSERT( NULL != addr ); + + (*addr) &= ~(1 << bit); +} + +MALI_STATIC_INLINE void _mali_internal_set_bit( u32 bit, u32 *addr ) +{ + MALI_DEBUG_ASSERT( bit < 32 ); + MALI_DEBUG_ASSERT( NULL != addr ); + + (*addr) |= (1 << bit); +} + +MALI_STATIC_INLINE u32 _mali_internal_test_bit( u32 bit, u32 value ) +{ + MALI_DEBUG_ASSERT( bit < 32 ); + return value & (1 << bit); +} + +MALI_STATIC_INLINE int _mali_internal_find_first_zero_bit( u32 value ) +{ + u32 inverted; + u32 negated; + u32 isolated; + u32 leading_zeros; + + /* Begin with xxx...x0yyy...y, where ys are 1, number of ys is in range 0..31 */ + inverted = ~value; /* zzz...z1000...0 */ + /* Using count_trailing_zeros on inverted value - + * See ARM System Developers Guide for details of count_trailing_zeros */ + + /* Isolate the zero: it is preceeded by a run of 1s, so add 1 to it */ + negated = (u32)-inverted ; /* -a == ~a + 1 (mod 2^n) for n-bit numbers */ + /* negated = xxx...x1000...0 */ + + isolated = negated & inverted ; /* xxx...x1000...0 & zzz...z1000...0, zs are ~xs */ + /* And so the first zero bit is in the same position as the 1 == number of 1s that preceeded it + * Note that the output is zero if value was all 1s */ + + leading_zeros = _mali_osk_clz( isolated ); + + return 31 - leading_zeros; +} + + +/** @defgroup _mali_osk_bitops OSK Non-atomic Bit-operations + * @{ */ + +/** + * These bit-operations do not work atomically, and so locks must be used if + * atomicity is required. + * + * Reference implementations for Little Endian are provided, and so it should + * not normally be necessary to re-implement these. Efficient bit-twiddling + * techniques are used where possible, implemented in portable C. + * + * Note that these reference implementations rely on _mali_osk_clz() being + * implemented. + */ + +/** @brief Clear a bit in a sequence of 32-bit words + * @param nr bit number to clear, starting from the (Little-endian) least + * significant bit + * @param addr starting point for counting. + */ +MALI_STATIC_INLINE void _mali_osk_clear_nonatomic_bit( u32 nr, u32 *addr ) +{ + addr += nr >> 5; /* find the correct word */ + nr = nr & ((1 << 5)-1); /* The bit number within the word */ + + _mali_internal_clear_bit( nr, addr ); +} + +/** @brief Set a bit in a sequence of 32-bit words + * @param nr bit number to set, starting from the (Little-endian) least + * significant bit + * @param addr starting point for counting. + */ +MALI_STATIC_INLINE void _mali_osk_set_nonatomic_bit( u32 nr, u32 *addr ) +{ + addr += nr >> 5; /* find the correct word */ + nr = nr & ((1 << 5)-1); /* The bit number within the word */ + + _mali_internal_set_bit( nr, addr ); +} + +/** @brief Test a bit in a sequence of 32-bit words + * @param nr bit number to test, starting from the (Little-endian) least + * significant bit + * @param addr starting point for counting. + * @return zero if bit was clear, non-zero if set. Do not rely on the return + * value being related to the actual word under test. + */ +MALI_STATIC_INLINE u32 _mali_osk_test_bit( u32 nr, u32 *addr ) +{ + addr += nr >> 5; /* find the correct word */ + nr = nr & ((1 << 5)-1); /* The bit number within the word */ + + return _mali_internal_test_bit( nr, *addr ); +} + +/* Return maxbit if not found */ +/** @brief Find the first zero bit in a sequence of 32-bit words + * @param addr starting point for search. + * @param maxbit the maximum number of bits to search + * @return the number of the first zero bit found, or maxbit if none were found + * in the specified range. + */ +MALI_STATIC_INLINE u32 _mali_osk_find_first_zero_bit( const u32 *addr, u32 maxbit ) +{ + u32 total; + + for ( total = 0; total < maxbit; total += 32, ++addr ) + { + int result; + result = _mali_internal_find_first_zero_bit( *addr ); + + /* non-negative signifies the bit was found */ + if ( result >= 0 ) + { + total += (u32)result; + break; + } + } + + /* Now check if we reached maxbit or above */ + if ( total >= maxbit ) + { + total = maxbit; + } + + return total; /* either the found bit nr, or maxbit if not found */ +} +/** @} */ /* end group _mali_osk_bitops */ + +#ifdef __cplusplus +} +#endif + +#endif /* __MALI_OSK_BITOPS_H__ */ |