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include: sbi_bitops: More useful bit operations

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This patch extends our bit operation library with mechanism to:
1. Iteratively traverse bits
2. Set bit
3. Clear bit
4. Change bit
5. ... other helpful functions ...

Most the above is adopted from Xvisor sources.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
This commit is contained in:
Anup Patel
2020-03-04 11:48:31 +05:30
committed by Anup Patel
parent 00d332bbe7
commit a148996a7f
3 changed files with 340 additions and 2 deletions
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141
include/sbi/sbi_bitops.h
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@@ -4,7 +4,7 @@
* Copyright (c) 2019 Western Digital Corporation or its affiliates.
*
* Authors:
* Atish Patra<atish.patra@wdc.com>
* Atish Patra <atish.patra@wdc.com>
*/
#ifndef __SBI_BITOPS_H__
@@ -25,8 +25,16 @@
#define INSERT_FIELD(val, which, fieldval) \
(((val) & ~(which)) | ((fieldval) * ((which) & ~((which)-1))))
#define BITS_TO_LONGS(nbits) (((nbits) + BITS_PER_LONG - 1) / \
BITS_PER_LONG)
#define BIT(nr) (1UL << (nr))
#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
#define BIT_WORD(bit) ((bit) / BITS_PER_LONG)
#define BIT_WORD_OFFSET(bit) ((bit) & (BITS_PER_LONG - 1))
#define GENMASK(h, l) \
(((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
/**
* ffs - Find first bit set
@@ -184,4 +192,133 @@ static inline unsigned long __fls(unsigned long word)
return num;
}
#define for_each_set_bit(bit, addr, size) \
for ((bit) = find_first_bit((addr), (size)); \
(bit) < (size); \
(bit) = find_next_bit((addr), (size), (bit) + 1))
/* same as for_each_set_bit() but use bit as value to start with */
#define for_each_set_bit_from(bit, addr, size) \
for ((bit) = find_next_bit((addr), (size), (bit)); \
(bit) < (size); \
(bit) = find_next_bit((addr), (size), (bit) + 1))
#define for_each_clear_bit(bit, addr, size) \
for ((bit) = find_first_zero_bit((addr), (size)); \
(bit) < (size); \
(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
/* same as for_each_clear_bit() but use bit as value to start with */
#define for_each_clear_bit_from(bit, addr, size) \
for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
(bit) < (size); \
(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
unsigned long find_first_bit(const unsigned long *addr,
unsigned long size);
unsigned long find_first_zero_bit(const unsigned long *addr,
unsigned long size);
unsigned long find_last_bit(const unsigned long *addr,
unsigned long size);
unsigned long find_next_bit(const unsigned long *addr,
unsigned long size, unsigned long offset);
unsigned long find_next_zero_bit(const unsigned long *addr,
unsigned long size,
unsigned long offset);
/**
* __set_bit - Set a bit in memory
* @nr: the bit to set
* @addr: the address to start counting from
*
* This function is non-atomic and may be reordered.
*/
static inline void __set_bit(int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
*p |= mask;
}
/**
* __clear_bit - Clear a bit in memory
* @nr: the bit to clear
* @addr: the address to start counting from
*
* This function is non-atomic and may be reordered.
*/
static inline void __clear_bit(int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
*p &= ~mask;
}
/**
* __change_bit - Toggle a bit in memory
* @nr: the bit to change
* @addr: the address to start counting from
*
* This function is non-atomic and may be reordered.
*/
static inline void __change_bit(int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
*p ^= mask;
}
/**
* __test_and_set_bit - Set a bit and return its old value
* @nr: Bit to set
* @addr: Address to count from
*
* This operation is non-atomic and can be reordered.
*/
static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
unsigned long old = *p;
*p = old | mask;
return (old & mask) != 0;
}
/**
* __test_and_clear_bit - Clear a bit and return its old value
* @nr: Bit to clear
* @addr: Address to count from
*
* This operation is non-atomic and can be reordered.
*/
static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
unsigned long old = *p;
*p = old & ~mask;
return (old & mask) != 0;
}
/**
* __test_bit - Determine whether a bit is set
* @nr: bit number to test
* @addr: Address to start counting from
*
* This operation is non-atomic and can be reordered.
*/
static inline int __test_bit(int nr, const volatile unsigned long *addr)
{
return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
}
#endif