^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * Copyright (C) 2017 Imagination Technologies
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) * Author: Paul Burton <paul.burton@mips.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #include <linux/bitops.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <asm/cmpxchg.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) unsigned long __xchg_small(volatile void *ptr, unsigned long val, unsigned int size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) u32 old32, new32, load32, mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) volatile u32 *ptr32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) unsigned int shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) /* Check that ptr is naturally aligned */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) WARN_ON((unsigned long)ptr & (size - 1));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) /* Mask value to the correct size. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) mask = GENMASK((size * BITS_PER_BYTE) - 1, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) val &= mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * Calculate a shift & mask that correspond to the value we wish to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) * exchange within the naturally aligned 4 byte integerthat includes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) shift = (unsigned long)ptr & 0x3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) shift ^= sizeof(u32) - size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) shift *= BITS_PER_BYTE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) mask <<= shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) * Calculate a pointer to the naturally aligned 4 byte integer that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * includes our byte of interest, and load its value.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) ptr32 = (volatile u32 *)((unsigned long)ptr & ~0x3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) load32 = *ptr32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) old32 = load32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) new32 = (load32 & ~mask) | (val << shift);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) load32 = cmpxchg(ptr32, old32, new32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) } while (load32 != old32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) return (load32 & mask) >> shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) unsigned long __cmpxchg_small(volatile void *ptr, unsigned long old,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) unsigned long new, unsigned int size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) u32 mask, old32, new32, load32, load;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) volatile u32 *ptr32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) unsigned int shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) /* Check that ptr is naturally aligned */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) WARN_ON((unsigned long)ptr & (size - 1));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) /* Mask inputs to the correct size. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) mask = GENMASK((size * BITS_PER_BYTE) - 1, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) old &= mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) new &= mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) * Calculate a shift & mask that correspond to the value we wish to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) * compare & exchange within the naturally aligned 4 byte integer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) * that includes it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) shift = (unsigned long)ptr & 0x3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) shift ^= sizeof(u32) - size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) shift *= BITS_PER_BYTE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) mask <<= shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) * Calculate a pointer to the naturally aligned 4 byte integer that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) * includes our byte of interest, and load its value.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) ptr32 = (volatile u32 *)((unsigned long)ptr & ~0x3);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) load32 = *ptr32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) while (true) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) * Ensure the byte we want to exchange matches the expected
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) * old value, and if not then bail.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) load = (load32 & mask) >> shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) if (load != old)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) return load;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) * Calculate the old & new values of the naturally aligned
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) * 4 byte integer that include the byte we want to exchange.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) * Attempt to exchange the old value for the new value, and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) * return if we succeed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) old32 = (load32 & ~mask) | (old << shift);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) new32 = (load32 & ~mask) | (new << shift);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) load32 = cmpxchg(ptr32, old32, new32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) if (load32 == old32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) return old;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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