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author | Christopher Browne <cbbrowne@ca.afilias.info> | 2016-07-07 17:13:22 +0200 |
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committer | Christopher Browne <cbbrowne@ca.afilias.info> | 2016-07-07 17:13:22 +0200 |
commit | 97dfbd1afce005392aa8f067e89bdf95334bdea5 (patch) | |
tree | 1b198dd239bcb49564c31f124978abde0b467a81 /quantum/serial_link/protocol/triple_buffered_object.c | |
parent | 2e1cfaf73fccdfaba2d7542f00bd7c3d49998d5d (diff) | |
parent | ad43d450ca1b988d196da80e2a745f45f24068f6 (diff) | |
download | qmk_firmware-97dfbd1afce005392aa8f067e89bdf95334bdea5.tar.gz qmk_firmware-97dfbd1afce005392aa8f067e89bdf95334bdea5.tar.xz |
Merge branch 'master' of https://github.com/jackhumbert/qmk_firmware
Diffstat (limited to 'quantum/serial_link/protocol/triple_buffered_object.c')
-rw-r--r-- | quantum/serial_link/protocol/triple_buffered_object.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/quantum/serial_link/protocol/triple_buffered_object.c b/quantum/serial_link/protocol/triple_buffered_object.c new file mode 100644 index 000000000..e3e8989d3 --- /dev/null +++ b/quantum/serial_link/protocol/triple_buffered_object.c @@ -0,0 +1,78 @@ +/* +The MIT License (MIT) + +Copyright (c) 2016 Fred Sundvik + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. +*/ + +#include "serial_link/protocol/triple_buffered_object.h" +#include "serial_link/system/serial_link.h" +#include <stdbool.h> +#include <stddef.h> + +#define GET_READ_INDEX() object->state & 3 +#define GET_WRITE_INDEX() (object->state >> 2) & 3 +#define GET_SHARED_INDEX() (object->state >> 4) & 3 +#define GET_DATA_AVAILABLE() (object->state >> 6) & 1 + +#define SET_READ_INDEX(i) object->state = ((object->state & ~3) | i) +#define SET_WRITE_INDEX(i) object->state = ((object->state & ~(3 << 2)) | (i << 2)) +#define SET_SHARED_INDEX(i) object->state = ((object->state & ~(3 << 4)) | (i << 4)) +#define SET_DATA_AVAILABLE(i) object->state = ((object->state & ~(1 << 6)) | (i << 6)) + +void triple_buffer_init(triple_buffer_object_t* object) { + object->state = 0; + SET_WRITE_INDEX(0); + SET_READ_INDEX(1); + SET_SHARED_INDEX(2); + SET_DATA_AVAILABLE(0); +} + +void* triple_buffer_read_internal(uint16_t object_size, triple_buffer_object_t* object) { + serial_link_lock(); + if (GET_DATA_AVAILABLE()) { + uint8_t shared_index = GET_SHARED_INDEX(); + uint8_t read_index = GET_READ_INDEX(); + SET_READ_INDEX(shared_index); + SET_SHARED_INDEX(read_index); + SET_DATA_AVAILABLE(false); + serial_link_unlock(); + return object->buffer + object_size * shared_index; + } + else { + serial_link_unlock(); + return NULL; + } +} + +void* triple_buffer_begin_write_internal(uint16_t object_size, triple_buffer_object_t* object) { + uint8_t write_index = GET_WRITE_INDEX(); + return object->buffer + object_size * write_index; +} + +void triple_buffer_end_write_internal(triple_buffer_object_t* object) { + serial_link_lock(); + uint8_t shared_index = GET_SHARED_INDEX(); + uint8_t write_index = GET_WRITE_INDEX(); + SET_SHARED_INDEX(write_index); + SET_WRITE_INDEX(shared_index); + SET_DATA_AVAILABLE(true); + serial_link_unlock(); +} |