diff options
author | Beniamino Galvani <b.galvani@gmail.com> | 2014-01-30 23:02:04 +0100 |
---|---|---|
committer | Peter Maydell <peter.maydell@linaro.org> | 2014-02-08 14:50:48 +0000 |
commit | c4e57af85272f98c28ccaaace040d2abb0ec85c4 (patch) | |
tree | 938aac8abdac098c0fe345eabae33c033894ceb2 /include/qemu | |
parent | 999b53ec8794f203964db3ecf939a3da5c4bc843 (diff) | |
download | hqemu-c4e57af85272f98c28ccaaace040d2abb0ec85c4.zip hqemu-c4e57af85272f98c28ccaaace040d2abb0ec85c4.tar.gz |
util/fifo8: implement push/pop of multiple bytes
The patch adds functions fifo8_push_all() and fifo8_pop_buf() which
can be used respectively to push the content of a memory buffer to the
fifo and to pop multiple bytes obtaining a pointer to the fifo backing
buffer.
In addition, it implements fifo8_num_free() and fifo8_num_used() which
allow to check if a multi-byte operation can be performed.
Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'include/qemu')
-rw-r--r-- | include/qemu/fifo8.h | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/include/qemu/fifo8.h b/include/qemu/fifo8.h index d318f71..8820780 100644 --- a/include/qemu/fifo8.h +++ b/include/qemu/fifo8.h @@ -44,6 +44,19 @@ void fifo8_destroy(Fifo8 *fifo); void fifo8_push(Fifo8 *fifo, uint8_t data); /** + * fifo8_push_all: + * @fifo: FIFO to push to + * @data: data to push + * @size: number of bytes to push + * + * Push a byte array to the FIFO. Behaviour is undefined if the FIFO is full. + * Clients are responsible for checking the space left in the FIFO using + * fifo8_num_free(). + */ + +void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num); + +/** * fifo8_pop: * @fifo: fifo to pop from * @@ -56,6 +69,32 @@ void fifo8_push(Fifo8 *fifo, uint8_t data); uint8_t fifo8_pop(Fifo8 *fifo); /** + * fifo8_pop_buf: + * @fifo: FIFO to pop from + * @max: maximum number of bytes to pop + * @num: actual number of returned bytes + * + * Pop a number of elements from the FIFO up to a maximum of max. The buffer + * containing the popped data is returned. This buffer points directly into + * the FIFO backing store and data is invalidated once any of the fifo8_* APIs + * are called on the FIFO. + * + * The function may return fewer bytes than requested when the data wraps + * around in the ring buffer; in this case only a contiguous part of the data + * is returned. + * + * The number of valid bytes returned is populated in *num; will always return + * at least 1 byte. max must not be 0 or greater than the number of bytes in + * the FIFO. + * + * Clients are responsible for checking the availability of requested data + * using fifo8_num_used(). + * + * Returns: A pointer to popped data. + */ +const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num); + +/** * fifo8_reset: * @fifo: FIFO to reset * @@ -86,6 +125,28 @@ bool fifo8_is_empty(Fifo8 *fifo); bool fifo8_is_full(Fifo8 *fifo); +/** + * fifo8_num_free: + * @fifo: FIFO to check + * + * Return the number of free bytes in the FIFO. + * + * Returns: Number of free bytes. + */ + +uint32_t fifo8_num_free(Fifo8 *fifo); + +/** + * fifo8_num_used: + * @fifo: FIFO to check + * + * Return the number of used bytes in the FIFO. + * + * Returns: Number of used bytes. + */ + +uint32_t fifo8_num_used(Fifo8 *fifo); + extern const VMStateDescription vmstate_fifo8; #define VMSTATE_FIFO8(_field, _state) { \ |