c4e57af852
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>
161 lines
3.9 KiB
C
161 lines
3.9 KiB
C
#ifndef FIFO_H
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#define FIFO_H
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#include "migration/vmstate.h"
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typedef struct {
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/* All fields are private */
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uint8_t *data;
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uint32_t capacity;
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uint32_t head;
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uint32_t num;
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} Fifo8;
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/**
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* fifo8_create:
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* @fifo: struct Fifo8 to initialise with new FIFO
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* @capacity: capacity of the newly created FIFO
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*
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* Create a FIFO of the specified size. Clients should call fifo8_destroy()
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* when finished using the fifo. The FIFO is initially empty.
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*/
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void fifo8_create(Fifo8 *fifo, uint32_t capacity);
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/**
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* fifo8_destroy:
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* @fifo: FIFO to cleanup
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*
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* Cleanup a FIFO created with fifo8_create(). Frees memory created for FIFO
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*storage. The FIFO is no longer usable after this has been called.
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*/
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void fifo8_destroy(Fifo8 *fifo);
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/**
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* fifo8_push:
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* @fifo: FIFO to push to
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* @data: data byte to push
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*
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* Push a data byte to the FIFO. Behaviour is undefined if the FIFO is full.
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* Clients are responsible for checking for fullness using fifo8_is_full().
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*/
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void fifo8_push(Fifo8 *fifo, uint8_t data);
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/**
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* fifo8_push_all:
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* @fifo: FIFO to push to
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* @data: data to push
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* @size: number of bytes to push
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*
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* Push a byte array to the FIFO. Behaviour is undefined if the FIFO is full.
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* Clients are responsible for checking the space left in the FIFO using
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* fifo8_num_free().
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*/
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void fifo8_push_all(Fifo8 *fifo, const uint8_t *data, uint32_t num);
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/**
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* fifo8_pop:
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* @fifo: fifo to pop from
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*
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* Pop a data byte from the FIFO. Behaviour is undefined if the FIFO is empty.
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* Clients are responsible for checking for emptyness using fifo8_is_empty().
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*
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* Returns: The popped data byte.
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*/
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uint8_t fifo8_pop(Fifo8 *fifo);
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/**
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* fifo8_pop_buf:
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* @fifo: FIFO to pop from
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* @max: maximum number of bytes to pop
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* @num: actual number of returned bytes
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*
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* Pop a number of elements from the FIFO up to a maximum of max. The buffer
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* containing the popped data is returned. This buffer points directly into
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* the FIFO backing store and data is invalidated once any of the fifo8_* APIs
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* are called on the FIFO.
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*
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* The function may return fewer bytes than requested when the data wraps
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* around in the ring buffer; in this case only a contiguous part of the data
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* is returned.
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*
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* The number of valid bytes returned is populated in *num; will always return
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* at least 1 byte. max must not be 0 or greater than the number of bytes in
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* the FIFO.
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*
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* Clients are responsible for checking the availability of requested data
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* using fifo8_num_used().
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*
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* Returns: A pointer to popped data.
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*/
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const uint8_t *fifo8_pop_buf(Fifo8 *fifo, uint32_t max, uint32_t *num);
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/**
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* fifo8_reset:
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* @fifo: FIFO to reset
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*
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* Reset a FIFO. All data is discarded and the FIFO is emptied.
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*/
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void fifo8_reset(Fifo8 *fifo);
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/**
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* fifo8_is_empty:
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* @fifo: FIFO to check
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*
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* Check if a FIFO is empty.
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*
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* Returns: True if the fifo is empty, false otherwise.
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*/
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bool fifo8_is_empty(Fifo8 *fifo);
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/**
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* fifo8_is_full:
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* @fifo: FIFO to check
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*
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* Check if a FIFO is full.
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*
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* Returns: True if the fifo is full, false otherwise.
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*/
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bool fifo8_is_full(Fifo8 *fifo);
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/**
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* fifo8_num_free:
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* @fifo: FIFO to check
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*
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* Return the number of free bytes in the FIFO.
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*
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* Returns: Number of free bytes.
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*/
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uint32_t fifo8_num_free(Fifo8 *fifo);
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/**
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* fifo8_num_used:
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* @fifo: FIFO to check
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*
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* Return the number of used bytes in the FIFO.
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*
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* Returns: Number of used bytes.
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*/
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uint32_t fifo8_num_used(Fifo8 *fifo);
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extern const VMStateDescription vmstate_fifo8;
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#define VMSTATE_FIFO8(_field, _state) { \
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.name = (stringify(_field)), \
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.size = sizeof(Fifo8), \
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.vmsd = &vmstate_fifo8, \
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.flags = VMS_STRUCT, \
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.offset = vmstate_offset_value(_state, _field, Fifo8), \
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}
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#endif /* FIFO_H */
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