From: Peter A. G. Crosthwaite <peter.crosthwa...@petalogix.com> Added a FIFO API that can be used to create and operate byte FIFOs.
Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwa...@petalogix.com> --- Changed since v8: Added documentation. Fixed copy paste error on VMSD name string hw/Makefile.objs | 1 + hw/fifo.c | 78 ++++++++++++++++++++++++++++++++++++++++++ hw/fifo.h | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 178 insertions(+), 0 deletions(-) create mode 100644 hw/fifo.c create mode 100644 hw/fifo.h diff --git a/hw/Makefile.objs b/hw/Makefile.objs index b59c749..66abbb2 100644 --- a/hw/Makefile.objs +++ b/hw/Makefile.objs @@ -35,6 +35,7 @@ common-obj-$(CONFIG_APPLESMC) += applesmc.o common-obj-$(CONFIG_SMARTCARD) += ccid-card-passthru.o common-obj-$(CONFIG_SMARTCARD_NSS) += ccid-card-emulated.o common-obj-$(CONFIG_I8259) += i8259_common.o i8259.o +common-obj-y += fifo.o # PPC devices common-obj-$(CONFIG_PREP_PCI) += prep_pci.o diff --git a/hw/fifo.c b/hw/fifo.c new file mode 100644 index 0000000..68a955a --- /dev/null +++ b/hw/fifo.c @@ -0,0 +1,78 @@ +/* + * Generic FIFO component, implemented as a circular buffer. + * + * Copyright (c) 2012 Peter A. G. Crosthwaite + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#include "fifo.h" + +void fifo8_create(Fifo8 *fifo, uint32_t capacity) +{ + fifo->data = g_new(uint8_t, capacity); + fifo->capacity = capacity; + fifo->head = 0; + fifo->num = 0; +} + +void fifo8_destroy(Fifo8 *fifo) +{ + g_free(fifo->data); +} + +void fifo8_push(Fifo8 *fifo, uint8_t data) +{ + if (fifo->num == fifo->capacity) { + abort(); + } + fifo->data[(fifo->head + fifo->num) % fifo->capacity] = data; + fifo->num++; +} + +uint8_t fifo8_pop(Fifo8 *fifo) +{ + uint8_t ret; + + if (fifo->num == 0) { + abort(); + } + ret = fifo->data[fifo->head++]; + fifo->head %= fifo->capacity; + fifo->num--; + return ret; +} + +void fifo8_reset(Fifo8 *fifo) +{ + fifo->num = 0; +} + +bool fifo8_is_empty(Fifo8 *fifo) +{ + return (fifo->num == 0); +} + +bool fifo8_is_full(Fifo8 *fifo) +{ + return (fifo->num == fifo->capacity); +} + +const VMStateDescription vmstate_fifo8 = { + .name = "Fifo8", + .version_id = 1, + .minimum_version_id = 1, + .minimum_version_id_old = 1, + .fields = (VMStateField[]) { + VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, 0, capacity), + VMSTATE_UINT32(head, Fifo8), + VMSTATE_UINT32(num, Fifo8), + VMSTATE_END_OF_LIST() + } +}; diff --git a/hw/fifo.h b/hw/fifo.h new file mode 100644 index 0000000..f23890a --- /dev/null +++ b/hw/fifo.h @@ -0,0 +1,99 @@ +#ifndef FIFO_H +#define FIFO_H + +#include "hw.h" + +typedef struct { + /* All fields are private */ + uint8_t *data; + uint32_t capacity; + uint32_t head; + uint32_t num; +} Fifo8; + +/** + * fifo8_create: + * @fifo: struct Fifo8 to initialise with new FIFO + * @capacity: capacity of the newly created FIFO + * + * Create a FIFO of the specified size. Clients should call fifo8_destroy() + * when finished using the fifo. The FIFO is initially empty. + */ + +void fifo8_create(Fifo8 *fifo, uint32_t capacity); + +/** + * fifo8_destroy: + * @fifo: FIFO to cleanup + * + * Cleanup a FIFO created with fifo8_create(). Frees memory created for FIFO + *storage. The FIFO is no longer usable after this has been called. + */ + +void fifo8_destroy(Fifo8 *fifo); + +/** + * fifo8_push: + * @fifo: FIFO to push to + * @data: data byte to push + * + * Push a data byte to the FIFO. Behaviour is undefined if the FIFO is full. + * Clients are responsible for checking for fullness using fifo8_is_full(). + */ + +void fifo8_push(Fifo8 *fifo, uint8_t data); + +/** + * fifo8_pop: + * @fifo: fifo to pop from + * + * Pop a data byte from the FIFO. Behaviour is undefined if the FIFO is empty. + * Clients are responsible for checking for emptyness using fifo8_is_empty(). + * + * Returns: The popped data byte. + */ + +uint8_t fifo8_pop(Fifo8 *fifo); + +/** + * fifo8_reset: + * @fifo: FIFO to reset + * + * Reset a FIFO. All data is discarded and the FIFO is emptied. + */ + +void fifo8_reset(Fifo8 *fifo); + +/** + * fifo8_is_empty: + * @fifo: FIFO to check + * + * Check if a FIFO is empty. + * + * Returns: True if the fifo is empty, false otherwise. + */ + +bool fifo8_is_empty(Fifo8 *fifo); + +/** + * fifo8_is_full: + * @fifo: FIFO to check + * + * Check if a FIFO is full. + * + * Returns: True if the fifo is full, false otherwise. + */ + +bool fifo8_is_full(Fifo8 *fifo); + +extern const VMStateDescription vmstate_fifo8; + +#define VMSTATE_FIFO8(_field, _state) { \ + .name = (stringify(_field)), \ + .size = sizeof(Fifo8), \ + .vmsd = &vmstate_fifo8, \ + .flags = VMS_STRUCT, \ + .offset = vmstate_offset_value(_state, _field, Fifo8), \ +} + +#endif /* FIFO_H */ -- 1.7.0.4
