1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright(c) 2010-2014 Intel Corporation. 4 */ 5 6 #ifndef _KNI_FIFO_H_ 7 #define _KNI_FIFO_H_ 8 9 #include <rte_kni_common.h> 10 11 /* Skip some memory barriers on Linux < 3.14 */ 12 #ifndef smp_load_acquire 13 #define smp_load_acquire(a) (*(a)) 14 #endif 15 #ifndef smp_store_release 16 #define smp_store_release(a, b) *(a) = (b) 17 #endif 18 19 /** 20 * Adds num elements into the fifo. Return the number actually written 21 */ 22 static inline uint32_t 23 kni_fifo_put(struct rte_kni_fifo *fifo, void **data, uint32_t num) 24 { 25 uint32_t i = 0; 26 uint32_t fifo_write = fifo->write; 27 uint32_t fifo_read = smp_load_acquire(&fifo->read); 28 uint32_t new_write = fifo_write; 29 30 for (i = 0; i < num; i++) { 31 new_write = (new_write + 1) & (fifo->len - 1); 32 33 if (new_write == fifo_read) 34 break; 35 fifo->buffer[fifo_write] = data[i]; 36 fifo_write = new_write; 37 } 38 smp_store_release(&fifo->write, fifo_write); 39 40 return i; 41 } 42 43 /** 44 * Get up to num elements from the FIFO. Return the number actually read 45 */ 46 static inline uint32_t 47 kni_fifo_get(struct rte_kni_fifo *fifo, void **data, uint32_t num) 48 { 49 uint32_t i = 0; 50 uint32_t new_read = fifo->read; 51 uint32_t fifo_write = smp_load_acquire(&fifo->write); 52 53 for (i = 0; i < num; i++) { 54 if (new_read == fifo_write) 55 break; 56 57 data[i] = fifo->buffer[new_read]; 58 new_read = (new_read + 1) & (fifo->len - 1); 59 } 60 smp_store_release(&fifo->read, new_read); 61 62 return i; 63 } 64 65 /** 66 * Get the num of elements in the fifo 67 */ 68 static inline uint32_t 69 kni_fifo_count(struct rte_kni_fifo *fifo) 70 { 71 uint32_t fifo_write = smp_load_acquire(&fifo->write); 72 uint32_t fifo_read = smp_load_acquire(&fifo->read); 73 return (fifo->len + fifo_write - fifo_read) & (fifo->len - 1); 74 } 75 76 /** 77 * Get the num of available elements in the fifo 78 */ 79 static inline uint32_t 80 kni_fifo_free_count(struct rte_kni_fifo *fifo) 81 { 82 uint32_t fifo_write = smp_load_acquire(&fifo->write); 83 uint32_t fifo_read = smp_load_acquire(&fifo->read); 84 return (fifo_read - fifo_write - 1) & (fifo->len - 1); 85 } 86 87 #endif /* _KNI_FIFO_H_ */ 88