ionic_queue.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/* Copyright (C) 2018-2025, Advanced Micro Devices, Inc. */
  3
  4#ifndef _IONIC_QUEUE_H_
  5#define _IONIC_QUEUE_H_
  6
  7#include <linux/io.h>
  8#include <ionic_regs.h>
  9
 10#define IONIC_MAX_DEPTH		0xffff
 11#define IONIC_MAX_CQ_DEPTH	0xffff
 12#define IONIC_CQ_RING_ARM	IONIC_DBELL_RING_1
 13#define IONIC_CQ_RING_SOL	IONIC_DBELL_RING_2
 14
 15/**
 16 * struct ionic_queue - Ring buffer used between device and driver
 17 * @size:	Size of the buffer, in bytes
 18 * @dma:	Dma address of the buffer
 19 * @ptr:	Buffer virtual address
 20 * @prod:	Driver position in the queue
 21 * @cons:	Device position in the queue
 22 * @mask:	Capacity of the queue, subtracting the hole
 23 *		This value is equal to ((1 << depth_log2) - 1)
 24 * @depth_log2: Log base two size depth of the queue
 25 * @stride_log2: Log base two size of an element in the queue
 26 * @dbell:	Doorbell identifying bits
 27 */
 28struct ionic_queue {
 29	size_t size;
 30	dma_addr_t dma;
 31	void *ptr;
 32	u16 prod;
 33	u16 cons;
 34	u16 mask;
 35	u8 depth_log2;
 36	u8 stride_log2;
 37	u64 dbell;
 38};
 39
 40/**
 41 * ionic_queue_init() - Initialize user space queue
 42 * @q:		Uninitialized queue structure
 43 * @dma_dev:	DMA device for mapping
 44 * @depth:	Depth of the queue
 45 * @stride:	Size of each element of the queue
 46 *
 47 * Return: status code
 48 */
 49int ionic_queue_init(struct ionic_queue *q, struct device *dma_dev,
 50		     int depth, size_t stride);
 51
 52/**
 53 * ionic_queue_destroy() - Destroy user space queue
 54 * @q:		Queue structure
 55 * @dma_dev:	DMA device for mapping
 56 *
 57 * Return: status code
 58 */
 59void ionic_queue_destroy(struct ionic_queue *q, struct device *dma_dev);
 60
 61/**
 62 * ionic_queue_empty() - Test if queue is empty
 63 * @q:		Queue structure
 64 *
 65 * This is only valid for to-device queues.
 66 *
 67 * Return: is empty
 68 */
 69static inline bool ionic_queue_empty(struct ionic_queue *q)
 70{
 71	return q->prod == q->cons;
 72}
 73
 74/**
 75 * ionic_queue_length() - Get the current length of the queue
 76 * @q:		Queue structure
 77 *
 78 * This is only valid for to-device queues.
 79 *
 80 * Return: length
 81 */
 82static inline u16 ionic_queue_length(struct ionic_queue *q)
 83{
 84	return (q->prod - q->cons) & q->mask;
 85}
 86
 87/**
 88 * ionic_queue_length_remaining() - Get the remaining length of the queue
 89 * @q:		Queue structure
 90 *
 91 * This is only valid for to-device queues.
 92 *
 93 * Return: length remaining
 94 */
 95static inline u16 ionic_queue_length_remaining(struct ionic_queue *q)
 96{
 97	return q->mask - ionic_queue_length(q);
 98}
 99
100/**
101 * ionic_queue_full() - Test if queue is full
102 * @q:		Queue structure
103 *
104 * This is only valid for to-device queues.
105 *
106 * Return: is full
107 */
108static inline bool ionic_queue_full(struct ionic_queue *q)
109{
110	return q->mask == ionic_queue_length(q);
111}
112
113/**
114 * ionic_color_wrap() - Flip the color if prod is wrapped
115 * @prod:	Queue index just after advancing
116 * @color:	Queue color just prior to advancing the index
117 *
118 * Return: color after advancing the index
119 */
120static inline bool ionic_color_wrap(u16 prod, bool color)
121{
122	/* logical xor color with (prod == 0) */
123	return color != (prod == 0);
124}
125
126/**
127 * ionic_queue_at() - Get the element at the given index
128 * @q:		Queue structure
129 * @idx:	Index in the queue
130 *
131 * The index must be within the bounds of the queue.  It is not checked here.
132 *
133 * Return: pointer to element at index
134 */
135static inline void *ionic_queue_at(struct ionic_queue *q, u16 idx)
136{
137	return q->ptr + ((unsigned long)idx << q->stride_log2);
138}
139
140/**
141 * ionic_queue_at_prod() - Get the element at the producer index
142 * @q:		Queue structure
143 *
144 * Return: pointer to element at producer index
145 */
146static inline void *ionic_queue_at_prod(struct ionic_queue *q)
147{
148	return ionic_queue_at(q, q->prod);
149}
150
151/**
152 * ionic_queue_at_cons() - Get the element at the consumer index
153 * @q:		Queue structure
154 *
155 * Return: pointer to element at consumer index
156 */
157static inline void *ionic_queue_at_cons(struct ionic_queue *q)
158{
159	return ionic_queue_at(q, q->cons);
160}
161
162/**
163 * ionic_queue_next() - Compute the next index
164 * @q:		Queue structure
165 * @idx:	Index
166 *
167 * Return: next index after idx
168 */
169static inline u16 ionic_queue_next(struct ionic_queue *q, u16 idx)
170{
171	return (idx + 1) & q->mask;
172}
173
174/**
175 * ionic_queue_produce() - Increase the producer index
176 * @q:		Queue structure
177 *
178 * Caller must ensure that the queue is not full.  It is not checked here.
179 */
180static inline void ionic_queue_produce(struct ionic_queue *q)
181{
182	q->prod = ionic_queue_next(q, q->prod);
183}
184
185/**
186 * ionic_queue_consume() - Increase the consumer index
187 * @q:		Queue structure
188 *
189 * Caller must ensure that the queue is not empty.  It is not checked here.
190 *
191 * This is only valid for to-device queues.
192 */
193static inline void ionic_queue_consume(struct ionic_queue *q)
194{
195	q->cons = ionic_queue_next(q, q->cons);
196}
197
198/**
199 * ionic_queue_consume_entries() - Increase the consumer index by entries
200 * @q:				Queue structure
201 * @entries:		Number of entries to increment
202 *
203 * Caller must ensure that the queue is not empty.  It is not checked here.
204 *
205 * This is only valid for to-device queues.
206 */
207static inline void ionic_queue_consume_entries(struct ionic_queue *q,
208					       u16 entries)
209{
210	q->cons = (q->cons + entries) & q->mask;
211}
212
213/**
214 * ionic_queue_dbell_init() - Initialize doorbell bits for queue id
215 * @q:		Queue structure
216 * @qid:	Queue identifying number
217 */
218static inline void ionic_queue_dbell_init(struct ionic_queue *q, u32 qid)
219{
220	q->dbell = IONIC_DBELL_QID(qid);
221}
222
223/**
224 * ionic_queue_dbell_val() - Get current doorbell update value
225 * @q:		Queue structure
226 *
227 * Return: current doorbell update value
228 */
229static inline u64 ionic_queue_dbell_val(struct ionic_queue *q)
230{
231	return q->dbell | q->prod;
232}
233
234#endif /* _IONIC_QUEUE_H_ */