zfcp_qdio.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * zfcp device driver
  4 *
  5 * Header file for zfcp qdio interface
  6 *
  7 * Copyright IBM Corp. 2010
  8 */
  9
 10#ifndef ZFCP_QDIO_H
 11#define ZFCP_QDIO_H
 12
 13#include <linux/interrupt.h>
 14#include <asm/qdio.h>
 15
 16#define ZFCP_QDIO_SBALE_LEN	PAGE_SIZE
 17
 18/* Max SBALS for chaining */
 19#define ZFCP_QDIO_MAX_SBALS_PER_REQ	36
 20
 21/**
 22 * struct zfcp_qdio - basic qdio data structure
 23 * @res_q: response queue
 24 * @req_q: request queue
 25 * @req_q_idx: index of next free buffer
 26 * @req_q_free: number of free buffers in queue
 27 * @stat_lock: lock to protect req_q_util and req_q_time
 28 * @req_q_lock: lock to serialize access to request queue
 29 * @req_q_time: time of last fill level change
 30 * @req_q_util: used for accounting
 31 * @req_q_full: queue full incidents
 32 * @req_q_wq: used to wait for SBAL availability
 33 * @irq_tasklet: used for QDIO interrupt processing
 34 * @request_tasklet: used for Request Queue completion processing
 35 * @request_timer: used to trigger the Request Queue completion processing
 36 * @adapter: adapter used in conjunction with this qdio structure
 37 * @max_sbale_per_sbal: qdio limit per sbal
 38 * @max_sbale_per_req: qdio limit per request
 39 */
 40struct zfcp_qdio {
 41	struct qdio_buffer	*res_q[QDIO_MAX_BUFFERS_PER_Q];
 42	struct qdio_buffer	*req_q[QDIO_MAX_BUFFERS_PER_Q];
 43	u8			req_q_idx;
 44	atomic_t		req_q_free;
 45	spinlock_t		stat_lock;
 46	spinlock_t		req_q_lock;
 47	unsigned long long	req_q_time;
 48	u64			req_q_util;
 49	atomic_t		req_q_full;
 50	wait_queue_head_t	req_q_wq;
 51	struct tasklet_struct	irq_tasklet;
 52	struct tasklet_struct	request_tasklet;
 53	struct timer_list	request_timer;
 54	struct zfcp_adapter	*adapter;
 55	u16			max_sbale_per_sbal;
 56	u16			max_sbale_per_req;
 57};
 58
 59/**
 60 * struct zfcp_qdio_req - qdio queue related values for a request
 61 * @sbtype: sbal type flags for sbale 0
 62 * @sbal_number: number of free sbals
 63 * @sbal_first: first sbal for this request
 64 * @sbal_last: last sbal for this request
 65 * @sbal_limit: last possible sbal for this request
 66 * @sbale_curr: current sbale at creation of this request
 67 * @qdio_outb_usage: usage of outbound queue
 68 */
 69struct zfcp_qdio_req {
 70	u8	sbtype;
 71	u8	sbal_number;
 72	u8	sbal_first;
 73	u8	sbal_last;
 74	u8	sbal_limit;
 75	u8	sbale_curr;
 76	u16	qdio_outb_usage;
 77};
 78
 79/**
 80 * zfcp_qdio_sbale_req - return pointer to sbale on req_q for a request
 81 * @qdio: pointer to struct zfcp_qdio
 82 * @q_req: pointer to struct zfcp_qdio_req
 83 * Returns: pointer to qdio_buffer_element (sbale) structure
 84 */
 85static inline struct qdio_buffer_element *
 86zfcp_qdio_sbale_req(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 87{
 88	return &qdio->req_q[q_req->sbal_last]->element[0];
 89}
 90
 91/**
 92 * zfcp_qdio_sbale_curr - return current sbale on req_q for a request
 93 * @qdio: pointer to struct zfcp_qdio
 94 * @q_req: pointer to struct zfcp_qdio_req
 95 * Returns: pointer to qdio_buffer_element (sbale) structure
 96 */
 97static inline struct qdio_buffer_element *
 98zfcp_qdio_sbale_curr(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 99{
100	return &qdio->req_q[q_req->sbal_last]->element[q_req->sbale_curr];
101}
102
103/**
104 * zfcp_qdio_req_init - initialize qdio request
105 * @qdio: request queue where to start putting the request
106 * @q_req: the qdio request to start
107 * @req_id: The request id
108 * @sbtype: type flags to set for all sbals
109 * @data: First data block
110 * @len: Length of first data block
111 *
112 * This is the start of putting the request into the queue, the last
113 * step is passing the request to zfcp_qdio_send. The request queue
114 * lock must be held during the whole process from init to send.
115 */
116static inline
117void zfcp_qdio_req_init(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
118			u64 req_id, u8 sbtype, void *data, u32 len)
119{
120	struct qdio_buffer_element *sbale;
121	int count = min(atomic_read(&qdio->req_q_free),
122			ZFCP_QDIO_MAX_SBALS_PER_REQ);
123
124	q_req->sbal_first = q_req->sbal_last = qdio->req_q_idx;
125	q_req->sbal_number = 1;
126	q_req->sbtype = sbtype;
127	q_req->sbale_curr = 1;
128	q_req->sbal_limit = (q_req->sbal_first + count - 1)
129					% QDIO_MAX_BUFFERS_PER_Q;
130
131	sbale = zfcp_qdio_sbale_req(qdio, q_req);
132	sbale->addr = u64_to_dma64(req_id);
133	sbale->eflags = 0;
134	sbale->sflags = SBAL_SFLAGS0_COMMAND | sbtype;
135
136	if (unlikely(!data))
137		return;
138	sbale++;
139	sbale->addr = virt_to_dma64(data);
140	sbale->length = len;
141}
142
143/**
144 * zfcp_qdio_fill_next - Fill next sbale, only for single sbal requests
145 * @qdio: pointer to struct zfcp_qdio
146 * @q_req: pointer to struct zfcp_queue_req
147 * @data: pointer to data
148 * @len: length of data
149 *
150 * This is only required for single sbal requests, calling it when
151 * wrapping around to the next sbal is a bug.
152 */
153static inline
154void zfcp_qdio_fill_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
155			 void *data, u32 len)
156{
157	struct qdio_buffer_element *sbale;
158
159	BUG_ON(q_req->sbale_curr == qdio->max_sbale_per_sbal - 1);
160	q_req->sbale_curr++;
161	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
162	sbale->addr = virt_to_dma64(data);
163	sbale->length = len;
164}
165
166/**
167 * zfcp_qdio_set_sbale_last - set last entry flag in current sbale
168 * @qdio: pointer to struct zfcp_qdio
169 * @q_req: pointer to struct zfcp_queue_req
170 */
171static inline
172void zfcp_qdio_set_sbale_last(struct zfcp_qdio *qdio,
173			      struct zfcp_qdio_req *q_req)
174{
175	struct qdio_buffer_element *sbale;
176
177	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
178	sbale->eflags |= SBAL_EFLAGS_LAST_ENTRY;
179}
180
181/**
182 * zfcp_qdio_sg_one_sbal - check if one sbale is enough for sg data
183 * @sg: The scatterlist where to check the data size
184 *
185 * Returns: 1 when one sbale is enough for the data in the scatterlist,
186 *	    0 if not.
187 */
188static inline
189int zfcp_qdio_sg_one_sbale(struct scatterlist *sg)
190{
191	return sg_is_last(sg) && sg->length <= ZFCP_QDIO_SBALE_LEN;
192}
193
194/**
195 * zfcp_qdio_skip_to_last_sbale - skip to last sbale in sbal
196 * @qdio: pointer to struct zfcp_qdio
197 * @q_req: The current zfcp_qdio_req
198 */
199static inline
200void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio *qdio,
201				  struct zfcp_qdio_req *q_req)
202{
203	q_req->sbale_curr = qdio->max_sbale_per_sbal - 1;
204}
205
206/**
207 * zfcp_qdio_sbal_limit - set the sbal limit for a request in q_req
208 * @qdio: pointer to struct zfcp_qdio
209 * @q_req: The current zfcp_qdio_req
210 * @max_sbals: maximum number of SBALs allowed
211 */
212static inline
213void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
214			  struct zfcp_qdio_req *q_req, int max_sbals)
215{
216	int count = min(atomic_read(&qdio->req_q_free), max_sbals);
217
218	q_req->sbal_limit = (q_req->sbal_first + count - 1) %
219				QDIO_MAX_BUFFERS_PER_Q;
220}
221
222/**
223 * zfcp_qdio_set_data_div - set data division count
224 * @qdio: pointer to struct zfcp_qdio
225 * @q_req: The current zfcp_qdio_req
226 * @count: The data division count
227 */
228static inline
229void zfcp_qdio_set_data_div(struct zfcp_qdio *qdio,
230			    struct zfcp_qdio_req *q_req, u32 count)
231{
232	struct qdio_buffer_element *sbale;
233
234	sbale = qdio->req_q[q_req->sbal_first]->element;
235	sbale->length = count;
236}
237
238/**
239 * zfcp_qdio_real_bytes - count bytes used
240 * @sg: pointer to struct scatterlist
241 */
242static inline
243unsigned int zfcp_qdio_real_bytes(struct scatterlist *sg)
244{
245	unsigned int real_bytes = 0;
246
247	for (; sg; sg = sg_next(sg))
248		real_bytes += sg->length;
249
250	return real_bytes;
251}
252
253/**
254 * zfcp_qdio_set_scount - set SBAL count value
255 * @qdio: pointer to struct zfcp_qdio
256 * @q_req: The current zfcp_qdio_req
257 */
258static inline
259void zfcp_qdio_set_scount(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
260{
261	struct qdio_buffer_element *sbale;
262
263	sbale = qdio->req_q[q_req->sbal_first]->element;
264	sbale->scount = q_req->sbal_number - 1;
265}
266
267#endif /* ZFCP_QDIO_H */