xref: /linux/drivers/s390/scsi/zfcp_qdio.h (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
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  */
40 struct 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  */
69 struct 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  */
85 static inline struct qdio_buffer_element *
86 zfcp_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  */
97 static inline struct qdio_buffer_element *
98 zfcp_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  */
116 static inline
117 void 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  */
153 static inline
154 void 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  */
171 static inline
172 void 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  */
188 static inline
189 int 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  */
199 static inline
200 void 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  */
212 static inline
213 void 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  */
228 static inline
229 void 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  */
242 static inline
243 unsigned 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  */
258 static inline
259 void 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 */
268