drivers/s390/scsi/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 <asm/qdio.h>
  14
  15 #define ZFCP_QDIO_SBALE_LEN     PAGE_SIZE
  16
  17 /* Max SBALS for chaining */
  18 #define ZFCP_QDIO_MAX_SBALS_PER_REQ     36
  19
  20 /**
  21  * struct zfcp_qdio - basic qdio data structure
  22  * @res_q: response queue
  23  * @req_q: request queue
  24  * @req_q_idx: index of next free buffer
  25  * @req_q_free: number of free buffers in queue
  26  * @stat_lock: lock to protect req_q_util and req_q_time
  27  * @req_q_lock: lock to serialize access to request queue
  28  * @req_q_time: time of last fill level change
  29  * @req_q_util: used for accounting
  30  * @req_q_full: queue full incidents
  31  * @req_q_wq: used to wait for SBAL availability
  32  * @adapter: adapter used in conjunction with this qdio structure
  33  * @max_sbale_per_sbal: qdio limit per sbal
  34  * @max_sbale_per_req: qdio limit per request
  35  */
  36 struct zfcp_qdio {
  37         struct qdio_buffer      *res_q[QDIO_MAX_BUFFERS_PER_Q];
  38         struct qdio_buffer      *req_q[QDIO_MAX_BUFFERS_PER_Q];
  39         u8                      req_q_idx;
  40         atomic_t                req_q_free;
  41         spinlock_t              stat_lock;
  42         spinlock_t              req_q_lock;
  43         unsigned long long      req_q_time;
  44         u64                     req_q_util;
  45         atomic_t                req_q_full;
  46         wait_queue_head_t       req_q_wq;
  47         struct zfcp_adapter     *adapter;
  48         u16                     max_sbale_per_sbal;
  49         u16                     max_sbale_per_req;
  50 };
  51
  52 /**
  53  * struct zfcp_qdio_req - qdio queue related values for a request
  54  * @sbtype: sbal type flags for sbale 0
  55  * @sbal_number: number of free sbals
  56  * @sbal_first: first sbal for this request
  57  * @sbal_last: last sbal for this request
  58  * @sbal_limit: last possible sbal for this request
  59  * @sbale_curr: current sbale at creation of this request
  60  * @qdio_outb_usage: usage of outbound queue
  61  */
  62 struct zfcp_qdio_req {
  63         u8      sbtype;
  64         u8      sbal_number;
  65         u8      sbal_first;
  66         u8      sbal_last;
  67         u8      sbal_limit;
  68         u8      sbale_curr;
  69         u16     qdio_outb_usage;
  70 };
  71
  72 /**
  73  * zfcp_qdio_sbale_req - return pointer to sbale on req_q for a request
  74  * @qdio: pointer to struct zfcp_qdio
  75  * @q_req: pointer to struct zfcp_qdio_req
  76  * Returns: pointer to qdio_buffer_element (sbale) structure
  77  */
  78 static inline struct qdio_buffer_element *
  79 zfcp_qdio_sbale_req(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  80 {
  81         return &qdio->req_q[q_req->sbal_last]->element[0];
  82 }
  83
  84 /**
  85  * zfcp_qdio_sbale_curr - return current sbale on req_q for a request
  86  * @qdio: pointer to struct zfcp_qdio
  87  * @q_req: pointer to struct zfcp_qdio_req
  88  * Returns: pointer to qdio_buffer_element (sbale) structure
  89  */
  90 static inline struct qdio_buffer_element *
  91 zfcp_qdio_sbale_curr(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  92 {
  93         return &qdio->req_q[q_req->sbal_last]->element[q_req->sbale_curr];
  94 }
  95
  96 /**
  97  * zfcp_qdio_req_init - initialize qdio request
  98  * @qdio: request queue where to start putting the request
  99  * @q_req: the qdio request to start
 100  * @req_id: The request id
 101  * @sbtype: type flags to set for all sbals
 102  * @data: First data block
 103  * @len: Length of first data block
 104  *
 105  * This is the start of putting the request into the queue, the last
 106  * step is passing the request to zfcp_qdio_send. The request queue
 107  * lock must be held during the whole process from init to send.
 108  */
 109 static inline
 110 void zfcp_qdio_req_init(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 111                         unsigned long req_id, u8 sbtype, void *data, u32 len)
 112 {
 113         struct qdio_buffer_element *sbale;
 114         int count = min(atomic_read(&qdio->req_q_free),
 115                         ZFCP_QDIO_MAX_SBALS_PER_REQ);
 116
 117         q_req->sbal_first = q_req->sbal_last = qdio->req_q_idx;
 118         q_req->sbal_number = 1;
 119         q_req->sbtype = sbtype;
 120         q_req->sbale_curr = 1;
 121         q_req->sbal_limit = (q_req->sbal_first + count - 1)
 122                                         % QDIO_MAX_BUFFERS_PER_Q;
 123
 124         sbale = zfcp_qdio_sbale_req(qdio, q_req);
 125         sbale->addr = req_id;
 126         sbale->eflags = 0;
 127         sbale->sflags = SBAL_SFLAGS0_COMMAND | sbtype;
 128
 129         if (unlikely(!data))
 130                 return;
 131         sbale++;
 132         sbale->addr = virt_to_phys(data);
 133         sbale->length = len;
 134 }
 135
 136 /**
 137  * zfcp_qdio_fill_next - Fill next sbale, only for single sbal requests
 138  * @qdio: pointer to struct zfcp_qdio
 139  * @q_req: pointer to struct zfcp_queue_req
 140  * @data: pointer to data
 141  * @len: length of data
 142  *
 143  * This is only required for single sbal requests, calling it when
 144  * wrapping around to the next sbal is a bug.
 145  */
 146 static inline
 147 void zfcp_qdio_fill_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 148                          void *data, u32 len)
 149 {
 150         struct qdio_buffer_element *sbale;
 151
 152         BUG_ON(q_req->sbale_curr == qdio->max_sbale_per_sbal - 1);
 153         q_req->sbale_curr++;
 154         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 155         sbale->addr = virt_to_phys(data);
 156         sbale->length = len;
 157 }
 158
 159 /**
 160  * zfcp_qdio_set_sbale_last - set last entry flag in current sbale
 161  * @qdio: pointer to struct zfcp_qdio
 162  * @q_req: pointer to struct zfcp_queue_req
 163  */
 164 static inline
 165 void zfcp_qdio_set_sbale_last(struct zfcp_qdio *qdio,
 166                               struct zfcp_qdio_req *q_req)
 167 {
 168         struct qdio_buffer_element *sbale;
 169
 170         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 171         sbale->eflags |= SBAL_EFLAGS_LAST_ENTRY;
 172 }
 173
 174 /**
 175  * zfcp_qdio_sg_one_sbal - check if one sbale is enough for sg data
 176  * @sg: The scatterlist where to check the data size
 177  *
 178  * Returns: 1 when one sbale is enough for the data in the scatterlist,
 179  *          0 if not.
 180  */
 181 static inline
 182 int zfcp_qdio_sg_one_sbale(struct scatterlist *sg)
 183 {
 184         return sg_is_last(sg) && sg->length <= ZFCP_QDIO_SBALE_LEN;
 185 }
 186
 187 /**
 188  * zfcp_qdio_skip_to_last_sbale - skip to last sbale in sbal
 189  * @qdio: pointer to struct zfcp_qdio
 190  * @q_req: The current zfcp_qdio_req
 191  */
 192 static inline
 193 void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio *qdio,
 194                                   struct zfcp_qdio_req *q_req)
 195 {
 196         q_req->sbale_curr = qdio->max_sbale_per_sbal - 1;
 197 }
 198
 199 /**
 200  * zfcp_qdio_sbal_limit - set the sbal limit for a request in q_req
 201  * @qdio: pointer to struct zfcp_qdio
 202  * @q_req: The current zfcp_qdio_req
 203  * @max_sbals: maximum number of SBALs allowed
 204  */
 205 static inline
 206 void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
 207                           struct zfcp_qdio_req *q_req, int max_sbals)
 208 {
 209         int count = min(atomic_read(&qdio->req_q_free), max_sbals);
 210
 211         q_req->sbal_limit = (q_req->sbal_first + count - 1) %
 212                                 QDIO_MAX_BUFFERS_PER_Q;
 213 }
 214
 215 /**
 216  * zfcp_qdio_set_data_div - set data division count
 217  * @qdio: pointer to struct zfcp_qdio
 218  * @q_req: The current zfcp_qdio_req
 219  * @count: The data division count
 220  */
 221 static inline
 222 void zfcp_qdio_set_data_div(struct zfcp_qdio *qdio,
 223                             struct zfcp_qdio_req *q_req, u32 count)
 224 {
 225         struct qdio_buffer_element *sbale;
 226
 227         sbale = qdio->req_q[q_req->sbal_first]->element;
 228         sbale->length = count;
 229 }
 230
 231 /**
 232  * zfcp_qdio_real_bytes - count bytes used
 233  * @sg: pointer to struct scatterlist
 234  */
 235 static inline
 236 unsigned int zfcp_qdio_real_bytes(struct scatterlist *sg)
 237 {
 238         unsigned int real_bytes = 0;
 239
 240         for (; sg; sg = sg_next(sg))
 241                 real_bytes += sg->length;
 242
 243         return real_bytes;
 244 }
 245
 246 /**
 247  * zfcp_qdio_set_scount - set SBAL count value
 248  * @qdio: pointer to struct zfcp_qdio
 249  * @q_req: The current zfcp_qdio_req
 250  */
 251 static inline
 252 void zfcp_qdio_set_scount(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 253 {
 254         struct qdio_buffer_element *sbale;
 255
 256         sbale = qdio->req_q[q_req->sbal_first]->element;
 257         sbale->scount = q_req->sbal_number - 1;
 258 }
 259
 260 #endif /* ZFCP_QDIO_H */