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