drivers/s390/scsi/zfcp_qdio.h

   1 /*
   2  * zfcp device driver
   3  *
   4  * Header file for zfcp qdio interface
   5  *
   6  * Copyright IBM Corporation 2010
   7  */
   8
   9 #ifndef ZFCP_QDIO_H
  10 #define ZFCP_QDIO_H
  11
  12 #include <asm/qdio.h>
  13
  14 #define ZFCP_QDIO_SBALE_LEN     PAGE_SIZE
  15
  16 /* Max SBALS for chaining */
  17 #define ZFCP_QDIO_MAX_SBALS_PER_REQ     36
  18
  19 /**
  20  * struct zfcp_qdio - basic qdio data structure
  21  * @res_q: response queue
  22  * @req_q: request queue
  23  * @req_q_idx: index of next free buffer
  24  * @req_q_free: number of free buffers in queue
  25  * @stat_lock: lock to protect req_q_util and req_q_time
  26  * @req_q_lock: lock to serialize access to request queue
  27  * @req_q_time: time of last fill level change
  28  * @req_q_util: used for accounting
  29  * @req_q_full: queue full incidents
  30  * @req_q_wq: used to wait for SBAL availability
  31  * @adapter: adapter used in conjunction with this qdio structure
  32  */
  33 struct zfcp_qdio {
  34         struct qdio_buffer      *res_q[QDIO_MAX_BUFFERS_PER_Q];
  35         struct qdio_buffer      *req_q[QDIO_MAX_BUFFERS_PER_Q];
  36         u8                      req_q_idx;
  37         atomic_t                req_q_free;
  38         spinlock_t              stat_lock;
  39         spinlock_t              req_q_lock;
  40         unsigned long long      req_q_time;
  41         u64                     req_q_util;
  42         atomic_t                req_q_full;
  43         wait_queue_head_t       req_q_wq;
  44         struct zfcp_adapter     *adapter;
  45         u16                     max_sbale_per_sbal;
  46         u16                     max_sbale_per_req;
  47 };
  48
  49 /**
  50  * struct zfcp_qdio_req - qdio queue related values for a request
  51  * @sbtype: sbal type flags for sbale 0
  52  * @sbal_number: number of free sbals
  53  * @sbal_first: first sbal for this request
  54  * @sbal_last: last sbal for this request
  55  * @sbal_limit: last possible sbal for this request
  56  * @sbale_curr: current sbale at creation of this request
  57  * @sbal_response: sbal used in interrupt
  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         u8      sbal_response;
  68         u16     qdio_outb_usage;
  69 };
  70
  71 /**
  72  * zfcp_qdio_sbale_req - return pointer to sbale on req_q for a request
  73  * @qdio: pointer to struct zfcp_qdio
  74  * @q_rec: pointer to struct zfcp_qdio_req
  75  * Returns: pointer to qdio_buffer_element (sbale) structure
  76  */
  77 static inline struct qdio_buffer_element *
  78 zfcp_qdio_sbale_req(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  79 {
  80         return &qdio->req_q[q_req->sbal_last]->element[0];
  81 }
  82
  83 /**
  84  * zfcp_qdio_sbale_curr - return current sbale on req_q for a request
  85  * @qdio: pointer to struct zfcp_qdio
  86  * @fsf_req: pointer to struct zfcp_fsf_req
  87  * Returns: pointer to qdio_buffer_element (sbale) structure
  88  */
  89 static inline struct qdio_buffer_element *
  90 zfcp_qdio_sbale_curr(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  91 {
  92         return &qdio->req_q[q_req->sbal_last]->element[q_req->sbale_curr];
  93 }
  94
  95 /**
  96  * zfcp_qdio_req_init - initialize qdio request
  97  * @qdio: request queue where to start putting the request
  98  * @q_req: the qdio request to start
  99  * @req_id: The request id
 100  * @sbtype: type flags to set for all sbals
 101  * @data: First data block
 102  * @len: Length of first data block
 103  *
 104  * This is the start of putting the request into the queue, the last
 105  * step is passing the request to zfcp_qdio_send. The request queue
 106  * lock must be held during the whole process from init to send.
 107  */
 108 static inline
 109 void zfcp_qdio_req_init(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 110                         unsigned long req_id, u8 sbtype, void *data, u32 len)
 111 {
 112         struct qdio_buffer_element *sbale;
 113         int count = min(atomic_read(&qdio->req_q_free),
 114                         ZFCP_QDIO_MAX_SBALS_PER_REQ);
 115
 116         q_req->sbal_first = q_req->sbal_last = qdio->req_q_idx;
 117         q_req->sbal_number = 1;
 118         q_req->sbtype = sbtype;
 119         q_req->sbale_curr = 1;
 120         q_req->sbal_limit = (q_req->sbal_first + count - 1)
 121                                         % QDIO_MAX_BUFFERS_PER_Q;
 122
 123         sbale = zfcp_qdio_sbale_req(qdio, q_req);
 124         sbale->addr = (void *) req_id;
 125         sbale->eflags = 0;
 126         sbale->sflags = SBAL_SFLAGS0_COMMAND | sbtype;
 127
 128         if (unlikely(!data))
 129                 return;
 130         sbale++;
 131         sbale->addr = data;
 132         sbale->length = len;
 133 }
 134
 135 /**
 136  * zfcp_qdio_fill_next - Fill next sbale, only for single sbal requests
 137  * @qdio: pointer to struct zfcp_qdio
 138  * @q_req: pointer to struct zfcp_queue_req
 139  *
 140  * This is only required for single sbal requests, calling it when
 141  * wrapping around to the next sbal is a bug.
 142  */
 143 static inline
 144 void zfcp_qdio_fill_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 145                          void *data, u32 len)
 146 {
 147         struct qdio_buffer_element *sbale;
 148
 149         BUG_ON(q_req->sbale_curr == qdio->max_sbale_per_sbal - 1);
 150         q_req->sbale_curr++;
 151         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 152         sbale->addr = data;
 153         sbale->length = len;
 154 }
 155
 156 /**
 157  * zfcp_qdio_set_sbale_last - set last entry flag in current sbale
 158  * @qdio: pointer to struct zfcp_qdio
 159  * @q_req: pointer to struct zfcp_queue_req
 160  */
 161 static inline
 162 void zfcp_qdio_set_sbale_last(struct zfcp_qdio *qdio,
 163                               struct zfcp_qdio_req *q_req)
 164 {
 165         struct qdio_buffer_element *sbale;
 166
 167         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 168         sbale->eflags |= SBAL_EFLAGS_LAST_ENTRY;
 169 }
 170
 171 /**
 172  * zfcp_qdio_sg_one_sbal - check if one sbale is enough for sg data
 173  * @sg: The scatterlist where to check the data size
 174  *
 175  * Returns: 1 when one sbale is enough for the data in the scatterlist,
 176  *          0 if not.
 177  */
 178 static inline
 179 int zfcp_qdio_sg_one_sbale(struct scatterlist *sg)
 180 {
 181         return sg_is_last(sg) && sg->length <= ZFCP_QDIO_SBALE_LEN;
 182 }
 183
 184 /**
 185  * zfcp_qdio_skip_to_last_sbale - skip to last sbale in sbal
 186  * @q_req: The current zfcp_qdio_req
 187  */
 188 static inline
 189 void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio *qdio,
 190                                   struct zfcp_qdio_req *q_req)
 191 {
 192         q_req->sbale_curr = qdio->max_sbale_per_sbal - 1;
 193 }
 194
 195 /**
 196  * zfcp_qdio_sbal_limit - set the sbal limit for a request in q_req
 197  * @qdio: pointer to struct zfcp_qdio
 198  * @q_req: The current zfcp_qdio_req
 199  * @max_sbals: maximum number of SBALs allowed
 200  */
 201 static inline
 202 void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
 203                           struct zfcp_qdio_req *q_req, int max_sbals)
 204 {
 205         int count = min(atomic_read(&qdio->req_q_free), max_sbals);
 206
 207         q_req->sbal_limit = (q_req->sbal_first + count - 1) %
 208                                 QDIO_MAX_BUFFERS_PER_Q;
 209 }
 210
 211 /**
 212  * zfcp_qdio_set_data_div - set data division count
 213  * @qdio: pointer to struct zfcp_qdio
 214  * @q_req: The current zfcp_qdio_req
 215  * @count: The data division count
 216  */
 217 static inline
 218 void zfcp_qdio_set_data_div(struct zfcp_qdio *qdio,
 219                             struct zfcp_qdio_req *q_req, u32 count)
 220 {
 221         struct qdio_buffer_element *sbale;
 222
 223         sbale = qdio->req_q[q_req->sbal_first]->element;
 224         sbale->length = count;
 225 }
 226
 227 /**
 228  * zfcp_qdio_sbale_count - count sbale used
 229  * @sg: pointer to struct scatterlist
 230  */
 231 static inline
 232 unsigned int zfcp_qdio_sbale_count(struct scatterlist *sg)
 233 {
 234         unsigned int count = 0;
 235
 236         for (; sg; sg = sg_next(sg))
 237                 count++;
 238
 239         return count;
 240 }
 241
 242 /**
 243  * zfcp_qdio_real_bytes - count bytes used
 244  * @sg: pointer to struct scatterlist
 245  */
 246 static inline
 247 unsigned int zfcp_qdio_real_bytes(struct scatterlist *sg)
 248 {
 249         unsigned int real_bytes = 0;
 250
 251         for (; sg; sg = sg_next(sg))
 252                 real_bytes += sg->length;
 253
 254         return real_bytes;
 255 }
 256
 257 /**
 258  * zfcp_qdio_set_scount - set SBAL count value
 259  * @qdio: pointer to struct zfcp_qdio
 260  * @q_req: The current zfcp_qdio_req
 261  */
 262 static inline
 263 void zfcp_qdio_set_scount(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 264 {
 265         struct qdio_buffer_element *sbale;
 266
 267         sbale = qdio->req_q[q_req->sbal_first]->element;
 268         sbale->scount = q_req->sbal_number - 1;
 269 }
 270
 271 #endif /* ZFCP_QDIO_H */