linux/drivers/s390/scsi/zfcp_qdio.h
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   1/*
   2 * zfcp device driver
   3 *
   4 * Header file for zfcp qdio interface
   5 *
   6 * Copyright IBM Corp. 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 */
  33struct 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 */
  60struct 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 */
  77static inline struct qdio_buffer_element *
  78zfcp_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 */
  89static inline struct qdio_buffer_element *
  90zfcp_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 */
 108static inline
 109void 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 */
 143static inline
 144void 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 */
 161static inline
 162void 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 */
 178static inline
 179int 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 */
 188static inline
 189void 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 */
 201static inline
 202void 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 */
 217static inline
 218void 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 */
 231static inline
 232unsigned 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 */
 246static inline
 247unsigned 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 */
 262static inline
 263void 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 */
 272