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 <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  * @adapter: adapter used in conjunction with this qdio structure
  34  * @max_sbale_per_sbal: qdio limit per sbal
  35  * @max_sbale_per_req: qdio limit per request
  36  */
  37 struct zfcp_qdio {
  38         struct qdio_buffer      *res_q[QDIO_MAX_BUFFERS_PER_Q];
  39         struct qdio_buffer      *req_q[QDIO_MAX_BUFFERS_PER_Q];
  40         u8                      req_q_idx;
  41         atomic_t                req_q_free;
  42         spinlock_t              stat_lock;
  43         spinlock_t              req_q_lock;
  44         unsigned long long      req_q_time;
  45         u64                     req_q_util;
  46         atomic_t                req_q_full;
  47         wait_queue_head_t       req_q_wq;
  48         struct tasklet_struct   irq_tasklet;
  49         struct zfcp_adapter     *adapter;
  50         u16                     max_sbale_per_sbal;
  51         u16                     max_sbale_per_req;
  52 };
  53
  54 /**
  55  * struct zfcp_qdio_req - qdio queue related values for a request
  56  * @sbtype: sbal type flags for sbale 0
  57  * @sbal_number: number of free sbals
  58  * @sbal_first: first sbal for this request
  59  * @sbal_last: last sbal for this request
  60  * @sbal_limit: last possible sbal for this request
  61  * @sbale_curr: current sbale at creation of this request
  62  * @qdio_outb_usage: usage of outbound queue
  63  */
  64 struct zfcp_qdio_req {
  65         u8      sbtype;
  66         u8      sbal_number;
  67         u8      sbal_first;
  68         u8      sbal_last;
  69         u8      sbal_limit;
  70         u8      sbale_curr;
  71         u16     qdio_outb_usage;
  72 };
  73
  74 /**
  75  * zfcp_qdio_sbale_req - return pointer to sbale on req_q for a request
  76  * @qdio: pointer to struct zfcp_qdio
  77  * @q_req: pointer to struct zfcp_qdio_req
  78  * Returns: pointer to qdio_buffer_element (sbale) structure
  79  */
  80 static inline struct qdio_buffer_element *
  81 zfcp_qdio_sbale_req(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  82 {
  83         return &qdio->req_q[q_req->sbal_last]->element[0];
  84 }
  85
  86 /**
  87  * zfcp_qdio_sbale_curr - return current sbale on req_q for a request
  88  * @qdio: pointer to struct zfcp_qdio
  89  * @q_req: pointer to struct zfcp_qdio_req
  90  * Returns: pointer to qdio_buffer_element (sbale) structure
  91  */
  92 static inline struct qdio_buffer_element *
  93 zfcp_qdio_sbale_curr(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  94 {
  95         return &qdio->req_q[q_req->sbal_last]->element[q_req->sbale_curr];
  96 }
  97
  98 /**
  99  * zfcp_qdio_req_init - initialize qdio request
 100  * @qdio: request queue where to start putting the request
 101  * @q_req: the qdio request to start
 102  * @req_id: The request id
 103  * @sbtype: type flags to set for all sbals
 104  * @data: First data block
 105  * @len: Length of first data block
 106  *
 107  * This is the start of putting the request into the queue, the last
 108  * step is passing the request to zfcp_qdio_send. The request queue
 109  * lock must be held during the whole process from init to send.
 110  */
 111 static inline
 112 void zfcp_qdio_req_init(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 113                         unsigned long req_id, u8 sbtype, void *data, u32 len)
 114 {
 115         struct qdio_buffer_element *sbale;
 116         int count = min(atomic_read(&qdio->req_q_free),
 117                         ZFCP_QDIO_MAX_SBALS_PER_REQ);
 118
 119         q_req->sbal_first = q_req->sbal_last = qdio->req_q_idx;
 120         q_req->sbal_number = 1;
 121         q_req->sbtype = sbtype;
 122         q_req->sbale_curr = 1;
 123         q_req->sbal_limit = (q_req->sbal_first + count - 1)
 124                                         % QDIO_MAX_BUFFERS_PER_Q;
 125
 126         sbale = zfcp_qdio_sbale_req(qdio, q_req);
 127         sbale->addr = req_id;
 128         sbale->eflags = 0;
 129         sbale->sflags = SBAL_SFLAGS0_COMMAND | sbtype;
 130
 131         if (unlikely(!data))
 132                 return;
 133         sbale++;
 134         sbale->addr = virt_to_phys(data);
 135         sbale->length = len;
 136 }
 137
 138 /**
 139  * zfcp_qdio_fill_next - Fill next sbale, only for single sbal requests
 140  * @qdio: pointer to struct zfcp_qdio
 141  * @q_req: pointer to struct zfcp_queue_req
 142  * @data: pointer to data
 143  * @len: length of data
 144  *
 145  * This is only required for single sbal requests, calling it when
 146  * wrapping around to the next sbal is a bug.
 147  */
 148 static inline
 149 void zfcp_qdio_fill_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 150                          void *data, u32 len)
 151 {
 152         struct qdio_buffer_element *sbale;
 153
 154         BUG_ON(q_req->sbale_curr == qdio->max_sbale_per_sbal - 1);
 155         q_req->sbale_curr++;
 156         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 157         sbale->addr = virt_to_phys(data);
 158         sbale->length = len;
 159 }
 160
 161 /**
 162  * zfcp_qdio_set_sbale_last - set last entry flag in current sbale
 163  * @qdio: pointer to struct zfcp_qdio
 164  * @q_req: pointer to struct zfcp_queue_req
 165  */
 166 static inline
 167 void zfcp_qdio_set_sbale_last(struct zfcp_qdio *qdio,
 168                               struct zfcp_qdio_req *q_req)
 169 {
 170         struct qdio_buffer_element *sbale;
 171
 172         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 173         sbale->eflags |= SBAL_EFLAGS_LAST_ENTRY;
 174 }
 175
 176 /**
 177  * zfcp_qdio_sg_one_sbal - check if one sbale is enough for sg data
 178  * @sg: The scatterlist where to check the data size
 179  *
 180  * Returns: 1 when one sbale is enough for the data in the scatterlist,
 181  *          0 if not.
 182  */
 183 static inline
 184 int zfcp_qdio_sg_one_sbale(struct scatterlist *sg)
 185 {
 186         return sg_is_last(sg) && sg->length <= ZFCP_QDIO_SBALE_LEN;
 187 }
 188
 189 /**
 190  * zfcp_qdio_skip_to_last_sbale - skip to last sbale in sbal
 191  * @qdio: pointer to struct zfcp_qdio
 192  * @q_req: The current zfcp_qdio_req
 193  */
 194 static inline
 195 void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio *qdio,
 196                                   struct zfcp_qdio_req *q_req)
 197 {
 198         q_req->sbale_curr = qdio->max_sbale_per_sbal - 1;
 199 }
 200
 201 /**
 202  * zfcp_qdio_sbal_limit - set the sbal limit for a request in q_req
 203  * @qdio: pointer to struct zfcp_qdio
 204  * @q_req: The current zfcp_qdio_req
 205  * @max_sbals: maximum number of SBALs allowed
 206  */
 207 static inline
 208 void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
 209                           struct zfcp_qdio_req *q_req, int max_sbals)
 210 {
 211         int count = min(atomic_read(&qdio->req_q_free), max_sbals);
 212
 213         q_req->sbal_limit = (q_req->sbal_first + count - 1) %
 214                                 QDIO_MAX_BUFFERS_PER_Q;
 215 }
 216
 217 /**
 218  * zfcp_qdio_set_data_div - set data division count
 219  * @qdio: pointer to struct zfcp_qdio
 220  * @q_req: The current zfcp_qdio_req
 221  * @count: The data division count
 222  */
 223 static inline
 224 void zfcp_qdio_set_data_div(struct zfcp_qdio *qdio,
 225                             struct zfcp_qdio_req *q_req, u32 count)
 226 {
 227         struct qdio_buffer_element *sbale;
 228
 229         sbale = qdio->req_q[q_req->sbal_first]->element;
 230         sbale->length = count;
 231 }
 232
 233 /**
 234  * zfcp_qdio_real_bytes - count bytes used
 235  * @sg: pointer to struct scatterlist
 236  */
 237 static inline
 238 unsigned int zfcp_qdio_real_bytes(struct scatterlist *sg)
 239 {
 240         unsigned int real_bytes = 0;
 241
 242         for (; sg; sg = sg_next(sg))
 243                 real_bytes += sg->length;
 244
 245         return real_bytes;
 246 }
 247
 248 /**
 249  * zfcp_qdio_set_scount - set SBAL count value
 250  * @qdio: pointer to struct zfcp_qdio
 251  * @q_req: The current zfcp_qdio_req
 252  */
 253 static inline
 254 void zfcp_qdio_set_scount(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 255 {
 256         struct qdio_buffer_element *sbale;
 257
 258         sbale = qdio->req_q[q_req->sbal_first]->element;
 259         sbale->scount = q_req->sbal_number - 1;
 260 }
 261
 262 #endif /* ZFCP_QDIO_H */