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 /* DMQ bug workaround: don't use last SBALE */
  17 #define ZFCP_QDIO_MAX_SBALES_PER_SBAL   (QDIO_MAX_ELEMENTS_PER_BUFFER - 1)
  18
  19 /* index of last SBALE (with respect to DMQ bug workaround) */
  20 #define ZFCP_QDIO_LAST_SBALE_PER_SBAL   (ZFCP_QDIO_MAX_SBALES_PER_SBAL - 1)
  21
  22 /* Max SBALS for chaining */
  23 #define ZFCP_QDIO_MAX_SBALS_PER_REQ     36
  24
  25 /* max. number of (data buffer) SBALEs in largest SBAL chain
  26  * request ID + QTCB in SBALE 0 + 1 of first SBAL in chain   */
  27 #define ZFCP_QDIO_MAX_SBALES_PER_REQ     \
  28         (ZFCP_QDIO_MAX_SBALS_PER_REQ * ZFCP_QDIO_MAX_SBALES_PER_SBAL - 2)
  29
  30 /**
  31  * struct zfcp_qdio - basic qdio data structure
  32  * @res_q: response queue
  33  * @req_q: request queue
  34  * @req_q_idx: index of next free buffer
  35  * @req_q_free: number of free buffers in queue
  36  * @stat_lock: lock to protect req_q_util and req_q_time
  37  * @req_q_lock: lock to serialize access to request queue
  38  * @req_q_time: time of last fill level change
  39  * @req_q_util: used for accounting
  40  * @req_q_full: queue full incidents
  41  * @req_q_wq: used to wait for SBAL availability
  42  * @adapter: adapter used in conjunction with this qdio structure
  43  */
  44 struct zfcp_qdio {
  45         struct qdio_buffer      *res_q[QDIO_MAX_BUFFERS_PER_Q];
  46         struct qdio_buffer      *req_q[QDIO_MAX_BUFFERS_PER_Q];
  47         u8                      req_q_idx;
  48         atomic_t                req_q_free;
  49         spinlock_t              stat_lock;
  50         spinlock_t              req_q_lock;
  51         unsigned long long      req_q_time;
  52         u64                     req_q_util;
  53         atomic_t                req_q_full;
  54         wait_queue_head_t       req_q_wq;
  55         struct zfcp_adapter     *adapter;
  56 };
  57
  58 /**
  59  * struct zfcp_qdio_req - qdio queue related values for a request
  60  * @sbtype: sbal type flags for sbale 0
  61  * @sbal_number: number of free sbals
  62  * @sbal_first: first sbal for this request
  63  * @sbal_last: last sbal for this request
  64  * @sbal_limit: last possible sbal for this request
  65  * @sbale_curr: current sbale at creation of this request
  66  * @sbal_response: sbal used in interrupt
  67  * @qdio_outb_usage: usage of outbound queue
  68  */
  69 struct zfcp_qdio_req {
  70         u32     sbtype;
  71         u8      sbal_number;
  72         u8      sbal_first;
  73         u8      sbal_last;
  74         u8      sbal_limit;
  75         u8      sbale_curr;
  76         u8      sbal_response;
  77         u16     qdio_outb_usage;
  78 };
  79
  80 /**
  81  * zfcp_qdio_sbale_req - return pointer to sbale on req_q for a request
  82  * @qdio: pointer to struct zfcp_qdio
  83  * @q_rec: pointer to struct zfcp_qdio_req
  84  * Returns: pointer to qdio_buffer_element (sbale) structure
  85  */
  86 static inline struct qdio_buffer_element *
  87 zfcp_qdio_sbale_req(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  88 {
  89         return &qdio->req_q[q_req->sbal_last]->element[0];
  90 }
  91
  92 /**
  93  * zfcp_qdio_sbale_curr - return current sbale on req_q for a request
  94  * @qdio: pointer to struct zfcp_qdio
  95  * @fsf_req: pointer to struct zfcp_fsf_req
  96  * Returns: pointer to qdio_buffer_element (sbale) structure
  97  */
  98 static inline struct qdio_buffer_element *
  99 zfcp_qdio_sbale_curr(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 100 {
 101         return &qdio->req_q[q_req->sbal_last]->element[q_req->sbale_curr];
 102 }
 103
 104 /**
 105  * zfcp_qdio_req_init - initialize qdio request
 106  * @qdio: request queue where to start putting the request
 107  * @q_req: the qdio request to start
 108  * @req_id: The request id
 109  * @sbtype: type flags to set for all sbals
 110  * @data: First data block
 111  * @len: Length of first data block
 112  *
 113  * This is the start of putting the request into the queue, the last
 114  * step is passing the request to zfcp_qdio_send. The request queue
 115  * lock must be held during the whole process from init to send.
 116  */
 117 static inline
 118 void zfcp_qdio_req_init(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 119                         unsigned long req_id, u32 sbtype, void *data, u32 len)
 120 {
 121         struct qdio_buffer_element *sbale;
 122         int count = min(atomic_read(&qdio->req_q_free),
 123                         ZFCP_QDIO_MAX_SBALS_PER_REQ);
 124
 125         q_req->sbal_first = q_req->sbal_last = qdio->req_q_idx;
 126         q_req->sbal_number = 1;
 127         q_req->sbtype = sbtype;
 128         q_req->sbale_curr = 1;
 129         q_req->sbal_limit = (q_req->sbal_first + count - 1)
 130                                         % QDIO_MAX_BUFFERS_PER_Q;
 131
 132         sbale = zfcp_qdio_sbale_req(qdio, q_req);
 133         sbale->addr = (void *) req_id;
 134         sbale->flags = SBAL_FLAGS0_COMMAND | sbtype;
 135
 136         if (unlikely(!data))
 137                 return;
 138         sbale++;
 139         sbale->addr = data;
 140         sbale->length = len;
 141 }
 142
 143 /**
 144  * zfcp_qdio_fill_next - Fill next sbale, only for single sbal requests
 145  * @qdio: pointer to struct zfcp_qdio
 146  * @q_req: pointer to struct zfcp_queue_req
 147  *
 148  * This is only required for single sbal requests, calling it when
 149  * wrapping around to the next sbal is a bug.
 150  */
 151 static inline
 152 void zfcp_qdio_fill_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 153                          void *data, u32 len)
 154 {
 155         struct qdio_buffer_element *sbale;
 156
 157         BUG_ON(q_req->sbale_curr == ZFCP_QDIO_LAST_SBALE_PER_SBAL);
 158         q_req->sbale_curr++;
 159         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 160         sbale->addr = data;
 161         sbale->length = len;
 162 }
 163
 164 /**
 165  * zfcp_qdio_set_sbale_last - set last entry flag in current sbale
 166  * @qdio: pointer to struct zfcp_qdio
 167  * @q_req: pointer to struct zfcp_queue_req
 168  */
 169 static inline
 170 void zfcp_qdio_set_sbale_last(struct zfcp_qdio *qdio,
 171                               struct zfcp_qdio_req *q_req)
 172 {
 173         struct qdio_buffer_element *sbale;
 174
 175         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 176         sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
 177 }
 178
 179 /**
 180  * zfcp_qdio_sg_one_sbal - check if one sbale is enough for sg data
 181  * @sg: The scatterlist where to check the data size
 182  *
 183  * Returns: 1 when one sbale is enough for the data in the scatterlist,
 184  *          0 if not.
 185  */
 186 static inline
 187 int zfcp_qdio_sg_one_sbale(struct scatterlist *sg)
 188 {
 189         return sg_is_last(sg) && sg->length <= ZFCP_QDIO_SBALE_LEN;
 190 }
 191
 192 /**
 193  * zfcp_qdio_skip_to_last_sbale - skip to last sbale in sbal
 194  * @q_req: The current zfcp_qdio_req
 195  */
 196 static inline
 197 void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio_req *q_req)
 198 {
 199         q_req->sbale_curr = ZFCP_QDIO_LAST_SBALE_PER_SBAL;
 200 }
 201
 202 /**
 203  * zfcp_qdio_sbal_limit - set the sbal limit for a request in q_req
 204  * @qdio: pointer to struct zfcp_qdio
 205  * @q_req: The current zfcp_qdio_req
 206  * @max_sbals: maximum number of SBALs allowed
 207  */
 208 static inline
 209 void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
 210                           struct zfcp_qdio_req *q_req, int max_sbals)
 211 {
 212         int count = min(atomic_read(&qdio->req_q_free), max_sbals);
 213
 214         q_req->sbal_limit = (q_req->sbal_first + count - 1) %
 215                                 QDIO_MAX_BUFFERS_PER_Q;
 216 }
 217
 218 /**
 219  * zfcp_qdio_set_data_div - set data division count
 220  * @qdio: pointer to struct zfcp_qdio
 221  * @q_req: The current zfcp_qdio_req
 222  * @count: The data division count
 223  */
 224 static inline
 225 void zfcp_qdio_set_data_div(struct zfcp_qdio *qdio,
 226                             struct zfcp_qdio_req *q_req, u32 count)
 227 {
 228         struct qdio_buffer_element *sbale;
 229
 230         sbale = &qdio->req_q[q_req->sbal_first]->element[0];
 231         sbale->length = count;
 232 }
 233
 234 #endif /* ZFCP_QDIO_H */