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 /**
  23  * struct zfcp_qdio_queue - qdio queue buffer, zfcp index and free count
  24  * @sbal: qdio buffers
  25  * @first: index of next free buffer in queue
  26  * @count: number of free buffers in queue
  27  */
  28 struct zfcp_qdio_queue {
  29         struct qdio_buffer *sbal[QDIO_MAX_BUFFERS_PER_Q];
  30         u8                 first;
  31         atomic_t           count;
  32 };
  33
  34 /**
  35  * struct zfcp_qdio - basic qdio data structure
  36  * @resp_q: response queue
  37  * @req_q: request queue
  38  * @stat_lock: lock to protect req_q_util and req_q_time
  39  * @req_q_lock: lock to serialize access to request queue
  40  * @req_q_time: time of last fill level change
  41  * @req_q_util: used for accounting
  42  * @req_q_full: queue full incidents
  43  * @req_q_wq: used to wait for SBAL availability
  44  * @adapter: adapter used in conjunction with this qdio structure
  45  */
  46 struct zfcp_qdio {
  47         struct zfcp_qdio_queue  resp_q;
  48         struct zfcp_qdio_queue  req_q;
  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  * @qdio_inb_usage: usage of inbound queue
  69  */
  70 struct zfcp_qdio_req {
  71         u32     sbtype;
  72         u8      sbal_number;
  73         u8      sbal_first;
  74         u8      sbal_last;
  75         u8      sbal_limit;
  76         u8      sbale_curr;
  77         u8      sbal_response;
  78         u16     qdio_outb_usage;
  79         u16     qdio_inb_usage;
  80 };
  81
  82 /**
  83  * zfcp_qdio_sbale - return pointer to sbale in qdio queue
  84  * @q: queue where to find sbal
  85  * @sbal_idx: sbal index in queue
  86  * @sbale_idx: sbale index in sbal
  87  */
  88 static inline struct qdio_buffer_element *
  89 zfcp_qdio_sbale(struct zfcp_qdio_queue *q, int sbal_idx, int sbale_idx)
  90 {
  91         return &q->sbal[sbal_idx]->element[sbale_idx];
  92 }
  93
  94 /**
  95  * zfcp_qdio_sbale_req - return pointer to sbale on req_q for a request
  96  * @qdio: pointer to struct zfcp_qdio
  97  * @q_rec: pointer to struct zfcp_qdio_req
  98  * Returns: pointer to qdio_buffer_element (sbale) structure
  99  */
 100 static inline struct qdio_buffer_element *
 101 zfcp_qdio_sbale_req(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 102 {
 103         return zfcp_qdio_sbale(&qdio->req_q, q_req->sbal_last, 0);
 104 }
 105
 106 /**
 107  * zfcp_qdio_sbale_curr - return current sbale on req_q for a request
 108  * @qdio: pointer to struct zfcp_qdio
 109  * @fsf_req: pointer to struct zfcp_fsf_req
 110  * Returns: pointer to qdio_buffer_element (sbale) structure
 111  */
 112 static inline struct qdio_buffer_element *
 113 zfcp_qdio_sbale_curr(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 114 {
 115         return zfcp_qdio_sbale(&qdio->req_q, q_req->sbal_last,
 116                                q_req->sbale_curr);
 117 }
 118
 119 /**
 120  * zfcp_qdio_req_init - initialize qdio request
 121  * @qdio: request queue where to start putting the request
 122  * @q_req: the qdio request to start
 123  * @req_id: The request id
 124  * @sbtype: type flags to set for all sbals
 125  * @data: First data block
 126  * @len: Length of first data block
 127  *
 128  * This is the start of putting the request into the queue, the last
 129  * step is passing the request to zfcp_qdio_send. The request queue
 130  * lock must be held during the whole process from init to send.
 131  */
 132 static inline
 133 void zfcp_qdio_req_init(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 134                         unsigned long req_id, u32 sbtype, void *data, u32 len)
 135 {
 136         struct qdio_buffer_element *sbale;
 137
 138         q_req->sbal_first = q_req->sbal_last = qdio->req_q.first;
 139         q_req->sbal_number = 1;
 140         q_req->sbtype = sbtype;
 141
 142         sbale = zfcp_qdio_sbale_req(qdio, q_req);
 143         sbale->addr = (void *) req_id;
 144         sbale->flags |= SBAL_FLAGS0_COMMAND;
 145         sbale->flags |= sbtype;
 146
 147         q_req->sbale_curr = 1;
 148         sbale++;
 149         sbale->addr = data;
 150         if (likely(data))
 151                 sbale->length = len;
 152 }
 153
 154 /**
 155  * zfcp_qdio_fill_next - Fill next sbale, only for single sbal requests
 156  * @qdio: pointer to struct zfcp_qdio
 157  * @q_req: pointer to struct zfcp_queue_req
 158  *
 159  * This is only required for single sbal requests, calling it when
 160  * wrapping around to the next sbal is a bug.
 161  */
 162 static inline
 163 void zfcp_qdio_fill_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 164                          void *data, u32 len)
 165 {
 166         struct qdio_buffer_element *sbale;
 167
 168         BUG_ON(q_req->sbale_curr == ZFCP_QDIO_LAST_SBALE_PER_SBAL);
 169         q_req->sbale_curr++;
 170         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 171         sbale->addr = data;
 172         sbale->length = len;
 173 }
 174
 175 /**
 176  * zfcp_qdio_set_sbale_last - set last entry flag in current sbale
 177  * @qdio: pointer to struct zfcp_qdio
 178  * @q_req: pointer to struct zfcp_queue_req
 179  */
 180 static inline
 181 void zfcp_qdio_set_sbale_last(struct zfcp_qdio *qdio,
 182                               struct zfcp_qdio_req *q_req)
 183 {
 184         struct qdio_buffer_element *sbale;
 185
 186         sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 187         sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
 188 }
 189
 190 /**
 191  * zfcp_qdio_sg_one_sbal - check if one sbale is enough for sg data
 192  * @sg: The scatterlist where to check the data size
 193  *
 194  * Returns: 1 when one sbale is enough for the data in the scatterlist,
 195  *          0 if not.
 196  */
 197 static inline
 198 int zfcp_qdio_sg_one_sbale(struct scatterlist *sg)
 199 {
 200         return sg_is_last(sg) && sg->length <= ZFCP_QDIO_SBALE_LEN;
 201 }
 202
 203 /**
 204  * zfcp_qdio_skip_to_last_sbale - skip to last sbale in sbal
 205  * @q_req: The current zfcp_qdio_req
 206  */
 207 static inline
 208 void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio_req *q_req)
 209 {
 210         q_req->sbale_curr = ZFCP_QDIO_LAST_SBALE_PER_SBAL;
 211 }
 212
 213 #endif /* ZFCP_QDIO_H */