include/linux/qed/qed_chain.h

   1 /* QLogic qed NIC Driver
   2  * Copyright (c) 2015-2017  QLogic Corporation
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and /or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  */
  32
  33 #ifndef _QED_CHAIN_H
  34 #define _QED_CHAIN_H
  35
  36 #include <linux/types.h>
  37 #include <asm/byteorder.h>
  38 #include <linux/kernel.h>
  39 #include <linux/list.h>
  40 #include <linux/slab.h>
  41 #include <linux/qed/common_hsi.h>
  42
  43 enum qed_chain_mode {
  44         /* Each Page contains a next pointer at its end */
  45         QED_CHAIN_MODE_NEXT_PTR,
  46
  47         /* Chain is a single page (next ptr) is unrequired */
  48         QED_CHAIN_MODE_SINGLE,
  49
  50         /* Page pointers are located in a side list */
  51         QED_CHAIN_MODE_PBL,
  52 };
  53
  54 enum qed_chain_use_mode {
  55         QED_CHAIN_USE_TO_PRODUCE,               /* Chain starts empty */
  56         QED_CHAIN_USE_TO_CONSUME,               /* Chain starts full */
  57         QED_CHAIN_USE_TO_CONSUME_PRODUCE,       /* Chain starts empty */
  58 };
  59
  60 enum qed_chain_cnt_type {
  61         /* The chain's size/prod/cons are kept in 16-bit variables */
  62         QED_CHAIN_CNT_TYPE_U16,
  63
  64         /* The chain's size/prod/cons are kept in 32-bit variables  */
  65         QED_CHAIN_CNT_TYPE_U32,
  66 };
  67
  68 struct qed_chain_next {
  69         struct regpair  next_phys;
  70         void            *next_virt;
  71 };
  72
  73 struct qed_chain_pbl_u16 {
  74         u16 prod_page_idx;
  75         u16 cons_page_idx;
  76 };
  77
  78 struct qed_chain_pbl_u32 {
  79         u32 prod_page_idx;
  80         u32 cons_page_idx;
  81 };
  82
  83 struct qed_chain_ext_pbl {
  84         dma_addr_t p_pbl_phys;
  85         void *p_pbl_virt;
  86 };
  87
  88 struct qed_chain_u16 {
  89         /* Cyclic index of next element to produce/consme */
  90         u16 prod_idx;
  91         u16 cons_idx;
  92 };
  93
  94 struct qed_chain_u32 {
  95         /* Cyclic index of next element to produce/consme */
  96         u32 prod_idx;
  97         u32 cons_idx;
  98 };
  99
 100 struct qed_chain {
 101         /* fastpath portion of the chain - required for commands such
 102          * as produce / consume.
 103          */
 104         /* Point to next element to produce/consume */
 105         void *p_prod_elem;
 106         void *p_cons_elem;
 107
 108         /* Fastpath portions of the PBL [if exists] */
 109         struct {
 110                 /* Table for keeping the virtual addresses of the chain pages,
 111                  * respectively to the physical addresses in the pbl table.
 112                  */
 113                 void **pp_virt_addr_tbl;
 114
 115                 union {
 116                         struct qed_chain_pbl_u16 u16;
 117                         struct qed_chain_pbl_u32 u32;
 118                 } c;
 119         } pbl;
 120
 121         union {
 122                 struct qed_chain_u16 chain16;
 123                 struct qed_chain_u32 chain32;
 124         } u;
 125
 126         /* Capacity counts only usable elements */
 127         u32 capacity;
 128         u32 page_cnt;
 129
 130         enum qed_chain_mode mode;
 131
 132         /* Elements information for fast calculations */
 133         u16 elem_per_page;
 134         u16 elem_per_page_mask;
 135         u16 elem_size;
 136         u16 next_page_mask;
 137         u16 usable_per_page;
 138         u8 elem_unusable;
 139
 140         u8 cnt_type;
 141
 142         /* Slowpath of the chain - required for initialization and destruction,
 143          * but isn't involved in regular functionality.
 144          */
 145
 146         /* Base address of a pre-allocated buffer for pbl */
 147         struct {
 148                 dma_addr_t p_phys_table;
 149                 void *p_virt_table;
 150         } pbl_sp;
 151
 152         /* Address of first page of the chain - the address is required
 153          * for fastpath operation [consume/produce] but only for the the SINGLE
 154          * flavour which isn't considered fastpath [== SPQ].
 155          */
 156         void *p_virt_addr;
 157         dma_addr_t p_phys_addr;
 158
 159         /* Total number of elements [for entire chain] */
 160         u32 size;
 161
 162         u8 intended_use;
 163
 164         bool b_external_pbl;
 165 };
 166
 167 #define QED_CHAIN_PBL_ENTRY_SIZE        (8)
 168 #define QED_CHAIN_PAGE_SIZE             (0x1000)
 169 #define ELEMS_PER_PAGE(elem_size)       (QED_CHAIN_PAGE_SIZE / (elem_size))
 170
 171 #define UNUSABLE_ELEMS_PER_PAGE(elem_size, mode)         \
 172         (((mode) == QED_CHAIN_MODE_NEXT_PTR) ?           \
 173          (u8)(1 + ((sizeof(struct qed_chain_next) - 1) / \
 174                    (elem_size))) : 0)
 175
 176 #define USABLE_ELEMS_PER_PAGE(elem_size, mode) \
 177         ((u32)(ELEMS_PER_PAGE(elem_size) -     \
 178                UNUSABLE_ELEMS_PER_PAGE(elem_size, mode)))
 179
 180 #define QED_CHAIN_PAGE_CNT(elem_cnt, elem_size, mode) \
 181         DIV_ROUND_UP(elem_cnt, USABLE_ELEMS_PER_PAGE(elem_size, mode))
 182
 183 #define is_chain_u16(p) ((p)->cnt_type == QED_CHAIN_CNT_TYPE_U16)
 184 #define is_chain_u32(p) ((p)->cnt_type == QED_CHAIN_CNT_TYPE_U32)
 185
 186 /* Accessors */
 187 static inline u16 qed_chain_get_prod_idx(struct qed_chain *p_chain)
 188 {
 189         return p_chain->u.chain16.prod_idx;
 190 }
 191
 192 static inline u16 qed_chain_get_cons_idx(struct qed_chain *p_chain)
 193 {
 194         return p_chain->u.chain16.cons_idx;
 195 }
 196
 197 static inline u32 qed_chain_get_cons_idx_u32(struct qed_chain *p_chain)
 198 {
 199         return p_chain->u.chain32.cons_idx;
 200 }
 201
 202 static inline u16 qed_chain_get_elem_left(struct qed_chain *p_chain)
 203 {
 204         u16 used;
 205
 206         used = (u16) (((u32)0x10000 +
 207                        (u32)p_chain->u.chain16.prod_idx) -
 208                       (u32)p_chain->u.chain16.cons_idx);
 209         if (p_chain->mode == QED_CHAIN_MODE_NEXT_PTR)
 210                 used -= p_chain->u.chain16.prod_idx / p_chain->elem_per_page -
 211                     p_chain->u.chain16.cons_idx / p_chain->elem_per_page;
 212
 213         return (u16)(p_chain->capacity - used);
 214 }
 215
 216 static inline u32 qed_chain_get_elem_left_u32(struct qed_chain *p_chain)
 217 {
 218         u32 used;
 219
 220         used = (u32) (((u64)0x100000000ULL +
 221                        (u64)p_chain->u.chain32.prod_idx) -
 222                       (u64)p_chain->u.chain32.cons_idx);
 223         if (p_chain->mode == QED_CHAIN_MODE_NEXT_PTR)
 224                 used -= p_chain->u.chain32.prod_idx / p_chain->elem_per_page -
 225                     p_chain->u.chain32.cons_idx / p_chain->elem_per_page;
 226
 227         return p_chain->capacity - used;
 228 }
 229
 230 static inline u16 qed_chain_get_usable_per_page(struct qed_chain *p_chain)
 231 {
 232         return p_chain->usable_per_page;
 233 }
 234
 235 static inline u8 qed_chain_get_unusable_per_page(struct qed_chain *p_chain)
 236 {
 237         return p_chain->elem_unusable;
 238 }
 239
 240 static inline u32 qed_chain_get_page_cnt(struct qed_chain *p_chain)
 241 {
 242         return p_chain->page_cnt;
 243 }
 244
 245 static inline dma_addr_t qed_chain_get_pbl_phys(struct qed_chain *p_chain)
 246 {
 247         return p_chain->pbl_sp.p_phys_table;
 248 }
 249
 250 /**
 251  * @brief qed_chain_advance_page -
 252  *
 253  * Advance the next element accros pages for a linked chain
 254  *
 255  * @param p_chain
 256  * @param p_next_elem
 257  * @param idx_to_inc
 258  * @param page_to_inc
 259  */
 260 static inline void
 261 qed_chain_advance_page(struct qed_chain *p_chain,
 262                        void **p_next_elem, void *idx_to_inc, void *page_to_inc)
 263 {
 264         struct qed_chain_next *p_next = NULL;
 265         u32 page_index = 0;
 266
 267         switch (p_chain->mode) {
 268         case QED_CHAIN_MODE_NEXT_PTR:
 269                 p_next = *p_next_elem;
 270                 *p_next_elem = p_next->next_virt;
 271                 if (is_chain_u16(p_chain))
 272                         *(u16 *)idx_to_inc += p_chain->elem_unusable;
 273                 else
 274                         *(u32 *)idx_to_inc += p_chain->elem_unusable;
 275                 break;
 276         case QED_CHAIN_MODE_SINGLE:
 277                 *p_next_elem = p_chain->p_virt_addr;
 278                 break;
 279
 280         case QED_CHAIN_MODE_PBL:
 281                 if (is_chain_u16(p_chain)) {
 282                         if (++(*(u16 *)page_to_inc) == p_chain->page_cnt)
 283                                 *(u16 *)page_to_inc = 0;
 284                         page_index = *(u16 *)page_to_inc;
 285                 } else {
 286                         if (++(*(u32 *)page_to_inc) == p_chain->page_cnt)
 287                                 *(u32 *)page_to_inc = 0;
 288                         page_index = *(u32 *)page_to_inc;
 289                 }
 290                 *p_next_elem = p_chain->pbl.pp_virt_addr_tbl[page_index];
 291         }
 292 }
 293
 294 #define is_unusable_idx(p, idx) \
 295         (((p)->u.chain16.idx & (p)->elem_per_page_mask) == (p)->usable_per_page)
 296
 297 #define is_unusable_idx_u32(p, idx) \
 298         (((p)->u.chain32.idx & (p)->elem_per_page_mask) == (p)->usable_per_page)
 299 #define is_unusable_next_idx(p, idx)                             \
 300         ((((p)->u.chain16.idx + 1) & (p)->elem_per_page_mask) == \
 301          (p)->usable_per_page)
 302
 303 #define is_unusable_next_idx_u32(p, idx)                         \
 304         ((((p)->u.chain32.idx + 1) & (p)->elem_per_page_mask) == \
 305          (p)->usable_per_page)
 306
 307 #define test_and_skip(p, idx)                                              \
 308         do {                                            \
 309                 if (is_chain_u16(p)) {                                     \
 310                         if (is_unusable_idx(p, idx))                       \
 311                                 (p)->u.chain16.idx += (p)->elem_unusable;  \
 312                 } else {                                                   \
 313                         if (is_unusable_idx_u32(p, idx))                   \
 314                                 (p)->u.chain32.idx += (p)->elem_unusable;  \
 315                 }                                       \
 316         } while (0)
 317
 318 /**
 319  * @brief qed_chain_return_produced -
 320  *
 321  * A chain in which the driver "Produces" elements should use this API
 322  * to indicate previous produced elements are now consumed.
 323  *
 324  * @param p_chain
 325  */
 326 static inline void qed_chain_return_produced(struct qed_chain *p_chain)
 327 {
 328         if (is_chain_u16(p_chain))
 329                 p_chain->u.chain16.cons_idx++;
 330         else
 331                 p_chain->u.chain32.cons_idx++;
 332         test_and_skip(p_chain, cons_idx);
 333 }
 334
 335 /**
 336  * @brief qed_chain_produce -
 337  *
 338  * A chain in which the driver "Produces" elements should use this to get
 339  * a pointer to the next element which can be "Produced". It's driver
 340  * responsibility to validate that the chain has room for new element.
 341  *
 342  * @param p_chain
 343  *
 344  * @return void*, a pointer to next element
 345  */
 346 static inline void *qed_chain_produce(struct qed_chain *p_chain)
 347 {
 348         void *p_ret = NULL, *p_prod_idx, *p_prod_page_idx;
 349
 350         if (is_chain_u16(p_chain)) {
 351                 if ((p_chain->u.chain16.prod_idx &
 352                      p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
 353                         p_prod_idx = &p_chain->u.chain16.prod_idx;
 354                         p_prod_page_idx = &p_chain->pbl.c.u16.prod_page_idx;
 355                         qed_chain_advance_page(p_chain, &p_chain->p_prod_elem,
 356                                                p_prod_idx, p_prod_page_idx);
 357                 }
 358                 p_chain->u.chain16.prod_idx++;
 359         } else {
 360                 if ((p_chain->u.chain32.prod_idx &
 361                      p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
 362                         p_prod_idx = &p_chain->u.chain32.prod_idx;
 363                         p_prod_page_idx = &p_chain->pbl.c.u32.prod_page_idx;
 364                         qed_chain_advance_page(p_chain, &p_chain->p_prod_elem,
 365                                                p_prod_idx, p_prod_page_idx);
 366                 }
 367                 p_chain->u.chain32.prod_idx++;
 368         }
 369
 370         p_ret = p_chain->p_prod_elem;
 371         p_chain->p_prod_elem = (void *)(((u8 *)p_chain->p_prod_elem) +
 372                                         p_chain->elem_size);
 373
 374         return p_ret;
 375 }
 376
 377 /**
 378  * @brief qed_chain_get_capacity -
 379  *
 380  * Get the maximum number of BDs in chain
 381  *
 382  * @param p_chain
 383  * @param num
 384  *
 385  * @return number of unusable BDs
 386  */
 387 static inline u32 qed_chain_get_capacity(struct qed_chain *p_chain)
 388 {
 389         return p_chain->capacity;
 390 }
 391
 392 /**
 393  * @brief qed_chain_recycle_consumed -
 394  *
 395  * Returns an element which was previously consumed;
 396  * Increments producers so they could be written to FW.
 397  *
 398  * @param p_chain
 399  */
 400 static inline void qed_chain_recycle_consumed(struct qed_chain *p_chain)
 401 {
 402         test_and_skip(p_chain, prod_idx);
 403         if (is_chain_u16(p_chain))
 404                 p_chain->u.chain16.prod_idx++;
 405         else
 406                 p_chain->u.chain32.prod_idx++;
 407 }
 408
 409 /**
 410  * @brief qed_chain_consume -
 411  *
 412  * A Chain in which the driver utilizes data written by a different source
 413  * (i.e., FW) should use this to access passed buffers.
 414  *
 415  * @param p_chain
 416  *
 417  * @return void*, a pointer to the next buffer written
 418  */
 419 static inline void *qed_chain_consume(struct qed_chain *p_chain)
 420 {
 421         void *p_ret = NULL, *p_cons_idx, *p_cons_page_idx;
 422
 423         if (is_chain_u16(p_chain)) {
 424                 if ((p_chain->u.chain16.cons_idx &
 425                      p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
 426                         p_cons_idx = &p_chain->u.chain16.cons_idx;
 427                         p_cons_page_idx = &p_chain->pbl.c.u16.cons_page_idx;
 428                         qed_chain_advance_page(p_chain, &p_chain->p_cons_elem,
 429                                                p_cons_idx, p_cons_page_idx);
 430                 }
 431                 p_chain->u.chain16.cons_idx++;
 432         } else {
 433                 if ((p_chain->u.chain32.cons_idx &
 434                      p_chain->elem_per_page_mask) == p_chain->next_page_mask) {
 435                         p_cons_idx = &p_chain->u.chain32.cons_idx;
 436                         p_cons_page_idx = &p_chain->pbl.c.u32.cons_page_idx;
 437                         qed_chain_advance_page(p_chain, &p_chain->p_cons_elem,
 438                                                p_cons_idx, p_cons_page_idx);
 439                 }
 440                 p_chain->u.chain32.cons_idx++;
 441         }
 442
 443         p_ret = p_chain->p_cons_elem;
 444         p_chain->p_cons_elem = (void *)(((u8 *)p_chain->p_cons_elem) +
 445                                         p_chain->elem_size);
 446
 447         return p_ret;
 448 }
 449
 450 /**
 451  * @brief qed_chain_reset - Resets the chain to its start state
 452  *
 453  * @param p_chain pointer to a previously allocted chain
 454  */
 455 static inline void qed_chain_reset(struct qed_chain *p_chain)
 456 {
 457         u32 i;
 458
 459         if (is_chain_u16(p_chain)) {
 460                 p_chain->u.chain16.prod_idx = 0;
 461                 p_chain->u.chain16.cons_idx = 0;
 462         } else {
 463                 p_chain->u.chain32.prod_idx = 0;
 464                 p_chain->u.chain32.cons_idx = 0;
 465         }
 466         p_chain->p_cons_elem = p_chain->p_virt_addr;
 467         p_chain->p_prod_elem = p_chain->p_virt_addr;
 468
 469         if (p_chain->mode == QED_CHAIN_MODE_PBL) {
 470                 /* Use (page_cnt - 1) as a reset value for the prod/cons page's
 471                  * indices, to avoid unnecessary page advancing on the first
 472                  * call to qed_chain_produce/consume. Instead, the indices
 473                  * will be advanced to page_cnt and then will be wrapped to 0.
 474                  */
 475                 u32 reset_val = p_chain->page_cnt - 1;
 476
 477                 if (is_chain_u16(p_chain)) {
 478                         p_chain->pbl.c.u16.prod_page_idx = (u16)reset_val;
 479                         p_chain->pbl.c.u16.cons_page_idx = (u16)reset_val;
 480                 } else {
 481                         p_chain->pbl.c.u32.prod_page_idx = reset_val;
 482                         p_chain->pbl.c.u32.cons_page_idx = reset_val;
 483                 }
 484         }
 485
 486         switch (p_chain->intended_use) {
 487         case QED_CHAIN_USE_TO_CONSUME:
 488                 /* produce empty elements */
 489                 for (i = 0; i < p_chain->capacity; i++)
 490                         qed_chain_recycle_consumed(p_chain);
 491                 break;
 492
 493         case QED_CHAIN_USE_TO_CONSUME_PRODUCE:
 494         case QED_CHAIN_USE_TO_PRODUCE:
 495         default:
 496                 /* Do nothing */
 497                 break;
 498         }
 499 }
 500
 501 /**
 502  * @brief qed_chain_init - Initalizes a basic chain struct
 503  *
 504  * @param p_chain
 505  * @param p_virt_addr
 506  * @param p_phys_addr   physical address of allocated buffer's beginning
 507  * @param page_cnt      number of pages in the allocated buffer
 508  * @param elem_size     size of each element in the chain
 509  * @param intended_use
 510  * @param mode
 511  */
 512 static inline void qed_chain_init_params(struct qed_chain *p_chain,
 513                                          u32 page_cnt,
 514                                          u8 elem_size,
 515                                          enum qed_chain_use_mode intended_use,
 516                                          enum qed_chain_mode mode,
 517                                          enum qed_chain_cnt_type cnt_type)
 518 {
 519         /* chain fixed parameters */
 520         p_chain->p_virt_addr = NULL;
 521         p_chain->p_phys_addr = 0;
 522         p_chain->elem_size      = elem_size;
 523         p_chain->intended_use = (u8)intended_use;
 524         p_chain->mode           = mode;
 525         p_chain->cnt_type = (u8)cnt_type;
 526
 527         p_chain->elem_per_page = ELEMS_PER_PAGE(elem_size);
 528         p_chain->usable_per_page = USABLE_ELEMS_PER_PAGE(elem_size, mode);
 529         p_chain->elem_per_page_mask = p_chain->elem_per_page - 1;
 530         p_chain->elem_unusable = UNUSABLE_ELEMS_PER_PAGE(elem_size, mode);
 531         p_chain->next_page_mask = (p_chain->usable_per_page &
 532                                    p_chain->elem_per_page_mask);
 533
 534         p_chain->page_cnt = page_cnt;
 535         p_chain->capacity = p_chain->usable_per_page * page_cnt;
 536         p_chain->size = p_chain->elem_per_page * page_cnt;
 537
 538         p_chain->pbl_sp.p_phys_table = 0;
 539         p_chain->pbl_sp.p_virt_table = NULL;
 540         p_chain->pbl.pp_virt_addr_tbl = NULL;
 541 }
 542
 543 /**
 544  * @brief qed_chain_init_mem -
 545  *
 546  * Initalizes a basic chain struct with its chain buffers
 547  *
 548  * @param p_chain
 549  * @param p_virt_addr   virtual address of allocated buffer's beginning
 550  * @param p_phys_addr   physical address of allocated buffer's beginning
 551  *
 552  */
 553 static inline void qed_chain_init_mem(struct qed_chain *p_chain,
 554                                       void *p_virt_addr, dma_addr_t p_phys_addr)
 555 {
 556         p_chain->p_virt_addr = p_virt_addr;
 557         p_chain->p_phys_addr = p_phys_addr;
 558 }
 559
 560 /**
 561  * @brief qed_chain_init_pbl_mem -
 562  *
 563  * Initalizes a basic chain struct with its pbl buffers
 564  *
 565  * @param p_chain
 566  * @param p_virt_pbl    pointer to a pre allocated side table which will hold
 567  *                      virtual page addresses.
 568  * @param p_phys_pbl    pointer to a pre-allocated side table which will hold
 569  *                      physical page addresses.
 570  * @param pp_virt_addr_tbl
 571  *                      pointer to a pre-allocated side table which will hold
 572  *                      the virtual addresses of the chain pages.
 573  *
 574  */
 575 static inline void qed_chain_init_pbl_mem(struct qed_chain *p_chain,
 576                                           void *p_virt_pbl,
 577                                           dma_addr_t p_phys_pbl,
 578                                           void **pp_virt_addr_tbl)
 579 {
 580         p_chain->pbl_sp.p_phys_table = p_phys_pbl;
 581         p_chain->pbl_sp.p_virt_table = p_virt_pbl;
 582         p_chain->pbl.pp_virt_addr_tbl = pp_virt_addr_tbl;
 583 }
 584
 585 /**
 586  * @brief qed_chain_init_next_ptr_elem -
 587  *
 588  * Initalizes a next pointer element
 589  *
 590  * @param p_chain
 591  * @param p_virt_curr   virtual address of a chain page of which the next
 592  *                      pointer element is initialized
 593  * @param p_virt_next   virtual address of the next chain page
 594  * @param p_phys_next   physical address of the next chain page
 595  *
 596  */
 597 static inline void
 598 qed_chain_init_next_ptr_elem(struct qed_chain *p_chain,
 599                              void *p_virt_curr,
 600                              void *p_virt_next, dma_addr_t p_phys_next)
 601 {
 602         struct qed_chain_next *p_next;
 603         u32 size;
 604
 605         size = p_chain->elem_size * p_chain->usable_per_page;
 606         p_next = (struct qed_chain_next *)((u8 *)p_virt_curr + size);
 607
 608         DMA_REGPAIR_LE(p_next->next_phys, p_phys_next);
 609
 610         p_next->next_virt = p_virt_next;
 611 }
 612
 613 /**
 614  * @brief qed_chain_get_last_elem -
 615  *
 616  * Returns a pointer to the last element of the chain
 617  *
 618  * @param p_chain
 619  *
 620  * @return void*
 621  */
 622 static inline void *qed_chain_get_last_elem(struct qed_chain *p_chain)
 623 {
 624         struct qed_chain_next *p_next = NULL;
 625         void *p_virt_addr = NULL;
 626         u32 size, last_page_idx;
 627
 628         if (!p_chain->p_virt_addr)
 629                 goto out;
 630
 631         switch (p_chain->mode) {
 632         case QED_CHAIN_MODE_NEXT_PTR:
 633                 size = p_chain->elem_size * p_chain->usable_per_page;
 634                 p_virt_addr = p_chain->p_virt_addr;
 635                 p_next = (struct qed_chain_next *)((u8 *)p_virt_addr + size);
 636                 while (p_next->next_virt != p_chain->p_virt_addr) {
 637                         p_virt_addr = p_next->next_virt;
 638                         p_next = (struct qed_chain_next *)((u8 *)p_virt_addr +
 639                                                            size);
 640                 }
 641                 break;
 642         case QED_CHAIN_MODE_SINGLE:
 643                 p_virt_addr = p_chain->p_virt_addr;
 644                 break;
 645         case QED_CHAIN_MODE_PBL:
 646                 last_page_idx = p_chain->page_cnt - 1;
 647                 p_virt_addr = p_chain->pbl.pp_virt_addr_tbl[last_page_idx];
 648                 break;
 649         }
 650         /* p_virt_addr points at this stage to the last page of the chain */
 651         size = p_chain->elem_size * (p_chain->usable_per_page - 1);
 652         p_virt_addr = (u8 *)p_virt_addr + size;
 653 out:
 654         return p_virt_addr;
 655 }
 656
 657 /**
 658  * @brief qed_chain_set_prod - sets the prod to the given value
 659  *
 660  * @param prod_idx
 661  * @param p_prod_elem
 662  */
 663 static inline void qed_chain_set_prod(struct qed_chain *p_chain,
 664                                       u32 prod_idx, void *p_prod_elem)
 665 {
 666         if (p_chain->mode == QED_CHAIN_MODE_PBL) {
 667                 u32 cur_prod, page_mask, page_cnt, page_diff;
 668
 669                 cur_prod = is_chain_u16(p_chain) ? p_chain->u.chain16.prod_idx :
 670                            p_chain->u.chain32.prod_idx;
 671
 672                 /* Assume that number of elements in a page is power of 2 */
 673                 page_mask = ~p_chain->elem_per_page_mask;
 674
 675                 /* Use "cur_prod - 1" and "prod_idx - 1" since producer index
 676                  * reaches the first element of next page before the page index
 677                  * is incremented. See qed_chain_produce().
 678                  * Index wrap around is not a problem because the difference
 679                  * between current and given producer indices is always
 680                  * positive and lower than the chain's capacity.
 681                  */
 682                 page_diff = (((cur_prod - 1) & page_mask) -
 683                              ((prod_idx - 1) & page_mask)) /
 684                             p_chain->elem_per_page;
 685
 686                 page_cnt = qed_chain_get_page_cnt(p_chain);
 687                 if (is_chain_u16(p_chain))
 688                         p_chain->pbl.c.u16.prod_page_idx =
 689                                 (p_chain->pbl.c.u16.prod_page_idx -
 690                                  page_diff + page_cnt) % page_cnt;
 691                 else
 692                         p_chain->pbl.c.u32.prod_page_idx =
 693                                 (p_chain->pbl.c.u32.prod_page_idx -
 694                                  page_diff + page_cnt) % page_cnt;
 695         }
 696
 697         if (is_chain_u16(p_chain))
 698                 p_chain->u.chain16.prod_idx = (u16) prod_idx;
 699         else
 700                 p_chain->u.chain32.prod_idx = prod_idx;
 701         p_chain->p_prod_elem = p_prod_elem;
 702 }
 703
 704 /**
 705  * @brief qed_chain_pbl_zero_mem - set chain memory to 0
 706  *
 707  * @param p_chain
 708  */
 709 static inline void qed_chain_pbl_zero_mem(struct qed_chain *p_chain)
 710 {
 711         u32 i, page_cnt;
 712
 713         if (p_chain->mode != QED_CHAIN_MODE_PBL)
 714                 return;
 715
 716         page_cnt = qed_chain_get_page_cnt(p_chain);
 717
 718         for (i = 0; i < page_cnt; i++)
 719                 memset(p_chain->pbl.pp_virt_addr_tbl[i], 0,
 720                        QED_CHAIN_PAGE_SIZE);
 721 }
 722
 723 #endif