drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c

   1 /*
   2  * Copyright (c) 2018, Mellanox Technologies. All rights reserved.
   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 #include "port_buffer.h"
  33
  34 int mlx5e_port_query_buffer(struct mlx5e_priv *priv,
  35                             struct mlx5e_port_buffer *port_buffer)
  36 {
  37         u16 port_buff_cell_sz = priv->dcbx.port_buff_cell_sz;
  38         struct mlx5_core_dev *mdev = priv->mdev;
  39         int sz = MLX5_ST_SZ_BYTES(pbmc_reg);
  40         u32 total_used = 0;
  41         void *buffer;
  42         void *out;
  43         int err;
  44         int i;
  45
  46         out = kzalloc(sz, GFP_KERNEL);
  47         if (!out)
  48                 return -ENOMEM;
  49
  50         err = mlx5e_port_query_pbmc(mdev, out);
  51         if (err)
  52                 goto out;
  53
  54         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
  55                 buffer = MLX5_ADDR_OF(pbmc_reg, out, buffer[i]);
  56                 port_buffer->buffer[i].lossy =
  57                         MLX5_GET(bufferx_reg, buffer, lossy);
  58                 port_buffer->buffer[i].epsb =
  59                         MLX5_GET(bufferx_reg, buffer, epsb);
  60                 port_buffer->buffer[i].size =
  61                         MLX5_GET(bufferx_reg, buffer, size) * port_buff_cell_sz;
  62                 port_buffer->buffer[i].xon =
  63                         MLX5_GET(bufferx_reg, buffer, xon_threshold) * port_buff_cell_sz;
  64                 port_buffer->buffer[i].xoff =
  65                         MLX5_GET(bufferx_reg, buffer, xoff_threshold) * port_buff_cell_sz;
  66                 total_used += port_buffer->buffer[i].size;
  67
  68                 mlx5e_dbg(HW, priv, "buffer %d: size=%d, xon=%d, xoff=%d, epsb=%d, lossy=%d\n", i,
  69                           port_buffer->buffer[i].size,
  70                           port_buffer->buffer[i].xon,
  71                           port_buffer->buffer[i].xoff,
  72                           port_buffer->buffer[i].epsb,
  73                           port_buffer->buffer[i].lossy);
  74         }
  75
  76         port_buffer->headroom_size = total_used;
  77         port_buffer->port_buffer_size =
  78                 MLX5_GET(pbmc_reg, out, port_buffer_size) * port_buff_cell_sz;
  79         port_buffer->spare_buffer_size =
  80                 port_buffer->port_buffer_size - total_used;
  81
  82         mlx5e_dbg(HW, priv, "total buffer size=%d, spare buffer size=%d\n",
  83                   port_buffer->port_buffer_size,
  84                   port_buffer->spare_buffer_size);
  85 out:
  86         kfree(out);
  87         return err;
  88 }
  89
  90 struct mlx5e_buffer_pool {
  91         u32 infi_size;
  92         u32 size;
  93         u32 buff_occupancy;
  94 };
  95
  96 static int mlx5e_port_query_pool(struct mlx5_core_dev *mdev,
  97                                  struct mlx5e_buffer_pool *buffer_pool,
  98                                  u32 desc, u8 dir, u8 pool_idx)
  99 {
 100         u32 out[MLX5_ST_SZ_DW(sbpr_reg)] = {};
 101         int err;
 102
 103         err = mlx5e_port_query_sbpr(mdev, desc, dir, pool_idx, out,
 104                                     sizeof(out));
 105         if (err)
 106                 return err;
 107
 108         buffer_pool->size = MLX5_GET(sbpr_reg, out, size);
 109         buffer_pool->infi_size = MLX5_GET(sbpr_reg, out, infi_size);
 110         buffer_pool->buff_occupancy = MLX5_GET(sbpr_reg, out, buff_occupancy);
 111
 112         return err;
 113 }
 114
 115 enum {
 116         MLX5_INGRESS_DIR = 0,
 117         MLX5_EGRESS_DIR = 1,
 118 };
 119
 120 enum {
 121         MLX5_LOSSY_POOL = 0,
 122         MLX5_LOSSLESS_POOL = 1,
 123 };
 124
 125 /* No limit on usage of shared buffer pool (max_buff=0) */
 126 #define MLX5_SB_POOL_NO_THRESHOLD  0
 127 /* Shared buffer pool usage threshold when calculated
 128  * dynamically in alpha units. alpha=13 is equivalent to
 129  * HW_alpha of  [(1/128) * 2 ^ (alpha-1)] = 32, where HW_alpha
 130  * equates to the following portion of the shared buffer pool:
 131  * [32 / (1 + n * 32)] While *n* is the number of buffers
 132  * that are using the shared buffer pool.
 133  */
 134 #define MLX5_SB_POOL_THRESHOLD 13
 135
 136 /* Shared buffer class management parameters */
 137 struct mlx5_sbcm_params {
 138         u8 pool_idx;
 139         u8 max_buff;
 140         u8 infi_size;
 141 };
 142
 143 static const struct mlx5_sbcm_params sbcm_default = {
 144         .pool_idx = MLX5_LOSSY_POOL,
 145         .max_buff = MLX5_SB_POOL_NO_THRESHOLD,
 146         .infi_size = 0,
 147 };
 148
 149 static const struct mlx5_sbcm_params sbcm_lossy = {
 150         .pool_idx = MLX5_LOSSY_POOL,
 151         .max_buff = MLX5_SB_POOL_NO_THRESHOLD,
 152         .infi_size = 1,
 153 };
 154
 155 static const struct mlx5_sbcm_params sbcm_lossless = {
 156         .pool_idx = MLX5_LOSSLESS_POOL,
 157         .max_buff = MLX5_SB_POOL_THRESHOLD,
 158         .infi_size = 0,
 159 };
 160
 161 static const struct mlx5_sbcm_params sbcm_lossless_no_threshold = {
 162         .pool_idx = MLX5_LOSSLESS_POOL,
 163         .max_buff = MLX5_SB_POOL_NO_THRESHOLD,
 164         .infi_size = 1,
 165 };
 166
 167 /**
 168  * select_sbcm_params() - selects the shared buffer pool configuration
 169  *
 170  * @buffer: <input> port buffer to retrieve params of
 171  * @lossless_buff_count: <input> number of lossless buffers in total
 172  *
 173  * The selection is based on the following rules:
 174  * 1. If buffer size is 0, no shared buffer pool is used.
 175  * 2. If buffer is lossy, use lossy shared buffer pool.
 176  * 3. If there are more than 1 lossless buffers, use lossless shared buffer pool
 177  *    with threshold.
 178  * 4. If there is only 1 lossless buffer, use lossless shared buffer pool
 179  *    without threshold.
 180  *
 181  * @return const struct mlx5_sbcm_params* selected values
 182  */
 183 static const struct mlx5_sbcm_params *
 184 select_sbcm_params(struct mlx5e_bufferx_reg *buffer, u8 lossless_buff_count)
 185 {
 186         if (buffer->size == 0)
 187                 return &sbcm_default;
 188
 189         if (buffer->lossy)
 190                 return &sbcm_lossy;
 191
 192         if (lossless_buff_count > 1)
 193                 return &sbcm_lossless;
 194
 195         return &sbcm_lossless_no_threshold;
 196 }
 197
 198 static int port_update_pool_cfg(struct mlx5_core_dev *mdev,
 199                                 struct mlx5e_port_buffer *port_buffer)
 200 {
 201         const struct mlx5_sbcm_params *p;
 202         u8 lossless_buff_count = 0;
 203         int err;
 204         int i;
 205
 206         if (!MLX5_CAP_GEN(mdev, sbcam_reg))
 207                 return 0;
 208
 209         for (i = 0; i < MLX5E_MAX_BUFFER; i++)
 210                 lossless_buff_count += ((port_buffer->buffer[i].size) &&
 211                                        (!(port_buffer->buffer[i].lossy)));
 212
 213         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 214                 p = select_sbcm_params(&port_buffer->buffer[i], lossless_buff_count);
 215                 err = mlx5e_port_set_sbcm(mdev, 0, i,
 216                                           MLX5_INGRESS_DIR,
 217                                           p->infi_size,
 218                                           p->max_buff,
 219                                           p->pool_idx);
 220                 if (err)
 221                         return err;
 222         }
 223
 224         return 0;
 225 }
 226
 227 static int port_update_shared_buffer(struct mlx5_core_dev *mdev,
 228                                      u32 current_headroom_size,
 229                                      u32 new_headroom_size)
 230 {
 231         struct mlx5e_buffer_pool lossless_ipool;
 232         struct mlx5e_buffer_pool lossy_epool;
 233         u32 lossless_ipool_size;
 234         u32 shared_buffer_size;
 235         u32 total_buffer_size;
 236         u32 lossy_epool_size;
 237         int err;
 238
 239         if (!MLX5_CAP_GEN(mdev, sbcam_reg))
 240                 return 0;
 241
 242         err = mlx5e_port_query_pool(mdev, &lossy_epool, 0, MLX5_EGRESS_DIR,
 243                                     MLX5_LOSSY_POOL);
 244         if (err)
 245                 return err;
 246
 247         err = mlx5e_port_query_pool(mdev, &lossless_ipool, 0, MLX5_INGRESS_DIR,
 248                                     MLX5_LOSSLESS_POOL);
 249         if (err)
 250                 return err;
 251
 252         total_buffer_size = current_headroom_size + lossy_epool.size +
 253                             lossless_ipool.size;
 254         shared_buffer_size = total_buffer_size - new_headroom_size;
 255
 256         if (shared_buffer_size < 4) {
 257                 pr_err("Requested port buffer is too large, not enough space left for shared buffer\n");
 258                 return -EINVAL;
 259         }
 260
 261         /* Total shared buffer size is split in a ratio of 3:1 between
 262          * lossy and lossless pools respectively.
 263          */
 264         lossy_epool_size = (shared_buffer_size / 4) * 3;
 265         lossless_ipool_size = shared_buffer_size / 4;
 266
 267         mlx5e_port_set_sbpr(mdev, 0, MLX5_EGRESS_DIR, MLX5_LOSSY_POOL, 0,
 268                             lossy_epool_size);
 269         mlx5e_port_set_sbpr(mdev, 0, MLX5_INGRESS_DIR, MLX5_LOSSLESS_POOL, 0,
 270                             lossless_ipool_size);
 271         return 0;
 272 }
 273
 274 static int port_set_buffer(struct mlx5e_priv *priv,
 275                            struct mlx5e_port_buffer *port_buffer)
 276 {
 277         u16 port_buff_cell_sz = priv->dcbx.port_buff_cell_sz;
 278         struct mlx5_core_dev *mdev = priv->mdev;
 279         int sz = MLX5_ST_SZ_BYTES(pbmc_reg);
 280         u32 new_headroom_size = 0;
 281         u32 current_headroom_size;
 282         void *in;
 283         int err;
 284         int i;
 285
 286         current_headroom_size = port_buffer->headroom_size;
 287
 288         in = kzalloc(sz, GFP_KERNEL);
 289         if (!in)
 290                 return -ENOMEM;
 291
 292         err = mlx5e_port_query_pbmc(mdev, in);
 293         if (err)
 294                 goto out;
 295
 296         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 297                 void *buffer = MLX5_ADDR_OF(pbmc_reg, in, buffer[i]);
 298                 u64 size = port_buffer->buffer[i].size;
 299                 u64 xoff = port_buffer->buffer[i].xoff;
 300                 u64 xon = port_buffer->buffer[i].xon;
 301
 302                 new_headroom_size += size;
 303                 do_div(size, port_buff_cell_sz);
 304                 do_div(xoff, port_buff_cell_sz);
 305                 do_div(xon, port_buff_cell_sz);
 306                 MLX5_SET(bufferx_reg, buffer, size, size);
 307                 MLX5_SET(bufferx_reg, buffer, lossy, port_buffer->buffer[i].lossy);
 308                 MLX5_SET(bufferx_reg, buffer, xoff_threshold, xoff);
 309                 MLX5_SET(bufferx_reg, buffer, xon_threshold, xon);
 310         }
 311
 312         new_headroom_size /= port_buff_cell_sz;
 313         current_headroom_size /= port_buff_cell_sz;
 314         err = port_update_shared_buffer(priv->mdev, current_headroom_size,
 315                                         new_headroom_size);
 316         if (err)
 317                 goto out;
 318
 319         err = port_update_pool_cfg(priv->mdev, port_buffer);
 320         if (err)
 321                 goto out;
 322
 323         err = mlx5e_port_set_pbmc(mdev, in);
 324 out:
 325         kfree(in);
 326         return err;
 327 }
 328
 329 /* xoff = ((301+2.16 * len [m]) * speed [Gbps] + 2.72 MTU [B])
 330  * minimum speed value is 40Gbps
 331  */
 332 static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
 333 {
 334         u32 speed;
 335         u32 xoff;
 336         int err;
 337
 338         err = mlx5e_port_linkspeed(priv->mdev, &speed);
 339         if (err)
 340                 speed = SPEED_40000;
 341         speed = max_t(u32, speed, SPEED_40000);
 342
 343         xoff = (301 + 216 * priv->dcbx.cable_len / 100) * speed / 1000 + 272 * mtu / 100;
 344
 345         mlx5e_dbg(HW, priv, "%s: xoff=%d\n", __func__, xoff);
 346         return xoff;
 347 }
 348
 349 static int update_xoff_threshold(struct mlx5e_port_buffer *port_buffer,
 350                                  u32 xoff, unsigned int max_mtu, u16 port_buff_cell_sz)
 351 {
 352         int i;
 353
 354         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 355                 if (port_buffer->buffer[i].lossy) {
 356                         port_buffer->buffer[i].xoff = 0;
 357                         port_buffer->buffer[i].xon  = 0;
 358                         continue;
 359                 }
 360
 361                 if (port_buffer->buffer[i].size <
 362                     (xoff + max_mtu + port_buff_cell_sz)) {
 363                         pr_err("buffer_size[%d]=%d is not enough for lossless buffer\n",
 364                                i, port_buffer->buffer[i].size);
 365                         return -ENOMEM;
 366                 }
 367
 368                 port_buffer->buffer[i].xoff = port_buffer->buffer[i].size - xoff;
 369                 port_buffer->buffer[i].xon  =
 370                         port_buffer->buffer[i].xoff - max_mtu;
 371         }
 372
 373         return 0;
 374 }
 375
 376 /**
 377  *      update_buffer_lossy     - Update buffer configuration based on pfc
 378  *      @mdev: port function core device
 379  *      @max_mtu: netdev's max_mtu
 380  *      @pfc_en: <input> current pfc configuration
 381  *      @buffer: <input> current prio to buffer mapping
 382  *      @xoff:   <input> xoff value
 383  *      @port_buff_cell_sz: <input> port buffer cell_size
 384  *      @port_buffer: <output> port receive buffer configuration
 385  *      @change: <output>
 386  *
 387  *      Update buffer configuration based on pfc configuration and
 388  *      priority to buffer mapping.
 389  *      Buffer's lossy bit is changed to:
 390  *              lossless if there is at least one PFC enabled priority
 391  *              mapped to this buffer lossy if all priorities mapped to
 392  *              this buffer are PFC disabled
 393  *
 394  *      @return: 0 if no error,
 395  *      sets change to true if buffer configuration was modified.
 396  */
 397 static int update_buffer_lossy(struct mlx5_core_dev *mdev,
 398                                unsigned int max_mtu,
 399                                u8 pfc_en, u8 *buffer, u32 xoff, u16 port_buff_cell_sz,
 400                                struct mlx5e_port_buffer *port_buffer,
 401                                bool *change)
 402 {
 403         bool changed = false;
 404         u8 lossy_count;
 405         u8 prio_count;
 406         u8 lossy;
 407         int prio;
 408         int err;
 409         int i;
 410
 411         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 412                 prio_count = 0;
 413                 lossy_count = 0;
 414
 415                 for (prio = 0; prio < MLX5E_MAX_PRIORITY; prio++) {
 416                         if (buffer[prio] != i)
 417                                 continue;
 418
 419                         prio_count++;
 420                         lossy_count += !(pfc_en & (1 << prio));
 421                 }
 422
 423                 if (lossy_count == prio_count)
 424                         lossy = 1;
 425                 else /* lossy_count < prio_count */
 426                         lossy = 0;
 427
 428                 if (lossy != port_buffer->buffer[i].lossy) {
 429                         port_buffer->buffer[i].lossy = lossy;
 430                         changed = true;
 431                 }
 432         }
 433
 434         if (changed) {
 435                 err = port_update_pool_cfg(mdev, port_buffer);
 436                 if (err)
 437                         return err;
 438
 439                 err = update_xoff_threshold(port_buffer, xoff, max_mtu, port_buff_cell_sz);
 440                 if (err)
 441                         return err;
 442
 443                 *change = true;
 444         }
 445
 446         return 0;
 447 }
 448
 449 static int fill_pfc_en(struct mlx5_core_dev *mdev, u8 *pfc_en)
 450 {
 451         u32 g_rx_pause, g_tx_pause;
 452         int err;
 453
 454         err = mlx5_query_port_pause(mdev, &g_rx_pause, &g_tx_pause);
 455         if (err)
 456                 return err;
 457
 458         /* If global pause enabled, set all active buffers to lossless.
 459          * Otherwise, check PFC setting.
 460          */
 461         if (g_rx_pause || g_tx_pause)
 462                 *pfc_en = 0xff;
 463         else
 464                 err = mlx5_query_port_pfc(mdev, pfc_en, NULL);
 465
 466         return err;
 467 }
 468
 469 #define MINIMUM_MAX_MTU 9216
 470 int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
 471                                     u32 change, unsigned int mtu,
 472                                     struct ieee_pfc *pfc,
 473                                     u32 *buffer_size,
 474                                     u8 *prio2buffer)
 475 {
 476         u16 port_buff_cell_sz = priv->dcbx.port_buff_cell_sz;
 477         struct mlx5e_port_buffer port_buffer;
 478         u32 xoff = calculate_xoff(priv, mtu);
 479         bool update_prio2buffer = false;
 480         u8 buffer[MLX5E_MAX_PRIORITY];
 481         bool update_buffer = false;
 482         unsigned int max_mtu;
 483         u32 total_used = 0;
 484         u8 curr_pfc_en;
 485         int err;
 486         int i;
 487
 488         mlx5e_dbg(HW, priv, "%s: change=%x\n", __func__, change);
 489         max_mtu = max_t(unsigned int, priv->netdev->max_mtu, MINIMUM_MAX_MTU);
 490
 491         err = mlx5e_port_query_buffer(priv, &port_buffer);
 492         if (err)
 493                 return err;
 494
 495         if (change & MLX5E_PORT_BUFFER_CABLE_LEN) {
 496                 update_buffer = true;
 497                 err = update_xoff_threshold(&port_buffer, xoff, max_mtu, port_buff_cell_sz);
 498                 if (err)
 499                         return err;
 500         }
 501
 502         if (change & MLX5E_PORT_BUFFER_PFC) {
 503                 mlx5e_dbg(HW, priv, "%s: requested PFC per priority bitmask: 0x%x\n",
 504                           __func__, pfc->pfc_en);
 505                 err = mlx5e_port_query_priority2buffer(priv->mdev, buffer);
 506                 if (err)
 507                         return err;
 508
 509                 err = update_buffer_lossy(priv->mdev, max_mtu, pfc->pfc_en, buffer, xoff,
 510                                           port_buff_cell_sz, &port_buffer,
 511                                           &update_buffer);
 512                 if (err)
 513                         return err;
 514         }
 515
 516         if (change & MLX5E_PORT_BUFFER_PRIO2BUFFER) {
 517                 update_prio2buffer = true;
 518                 for (i = 0; i < MLX5E_MAX_BUFFER; i++)
 519                         mlx5e_dbg(HW, priv, "%s: requested to map prio[%d] to buffer %d\n",
 520                                   __func__, i, prio2buffer[i]);
 521
 522                 err = fill_pfc_en(priv->mdev, &curr_pfc_en);
 523                 if (err)
 524                         return err;
 525
 526                 err = update_buffer_lossy(priv->mdev, max_mtu, curr_pfc_en, prio2buffer, xoff,
 527                                           port_buff_cell_sz, &port_buffer, &update_buffer);
 528                 if (err)
 529                         return err;
 530         }
 531
 532         if (change & MLX5E_PORT_BUFFER_SIZE) {
 533                 for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 534                         mlx5e_dbg(HW, priv, "%s: buffer[%d]=%d\n", __func__, i, buffer_size[i]);
 535                         if (!port_buffer.buffer[i].lossy && !buffer_size[i]) {
 536                                 mlx5e_dbg(HW, priv, "%s: lossless buffer[%d] size cannot be zero\n",
 537                                           __func__, i);
 538                                 return -EINVAL;
 539                         }
 540
 541                         port_buffer.buffer[i].size = buffer_size[i];
 542                         total_used += buffer_size[i];
 543                 }
 544
 545                 mlx5e_dbg(HW, priv, "%s: total buffer requested=%d\n", __func__, total_used);
 546
 547                 if (total_used > port_buffer.port_buffer_size)
 548                         return -EINVAL;
 549
 550                 update_buffer = true;
 551                 err = update_xoff_threshold(&port_buffer, xoff, max_mtu, port_buff_cell_sz);
 552                 if (err)
 553                         return err;
 554         }
 555
 556         /* Need to update buffer configuration if xoff value is changed */
 557         if (!update_buffer && xoff != priv->dcbx.xoff) {
 558                 update_buffer = true;
 559                 err = update_xoff_threshold(&port_buffer, xoff, max_mtu, port_buff_cell_sz);
 560                 if (err)
 561                         return err;
 562         }
 563         priv->dcbx.xoff = xoff;
 564
 565         /* Apply the settings */
 566         if (update_buffer) {
 567                 err = port_set_buffer(priv, &port_buffer);
 568                 if (err)
 569                         return err;
 570         }
 571
 572         if (update_prio2buffer)
 573                 err = mlx5e_port_set_priority2buffer(priv->mdev, prio2buffer);
 574
 575         return err;
 576 }