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         struct mlx5_core_dev *mdev = priv->mdev;
  38         int sz = MLX5_ST_SZ_BYTES(pbmc_reg);
  39         u32 total_used = 0;
  40         void *buffer;
  41         void *out;
  42         int err;
  43         int i;
  44
  45         out = kzalloc(sz, GFP_KERNEL);
  46         if (!out)
  47                 return -ENOMEM;
  48
  49         err = mlx5e_port_query_pbmc(mdev, out);
  50         if (err)
  51                 goto out;
  52
  53         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
  54                 buffer = MLX5_ADDR_OF(pbmc_reg, out, buffer[i]);
  55                 port_buffer->buffer[i].lossy =
  56                         MLX5_GET(bufferx_reg, buffer, lossy);
  57                 port_buffer->buffer[i].epsb =
  58                         MLX5_GET(bufferx_reg, buffer, epsb);
  59                 port_buffer->buffer[i].size =
  60                         MLX5_GET(bufferx_reg, buffer, size) << MLX5E_BUFFER_CELL_SHIFT;
  61                 port_buffer->buffer[i].xon =
  62                         MLX5_GET(bufferx_reg, buffer, xon_threshold) << MLX5E_BUFFER_CELL_SHIFT;
  63                 port_buffer->buffer[i].xoff =
  64                         MLX5_GET(bufferx_reg, buffer, xoff_threshold) << MLX5E_BUFFER_CELL_SHIFT;
  65                 total_used += port_buffer->buffer[i].size;
  66
  67                 mlx5e_dbg(HW, priv, "buffer %d: size=%d, xon=%d, xoff=%d, epsb=%d, lossy=%d\n", i,
  68                           port_buffer->buffer[i].size,
  69                           port_buffer->buffer[i].xon,
  70                           port_buffer->buffer[i].xoff,
  71                           port_buffer->buffer[i].epsb,
  72                           port_buffer->buffer[i].lossy);
  73         }
  74
  75         port_buffer->port_buffer_size =
  76                 MLX5_GET(pbmc_reg, out, port_buffer_size) << MLX5E_BUFFER_CELL_SHIFT;
  77         port_buffer->spare_buffer_size =
  78                 port_buffer->port_buffer_size - total_used;
  79
  80         mlx5e_dbg(HW, priv, "total buffer size=%d, spare buffer size=%d\n",
  81                   port_buffer->port_buffer_size,
  82                   port_buffer->spare_buffer_size);
  83 out:
  84         kfree(out);
  85         return err;
  86 }
  87
  88 static int port_set_buffer(struct mlx5e_priv *priv,
  89                            struct mlx5e_port_buffer *port_buffer)
  90 {
  91         struct mlx5_core_dev *mdev = priv->mdev;
  92         int sz = MLX5_ST_SZ_BYTES(pbmc_reg);
  93         void *buffer;
  94         void *in;
  95         int err;
  96         int i;
  97
  98         in = kzalloc(sz, GFP_KERNEL);
  99         if (!in)
 100                 return -ENOMEM;
 101
 102         err = mlx5e_port_query_pbmc(mdev, in);
 103         if (err)
 104                 goto out;
 105
 106         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 107                 buffer = MLX5_ADDR_OF(pbmc_reg, in, buffer[i]);
 108
 109                 MLX5_SET(bufferx_reg, buffer, size,
 110                          port_buffer->buffer[i].size >> MLX5E_BUFFER_CELL_SHIFT);
 111                 MLX5_SET(bufferx_reg, buffer, lossy,
 112                          port_buffer->buffer[i].lossy);
 113                 MLX5_SET(bufferx_reg, buffer, xoff_threshold,
 114                          port_buffer->buffer[i].xoff >> MLX5E_BUFFER_CELL_SHIFT);
 115                 MLX5_SET(bufferx_reg, buffer, xon_threshold,
 116                          port_buffer->buffer[i].xon >> MLX5E_BUFFER_CELL_SHIFT);
 117         }
 118
 119         err = mlx5e_port_set_pbmc(mdev, in);
 120 out:
 121         kfree(in);
 122         return err;
 123 }
 124
 125 /* xoff = ((301+2.16 * len [m]) * speed [Gbps] + 2.72 MTU [B])
 126  * minimum speed value is 40Gbps
 127  */
 128 static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
 129 {
 130         u32 speed;
 131         u32 xoff;
 132         int err;
 133
 134         err = mlx5e_port_linkspeed(priv->mdev, &speed);
 135         if (err)
 136                 speed = SPEED_40000;
 137         speed = max_t(u32, speed, SPEED_40000);
 138
 139         xoff = (301 + 216 * priv->dcbx.cable_len / 100) * speed / 1000 + 272 * mtu / 100;
 140
 141         mlx5e_dbg(HW, priv, "%s: xoff=%d\n", __func__, xoff);
 142         return xoff;
 143 }
 144
 145 static int update_xoff_threshold(struct mlx5e_port_buffer *port_buffer,
 146                                  u32 xoff, unsigned int max_mtu)
 147 {
 148         int i;
 149
 150         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 151                 if (port_buffer->buffer[i].lossy) {
 152                         port_buffer->buffer[i].xoff = 0;
 153                         port_buffer->buffer[i].xon  = 0;
 154                         continue;
 155                 }
 156
 157                 if (port_buffer->buffer[i].size <
 158                     (xoff + max_mtu + (1 << MLX5E_BUFFER_CELL_SHIFT)))
 159                         return -ENOMEM;
 160
 161                 port_buffer->buffer[i].xoff = port_buffer->buffer[i].size - xoff;
 162                 port_buffer->buffer[i].xon  =
 163                         port_buffer->buffer[i].xoff - max_mtu;
 164         }
 165
 166         return 0;
 167 }
 168
 169 /**
 170  * update_buffer_lossy()
 171  *   max_mtu: netdev's max_mtu
 172  *   pfc_en: <input> current pfc configuration
 173  *   buffer: <input> current prio to buffer mapping
 174  *   xoff:   <input> xoff value
 175  *   port_buffer: <output> port receive buffer configuration
 176  *   change: <output>
 177  *
 178  *   Update buffer configuration based on pfc configuraiton and priority
 179  *   to buffer mapping.
 180  *   Buffer's lossy bit is changed to:
 181  *     lossless if there is at least one PFC enabled priority mapped to this buffer
 182  *     lossy if all priorities mapped to this buffer are PFC disabled
 183  *
 184  *   Return:
 185  *     Return 0 if no error.
 186  *     Set change to true if buffer configuration is modified.
 187  */
 188 static int update_buffer_lossy(unsigned int max_mtu,
 189                                u8 pfc_en, u8 *buffer, u32 xoff,
 190                                struct mlx5e_port_buffer *port_buffer,
 191                                bool *change)
 192 {
 193         bool changed = false;
 194         u8 lossy_count;
 195         u8 prio_count;
 196         u8 lossy;
 197         int prio;
 198         int err;
 199         int i;
 200
 201         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 202                 prio_count = 0;
 203                 lossy_count = 0;
 204
 205                 for (prio = 0; prio < MLX5E_MAX_PRIORITY; prio++) {
 206                         if (buffer[prio] != i)
 207                                 continue;
 208
 209                         prio_count++;
 210                         lossy_count += !(pfc_en & (1 << prio));
 211                 }
 212
 213                 if (lossy_count == prio_count)
 214                         lossy = 1;
 215                 else /* lossy_count < prio_count */
 216                         lossy = 0;
 217
 218                 if (lossy != port_buffer->buffer[i].lossy) {
 219                         port_buffer->buffer[i].lossy = lossy;
 220                         changed = true;
 221                 }
 222         }
 223
 224         if (changed) {
 225                 err = update_xoff_threshold(port_buffer, xoff, max_mtu);
 226                 if (err)
 227                         return err;
 228
 229                 *change = true;
 230         }
 231
 232         return 0;
 233 }
 234
 235 #define MINIMUM_MAX_MTU 9216
 236 int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
 237                                     u32 change, unsigned int mtu,
 238                                     struct ieee_pfc *pfc,
 239                                     u32 *buffer_size,
 240                                     u8 *prio2buffer)
 241 {
 242         struct mlx5e_port_buffer port_buffer;
 243         u32 xoff = calculate_xoff(priv, mtu);
 244         bool update_prio2buffer = false;
 245         u8 buffer[MLX5E_MAX_PRIORITY];
 246         bool update_buffer = false;
 247         unsigned int max_mtu;
 248         u32 total_used = 0;
 249         u8 curr_pfc_en;
 250         int err;
 251         int i;
 252
 253         mlx5e_dbg(HW, priv, "%s: change=%x\n", __func__, change);
 254         max_mtu = max_t(unsigned int, priv->netdev->max_mtu, MINIMUM_MAX_MTU);
 255
 256         err = mlx5e_port_query_buffer(priv, &port_buffer);
 257         if (err)
 258                 return err;
 259
 260         if (change & MLX5E_PORT_BUFFER_CABLE_LEN) {
 261                 update_buffer = true;
 262                 err = update_xoff_threshold(&port_buffer, xoff, max_mtu);
 263                 if (err)
 264                         return err;
 265         }
 266
 267         if (change & MLX5E_PORT_BUFFER_PFC) {
 268                 err = mlx5e_port_query_priority2buffer(priv->mdev, buffer);
 269                 if (err)
 270                         return err;
 271
 272                 err = update_buffer_lossy(max_mtu, pfc->pfc_en, buffer, xoff,
 273                                           &port_buffer, &update_buffer);
 274                 if (err)
 275                         return err;
 276         }
 277
 278         if (change & MLX5E_PORT_BUFFER_PRIO2BUFFER) {
 279                 update_prio2buffer = true;
 280                 err = mlx5_query_port_pfc(priv->mdev, &curr_pfc_en, NULL);
 281                 if (err)
 282                         return err;
 283
 284                 err = update_buffer_lossy(max_mtu, curr_pfc_en, prio2buffer,
 285                                           xoff, &port_buffer, &update_buffer);
 286                 if (err)
 287                         return err;
 288         }
 289
 290         if (change & MLX5E_PORT_BUFFER_SIZE) {
 291                 for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 292                         mlx5e_dbg(HW, priv, "%s: buffer[%d]=%d\n", __func__, i, buffer_size[i]);
 293                         if (!port_buffer.buffer[i].lossy && !buffer_size[i]) {
 294                                 mlx5e_dbg(HW, priv, "%s: lossless buffer[%d] size cannot be zero\n",
 295                                           __func__, i);
 296                                 return -EINVAL;
 297                         }
 298
 299                         port_buffer.buffer[i].size = buffer_size[i];
 300                         total_used += buffer_size[i];
 301                 }
 302
 303                 mlx5e_dbg(HW, priv, "%s: total buffer requested=%d\n", __func__, total_used);
 304
 305                 if (total_used > port_buffer.port_buffer_size)
 306                         return -EINVAL;
 307
 308                 update_buffer = true;
 309                 err = update_xoff_threshold(&port_buffer, xoff, max_mtu);
 310                 if (err)
 311                         return err;
 312         }
 313
 314         /* Need to update buffer configuration if xoff value is changed */
 315         if (!update_buffer && xoff != priv->dcbx.xoff) {
 316                 update_buffer = true;
 317                 err = update_xoff_threshold(&port_buffer, xoff, max_mtu);
 318                 if (err)
 319                         return err;
 320         }
 321         priv->dcbx.xoff = xoff;
 322
 323         /* Apply the settings */
 324         if (update_buffer) {
 325                 err = port_set_buffer(priv, &port_buffer);
 326                 if (err)
 327                         return err;
 328         }
 329
 330         if (update_prio2buffer)
 331                 err = mlx5e_port_set_priority2buffer(priv->mdev, prio2buffer);
 332
 333         return err;
 334 }