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 static u32 calculate_xoff(struct mlx5e_priv *priv, unsigned int mtu)
 127 {
 128         u32 speed;
 129         u32 xoff;
 130         int err;
 131
 132         err = mlx5e_port_linkspeed(priv->mdev, &speed);
 133         if (err) {
 134                 mlx5_core_warn(priv->mdev, "cannot get port speed\n");
 135                 return 0;
 136         }
 137
 138         xoff = (301 + 216 * priv->dcbx.cable_len / 100) * speed / 1000 + 272 * mtu / 100;
 139
 140         mlx5e_dbg(HW, priv, "%s: xoff=%d\n", __func__, xoff);
 141         return xoff;
 142 }
 143
 144 static int update_xoff_threshold(struct mlx5e_port_buffer *port_buffer,
 145                                  u32 xoff, unsigned int mtu)
 146 {
 147         int i;
 148
 149         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 150                 if (port_buffer->buffer[i].lossy) {
 151                         port_buffer->buffer[i].xoff = 0;
 152                         port_buffer->buffer[i].xon  = 0;
 153                         continue;
 154                 }
 155
 156                 if (port_buffer->buffer[i].size <
 157                     (xoff + mtu + (1 << MLX5E_BUFFER_CELL_SHIFT)))
 158                         return -ENOMEM;
 159
 160                 port_buffer->buffer[i].xoff = port_buffer->buffer[i].size - xoff;
 161                 port_buffer->buffer[i].xon  = port_buffer->buffer[i].xoff - mtu;
 162         }
 163
 164         return 0;
 165 }
 166
 167 /**
 168  *      update_buffer_lossy     - Update buffer configuration based on pfc
 169  *      @mtu: device's MTU
 170  *      @pfc_en: <input> current pfc configuration
 171  *      @buffer: <input> current prio to buffer mapping
 172  *      @xoff:   <input> xoff value
 173  *      @port_buffer: <output> port receive buffer configuration
 174  *      @change: <output>
 175  *
 176  *      Update buffer configuration based on pfc configuraiton and
 177  *      priority to buffer mapping.
 178  *      Buffer's lossy bit is changed to:
 179  *              lossless if there is at least one PFC enabled priority
 180  *              mapped to this buffer lossy if all priorities mapped to
 181  *              this buffer are PFC disabled
 182  *
 183  *      @return: 0 if no error,
 184  *      sets change to true if buffer configuration was modified.
 185  */
 186 static int update_buffer_lossy(unsigned int mtu,
 187                                u8 pfc_en, u8 *buffer, u32 xoff,
 188                                struct mlx5e_port_buffer *port_buffer,
 189                                bool *change)
 190 {
 191         bool changed = false;
 192         u8 lossy_count;
 193         u8 prio_count;
 194         u8 lossy;
 195         int prio;
 196         int err;
 197         int i;
 198
 199         for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 200                 prio_count = 0;
 201                 lossy_count = 0;
 202
 203                 for (prio = 0; prio < MLX5E_MAX_PRIORITY; prio++) {
 204                         if (buffer[prio] != i)
 205                                 continue;
 206
 207                         prio_count++;
 208                         lossy_count += !(pfc_en & (1 << prio));
 209                 }
 210
 211                 if (lossy_count == prio_count)
 212                         lossy = 1;
 213                 else /* lossy_count < prio_count */
 214                         lossy = 0;
 215
 216                 if (lossy != port_buffer->buffer[i].lossy) {
 217                         port_buffer->buffer[i].lossy = lossy;
 218                         changed = true;
 219                 }
 220         }
 221
 222         if (changed) {
 223                 err = update_xoff_threshold(port_buffer, xoff, mtu);
 224                 if (err)
 225                         return err;
 226
 227                 *change = true;
 228         }
 229
 230         return 0;
 231 }
 232
 233 int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
 234                                     u32 change, unsigned int mtu,
 235                                     struct ieee_pfc *pfc,
 236                                     u32 *buffer_size,
 237                                     u8 *prio2buffer)
 238 {
 239         struct mlx5e_port_buffer port_buffer;
 240         u32 xoff = calculate_xoff(priv, mtu);
 241         bool update_prio2buffer = false;
 242         u8 buffer[MLX5E_MAX_PRIORITY];
 243         bool update_buffer = false;
 244         u32 total_used = 0;
 245         u8 curr_pfc_en;
 246         int err;
 247         int i;
 248
 249         mlx5e_dbg(HW, priv, "%s: change=%x\n", __func__, change);
 250
 251         err = mlx5e_port_query_buffer(priv, &port_buffer);
 252         if (err)
 253                 return err;
 254
 255         if (change & MLX5E_PORT_BUFFER_CABLE_LEN) {
 256                 update_buffer = true;
 257                 err = update_xoff_threshold(&port_buffer, xoff, mtu);
 258                 if (err)
 259                         return err;
 260         }
 261
 262         if (change & MLX5E_PORT_BUFFER_PFC) {
 263                 err = mlx5e_port_query_priority2buffer(priv->mdev, buffer);
 264                 if (err)
 265                         return err;
 266
 267                 err = update_buffer_lossy(mtu, pfc->pfc_en, buffer, xoff,
 268                                           &port_buffer, &update_buffer);
 269                 if (err)
 270                         return err;
 271         }
 272
 273         if (change & MLX5E_PORT_BUFFER_PRIO2BUFFER) {
 274                 update_prio2buffer = true;
 275                 err = mlx5_query_port_pfc(priv->mdev, &curr_pfc_en, NULL);
 276                 if (err)
 277                         return err;
 278
 279                 err = update_buffer_lossy(mtu, curr_pfc_en, prio2buffer, xoff,
 280                                           &port_buffer, &update_buffer);
 281                 if (err)
 282                         return err;
 283         }
 284
 285         if (change & MLX5E_PORT_BUFFER_SIZE) {
 286                 for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
 287                         mlx5e_dbg(HW, priv, "%s: buffer[%d]=%d\n", __func__, i, buffer_size[i]);
 288                         if (!port_buffer.buffer[i].lossy && !buffer_size[i]) {
 289                                 mlx5e_dbg(HW, priv, "%s: lossless buffer[%d] size cannot be zero\n",
 290                                           __func__, i);
 291                                 return -EINVAL;
 292                         }
 293
 294                         port_buffer.buffer[i].size = buffer_size[i];
 295                         total_used += buffer_size[i];
 296                 }
 297
 298                 mlx5e_dbg(HW, priv, "%s: total buffer requested=%d\n", __func__, total_used);
 299
 300                 if (total_used > port_buffer.port_buffer_size)
 301                         return -EINVAL;
 302
 303                 update_buffer = true;
 304                 err = update_xoff_threshold(&port_buffer, xoff, mtu);
 305                 if (err)
 306                         return err;
 307         }
 308
 309         /* Need to update buffer configuration if xoff value is changed */
 310         if (!update_buffer && xoff != priv->dcbx.xoff) {
 311                 update_buffer = true;
 312                 err = update_xoff_threshold(&port_buffer, xoff, mtu);
 313                 if (err)
 314                         return err;
 315         }
 316         priv->dcbx.xoff = xoff;
 317
 318         /* Apply the settings */
 319         if (update_buffer) {
 320                 err = port_set_buffer(priv, &port_buffer);
 321                 if (err)
 322                         return err;
 323         }
 324
 325         if (update_prio2buffer)
 326                 err = mlx5e_port_set_priority2buffer(priv->mdev, prio2buffer);
 327
 328         return err;
 329 }