drivers/net/ixgbe/ixgbe_dcb.c

   1 /*******************************************************************************
   2
   3   Intel 10 Gigabit PCI Express Linux driver
   4   Copyright(c) 1999 - 2010 Intel Corporation.
   5
   6   This program is free software; you can redistribute it and/or modify it
   7   under the terms and conditions of the GNU General Public License,
   8   version 2, as published by the Free Software Foundation.
   9
  10   This program is distributed in the hope it will be useful, but WITHOUT
  11   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13   more details.
  14
  15   You should have received a copy of the GNU General Public License along with
  16   this program; if not, write to the Free Software Foundation, Inc.,
  17   51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18
  19   The full GNU General Public License is included in this distribution in
  20   the file called "COPYING".
  21
  22   Contact Information:
  23   Linux NICS <linux.nics@intel.com>
  24   e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
  25   Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
  26
  27 *******************************************************************************/
  28
  29
  30 #include "ixgbe.h"
  31 #include "ixgbe_type.h"
  32 #include "ixgbe_dcb.h"
  33 #include "ixgbe_dcb_82598.h"
  34 #include "ixgbe_dcb_82599.h"
  35
  36 /**
  37  * ixgbe_dcb_calculate_tc_credits - Calculates traffic class credits
  38  * @ixgbe_dcb_config: Struct containing DCB settings.
  39  * @direction: Configuring either Tx or Rx.
  40  *
  41  * This function calculates the credits allocated to each traffic class.
  42  * It should be called only after the rules are checked by
  43  * ixgbe_dcb_check_config().
  44  */
  45 s32 ixgbe_dcb_calculate_tc_credits(struct ixgbe_dcb_config *dcb_config,
  46                                    u8 direction)
  47 {
  48         struct tc_bw_alloc *p;
  49         s32 ret_val = 0;
  50         /* Initialization values default for Tx settings */
  51         u32 credit_refill       = 0;
  52         u32 credit_max          = 0;
  53         u16 link_percentage     = 0;
  54         u8  bw_percent          = 0;
  55         u8  i;
  56
  57         if (dcb_config == NULL) {
  58                 ret_val = DCB_ERR_CONFIG;
  59                 goto out;
  60         }
  61
  62         /* Find out the link percentage for each TC first */
  63         for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
  64                 p = &dcb_config->tc_config[i].path[direction];
  65                 bw_percent = dcb_config->bw_percentage[direction][p->bwg_id];
  66
  67                 link_percentage = p->bwg_percent;
  68                 /* Must be careful of integer division for very small nums */
  69                 link_percentage = (link_percentage * bw_percent) / 100;
  70                 if (p->bwg_percent > 0 && link_percentage == 0)
  71                         link_percentage = 1;
  72
  73                 /* Save link_percentage for reference */
  74                 p->link_percent = (u8)link_percentage;
  75
  76                 /* Calculate credit refill and save it */
  77                 credit_refill = link_percentage * MINIMUM_CREDIT_REFILL;
  78                 p->data_credits_refill = (u16)credit_refill;
  79
  80                 /* Calculate maximum credit for the TC */
  81                 credit_max = (link_percentage * MAX_CREDIT) / 100;
  82
  83                 /*
  84                  * Adjustment based on rule checking, if the percentage
  85                  * of a TC is too small, the maximum credit may not be
  86                  * enough to send out a jumbo frame in data plane arbitration.
  87                  */
  88                 if (credit_max && (credit_max < MINIMUM_CREDIT_FOR_JUMBO))
  89                         credit_max = MINIMUM_CREDIT_FOR_JUMBO;
  90
  91                 if (direction == DCB_TX_CONFIG) {
  92                         /*
  93                          * Adjustment based on rule checking, if the
  94                          * percentage of a TC is too small, the maximum
  95                          * credit may not be enough to send out a TSO
  96                          * packet in descriptor plane arbitration.
  97                          */
  98                         if (credit_max &&
  99                             (credit_max < MINIMUM_CREDIT_FOR_TSO))
 100                                 credit_max = MINIMUM_CREDIT_FOR_TSO;
 101
 102                         dcb_config->tc_config[i].desc_credits_max =
 103                                 (u16)credit_max;
 104                 }
 105
 106                 p->data_credits_max = (u16)credit_max;
 107         }
 108
 109 out:
 110         return ret_val;
 111 }
 112
 113 /**
 114  * ixgbe_dcb_hw_config - Config and enable DCB
 115  * @hw: pointer to hardware structure
 116  * @dcb_config: pointer to ixgbe_dcb_config structure
 117  *
 118  * Configure dcb settings and enable dcb mode.
 119  */
 120 s32 ixgbe_dcb_hw_config(struct ixgbe_hw *hw,
 121                         struct ixgbe_dcb_config *dcb_config)
 122 {
 123         s32 ret = 0;
 124         if (hw->mac.type == ixgbe_mac_82598EB)
 125                 ret = ixgbe_dcb_hw_config_82598(hw, dcb_config);
 126         else if (hw->mac.type == ixgbe_mac_82599EB)
 127                 ret = ixgbe_dcb_hw_config_82599(hw, dcb_config);
 128         return ret;
 129 }
 130