LXR linux/drivers/gpu/drm/nouveau/nvkm/subdev/pci/pcie.c

   1/*
   2 * Copyright 2015 Karol Herbst <nouveau@karolherbst.de>
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice shall be included in
  12 * all copies or substantial portions of the Software.
  13 *
  14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20 * OTHER DEALINGS IN THE SOFTWARE.
  21 *
  22 * Authors: Karol Herbst <git@karolherbst.de>
  23 */
  24#include "priv.h"
  25
  26static char *nvkm_pcie_speeds[] = {
  27        "2.5GT/s",
  28        "5.0GT/s",
  29        "8.0GT/s",
  30};
  31
  32static enum nvkm_pcie_speed
  33nvkm_pcie_speed(enum pci_bus_speed speed)
  34{
  35        switch (speed) {
  36        case PCIE_SPEED_2_5GT:
  37                return NVKM_PCIE_SPEED_2_5;
  38        case PCIE_SPEED_5_0GT:
  39                return NVKM_PCIE_SPEED_5_0;
  40        case PCIE_SPEED_8_0GT:
  41                return NVKM_PCIE_SPEED_8_0;
  42        default:
  43                /* XXX 0x16 is 8_0, assume 0x17 will be 16_0 for now */
  44                if (speed == 0x17)
  45                        return NVKM_PCIE_SPEED_8_0;
  46                return -1;
  47        }
  48}
  49
  50static int
  51nvkm_pcie_get_version(struct nvkm_pci *pci)
  52{
  53        if (!pci->func->pcie.version)
  54                return -ENOSYS;
  55
  56        return pci->func->pcie.version(pci);
  57}
  58
  59static int
  60nvkm_pcie_get_max_version(struct nvkm_pci *pci)
  61{
  62        if (!pci->func->pcie.version_supported)
  63                return -ENOSYS;
  64
  65        return pci->func->pcie.version_supported(pci);
  66}
  67
  68static int
  69nvkm_pcie_set_version(struct nvkm_pci *pci, int version)
  70{
  71        if (!pci->func->pcie.set_version)
  72                return -ENOSYS;
  73
  74        nvkm_trace(&pci->subdev, "set to version %i\n", version);
  75        pci->func->pcie.set_version(pci, version);
  76        return nvkm_pcie_get_version(pci);
  77}
  78
  79int
  80nvkm_pcie_oneinit(struct nvkm_pci *pci)
  81{
  82        if (pci->func->pcie.max_speed)
  83                nvkm_debug(&pci->subdev, "pcie max speed: %s\n",
  84                           nvkm_pcie_speeds[pci->func->pcie.max_speed(pci)]);
  85        return 0;
  86}
  87
  88int
  89nvkm_pcie_init(struct nvkm_pci *pci)
  90{
  91        struct nvkm_subdev *subdev = &pci->subdev;
  92        int ret;
  93
  94        /* raise pcie version first */
  95        ret = nvkm_pcie_get_version(pci);
  96        if (ret > 0) {
  97                int max_version = nvkm_pcie_get_max_version(pci);
  98                if (max_version > 0 && max_version > ret)
  99                        ret = nvkm_pcie_set_version(pci, max_version);
 100
 101                if (ret < max_version)
 102                        nvkm_error(subdev, "couldn't raise version: %i\n", ret);
 103        }
 104
 105        if (pci->func->pcie.init)
 106                pci->func->pcie.init(pci);
 107
 108        if (pci->pcie.speed != -1)
 109                nvkm_pcie_set_link(pci, pci->pcie.speed, pci->pcie.width);
 110
 111        return 0;
 112}
 113
 114int
 115nvkm_pcie_set_link(struct nvkm_pci *pci, enum nvkm_pcie_speed speed, u8 width)
 116{
 117        struct nvkm_subdev *subdev = &pci->subdev;
 118        enum nvkm_pcie_speed cur_speed, max_speed;
 119        struct pci_bus *pbus;
 120        int ret;
 121
 122        if (!pci || !pci_is_pcie(pci->pdev))
 123                return 0;
 124        pbus = pci->pdev->bus;
 125
 126        if (!pci->func->pcie.set_link)
 127                return -ENOSYS;
 128
 129        nvkm_trace(subdev, "requested %s\n", nvkm_pcie_speeds[speed]);
 130
 131        if (pci->func->pcie.version(pci) < 2) {
 132                nvkm_error(subdev, "setting link failed due to low version\n");
 133                return -ENODEV;
 134        }
 135
 136        cur_speed = pci->func->pcie.cur_speed(pci);
 137        max_speed = min(nvkm_pcie_speed(pbus->max_bus_speed),
 138                        pci->func->pcie.max_speed(pci));
 139
 140        nvkm_trace(subdev, "current speed: %s\n", nvkm_pcie_speeds[cur_speed]);
 141
 142        if (speed > max_speed) {
 143                nvkm_debug(subdev, "%s not supported by bus or card, dropping"
 144                           "requested speed to %s", nvkm_pcie_speeds[speed],
 145                           nvkm_pcie_speeds[max_speed]);
 146                speed = max_speed;
 147        }
 148
 149        pci->pcie.speed = speed;
 150        pci->pcie.width = width;
 151
 152        if (speed == cur_speed) {
 153                nvkm_debug(subdev, "requested matches current speed\n");
 154                return speed;
 155        }
 156
 157        nvkm_debug(subdev, "set link to %s x%i\n",
 158                   nvkm_pcie_speeds[speed], width);
 159
 160        ret = pci->func->pcie.set_link(pci, speed, width);
 161        if (ret < 0)
 162                nvkm_error(subdev, "setting link failed: %i\n", ret);
 163
 164        return ret;
 165}
 166