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      1 /*	$NetBSD: nouveau_nvkm_subdev_pci_pcie.c,v 1.5 2023/09/30 10:46:45 mrg Exp $	*/
      2 
      3 /*
      4  * Copyright 2015 Karol Herbst <nouveau (at) karolherbst.de>
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be included in
     14  * all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     19  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
     20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     22  * OTHER DEALINGS IN THE SOFTWARE.
     23  *
     24  * Authors: Karol Herbst <git (at) karolherbst.de>
     25  */
     26 #include <sys/cdefs.h>
     27 __KERNEL_RCSID(0, "$NetBSD: nouveau_nvkm_subdev_pci_pcie.c,v 1.5 2023/09/30 10:46:45 mrg Exp $");
     28 
     29 #include "priv.h"
     30 
     31 static const char *nvkm_pcie_speeds[] = {
     32 	"2.5GT/s",
     33 	"5.0GT/s",
     34 	"8.0GT/s",
     35 };
     36 
     37 static enum nvkm_pcie_speed
     38 nvkm_pcie_speed(enum pci_bus_speed speed)
     39 {
     40 	switch (speed) {
     41 	case PCIE_SPEED_2_5GT:
     42 		return NVKM_PCIE_SPEED_2_5;
     43 	case PCIE_SPEED_5_0GT:
     44 		return NVKM_PCIE_SPEED_5_0;
     45 	case PCIE_SPEED_8_0GT:
     46 		return NVKM_PCIE_SPEED_8_0;
     47 	default:
     48 		/* XXX 0x16 is 8_0, assume 0x17 will be 16_0 for now */
     49 		if (speed == 0x17)
     50 			return NVKM_PCIE_SPEED_8_0;
     51 		return NVKM_PCIE_SPEED_2_5;
     52 	}
     53 }
     54 
     55 static int
     56 nvkm_pcie_get_version(struct nvkm_pci *pci)
     57 {
     58 	if (!pci->func->pcie.version)
     59 		return -ENOSYS;
     60 
     61 	return pci->func->pcie.version(pci);
     62 }
     63 
     64 static int
     65 nvkm_pcie_get_max_version(struct nvkm_pci *pci)
     66 {
     67 	if (!pci->func->pcie.version_supported)
     68 		return -ENOSYS;
     69 
     70 	return pci->func->pcie.version_supported(pci);
     71 }
     72 
     73 static int
     74 nvkm_pcie_set_version(struct nvkm_pci *pci, int version)
     75 {
     76 	if (!pci->func->pcie.set_version)
     77 		return -ENOSYS;
     78 
     79 	nvkm_trace(&pci->subdev, "set to version %i\n", version);
     80 	pci->func->pcie.set_version(pci, version);
     81 	return nvkm_pcie_get_version(pci);
     82 }
     83 
     84 int
     85 nvkm_pcie_oneinit(struct nvkm_pci *pci)
     86 {
     87 	if (pci->func->pcie.max_speed)
     88 		nvkm_debug(&pci->subdev, "pcie max speed: %s\n",
     89 			   nvkm_pcie_speeds[pci->func->pcie.max_speed(pci)]);
     90 	return 0;
     91 }
     92 
     93 int
     94 nvkm_pcie_init(struct nvkm_pci *pci)
     95 {
     96 	struct nvkm_subdev *subdev = &pci->subdev;
     97 	int ret;
     98 
     99 	/* raise pcie version first */
    100 	ret = nvkm_pcie_get_version(pci);
    101 	if (ret > 0) {
    102 		int max_version = nvkm_pcie_get_max_version(pci);
    103 		if (max_version > 0 && max_version > ret)
    104 			ret = nvkm_pcie_set_version(pci, max_version);
    105 
    106 		if (ret < max_version)
    107 			nvkm_error(subdev, "couldn't raise version: %i\n", ret);
    108 	}
    109 
    110 	if (pci->func->pcie.init)
    111 		pci->func->pcie.init(pci);
    112 
    113 	if (pci->pcie.speed != -1)
    114 		nvkm_pcie_set_link(pci, pci->pcie.speed, pci->pcie.width);
    115 
    116 	return 0;
    117 }
    118 
    119 int
    120 nvkm_pcie_set_link(struct nvkm_pci *pci, enum nvkm_pcie_speed speed, u8 width)
    121 {
    122 	struct nvkm_subdev *subdev = &pci->subdev;
    123 	enum nvkm_pcie_speed cur_speed, max_speed;
    124 	struct pci_bus *pbus;
    125 	int ret;
    126 
    127 	if (!pci || !pci_is_pcie(pci->pdev))
    128 		return 0;
    129 	pbus = pci->pdev->bus;
    130 
    131 	if (!pci->func->pcie.set_link)
    132 		return -ENOSYS;
    133 
    134 	nvkm_trace(subdev, "requested %s\n", nvkm_pcie_speeds[speed]);
    135 
    136 	if (pci->func->pcie.version(pci) < 2) {
    137 		nvkm_error(subdev, "setting link failed due to low version\n");
    138 		return -ENODEV;
    139 	}
    140 
    141 	cur_speed = pci->func->pcie.cur_speed(pci);
    142 	max_speed = min(nvkm_pcie_speed(pbus->max_bus_speed),
    143 			pci->func->pcie.max_speed(pci));
    144 
    145 	nvkm_trace(subdev, "current speed: %s\n", nvkm_pcie_speeds[cur_speed]);
    146 
    147 	if (speed > max_speed) {
    148 		nvkm_debug(subdev, "%s not supported by bus or card, dropping"
    149 			   "requested speed to %s", nvkm_pcie_speeds[speed],
    150 			   nvkm_pcie_speeds[max_speed]);
    151 		speed = max_speed;
    152 	}
    153 
    154 	pci->pcie.speed = speed;
    155 	pci->pcie.width = width;
    156 
    157 	if (speed == cur_speed) {
    158 		nvkm_debug(subdev, "requested matches current speed\n");
    159 		return speed;
    160 	}
    161 
    162 	nvkm_debug(subdev, "set link to %s x%i\n",
    163 		   nvkm_pcie_speeds[speed], width);
    164 
    165 	ret = pci->func->pcie.set_link(pci, speed, width);
    166 	if (ret < 0)
    167 		nvkm_error(subdev, "setting link failed: %i\n", ret);
    168 
    169 	return ret;
    170 }
    171