drm/nouveau/pci: implement generic code for pcie speed change

v2: rename and group functions
v4: change copyright information
    move printing of pcie speeds into oneinit,
    rename all pcie functions to nvkm_pcie_*
    don't try to raise the pcie version when no higher one is supported
v5: revert Copyright changes and rename nvkm_pcie_raise_version to nvkm_pcie_set_version
v6: remove some useless pci_is_pcie checks and rework messages

Signed-off-by: Karol Herbst <nouveau@karolherbst.de>

drivers/gpu/drm/nouveau/include/nvkm/subdev/pci.h

@@ -2,6 +2,12 @@
 #define __NVKM_PCI_H__
 #include <core/subdev.h>
 
+enum nvkm_pcie_speed {
+	NVKM_PCIE_SPEED_2_5,
+	NVKM_PCIE_SPEED_5_0,
+	NVKM_PCIE_SPEED_8_0,
+};
+
 struct nvkm_pci {
 	const struct nvkm_pci_func *func;
 	struct nvkm_subdev subdev;
@@ -18,6 +24,11 @@ struct nvkm_pci {
 		bool acquired;
 	} agp;
 
+	struct {
+		enum nvkm_pcie_speed speed;
+		u8 width;
+	} pcie;
+
 	bool msi;
 };
 
@@ -36,4 +47,7 @@ int g94_pci_new(struct nvkm_device *, int, struct nvkm_pci **);
 int gf100_pci_new(struct nvkm_device *, int, struct nvkm_pci **);
 int gf106_pci_new(struct nvkm_device *, int, struct nvkm_pci **);
 int gk104_pci_new(struct nvkm_device *, int, struct nvkm_pci **);
+
+/* pcie functions */
+int nvkm_pcie_set_link(struct nvkm_pci *, enum nvkm_pcie_speed, u8 width);
 #endif

drivers/gpu/drm/nouveau/nvkm/subdev/pci/Kbuild

@@ -1,5 +1,6 @@
 nvkm-y += nvkm/subdev/pci/agp.o
 nvkm-y += nvkm/subdev/pci/base.o
+nvkm-y += nvkm/subdev/pci/pcie.o
 nvkm-y += nvkm/subdev/pci/nv04.o
 nvkm-y += nvkm/subdev/pci/nv40.o
 nvkm-y += nvkm/subdev/pci/nv46.o

drivers/gpu/drm/nouveau/nvkm/subdev/pci/base.c

@@ -106,6 +106,15 @@ nvkm_pci_preinit(struct nvkm_subdev *subdev)
 	return 0;
 }
 
+static int
+nvkm_pci_oneinit(struct nvkm_subdev *subdev)
+{
+	struct nvkm_pci *pci = nvkm_pci(subdev);
+	if (pci_is_pcie(pci->pdev))
+		return nvkm_pcie_oneinit(pci);
+	return 0;
+}
+
 static int
 nvkm_pci_init(struct nvkm_subdev *subdev)
 {
@@ -117,6 +126,8 @@ nvkm_pci_init(struct nvkm_subdev *subdev)
 		ret = nvkm_agp_init(pci);
 		if (ret)
 			return ret;
+	} else if (pci_is_pcie(pci->pdev)) {
+		nvkm_pcie_init(pci);
 	}
 
 	if (pci->func->init)
@@ -143,6 +154,7 @@ nvkm_pci_dtor(struct nvkm_subdev *subdev)
 static const struct nvkm_subdev_func
 nvkm_pci_func = {
 	.dtor = nvkm_pci_dtor,
+	.oneinit = nvkm_pci_oneinit,
 	.preinit = nvkm_pci_preinit,
 	.init = nvkm_pci_init,
 	.fini = nvkm_pci_fini,
@@ -160,6 +172,8 @@ nvkm_pci_new_(const struct nvkm_pci_func *func, struct nvkm_device *device,
 	pci->func = func;
 	pci->pdev = device->func->pci(device)->pdev;
 	pci->irq = -1;
+	pci->pcie.speed = -1;
+	pci->pcie.width = -1;
 
 	if (device->type == NVKM_DEVICE_AGP)
 		nvkm_agp_ctor(pci);

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

@@ -0,0 +1,165 @@
+/*
+ * Copyright 2015 Karol Herbst <nouveau@karolherbst.de>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: Karol Herbst <git@karolherbst.de>
+ */
+#include "priv.h"
+
+static char *nvkm_pcie_speeds[] = {
+	"2.5GT/s",
+	"5.0GT/s",
+	"8.0GT/s",
+};
+
+static enum nvkm_pcie_speed
+nvkm_pcie_speed(enum pci_bus_speed speed)
+{
+	switch (speed) {
+	case PCIE_SPEED_2_5GT:
+		return NVKM_PCIE_SPEED_2_5;
+	case PCIE_SPEED_5_0GT:
+		return NVKM_PCIE_SPEED_5_0;
+	case PCIE_SPEED_8_0GT:
+		return NVKM_PCIE_SPEED_8_0;
+	default:
+		/* XXX 0x16 is 8_0, assume 0x17 will be 16_0 for now */
+		if (speed == 0x17)
+			return NVKM_PCIE_SPEED_8_0;
+		return -1;
+	}
+}
+
+static int
+nvkm_pcie_get_version(struct nvkm_pci *pci)
+{
+	if (!pci->func->pcie.version)
+		return -ENOSYS;
+
+	return pci->func->pcie.version(pci);
+}
+
+static int
+nvkm_pcie_get_max_version(struct nvkm_pci *pci)
+{
+	if (!pci->func->pcie.version_supported)
+		return -ENOSYS;
+
+	return pci->func->pcie.version_supported(pci);
+}
+
+static int
+nvkm_pcie_set_version(struct nvkm_pci *pci, int version)
+{
+	if (!pci->func->pcie.set_version)
+		return -ENOSYS;
+
+	nvkm_trace(&pci->subdev, "set to version %i\n", version);
+	pci->func->pcie.set_version(pci, version);
+	return nvkm_pcie_get_version(pci);
+}
+
+int
+nvkm_pcie_oneinit(struct nvkm_pci *pci)
+{
+	if (pci->func->pcie.max_speed)
+		nvkm_debug(&pci->subdev, "pcie max speed: %s\n",
+			   nvkm_pcie_speeds[pci->func->pcie.max_speed(pci)]);
+	return 0;
+}
+
+int
+nvkm_pcie_init(struct nvkm_pci *pci)
+{
+	struct nvkm_subdev *subdev = &pci->subdev;
+	int ret;
+
+	/* raise pcie version first */
+	ret = nvkm_pcie_get_version(pci);
+	if (ret > 0) {
+		int max_version = nvkm_pcie_get_max_version(pci);
+		if (max_version > 0 && max_version > ret)
+			ret = nvkm_pcie_set_version(pci, max_version);
+
+		if (ret < max_version)
+			nvkm_error(subdev, "couldn't raise version: %i\n", ret);
+	}
+
+	if (pci->func->pcie.init)
+		pci->func->pcie.init(pci);
+
+	if (pci->pcie.speed != -1)
+		nvkm_pcie_set_link(pci, pci->pcie.speed, pci->pcie.width);
+
+	return 0;
+}
+
+int
+nvkm_pcie_set_link(struct nvkm_pci *pci, enum nvkm_pcie_speed speed, u8 width)
+{
+	struct nvkm_subdev *subdev = &pci->subdev;
+	enum nvkm_pcie_speed cur_speed, max_speed;
+	struct pci_bus *pbus;
+	int ret;
+
+	if (pci || !pci_is_pcie(pci->pdev))
+		return 0;
+	pbus = pci->pdev->bus;
+
+	if (!pci->func->pcie.set_link)
+		return -ENOSYS;
+
+	nvkm_trace(subdev, "requested %s\n", nvkm_pcie_speeds[speed]);
+
+	if (pci->func->pcie.version(pci) < 2) {
+		nvkm_error(subdev, "setting link failed due to low version\n");
+		return -ENODEV;
+	}
+
+	cur_speed = pci->func->pcie.cur_speed(pci);
+	max_speed = min(nvkm_pcie_speed(pbus->max_bus_speed),
+			pci->func->pcie.max_speed(pci));
+
+	nvkm_trace(subdev, "current speed: %s\n", nvkm_pcie_speeds[cur_speed]);
+
+	if (speed > max_speed) {
+		nvkm_debug(subdev, "%s not supported by bus or card, dropping"
+			   "requested speed to %s", nvkm_pcie_speeds[speed],
+			   nvkm_pcie_speeds[max_speed]);
+		speed = max_speed;
+	}
+
+	pci->pcie.speed = speed;
+	pci->pcie.width = width;
+
+	if (speed == cur_speed) {
+		nvkm_debug(subdev, "requested matches current speed\n");
+		return speed;
+	}
+
+	nvkm_debug(subdev, "set link to %s x%i\n",
+		   nvkm_pcie_speeds[speed], width);
+
+	ret = pci->func->pcie.set_link(pci, speed, width);
+	if (ret < 0)
+		nvkm_error(subdev, "setting link failed: %i\n", ret);
+
+	return ret;
+}

drivers/gpu/drm/nouveau/nvkm/subdev/pci/priv.h

@@ -12,6 +12,18 @@ struct nvkm_pci_func {
 	void (*wr08)(struct nvkm_pci *, u16 addr, u8 data);
 	void (*wr32)(struct nvkm_pci *, u16 addr, u32 data);
 	void (*msi_rearm)(struct nvkm_pci *);
+
+	struct {
+		int (*init)(struct nvkm_pci *);
+		int (*set_link)(struct nvkm_pci *, enum nvkm_pcie_speed, u8);
+
+		enum nvkm_pcie_speed (*max_speed)(struct nvkm_pci *);
+		enum nvkm_pcie_speed (*cur_speed)(struct nvkm_pci *);
+
+		void (*set_version)(struct nvkm_pci *, u8);
+		int (*version)(struct nvkm_pci *);
+		int (*version_supported)(struct nvkm_pci *);
+	} pcie;
 };
 
 u32 nv40_pci_rd32(struct nvkm_pci *, u16);
@@ -22,4 +34,8 @@ void nv40_pci_msi_rearm(struct nvkm_pci *);
 void nv46_pci_msi_rearm(struct nvkm_pci *);
 
 void g84_pci_init(struct nvkm_pci *pci);
+
+/* pcie functions */
+int nvkm_pcie_oneinit(struct nvkm_pci *);
+int nvkm_pcie_init(struct nvkm_pci *);
 #endif