drm/nouveau/intr: add shared interrupt plumbing between pci/tegra

Unifies the handling between PCI-based and Tegra GPUs, and makes more
explicit/obvious where device interrupts can be expected.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

drivers/gpu/drm/nouveau/include/nvkm/core/device.h

@@ -2,6 +2,7 @@
 #ifndef __NVKM_DEVICE_H__
 #define __NVKM_DEVICE_H__
 #include <core/oclass.h>
+#include <core/intr.h>
 enum nvkm_subdev_type;
 
 enum nvkm_device_type {
@@ -60,6 +61,13 @@ struct nvkm_device {
 #undef NVKM_LAYOUT_INST
 #undef NVKM_LAYOUT_ONCE
 	struct list_head subdev;
+
+	struct {
+		spinlock_t lock;
+		int irq;
+		bool alloc;
+		bool armed;
+	} intr;
 };
 
 struct nvkm_subdev *nvkm_device_subdev(struct nvkm_device *, int type, int inst);
@@ -72,6 +80,7 @@ struct nvkm_device_func {
 	int (*preinit)(struct nvkm_device *);
 	int (*init)(struct nvkm_device *);
 	void (*fini)(struct nvkm_device *, bool suspend);
+	int (*irq)(struct nvkm_device *);
 	resource_size_t (*resource_addr)(struct nvkm_device *, unsigned bar);
 	resource_size_t (*resource_size)(struct nvkm_device *, unsigned bar);
 	bool cpu_coherent;

drivers/gpu/drm/nouveau/include/nvkm/core/intr.h

+/* SPDX-License-Identifier: MIT */
+#ifndef __NVKM_INTR_H__
+#define __NVKM_INTR_H__
+#include <core/os.h>
+struct nvkm_device;
+
+void nvkm_intr_ctor(struct nvkm_device *);
+void nvkm_intr_dtor(struct nvkm_device *);
+int nvkm_intr_install(struct nvkm_device *);
+void nvkm_intr_unarm(struct nvkm_device *);
+void nvkm_intr_rearm(struct nvkm_device *);
+#endif

drivers/gpu/drm/nouveau/include/nvkm/core/tegra.h

@@ -8,7 +8,6 @@ struct nvkm_device_tegra {
 	const struct nvkm_device_tegra_func *func;
 	struct nvkm_device device;
 	struct platform_device *pdev;
-	int irq;
 
 	struct reset_control *rst;
 	struct clk *clk;

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

@@ -13,7 +13,6 @@ struct nvkm_pci {
 	const struct nvkm_pci_func *func;
 	struct nvkm_subdev subdev;
 	struct pci_dev *pdev;
-	int irq;
 
 	struct {
 		struct agp_bridge_data *bridge;
@@ -38,6 +37,7 @@ void nvkm_pci_wr08(struct nvkm_pci *, u16 addr, u8 data);
 void nvkm_pci_wr32(struct nvkm_pci *, u16 addr, u32 data);
 u32 nvkm_pci_mask(struct nvkm_pci *, u16 addr, u32 mask, u32 value);
 void nvkm_pci_rom_shadow(struct nvkm_pci *, bool shadow);
+void nvkm_pci_msi_rearm(struct nvkm_device *);
 
 int nv04_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct nvkm_pci **);
 int nv40_pci_new(struct nvkm_device *, enum nvkm_subdev_type, int inst, struct nvkm_pci **);

drivers/gpu/drm/nouveau/nvkm/core/Kbuild

@@ -5,6 +5,7 @@ nvkm-y += nvkm/core/enum.o
 nvkm-y += nvkm/core/event.o
 nvkm-y += nvkm/core/firmware.o
 nvkm-y += nvkm/core/gpuobj.o
+nvkm-y += nvkm/core/intr.o
 nvkm-y += nvkm/core/ioctl.o
 nvkm-y += nvkm/core/memory.o
 nvkm-y += nvkm/core/mm.o

drivers/gpu/drm/nouveau/nvkm/core/intr.c

+/*
+ * Copyright 2021 Red Hat Inc.
+ *
+ * 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.
+ */
+#include <core/intr.h>
+
+#include <subdev/pci.h>
+#include <subdev/mc.h>
+
+static void
+nvkm_intr_rearm_locked(struct nvkm_device *device)
+{
+	nvkm_mc_intr_rearm(device);
+}
+
+static void
+nvkm_intr_unarm_locked(struct nvkm_device *device)
+{
+	nvkm_mc_intr_unarm(device);
+}
+
+static irqreturn_t
+nvkm_intr(int irq, void *arg)
+{
+	struct nvkm_device *device = arg;
+	irqreturn_t ret = IRQ_NONE;
+	bool handled;
+
+	spin_lock(&device->intr.lock);
+	if (!device->intr.armed)
+		goto done_unlock;
+
+	nvkm_intr_unarm_locked(device);
+	nvkm_pci_msi_rearm(device);
+
+	nvkm_mc_intr(device, &handled);
+	if (handled)
+		ret = IRQ_HANDLED;
+
+	nvkm_intr_rearm_locked(device);
+done_unlock:
+	spin_unlock(&device->intr.lock);
+	return ret;
+}
+
+void
+nvkm_intr_rearm(struct nvkm_device *device)
+{
+	spin_lock_irq(&device->intr.lock);
+	nvkm_intr_rearm_locked(device);
+	device->intr.armed = true;
+	spin_unlock_irq(&device->intr.lock);
+}
+
+void
+nvkm_intr_unarm(struct nvkm_device *device)
+{
+	spin_lock_irq(&device->intr.lock);
+	nvkm_intr_unarm_locked(device);
+	device->intr.armed = false;
+	spin_unlock_irq(&device->intr.lock);
+}
+
+int
+nvkm_intr_install(struct nvkm_device *device)
+{
+	int ret;
+
+	device->intr.irq = device->func->irq(device);
+	if (device->intr.irq < 0)
+		return device->intr.irq;
+
+	ret = request_irq(device->intr.irq, nvkm_intr, IRQF_SHARED, "nvkm", device);
+	if (ret)
+		return ret;
+
+	device->intr.alloc = true;
+	return 0;
+}
+
+void
+nvkm_intr_dtor(struct nvkm_device *device)
+{
+	if (device->intr.alloc)
+		free_irq(device->intr.irq, device);
+}
+
+void
+nvkm_intr_ctor(struct nvkm_device *device)
+{
+	spin_lock_init(&device->intr.lock);
+}

drivers/gpu/drm/nouveau/nvkm/engine/device/base.c

@@ -2734,6 +2734,8 @@ nvkm_device_fini(struct nvkm_device *device, bool suspend)
 	if (device->func->fini)
 		device->func->fini(device, suspend);
 
+	nvkm_intr_unarm(device);
+
 	time = ktime_to_us(ktime_get()) - time;
 	nvdev_trace(device, "%s completed in %lldus...\n", action, time);
 	return 0;
@@ -2759,6 +2761,8 @@ nvkm_device_preinit(struct nvkm_device *device)
 	nvdev_trace(device, "preinit running...\n");
 	time = ktime_to_us(ktime_get());
 
+	nvkm_intr_unarm(device);
+
 	if (device->func->preinit) {
 		ret = device->func->preinit(device);
 		if (ret)
@@ -2804,6 +2808,8 @@ nvkm_device_init(struct nvkm_device *device)
 	nvdev_trace(device, "init running...\n");
 	time = ktime_to_us(ktime_get());
 
+	nvkm_intr_rearm(device);
+
 	if (device->func->init) {
 		ret = device->func->init(device);
 		if (ret)
@@ -2841,6 +2847,8 @@ nvkm_device_del(struct nvkm_device **pdevice)
 	if (device) {
 		mutex_lock(&nv_devices_mutex);
 
+		nvkm_intr_dtor(device);
+
 		list_for_each_entry_safe_reverse(subdev, subtmp, &device->subdev, head)
 			nvkm_subdev_del(&subdev);
 
@@ -3148,6 +3156,7 @@ nvkm_device_ctor(const struct nvkm_device_func *func,
 		device->name = device->chip->name;
 
 	mutex_init(&device->mutex);
+	nvkm_intr_ctor(device);
 
 #define NVKM_LAYOUT_ONCE(type,data,ptr)                                                      \
 	if (device->chip->ptr.inst && (subdev_mask & (BIT_ULL(type)))) {                     \
@@ -3189,7 +3198,7 @@ nvkm_device_ctor(const struct nvkm_device_func *func,
 #undef NVKM_LAYOUT_INST
 #undef NVKM_LAYOUT_ONCE
 
-	ret = 0;
+	ret = nvkm_intr_install(device);
 done:
 	if (device->pri && (!mmio || ret)) {
 		iounmap(device->pri);

drivers/gpu/drm/nouveau/nvkm/engine/device/pci.c

@@ -1574,6 +1574,12 @@ nvkm_device_pci_resource_size(struct nvkm_device *device, unsigned bar)
 	return pci_resource_len(pdev->pdev, bar);
 }
 
+static int
+nvkm_device_pci_irq(struct nvkm_device *device)
+{
+	return nvkm_device_pci(device)->pdev->irq;
+}
+
 static void
 nvkm_device_pci_fini(struct nvkm_device *device, bool suspend)
 {
@@ -1612,6 +1618,7 @@ nvkm_device_pci_func = {
 	.dtor = nvkm_device_pci_dtor,
 	.preinit = nvkm_device_pci_preinit,
 	.fini = nvkm_device_pci_fini,
+	.irq = nvkm_device_pci_irq,
 	.resource_addr = nvkm_device_pci_resource_addr,
 	.resource_size = nvkm_device_pci_resource_size,
 	.cpu_coherent = !IS_ENABLED(CONFIG_ARM),

drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c

@@ -206,45 +206,12 @@ nvkm_device_tegra_resource_size(struct nvkm_device *device, unsigned bar)
 	return res ? resource_size(res) : 0;
 }
 
-static irqreturn_t
-nvkm_device_tegra_intr(int irq, void *arg)
-{
-	struct nvkm_device_tegra *tdev = arg;
-	struct nvkm_device *device = &tdev->device;
-	bool handled = false;
-	nvkm_mc_intr_unarm(device);
-	nvkm_mc_intr(device, &handled);
-	nvkm_mc_intr_rearm(device);
-	return handled ? IRQ_HANDLED : IRQ_NONE;
-}
-
-static void
-nvkm_device_tegra_fini(struct nvkm_device *device, bool suspend)
-{
-	struct nvkm_device_tegra *tdev = nvkm_device_tegra(device);
-	if (tdev->irq) {
-		free_irq(tdev->irq, tdev);
-		tdev->irq = 0;
-	}
-}
-
 static int
-nvkm_device_tegra_init(struct nvkm_device *device)
+nvkm_device_tegra_irq(struct nvkm_device *device)
 {
 	struct nvkm_device_tegra *tdev = nvkm_device_tegra(device);
-	int irq, ret;
-
-	irq = platform_get_irq_byname(tdev->pdev, "stall");
-	if (irq < 0)
-		return irq;
 
-	ret = request_irq(irq, nvkm_device_tegra_intr,
-			  IRQF_SHARED, "nvkm", tdev);
-	if (ret)
-		return ret;
-
-	tdev->irq = irq;
-	return 0;
+	return platform_get_irq_byname(tdev->pdev, "stall");
 }
 
 static void *
@@ -260,8 +227,7 @@ static const struct nvkm_device_func
 nvkm_device_tegra_func = {
 	.tegra = nvkm_device_tegra,
 	.dtor = nvkm_device_tegra_dtor,
-	.init = nvkm_device_tegra_init,
-	.fini = nvkm_device_tegra_fini,
+	.irq = nvkm_device_tegra_irq,
 	.resource_addr = nvkm_device_tegra_resource_addr,
 	.resource_size = nvkm_device_tegra_resource_size,
 	.cpu_coherent = false,

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

@@ -26,7 +26,15 @@
 
 #include <core/option.h>
 #include <core/pci.h>
-#include <subdev/mc.h>
+
+void
+nvkm_pci_msi_rearm(struct nvkm_device *device)
+{
+	struct nvkm_pci *pci = device->pci;
+
+	if (pci && pci->msi)
+		pci->func->msi_rearm(pci);
+}
 
 u32
 nvkm_pci_rd32(struct nvkm_pci *pci, u16 addr)
@@ -65,24 +73,6 @@ nvkm_pci_rom_shadow(struct nvkm_pci *pci, bool shadow)
 	nvkm_pci_wr32(pci, 0x0050, data);
 }
 
-static irqreturn_t
-nvkm_pci_intr(int irq, void *arg)
-{
-	struct nvkm_pci *pci = arg;
-	struct nvkm_device *device = pci->subdev.device;
-	bool handled = false;
-
-	if (pci->irq < 0)
-		return IRQ_HANDLED;
-
-	nvkm_mc_intr_unarm(device);
-	if (pci->msi)
-		pci->func->msi_rearm(pci);
-	nvkm_mc_intr(device, &handled);
-	nvkm_mc_intr_rearm(device);
-	return handled ? IRQ_HANDLED : IRQ_NONE;
-}
-
 static int
 nvkm_pci_fini(struct nvkm_subdev *subdev, bool suspend)
 {
@@ -107,7 +97,6 @@ static int
 nvkm_pci_oneinit(struct nvkm_subdev *subdev)
 {
 	struct nvkm_pci *pci = nvkm_pci(subdev);
-	struct pci_dev *pdev = pci->pdev;
 	int ret;
 
 	if (pci_is_pcie(pci->pdev)) {
@@ -116,11 +105,6 @@ nvkm_pci_oneinit(struct nvkm_subdev *subdev)
 			return ret;
 	}
 
-	ret = request_irq(pdev->irq, nvkm_pci_intr, IRQF_SHARED, "nvkm", pci);
-	if (ret)
-		return ret;
-
-	pci->irq = pdev->irq;
 	return 0;
 }
 
@@ -157,15 +141,6 @@ nvkm_pci_dtor(struct nvkm_subdev *subdev)
 
 	nvkm_agp_dtor(pci);
 
-	if (pci->irq >= 0) {
-		/* freq_irq() will call the handler, we use pci->irq == -1
-		 * to signal that it's been torn down and should be a noop.
-		 */
-		int irq = pci->irq;
-		pci->irq = -1;
-		free_irq(irq, pci);
-	}
-
 	if (pci->msi)
 		pci_disable_msi(pci->pdev);
 
@@ -192,7 +167,6 @@ nvkm_pci_new_(const struct nvkm_pci_func *func, struct nvkm_device *device,
 	nvkm_subdev_ctor(&nvkm_pci_func, device, type, inst, &pci->subdev);
 	pci->func = func;
 	pci->pdev = device->func->pci(device)->pdev;
-	pci->irq = -1;
 	pci->pcie.speed = -1;
 	pci->pcie.width = -1;