drm/tegra: Implement new UAPI

Implement the non-submission parts of the new UAPI, including
channel management and memory mapping. The UAPI is under the
CONFIG_DRM_TEGRA_STAGING config flag for now.

Signed-off-by: Mikko Perttunen <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

drivers/gpu/drm/tegra/Makefile

···
 
 tegra-drm-y := \
 	drm.o \
+	uapi.o \
 	gem.o \
 	fb.o \
 	dp.o \

drivers/gpu/drm/tegra/drm.c

···
 #include <drm/drm_prime.h>
 #include <drm/drm_vblank.h>
 
+#include "uapi.h"
 #include "drm.h"
 #include "gem.h"
 
···
 
 #define CARVEOUT_SZ SZ_64M
 #define CDMA_GATHER_FETCHES_MAX_NB 16383
-
-struct tegra_drm_file {
-	struct idr contexts;
-	struct mutex lock;
-};
 
 static int tegra_atomic_check(struct drm_device *drm,
 			      struct drm_atomic_state *state)
···
 	if (!fpriv)
 		return -ENOMEM;
 
-	idr_init_base(&fpriv->contexts, 1);
+	idr_init_base(&fpriv->legacy_contexts, 1);
+	xa_init_flags(&fpriv->contexts, XA_FLAGS_ALLOC1);
 	mutex_init(&fpriv->lock);
 	filp->driver_priv = fpriv;
 
···
 	if (err < 0)
 		return err;
 
-	err = idr_alloc(&fpriv->contexts, context, 1, 0, GFP_KERNEL);
+	err = idr_alloc(&fpriv->legacy_contexts, context, 1, 0, GFP_KERNEL);
 	if (err < 0) {
 		client->ops->close_channel(context);
 		return err;
···
 
 	mutex_lock(&fpriv->lock);
 
-	context = idr_find(&fpriv->contexts, args->context);
+	context = idr_find(&fpriv->legacy_contexts, args->context);
 	if (!context) {
 		err = -EINVAL;
 		goto unlock;
 	}
 
-	idr_remove(&fpriv->contexts, context->id);
+	idr_remove(&fpriv->legacy_contexts, context->id);
 	tegra_drm_context_free(context);
 
 unlock:
···
 
 	mutex_lock(&fpriv->lock);
 
-	context = idr_find(&fpriv->contexts, args->context);
+	context = idr_find(&fpriv->legacy_contexts, args->context);
 	if (!context) {
 		err = -ENODEV;
 		goto unlock;
···
 
 	mutex_lock(&fpriv->lock);
 
-	context = idr_find(&fpriv->contexts, args->context);
+	context = idr_find(&fpriv->legacy_contexts, args->context);
 	if (!context) {
 		err = -ENODEV;
 		goto unlock;
···
 
 	mutex_lock(&fpriv->lock);
 
-	context = idr_find(&fpriv->contexts, args->context);
+	context = idr_find(&fpriv->legacy_contexts, args->context);
 	if (!context) {
 		err = -ENODEV;
 		goto unlock;
···
 
 static const struct drm_ioctl_desc tegra_drm_ioctls[] = {
 #ifdef CONFIG_DRM_TEGRA_STAGING
-	DRM_IOCTL_DEF_DRV(TEGRA_GEM_CREATE, tegra_gem_create,
+	DRM_IOCTL_DEF_DRV(TEGRA_CHANNEL_OPEN, tegra_drm_ioctl_channel_open,
 			  DRM_RENDER_ALLOW),
-	DRM_IOCTL_DEF_DRV(TEGRA_GEM_MMAP, tegra_gem_mmap,
+	DRM_IOCTL_DEF_DRV(TEGRA_CHANNEL_CLOSE, tegra_drm_ioctl_channel_close,
 			  DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(TEGRA_CHANNEL_MAP, tegra_drm_ioctl_channel_map,
+			  DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(TEGRA_CHANNEL_UNMAP, tegra_drm_ioctl_channel_unmap,
+			  DRM_RENDER_ALLOW),
+
+	DRM_IOCTL_DEF_DRV(TEGRA_GEM_CREATE, tegra_gem_create, DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(TEGRA_GEM_MMAP, tegra_gem_mmap, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(TEGRA_SYNCPT_READ, tegra_syncpt_read,
 			  DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(TEGRA_SYNCPT_INCR, tegra_syncpt_incr,
···
 	struct tegra_drm_file *fpriv = file->driver_priv;
 
 	mutex_lock(&fpriv->lock);
-	idr_for_each(&fpriv->contexts, tegra_drm_context_cleanup, NULL);
+	idr_for_each(&fpriv->legacy_contexts, tegra_drm_context_cleanup, NULL);
+	tegra_drm_uapi_close_file(fpriv);
 	mutex_unlock(&fpriv->lock);
 
-	idr_destroy(&fpriv->contexts);
+	idr_destroy(&fpriv->legacy_contexts);
 	mutex_destroy(&fpriv->lock);
 	kfree(fpriv);
 }

drivers/gpu/drm/tegra/drm.h

···
 	struct tegra_display_hub *hub;
 };
 
+static inline struct host1x *tegra_drm_to_host1x(struct tegra_drm *tegra)
+{
+	return dev_get_drvdata(tegra->drm->dev->parent);
+}
+
 struct tegra_drm_client;
 
 struct tegra_drm_context {
 	struct tegra_drm_client *client;
 	struct host1x_channel *channel;
+
+	/* Only used by legacy UAPI. */
 	unsigned int id;
+
+	/* Only used by new UAPI. */
+	struct xarray mappings;
 };
 
 struct tegra_drm_client_ops {

drivers/gpu/drm/tegra/uapi.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2020 NVIDIA Corporation */
+
+#include <linux/host1x.h>
+#include <linux/iommu.h>
+#include <linux/list.h>
+
+#include <drm/drm_drv.h>
+#include <drm/drm_file.h>
+
+#include "drm.h"
+#include "uapi.h"
+
+static void tegra_drm_mapping_release(struct kref *ref)
+{
+	struct tegra_drm_mapping *mapping =
+		container_of(ref, struct tegra_drm_mapping, ref);
+
+	if (mapping->sgt)
+		dma_unmap_sgtable(mapping->dev, mapping->sgt, mapping->direction,
+				  DMA_ATTR_SKIP_CPU_SYNC);
+
+	host1x_bo_unpin(mapping->dev, mapping->bo, mapping->sgt);
+	host1x_bo_put(mapping->bo);
+
+	kfree(mapping);
+}
+
+void tegra_drm_mapping_put(struct tegra_drm_mapping *mapping)
+{
+	kref_put(&mapping->ref, tegra_drm_mapping_release);
+}
+
+static void tegra_drm_channel_context_close(struct tegra_drm_context *context)
+{
+	struct tegra_drm_mapping *mapping;
+	unsigned long id;
+
+	xa_for_each(&context->mappings, id, mapping)
+		tegra_drm_mapping_put(mapping);
+
+	xa_destroy(&context->mappings);
+
+	host1x_channel_put(context->channel);
+
+	kfree(context);
+}
+
+void tegra_drm_uapi_close_file(struct tegra_drm_file *file)
+{
+	struct tegra_drm_context *context;
+	unsigned long id;
+
+	xa_for_each(&file->contexts, id, context)
+		tegra_drm_channel_context_close(context);
+
+	xa_destroy(&file->contexts);
+}
+
+static struct tegra_drm_client *tegra_drm_find_client(struct tegra_drm *tegra, u32 class)
+{
+	struct tegra_drm_client *client;
+
+	list_for_each_entry(client, &tegra->clients, list)
+		if (client->base.class == class)
+			return client;
+
+	return NULL;
+}
+
+int tegra_drm_ioctl_channel_open(struct drm_device *drm, void *data, struct drm_file *file)
+{
+	struct tegra_drm_file *fpriv = file->driver_priv;
+	struct tegra_drm *tegra = drm->dev_private;
+	struct drm_tegra_channel_open *args = data;
+	struct tegra_drm_client *client = NULL;
+	struct tegra_drm_context *context;
+	int err;
+
+	if (args->flags)
+		return -EINVAL;
+
+	context = kzalloc(sizeof(*context), GFP_KERNEL);
+	if (!context)
+		return -ENOMEM;
+
+	client = tegra_drm_find_client(tegra, args->host1x_class);
+	if (!client) {
+		err = -ENODEV;
+		goto free;
+	}
+
+	if (client->shared_channel) {
+		context->channel = host1x_channel_get(client->shared_channel);
+	} else {
+		context->channel = host1x_channel_request(&client->base);
+		if (!context->channel) {
+			err = -EBUSY;
+			goto free;
+		}
+	}
+
+	err = xa_alloc(&fpriv->contexts, &args->context, context, XA_LIMIT(1, U32_MAX),
+		       GFP_KERNEL);
+	if (err < 0)
+		goto put_channel;
+
+	context->client = client;
+	xa_init_flags(&context->mappings, XA_FLAGS_ALLOC1);
+
+	args->version = client->version;
+	args->capabilities = 0;
+
+	if (device_get_dma_attr(client->base.dev) == DEV_DMA_COHERENT)
+		args->capabilities |= DRM_TEGRA_CHANNEL_CAP_CACHE_COHERENT;
+
+	return 0;
+
+put_channel:
+	host1x_channel_put(context->channel);
+free:
+	kfree(context);
+
+	return err;
+}
+
+int tegra_drm_ioctl_channel_close(struct drm_device *drm, void *data, struct drm_file *file)
+{
+	struct tegra_drm_file *fpriv = file->driver_priv;
+	struct drm_tegra_channel_close *args = data;
+	struct tegra_drm_context *context;
+
+	mutex_lock(&fpriv->lock);
+
+	context = xa_load(&fpriv->contexts, args->context);
+	if (!context) {
+		mutex_unlock(&fpriv->lock);
+		return -EINVAL;
+	}
+
+	xa_erase(&fpriv->contexts, args->context);
+
+	mutex_unlock(&fpriv->lock);
+
+	tegra_drm_channel_context_close(context);
+
+	return 0;
+}
+
+int tegra_drm_ioctl_channel_map(struct drm_device *drm, void *data, struct drm_file *file)
+{
+	struct tegra_drm_file *fpriv = file->driver_priv;
+	struct drm_tegra_channel_map *args = data;
+	struct tegra_drm_mapping *mapping;
+	struct tegra_drm_context *context;
+	int err = 0;
+
+	if (args->flags & ~DRM_TEGRA_CHANNEL_MAP_READ_WRITE)
+		return -EINVAL;
+
+	mutex_lock(&fpriv->lock);
+
+	context = xa_load(&fpriv->contexts, args->context);
+	if (!context) {
+		mutex_unlock(&fpriv->lock);
+		return -EINVAL;
+	}
+
+	mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
+	if (!mapping) {
+		err = -ENOMEM;
+		goto unlock;
+	}
+
+	kref_init(&mapping->ref);
+
+	mapping->dev = context->client->base.dev;
+	mapping->bo = tegra_gem_lookup(file, args->handle);
+	if (!mapping->bo) {
+		err = -EINVAL;
+		goto unlock;
+	}
+
+	if (context->client->base.group) {
+		/* IOMMU domain managed directly using IOMMU API */
+		host1x_bo_pin(mapping->dev, mapping->bo, &mapping->iova);
+	} else {
+		switch (args->flags & DRM_TEGRA_CHANNEL_MAP_READ_WRITE) {
+		case DRM_TEGRA_CHANNEL_MAP_READ_WRITE:
+			mapping->direction = DMA_BIDIRECTIONAL;
+			break;
+
+		case DRM_TEGRA_CHANNEL_MAP_WRITE:
+			mapping->direction = DMA_FROM_DEVICE;
+			break;
+
+		case DRM_TEGRA_CHANNEL_MAP_READ:
+			mapping->direction = DMA_TO_DEVICE;
+			break;
+
+		default:
+			return -EINVAL;
+		}
+
+		mapping->sgt = host1x_bo_pin(mapping->dev, mapping->bo, NULL);
+		if (IS_ERR(mapping->sgt)) {
+			err = PTR_ERR(mapping->sgt);
+			goto put_gem;
+		}
+
+		err = dma_map_sgtable(mapping->dev, mapping->sgt, mapping->direction,
+				      DMA_ATTR_SKIP_CPU_SYNC);
+		if (err)
+			goto unpin;
+
+		mapping->iova = sg_dma_address(mapping->sgt->sgl);
+	}
+
+	mapping->iova_end = mapping->iova + host1x_to_tegra_bo(mapping->bo)->size;
+
+	err = xa_alloc(&context->mappings, &args->mapping, mapping, XA_LIMIT(1, U32_MAX),
+		       GFP_KERNEL);
+	if (err < 0)
+		goto unmap;
+
+	mutex_unlock(&fpriv->lock);
+
+	return 0;
+
+unmap:
+	if (mapping->sgt) {
+		dma_unmap_sgtable(mapping->dev, mapping->sgt, mapping->direction,
+				  DMA_ATTR_SKIP_CPU_SYNC);
+	}
+unpin:
+	host1x_bo_unpin(mapping->dev, mapping->bo, mapping->sgt);
+put_gem:
+	host1x_bo_put(mapping->bo);
+	kfree(mapping);
+unlock:
+	mutex_unlock(&fpriv->lock);
+	return err;
+}
+
+int tegra_drm_ioctl_channel_unmap(struct drm_device *drm, void *data, struct drm_file *file)
+{
+	struct tegra_drm_file *fpriv = file->driver_priv;
+	struct drm_tegra_channel_unmap *args = data;
+	struct tegra_drm_mapping *mapping;
+	struct tegra_drm_context *context;
+
+	mutex_lock(&fpriv->lock);
+
+	context = xa_load(&fpriv->contexts, args->context);
+	if (!context) {
+		mutex_unlock(&fpriv->lock);
+		return -EINVAL;
+	}
+
+	mapping = xa_erase(&context->mappings, args->mapping);
+
+	mutex_unlock(&fpriv->lock);
+
+	if (!mapping)
+		return -EINVAL;
+
+	tegra_drm_mapping_put(mapping);
+	return 0;
+}
+
+int tegra_drm_ioctl_gem_create(struct drm_device *drm, void *data,
+			       struct drm_file *file)
+{
+	struct drm_tegra_gem_create *args = data;
+	struct tegra_bo *bo;
+
+	if (args->flags)
+		return -EINVAL;
+
+	bo = tegra_bo_create_with_handle(file, drm, args->size, args->flags,
+					 &args->handle);
+	if (IS_ERR(bo))
+		return PTR_ERR(bo);
+
+	return 0;
+}
+
+int tegra_drm_ioctl_gem_mmap(struct drm_device *drm, void *data,
+			     struct drm_file *file)
+{
+	struct drm_tegra_gem_mmap *args = data;
+	struct drm_gem_object *gem;
+	struct tegra_bo *bo;
+
+	gem = drm_gem_object_lookup(file, args->handle);
+	if (!gem)
+		return -EINVAL;
+
+	bo = to_tegra_bo(gem);
+
+	args->offset = drm_vma_node_offset_addr(&bo->gem.vma_node);
+
+	drm_gem_object_put(gem);
+
+	return 0;
+}

drivers/gpu/drm/tegra/uapi.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (c) 2020 NVIDIA Corporation */
+
+#ifndef _TEGRA_DRM_UAPI_H
+#define _TEGRA_DRM_UAPI_H
+
+#include <linux/dma-mapping.h>
+#include <linux/idr.h>
+#include <linux/kref.h>
+#include <linux/xarray.h>
+
+#include <drm/drm.h>
+
+struct drm_file;
+struct drm_device;
+
+struct tegra_drm_file {
+	/* Legacy UAPI state */
+	struct idr legacy_contexts;
+	struct mutex lock;
+
+	/* New UAPI state */
+	struct xarray contexts;
+};
+
+struct tegra_drm_mapping {
+	struct kref ref;
+
+	struct device *dev;
+	struct host1x_bo *bo;
+	struct sg_table *sgt;
+	enum dma_data_direction direction;
+	dma_addr_t iova;
+	dma_addr_t iova_end;
+};
+
+int tegra_drm_ioctl_channel_open(struct drm_device *drm, void *data,
+				 struct drm_file *file);
+int tegra_drm_ioctl_channel_close(struct drm_device *drm, void *data,
+				  struct drm_file *file);
+int tegra_drm_ioctl_channel_map(struct drm_device *drm, void *data,
+				struct drm_file *file);
+int tegra_drm_ioctl_channel_unmap(struct drm_device *drm, void *data,
+				  struct drm_file *file);
+int tegra_drm_ioctl_channel_submit(struct drm_device *drm, void *data,
+				   struct drm_file *file);
+
+void tegra_drm_uapi_close_file(struct tegra_drm_file *file);
+void tegra_drm_mapping_put(struct tegra_drm_mapping *mapping);
+
+#endif