1 files changed, 501 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
new file mode 100644
index 000000000..ba3a87cb8
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
@@ -0,0 +1,501 @@
+/*
+ * Copyright 2019 Advanced Micro Devices, 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.
+ *
+ * based on nouveau_prime.c
+ *
+ * Authors: Alex Deucher
+ */
+
+/**
+ * DOC: PRIME Buffer Sharing
+ *
+ * The following callback implementations are used for :ref:`sharing GEM buffer
+ * objects between different devices via PRIME <prime_buffer_sharing>`.
+ */
+
+#include "amdgpu.h"
+#include "amdgpu_display.h"
+#include "amdgpu_gem.h"
+#include "amdgpu_dma_buf.h"
+#include "amdgpu_xgmi.h"
+#include <drm/amdgpu_drm.h>
+#include <drm/ttm/ttm_tt.h>
+#include <linux/dma-buf.h>
+#include <linux/dma-fence-array.h>
+#include <linux/pci-p2pdma.h>
+#include <linux/pm_runtime.h>
+
+/**
+ * amdgpu_dma_buf_attach - &dma_buf_ops.attach implementation
+ *
+ * @dmabuf: DMA-buf where we attach to
+ * @attach: attachment to add
+ *
+ * Add the attachment as user to the exported DMA-buf.
+ */
+static int amdgpu_dma_buf_attach(struct dma_buf *dmabuf,
+				 struct dma_buf_attachment *attach)
+{
+	struct drm_gem_object *obj = dmabuf->priv;
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
+	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
+	int r;
+
+	if (pci_p2pdma_distance(adev->pdev, attach->dev, false) < 0)
+		attach->peer2peer = false;
+
+	r = pm_runtime_get_sync(adev_to_drm(adev)->dev);
+	if (r < 0)
+		goto out;
+
+	return 0;
+
+out:
+	pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
+	return r;
+}
+
+/**
+ * amdgpu_dma_buf_detach - &dma_buf_ops.detach implementation
+ *
+ * @dmabuf: DMA-buf where we remove the attachment from
+ * @attach: the attachment to remove
+ *
+ * Called when an attachment is removed from the DMA-buf.
+ */
+static void amdgpu_dma_buf_detach(struct dma_buf *dmabuf,
+				  struct dma_buf_attachment *attach)
+{
+	struct drm_gem_object *obj = dmabuf->priv;
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
+	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
+
+	pm_runtime_mark_last_busy(adev_to_drm(adev)->dev);
+	pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
+}
+
+/**
+ * amdgpu_dma_buf_pin - &dma_buf_ops.pin implementation
+ *
+ * @attach: attachment to pin down
+ *
+ * Pin the BO which is backing the DMA-buf so that it can't move any more.
+ */
+static int amdgpu_dma_buf_pin(struct dma_buf_attachment *attach)
+{
+	struct drm_gem_object *obj = attach->dmabuf->priv;
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
+
+	/* pin buffer into GTT */
+	return amdgpu_bo_pin(bo, AMDGPU_GEM_DOMAIN_GTT);
+}
+
+/**
+ * amdgpu_dma_buf_unpin - &dma_buf_ops.unpin implementation
+ *
+ * @attach: attachment to unpin
+ *
+ * Unpin a previously pinned BO to make it movable again.
+ */
+static void amdgpu_dma_buf_unpin(struct dma_buf_attachment *attach)
+{
+	struct drm_gem_object *obj = attach->dmabuf->priv;
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
+
+	amdgpu_bo_unpin(bo);
+}
+
+/**
+ * amdgpu_dma_buf_map - &dma_buf_ops.map_dma_buf implementation
+ * @attach: DMA-buf attachment
+ * @dir: DMA direction
+ *
+ * Makes sure that the shared DMA buffer can be accessed by the target device.
+ * For now, simply pins it to the GTT domain, where it should be accessible by
+ * all DMA devices.
+ *
+ * Returns:
+ * sg_table filled with the DMA addresses to use or ERR_PRT with negative error
+ * code.
+ */
+static struct sg_table *amdgpu_dma_buf_map(struct dma_buf_attachment *attach,
+					   enum dma_data_direction dir)
+{
+	struct dma_buf *dma_buf = attach->dmabuf;
+	struct drm_gem_object *obj = dma_buf->priv;
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
+	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
+	struct sg_table *sgt;
+	long r;
+
+	if (!bo->tbo.pin_count) {
+		/* move buffer into GTT or VRAM */
+		struct ttm_operation_ctx ctx = { false, false };
+		unsigned int domains = AMDGPU_GEM_DOMAIN_GTT;
+
+		if (bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM &&
+		    attach->peer2peer) {
+			bo->flags |= AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
+			domains |= AMDGPU_GEM_DOMAIN_VRAM;
+		}
+		amdgpu_bo_placement_from_domain(bo, domains);
+		r = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
+		if (r)
+			return ERR_PTR(r);
+
+	} else if (!(amdgpu_mem_type_to_domain(bo->tbo.resource->mem_type) &
+		     AMDGPU_GEM_DOMAIN_GTT)) {
+		return ERR_PTR(-EBUSY);
+	}
+
+	switch (bo->tbo.resource->mem_type) {
+	case TTM_PL_TT:
+		sgt = drm_prime_pages_to_sg(obj->dev,
+					    bo->tbo.ttm->pages,
+					    bo->tbo.ttm->num_pages);
+		if (IS_ERR(sgt))
+			return sgt;
+
+		if (dma_map_sgtable(attach->dev, sgt, dir,
+				    DMA_ATTR_SKIP_CPU_SYNC))
+			goto error_free;
+		break;
+
+	case TTM_PL_VRAM:
+		r = amdgpu_vram_mgr_alloc_sgt(adev, bo->tbo.resource, 0,
+					      bo->tbo.base.size, attach->dev,
+					      dir, &sgt);
+		if (r)
+			return ERR_PTR(r);
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+
+	return sgt;
+
+error_free:
+	sg_free_table(sgt);
+	kfree(sgt);
+	return ERR_PTR(-EBUSY);
+}
+
+/**
+ * amdgpu_dma_buf_unmap - &dma_buf_ops.unmap_dma_buf implementation
+ * @attach: DMA-buf attachment
+ * @sgt: sg_table to unmap
+ * @dir: DMA direction
+ *
+ * This is called when a shared DMA buffer no longer needs to be accessible by
+ * another device. For now, simply unpins the buffer from GTT.
+ */
+static void amdgpu_dma_buf_unmap(struct dma_buf_attachment *attach,
+				 struct sg_table *sgt,
+				 enum dma_data_direction dir)
+{
+	if (sgt->sgl->page_link) {
+		dma_unmap_sgtable(attach->dev, sgt, dir, 0);
+		sg_free_table(sgt);
+		kfree(sgt);
+	} else {
+		amdgpu_vram_mgr_free_sgt(attach->dev, dir, sgt);
+	}
+}
+
+/**
+ * amdgpu_dma_buf_begin_cpu_access - &dma_buf_ops.begin_cpu_access implementation
+ * @dma_buf: Shared DMA buffer
+ * @direction: Direction of DMA transfer
+ *
+ * This is called before CPU access to the shared DMA buffer's memory. If it's
+ * a read access, the buffer is moved to the GTT domain if possible, for optimal
+ * CPU read performance.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+static int amdgpu_dma_buf_begin_cpu_access(struct dma_buf *dma_buf,
+					   enum dma_data_direction direction)
+{
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(dma_buf->priv);
+	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
+	struct ttm_operation_ctx ctx = { true, false };
+	u32 domain = amdgpu_display_supported_domains(adev, bo->flags);
+	int ret;
+	bool reads = (direction == DMA_BIDIRECTIONAL ||
+		      direction == DMA_FROM_DEVICE);
+
+	if (!reads || !(domain & AMDGPU_GEM_DOMAIN_GTT))
+		return 0;
+
+	/* move to gtt */
+	ret = amdgpu_bo_reserve(bo, false);
+	if (unlikely(ret != 0))
+		return ret;
+
+	if (!bo->tbo.pin_count &&
+	    (bo->allowed_domains & AMDGPU_GEM_DOMAIN_GTT)) {
+		amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);
+		ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
+	}
+
+	amdgpu_bo_unreserve(bo);
+	return ret;
+}
+
+const struct dma_buf_ops amdgpu_dmabuf_ops = {
+	.attach = amdgpu_dma_buf_attach,
+	.detach = amdgpu_dma_buf_detach,
+	.pin = amdgpu_dma_buf_pin,
+	.unpin = amdgpu_dma_buf_unpin,
+	.map_dma_buf = amdgpu_dma_buf_map,
+	.unmap_dma_buf = amdgpu_dma_buf_unmap,
+	.release = drm_gem_dmabuf_release,
+	.begin_cpu_access = amdgpu_dma_buf_begin_cpu_access,
+	.mmap = drm_gem_dmabuf_mmap,
+	.vmap = drm_gem_dmabuf_vmap,
+	.vunmap = drm_gem_dmabuf_vunmap,
+};
+
+/**
+ * amdgpu_gem_prime_export - &drm_driver.gem_prime_export implementation
+ * @gobj: GEM BO
+ * @flags: Flags such as DRM_CLOEXEC and DRM_RDWR.
+ *
+ * The main work is done by the &drm_gem_prime_export helper.
+ *
+ * Returns:
+ * Shared DMA buffer representing the GEM BO from the given device.
+ */
+struct dma_buf *amdgpu_gem_prime_export(struct drm_gem_object *gobj,
+					int flags)
+{
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(gobj);
+	struct dma_buf *buf;
+
+	if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm) ||
+	    bo->flags & AMDGPU_GEM_CREATE_VM_ALWAYS_VALID)
+		return ERR_PTR(-EPERM);
+
+	buf = drm_gem_prime_export(gobj, flags);
+	if (!IS_ERR(buf))
+		buf->ops = &amdgpu_dmabuf_ops;
+
+	return buf;
+}
+
+/**
+ * amdgpu_dma_buf_create_obj - create BO for DMA-buf import
+ *
+ * @dev: DRM device
+ * @dma_buf: DMA-buf
+ *
+ * Creates an empty SG BO for DMA-buf import.
+ *
+ * Returns:
+ * A new GEM BO of the given DRM device, representing the memory
+ * described by the given DMA-buf attachment and scatter/gather table.
+ */
+static struct drm_gem_object *
+amdgpu_dma_buf_create_obj(struct drm_device *dev, struct dma_buf *dma_buf)
+{
+	struct dma_resv *resv = dma_buf->resv;
+	struct amdgpu_device *adev = drm_to_adev(dev);
+	struct drm_gem_object *gobj;
+	struct amdgpu_bo *bo;
+	uint64_t flags = 0;
+	int ret;
+
+	dma_resv_lock(resv, NULL);
+
+	if (dma_buf->ops == &amdgpu_dmabuf_ops) {
+		struct amdgpu_bo *other = gem_to_amdgpu_bo(dma_buf->priv);
+
+		flags |= other->flags & (AMDGPU_GEM_CREATE_CPU_GTT_USWC |
+					 AMDGPU_GEM_CREATE_COHERENT |
+					 AMDGPU_GEM_CREATE_UNCACHED);
+	}
+
+	ret = amdgpu_gem_object_create(adev, dma_buf->size, PAGE_SIZE,
+				       AMDGPU_GEM_DOMAIN_CPU, flags,
+				       ttm_bo_type_sg, resv, &gobj, 0);
+	if (ret)
+		goto error;
+
+	bo = gem_to_amdgpu_bo(gobj);
+	bo->allowed_domains = AMDGPU_GEM_DOMAIN_GTT;
+	bo->preferred_domains = AMDGPU_GEM_DOMAIN_GTT;
+
+	dma_resv_unlock(resv);
+	return gobj;
+
+error:
+	dma_resv_unlock(resv);
+	return ERR_PTR(ret);
+}
+
+/**
+ * amdgpu_dma_buf_move_notify - &attach.move_notify implementation
+ *
+ * @attach: the DMA-buf attachment
+ *
+ * Invalidate the DMA-buf attachment, making sure that the we re-create the
+ * mapping before the next use.
+ */
+static void
+amdgpu_dma_buf_move_notify(struct dma_buf_attachment *attach)
+{
+	struct drm_gem_object *obj = attach->importer_priv;
+	struct ww_acquire_ctx *ticket = dma_resv_locking_ctx(obj->resv);
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
+	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
+	struct ttm_operation_ctx ctx = { false, false };
+	struct ttm_placement placement = {};
+	struct amdgpu_vm_bo_base *bo_base;
+	int r;
+
+	if (!bo->tbo.resource || bo->tbo.resource->mem_type == TTM_PL_SYSTEM)
+		return;
+
+	r = ttm_bo_validate(&bo->tbo, &placement, &ctx);
+	if (r) {
+		DRM_ERROR("Failed to invalidate DMA-buf import (%d))\n", r);
+		return;
+	}
+
+	for (bo_base = bo->vm_bo; bo_base; bo_base = bo_base->next) {
+		struct amdgpu_vm *vm = bo_base->vm;
+		struct dma_resv *resv = vm->root.bo->tbo.base.resv;
+
+		if (ticket) {
+			/* When we get an error here it means that somebody
+			 * else is holding the VM lock and updating page tables
+			 * So we can just continue here.
+			 */
+			r = dma_resv_lock(resv, ticket);
+			if (r)
+				continue;
+
+		} else {
+			/* TODO: This is more problematic and we actually need
+			 * to allow page tables updates without holding the
+			 * lock.
+			 */
+			if (!dma_resv_trylock(resv))
+				continue;
+		}
+
+		/* Reserve fences for two SDMA page table updates */
+		r = dma_resv_reserve_fences(resv, 2);
+		if (!r)
+			r = amdgpu_vm_clear_freed(adev, vm, NULL);
+		if (!r)
+			r = amdgpu_vm_handle_moved(adev, vm);
+
+		if (r && r != -EBUSY)
+			DRM_ERROR("Failed to invalidate VM page tables (%d))\n",
+				  r);
+
+		dma_resv_unlock(resv);
+	}
+}
+
+static const struct dma_buf_attach_ops amdgpu_dma_buf_attach_ops = {
+	.allow_peer2peer = true,
+	.move_notify = amdgpu_dma_buf_move_notify
+};
+
+/**
+ * amdgpu_gem_prime_import - &drm_driver.gem_prime_import implementation
+ * @dev: DRM device
+ * @dma_buf: Shared DMA buffer
+ *
+ * Import a dma_buf into a the driver and potentially create a new GEM object.
+ *
+ * Returns:
+ * GEM BO representing the shared DMA buffer for the given device.
+ */
+struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,
+					       struct dma_buf *dma_buf)
+{
+	struct dma_buf_attachment *attach;
+	struct drm_gem_object *obj;
+
+	if (dma_buf->ops == &amdgpu_dmabuf_ops) {
+		obj = dma_buf->priv;
+		if (obj->dev == dev) {
+			/*
+			 * Importing dmabuf exported from out own gem increases
+			 * refcount on gem itself instead of f_count of dmabuf.
+			 */
+			drm_gem_object_get(obj);
+			return obj;
+		}
+	}
+
+	obj = amdgpu_dma_buf_create_obj(dev, dma_buf);
+	if (IS_ERR(obj))
+		return obj;
+
+	attach = dma_buf_dynamic_attach(dma_buf, dev->dev,
+					&amdgpu_dma_buf_attach_ops, obj);
+	if (IS_ERR(attach)) {
+		drm_gem_object_put(obj);
+		return ERR_CAST(attach);
+	}
+
+	get_dma_buf(dma_buf);
+	obj->import_attach = attach;
+	return obj;
+}
+
+/**
+ * amdgpu_dmabuf_is_xgmi_accessible - Check if xgmi available for P2P transfer
+ *
+ * @adev: amdgpu_device pointer of the importer
+ * @bo: amdgpu buffer object
+ *
+ * Returns:
+ * True if dmabuf accessible over xgmi, false otherwise.
+ */
+bool amdgpu_dmabuf_is_xgmi_accessible(struct amdgpu_device *adev,
+				      struct amdgpu_bo *bo)
+{
+	struct drm_gem_object *obj = &bo->tbo.base;
+	struct drm_gem_object *gobj;
+
+	if (obj->import_attach) {
+		struct dma_buf *dma_buf = obj->import_attach->dmabuf;
+
+		if (dma_buf->ops != &amdgpu_dmabuf_ops)
+			/* No XGMI with non AMD GPUs */
+			return false;
+
+		gobj = dma_buf->priv;
+		bo = gem_to_amdgpu_bo(gobj);
+	}
+
+	if (amdgpu_xgmi_same_hive(adev, amdgpu_ttm_adev(bo->tbo.bdev)) &&
+			(bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM))
+		return true;
+
+	return false;
+}