1 files changed, 349 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
new file mode 100644
index 000000000..824971a1c
--- /dev/null
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -0,0 +1,349 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright 2012 Red Hat Inc
+ */
+
+#include <linux/dma-buf.h>
+#include <linux/highmem.h>
+#include <linux/dma-resv.h>
+#include <linux/module.h>
+
+#include <asm/smp.h>
+
+#include "gem/i915_gem_dmabuf.h"
+#include "i915_drv.h"
+#include "i915_gem_object.h"
+#include "i915_scatterlist.h"
+
+MODULE_IMPORT_NS(DMA_BUF);
+
+I915_SELFTEST_DECLARE(static bool force_different_devices;)
+
+static struct drm_i915_gem_object *dma_buf_to_obj(struct dma_buf *buf)
+{
+	return to_intel_bo(buf->priv);
+}
+
+static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachment,
+					     enum dma_data_direction dir)
+{
+	struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf);
+	struct sg_table *st;
+	struct scatterlist *src, *dst;
+	int ret, i;
+
+	/* Copy sg so that we make an independent mapping */
+	st = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
+	if (st == NULL) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = sg_alloc_table(st, obj->mm.pages->orig_nents, GFP_KERNEL);
+	if (ret)
+		goto err_free;
+
+	src = obj->mm.pages->sgl;
+	dst = st->sgl;
+	for (i = 0; i < obj->mm.pages->orig_nents; i++) {
+		sg_set_page(dst, sg_page(src), src->length, 0);
+		dst = sg_next(dst);
+		src = sg_next(src);
+	}
+
+	ret = dma_map_sgtable(attachment->dev, st, dir, DMA_ATTR_SKIP_CPU_SYNC);
+	if (ret)
+		goto err_free_sg;
+
+	return st;
+
+err_free_sg:
+	sg_free_table(st);
+err_free:
+	kfree(st);
+err:
+	return ERR_PTR(ret);
+}
+
+static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf,
+				struct iosys_map *map)
+{
+	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
+	void *vaddr;
+
+	vaddr = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WB);
+	if (IS_ERR(vaddr))
+		return PTR_ERR(vaddr);
+
+	iosys_map_set_vaddr(map, vaddr);
+
+	return 0;
+}
+
+static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf,
+				   struct iosys_map *map)
+{
+	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
+
+	i915_gem_object_flush_map(obj);
+	i915_gem_object_unpin_map(obj);
+}
+
+static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
+{
+	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+	int ret;
+
+	if (obj->base.size < vma->vm_end - vma->vm_start)
+		return -EINVAL;
+
+	if (HAS_LMEM(i915))
+		return drm_gem_prime_mmap(&obj->base, vma);
+
+	if (!obj->base.filp)
+		return -ENODEV;
+
+	ret = call_mmap(obj->base.filp, vma);
+	if (ret)
+		return ret;
+
+	vma_set_file(vma, obj->base.filp);
+
+	return 0;
+}
+
+static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
+{
+	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
+	bool write = (direction == DMA_BIDIRECTIONAL || direction == DMA_TO_DEVICE);
+	struct i915_gem_ww_ctx ww;
+	int err;
+
+	i915_gem_ww_ctx_init(&ww, true);
+retry:
+	err = i915_gem_object_lock(obj, &ww);
+	if (!err)
+		err = i915_gem_object_pin_pages(obj);
+	if (!err) {
+		err = i915_gem_object_set_to_cpu_domain(obj, write);
+		i915_gem_object_unpin_pages(obj);
+	}
+	if (err == -EDEADLK) {
+		err = i915_gem_ww_ctx_backoff(&ww);
+		if (!err)
+			goto retry;
+	}
+	i915_gem_ww_ctx_fini(&ww);
+	return err;
+}
+
+static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
+{
+	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
+	struct i915_gem_ww_ctx ww;
+	int err;
+
+	i915_gem_ww_ctx_init(&ww, true);
+retry:
+	err = i915_gem_object_lock(obj, &ww);
+	if (!err)
+		err = i915_gem_object_pin_pages(obj);
+	if (!err) {
+		err = i915_gem_object_set_to_gtt_domain(obj, false);
+		i915_gem_object_unpin_pages(obj);
+	}
+	if (err == -EDEADLK) {
+		err = i915_gem_ww_ctx_backoff(&ww);
+		if (!err)
+			goto retry;
+	}
+	i915_gem_ww_ctx_fini(&ww);
+	return err;
+}
+
+static int i915_gem_dmabuf_attach(struct dma_buf *dmabuf,
+				  struct dma_buf_attachment *attach)
+{
+	struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf);
+	struct i915_gem_ww_ctx ww;
+	int err;
+
+	if (!i915_gem_object_can_migrate(obj, INTEL_REGION_SMEM))
+		return -EOPNOTSUPP;
+
+	for_i915_gem_ww(&ww, err, true) {
+		err = i915_gem_object_lock(obj, &ww);
+		if (err)
+			continue;
+
+		err = i915_gem_object_migrate(obj, &ww, INTEL_REGION_SMEM);
+		if (err)
+			continue;
+
+		err = i915_gem_object_wait_migration(obj, 0);
+		if (err)
+			continue;
+
+		err = i915_gem_object_pin_pages(obj);
+	}
+
+	return err;
+}
+
+static void i915_gem_dmabuf_detach(struct dma_buf *dmabuf,
+				   struct dma_buf_attachment *attach)
+{
+	struct drm_i915_gem_object *obj = dma_buf_to_obj(dmabuf);
+
+	i915_gem_object_unpin_pages(obj);
+}
+
+static const struct dma_buf_ops i915_dmabuf_ops =  {
+	.attach = i915_gem_dmabuf_attach,
+	.detach = i915_gem_dmabuf_detach,
+	.map_dma_buf = i915_gem_map_dma_buf,
+	.unmap_dma_buf = drm_gem_unmap_dma_buf,
+	.release = drm_gem_dmabuf_release,
+	.mmap = i915_gem_dmabuf_mmap,
+	.vmap = i915_gem_dmabuf_vmap,
+	.vunmap = i915_gem_dmabuf_vunmap,
+	.begin_cpu_access = i915_gem_begin_cpu_access,
+	.end_cpu_access = i915_gem_end_cpu_access,
+};
+
+struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags)
+{
+	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &i915_dmabuf_ops;
+	exp_info.size = gem_obj->size;
+	exp_info.flags = flags;
+	exp_info.priv = gem_obj;
+	exp_info.resv = obj->base.resv;
+
+	if (obj->ops->dmabuf_export) {
+		int ret = obj->ops->dmabuf_export(obj);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	return drm_gem_dmabuf_export(gem_obj->dev, &exp_info);
+}
+
+static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
+{
+	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+	struct sg_table *pages;
+	unsigned int sg_page_sizes;
+
+	assert_object_held(obj);
+
+	pages = dma_buf_map_attachment(obj->base.import_attach,
+				       DMA_BIDIRECTIONAL);
+	if (IS_ERR(pages))
+		return PTR_ERR(pages);
+
+	/*
+	 * DG1 is special here since it still snoops transactions even with
+	 * CACHE_NONE. This is not the case with other HAS_SNOOP platforms. We
+	 * might need to revisit this as we add new discrete platforms.
+	 *
+	 * XXX: Consider doing a vmap flush or something, where possible.
+	 * Currently we just do a heavy handed wbinvd_on_all_cpus() here since
+	 * the underlying sg_table might not even point to struct pages, so we
+	 * can't just call drm_clflush_sg or similar, like we do elsewhere in
+	 * the driver.
+	 */
+	if (i915_gem_object_can_bypass_llc(obj) ||
+	    (!HAS_LLC(i915) && !IS_DG1(i915)))
+		wbinvd_on_all_cpus();
+
+	sg_page_sizes = i915_sg_dma_sizes(pages->sgl);
+	__i915_gem_object_set_pages(obj, pages, sg_page_sizes);
+
+	return 0;
+}
+
+static void i915_gem_object_put_pages_dmabuf(struct drm_i915_gem_object *obj,
+					     struct sg_table *pages)
+{
+	dma_buf_unmap_attachment(obj->base.import_attach, pages,
+				 DMA_BIDIRECTIONAL);
+}
+
+static const struct drm_i915_gem_object_ops i915_gem_object_dmabuf_ops = {
+	.name = "i915_gem_object_dmabuf",
+	.get_pages = i915_gem_object_get_pages_dmabuf,
+	.put_pages = i915_gem_object_put_pages_dmabuf,
+};
+
+struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
+					     struct dma_buf *dma_buf)
+{
+	static struct lock_class_key lock_class;
+	struct dma_buf_attachment *attach;
+	struct drm_i915_gem_object *obj;
+	int ret;
+
+	/* is this one of own objects? */
+	if (dma_buf->ops == &i915_dmabuf_ops) {
+		obj = dma_buf_to_obj(dma_buf);
+		/* is it from our device? */
+		if (obj->base.dev == dev &&
+		    !I915_SELFTEST_ONLY(force_different_devices)) {
+			/*
+			 * Importing dmabuf exported from out own gem increases
+			 * refcount on gem itself instead of f_count of dmabuf.
+			 */
+			return &i915_gem_object_get(obj)->base;
+		}
+	}
+
+	if (i915_gem_object_size_2big(dma_buf->size))
+		return ERR_PTR(-E2BIG);
+
+	/* need to attach */
+	attach = dma_buf_attach(dma_buf, dev->dev);
+	if (IS_ERR(attach))
+		return ERR_CAST(attach);
+
+	get_dma_buf(dma_buf);
+
+	obj = i915_gem_object_alloc();
+	if (obj == NULL) {
+		ret = -ENOMEM;
+		goto fail_detach;
+	}
+
+	drm_gem_private_object_init(dev, &obj->base, dma_buf->size);
+	i915_gem_object_init(obj, &i915_gem_object_dmabuf_ops, &lock_class,
+			     I915_BO_ALLOC_USER);
+	obj->base.import_attach = attach;
+	obj->base.resv = dma_buf->resv;
+
+	/* We use GTT as shorthand for a coherent domain, one that is
+	 * neither in the GPU cache nor in the CPU cache, where all
+	 * writes are immediately visible in memory. (That's not strictly
+	 * true, but it's close! There are internal buffers such as the
+	 * write-combined buffer or a delay through the chipset for GTT
+	 * writes that do require us to treat GTT as a separate cache domain.)
+	 */
+	obj->read_domains = I915_GEM_DOMAIN_GTT;
+	obj->write_domain = 0;
+
+	return &obj->base;
+
+fail_detach:
+	dma_buf_detach(dma_buf, attach);
+	dma_buf_put(dma_buf);
+
+	return ERR_PTR(ret);
+}
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "selftests/mock_dmabuf.c"
+#include "selftests/i915_gem_dmabuf.c"
+#endif