drm/i915: Implement dma_buf_ops->kmap

Since kmap allows us to block we can pin the pages and use our normal
page lookup routine making the implementation simple, or as some might
say quick and dirty.

Testcase: igt/drv_selftest/dmabuf
Testcase: igt/prime_rw
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170503202517.16797-1-chris@chris-wilson.co.uk

1 files changed, 100 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/selftests/i915_gem_dmabuf.c
index 817bef74bbcb..d15cc9d3a5cd 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_dmabuf.c
@@ -271,6 +271,105 @@ err_obj:
 	return err;
 }
 
+static int igt_dmabuf_export_kmap(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct drm_i915_gem_object *obj;
+	struct dma_buf *dmabuf;
+	void *ptr;
+	int err;
+
+	obj = i915_gem_object_create(i915, 2*PAGE_SIZE);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+
+	dmabuf = i915_gem_prime_export(&i915->drm, &obj->base, 0);
+	i915_gem_object_put(obj);
+	if (IS_ERR(dmabuf)) {
+		err = PTR_ERR(dmabuf);
+		pr_err("i915_gem_prime_export failed with err=%d\n", err);
+		return err;
+	}
+
+	ptr = dma_buf_kmap(dmabuf, 0);
+	if (!ptr) {
+		pr_err("dma_buf_kmap failed\n");
+		err = -ENOMEM;
+		goto err;
+	}
+
+	if (memchr_inv(ptr, 0, PAGE_SIZE)) {
+		dma_buf_kunmap(dmabuf, 0, ptr);
+		pr_err("Exported page[0] not initialiased to zero!\n");
+		err = -EINVAL;
+		goto err;
+	}
+
+	memset(ptr, 0xc5, PAGE_SIZE);
+	dma_buf_kunmap(dmabuf, 0, ptr);
+
+	ptr = i915_gem_object_pin_map(obj, I915_MAP_WB);
+	if (IS_ERR(ptr)) {
+		err = PTR_ERR(ptr);
+		pr_err("i915_gem_object_pin_map failed with err=%d\n", err);
+		goto err;
+	}
+	memset(ptr + PAGE_SIZE, 0xaa, PAGE_SIZE);
+	i915_gem_object_unpin_map(obj);
+
+	ptr = dma_buf_kmap(dmabuf, 1);
+	if (!ptr) {
+		pr_err("dma_buf_kmap failed\n");
+		err = -ENOMEM;
+		goto err;
+	}
+
+	if (memchr_inv(ptr, 0xaa, PAGE_SIZE)) {
+		dma_buf_kunmap(dmabuf, 1, ptr);
+		pr_err("Exported page[1] not set to 0xaa!\n");
+		err = -EINVAL;
+		goto err;
+	}
+
+	memset(ptr, 0xc5, PAGE_SIZE);
+	dma_buf_kunmap(dmabuf, 1, ptr);
+
+	ptr = dma_buf_kmap(dmabuf, 0);
+	if (!ptr) {
+		pr_err("dma_buf_kmap failed\n");
+		err = -ENOMEM;
+		goto err;
+	}
+	if (memchr_inv(ptr, 0xc5, PAGE_SIZE)) {
+		dma_buf_kunmap(dmabuf, 0, ptr);
+		pr_err("Exported page[0] did not retain 0xc5!\n");
+		err = -EINVAL;
+		goto err;
+	}
+	dma_buf_kunmap(dmabuf, 0, ptr);
+
+	ptr = dma_buf_kmap(dmabuf, 2);
+	if (ptr) {
+		pr_err("Erroneously kmapped beyond the end of the object!\n");
+		dma_buf_kunmap(dmabuf, 2, ptr);
+		err = -EINVAL;
+		goto err;
+	}
+
+	ptr = dma_buf_kmap(dmabuf, -1);
+	if (ptr) {
+		pr_err("Erroneously kmapped before the start of the object!\n");
+		dma_buf_kunmap(dmabuf, -1, ptr);
+		err = -EINVAL;
+		goto err;
+	}
+
+	err = 0;
+err:
+	dma_buf_put(dmabuf);
+	return err;
+}
+
 int i915_gem_dmabuf_mock_selftests(void)
 {
 	static const struct i915_subtest tests[] = {
@@ -279,6 +378,7 @@ int i915_gem_dmabuf_mock_selftests(void)
 		SUBTEST(igt_dmabuf_import),
 		SUBTEST(igt_dmabuf_import_ownership),
 		SUBTEST(igt_dmabuf_export_vmap),
+		SUBTEST(igt_dmabuf_export_kmap),
 	};
 	struct drm_i915_private *i915;
 	int err;