1 files changed, 63 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/st_shmem_utils.c b/drivers/gpu/drm/i915/gt/st_shmem_utils.c
new file mode 100644
index 000000000000..b279fe88b70e
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/st_shmem_utils.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2020 Intel Corporation
+ */
+
+/* Just a quick and causal check of the shmem_utils API */
+
+static int igt_shmem_basic(void *ignored)
+{
+	u32 datum = 0xdeadbeef, result;
+	struct file *file;
+	u32 *map;
+	int err;
+
+	file = shmem_create_from_data("mock", &datum, sizeof(datum));
+	if (IS_ERR(file))
+		return PTR_ERR(file);
+
+	result = 0;
+	err = shmem_read(file, 0, &result, sizeof(result));
+	if (err)
+		goto out_file;
+
+	if (result != datum) {
+		pr_err("Incorrect read back from shmemfs: %x != %x\n",
+		       result, datum);
+		err = -EINVAL;
+		goto out_file;
+	}
+
+	result = 0xc0ffee;
+	err = shmem_write(file, 0, &result, sizeof(result));
+	if (err)
+		goto out_file;
+
+	map = shmem_pin_map(file);
+	if (!map) {
+		err = -ENOMEM;
+		goto out_file;
+	}
+
+	if (*map != result) {
+		pr_err("Incorrect read back via mmap of last write: %x != %x\n",
+		       *map, result);
+		err = -EINVAL;
+		goto out_map;
+	}
+
+out_map:
+	shmem_unpin_map(file, map);
+out_file:
+	fput(file);
+	return err;
+}
+
+int shmem_utils_mock_selftests(void)
+{
+	static const struct i915_subtest tests[] = {
+		SUBTEST(igt_shmem_basic),
+	};
+
+	return i915_subtests(tests, NULL);
+}