ion: add test device for unit tests to interact with dma_bufs

Add a /dev/ion-test device that will be created if CONFIG_ION_TEST
is set.  The device accepts a dma_buf fd and allows reading and
writing to the backing memory using DMA-like apis or kernel mapping
apis.  Can be used to test the dma_buf mapping ops, including
the ion implementations, from userspace.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 71 insertions, 0 deletions

diff --git a/drivers/staging/android/uapi/ion_test.h b/drivers/staging/android/uapi/ion_test.h
new file mode 100644
index 000000000000..352379a02690
--- /dev/null
+++ b/drivers/staging/android/uapi/ion_test.h
@@ -0,0 +1,71 @@
+/*
+ * drivers/staging/android/uapi/ion.h
+ *
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _UAPI_LINUX_ION_TEST_H
+#define _UAPI_LINUX_ION_TEST_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+typedef int ion_user_handle_t;
+
+/**
+ * struct ion_test_rw_data - metadata passed to the kernel to read handle
+ * @ptr:	a pointer to an area at least as large as size
+ * @offset:	offset into the ion buffer to start reading
+ * @size:	size to read or write
+ * @write:	1 to write, 0 to read
+ */
+struct ion_test_rw_data {
+	__u64 ptr;
+	__u64 offset;
+	__u64 size;
+	int write;
+};
+
+#define ION_IOC_MAGIC		'I'
+
+/**
+ * DOC: ION_IOC_TEST_SET_DMA_BUF - attach a dma buf to the test driver
+ *
+ * Attaches a dma buf fd to the test driver.  Passing a second fd or -1 will
+ * release the first fd.
+ */
+#define ION_IOC_TEST_SET_FD \
+			_IO(ION_IOC_MAGIC, 0xf0)
+
+/**
+ * DOC: ION_IOC_TEST_DMA_MAPPING - read or write memory from a handle as DMA
+ *
+ * Reads or writes the memory from a handle using an uncached mapping.  Can be
+ * used by unit tests to emulate a DMA engine as close as possible.  Only
+ * expected to be used for debugging and testing, may not always be available.
+ */
+#define ION_IOC_TEST_DMA_MAPPING \
+			_IOW(ION_IOC_MAGIC, 0xf1, struct ion_test_rw_data)
+
+/**
+ * DOC: ION_IOC_TEST_KERNEL_MAPPING - read or write memory from a handle
+ *
+ * Reads or writes the memory from a handle using a kernel mapping.  Can be
+ * used by unit tests to test heap map_kernel functions.  Only expected to be
+ * used for debugging and testing, may not always be available.
+ */
+#define ION_IOC_TEST_KERNEL_MAPPING \
+			_IOW(ION_IOC_MAGIC, 0xf2, struct ion_test_rw_data)
+
+
+#endif /* _UAPI_LINUX_ION_H */