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| -rw-r--r-- | tools/testing/selftests/android/ion/README | 101 |
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diff --git a/tools/testing/selftests/android/ion/README b/tools/testing/selftests/android/ion/README new file mode 100644 index 000000000..21783e9c4 --- /dev/null +++ b/tools/testing/selftests/android/ion/README @@ -0,0 +1,101 @@ +ION BUFFER SHARING UTILITY +========================== +File: ion_test.sh : Utility to test ION driver buffer sharing mechanism. +Author: Pintu Kumar <pintu.ping@gmail.com> + +Introduction: +------------- +This is a test utility to verify ION buffer sharing in user space +between 2 independent processes. +It uses unix domain socket (with SCM_RIGHTS) as IPC to transfer an FD to +another process to share the same buffer. +This utility demonstrates how ION buffer sharing can be implemented between +two user space processes, using various heap types. +The following heap types are supported by ION driver. +ION_HEAP_TYPE_SYSTEM (0) +ION_HEAP_TYPE_SYSTEM_CONTIG (1) +ION_HEAP_TYPE_CARVEOUT (2) +ION_HEAP_TYPE_CHUNK (3) +ION_HEAP_TYPE_DMA (4) + +By default only the SYSTEM and SYSTEM_CONTIG heaps are supported. +Each heap is associated with the respective heap id. +This utility is designed in the form of client/server program. +The server part (ionapp_export) is the exporter of the buffer. +It is responsible for creating an ION client, allocating the buffer based on +the heap id, writing some data to this buffer and then exporting the FD +(associated with this buffer) to another process using socket IPC. +This FD is called as buffer FD (which is different than the ION client FD). + +The client part (ionapp_import) is the importer of the buffer. +It retrives the FD from the socket data and installs into its address space. +This new FD internally points to the same kernel buffer. +So first it reads the data that is stored in this buffer and prints it. +Then it writes the different size of data (it could be different data) to the +same buffer. +Finally the buffer FD must be closed by both the exporter and importer. +Thus the same kernel buffer is shared among two user space processes using +ION driver and only one time allocation. + +Prerequisite: +------------- +This utility works only if /dev/ion interface is present. +The following configs needs to be enabled in kernel to include ion driver. +CONFIG_ANDROID=y +CONFIG_STAGING=y +CONFIG_ION=y +CONFIG_ION_SYSTEM_HEAP=y + +This utility requires to be run as root user. + + +Compile and test: +----------------- +This utility is made to be run as part of kselftest framework in kernel. +To compile and run using kselftest you can simply do the following from the +kernel top directory. +linux$ make TARGETS=android kselftest +Or you can also use: +linux$ make -C tools/testing/selftests TARGETS=android run_tests +Using the selftest it can directly execute the ion_test.sh script to test the +buffer sharing using ion system heap. +Currently the heap size is hard coded as just 10 bytes inside this script. +You need to be a root user to run under selftest. + +You can also compile and test manually using the following steps: +ion$ make +These will generate 2 executable: ionapp_export, ionapp_import +Now you can run the export and import manually by specifying the heap type +and the heap size. +You can also directly execute the shell script to run the test automatically. +Simply use the following command to run the test. +ion$ sudo ./ion_test.sh + +Test Results: +------------- +The utility is verified on Ubuntu-32 bit system with Linux Kernel 4.14. +Here is the snapshot of the test result using kselftest. + +linux# make TARGETS=android kselftest +heap_type: 0, heap_size: 10 +-------------------------------------- +heap type: 0 + heap id: 1 +heap name: ion_system_heap +-------------------------------------- +Fill buffer content: +0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd +Sharing fd: 6, Client fd: 5 +<ion_close_buffer_fd>: buffer release successfully.... +Received buffer fd: 4 +Read buffer content: +0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0x0 0x0 0x0 0x0 0x0 0x0 +0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 +Fill buffer content: +0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd +0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd 0xfd +0xfd 0xfd +<ion_close_buffer_fd>: buffer release successfully.... +ion_test.sh: heap_type: 0 - [PASS] + +ion_test.sh: done |