Re: [RFC PATCH 1/4] fpga: add initial KUnit test suite

[Marco Pagani <marpagan@redhat.com>]

On 2023-02-14 00:37, Russ Weight wrote:
> 
> 
> On 2/3/23 09:06, Marco Pagani wrote:
>> Introduce an initial KUnit suite to test the core components of the
>> FPGA subsystem.
>>
>> The test suite consists of two test cases. The first test case checks
>> the programming of a static image on a fake FPGA with a single hardware
>> bridge. The FPGA is first programmed using a test image stored in a
>> buffer, and then with the same image linked to a single-entry
>> scatter-gather list.
>>
>> The second test case models dynamic partial reconfiguration. The FPGA
>> is first configured with a static image that implements a
>> reconfigurable design containing a sub-region controlled by two soft
>> bridges. Then, the reconfigurable sub-region is reconfigured using
>> a fake partial bitstream image. After the reconfiguration, the test
>> checks that the soft bridges have been correctly activated.
>>
>> Signed-off-by: Marco Pagani <marpagan@redhat.com>
>> ---
>>  drivers/fpga/Kconfig            |   2 +
>>  drivers/fpga/Makefile           |   3 +
>>  drivers/fpga/tests/.kunitconfig |   5 +
>>  drivers/fpga/tests/Kconfig      |  15 ++
>>  drivers/fpga/tests/Makefile     |   6 +
>>  drivers/fpga/tests/fpga-tests.c | 264 ++++++++++++++++++++++++++++++++
>>  6 files changed, 295 insertions(+)
>>  create mode 100644 drivers/fpga/tests/.kunitconfig
>>  create mode 100644 drivers/fpga/tests/Kconfig
>>  create mode 100644 drivers/fpga/tests/Makefile
>>  create mode 100644 drivers/fpga/tests/fpga-tests.c
>>
>> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
>> index 0a00763b9f28..2f689ac4ba3a 100644
>> --- a/drivers/fpga/Kconfig
>> +++ b/drivers/fpga/Kconfig
>> @@ -276,4 +276,6 @@ config FPGA_MGR_LATTICE_SYSCONFIG_SPI
>>  	  FPGA manager driver support for Lattice FPGAs programming over slave
>>  	  SPI sysCONFIG interface.
>>  
>> +source "drivers/fpga/tests/Kconfig"
>> +
>>  endif # FPGA
>> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
>> index 72e554b4d2f7..352a2612623e 100644
>> --- a/drivers/fpga/Makefile
>> +++ b/drivers/fpga/Makefile
>> @@ -55,3 +55,6 @@ obj-$(CONFIG_FPGA_DFL_NIOS_INTEL_PAC_N3000)	+= dfl-n3000-nios.o
>>  
>>  # Drivers for FPGAs which implement DFL
>>  obj-$(CONFIG_FPGA_DFL_PCI)		+= dfl-pci.o
>> +
>> +# KUnit tests
>> +obj-$(CONFIG_FPGA_KUNIT_TESTS)		+= tests/
>> diff --git a/drivers/fpga/tests/.kunitconfig b/drivers/fpga/tests/.kunitconfig
>> new file mode 100644
>> index 000000000000..a1c2a2974c39
>> --- /dev/null
>> +++ b/drivers/fpga/tests/.kunitconfig
>> @@ -0,0 +1,5 @@
>> +CONFIG_KUNIT=y
>> +CONFIG_FPGA=y
>> +CONFIG_FPGA_REGION=y
>> +CONFIG_FPGA_BRIDGE=y
>> +CONFIG_FPGA_KUNIT_TESTS=y
>> diff --git a/drivers/fpga/tests/Kconfig b/drivers/fpga/tests/Kconfig
>> new file mode 100644
>> index 000000000000..5198e605b38d
>> --- /dev/null
>> +++ b/drivers/fpga/tests/Kconfig
>> @@ -0,0 +1,15 @@
>> +config FPGA_KUNIT_TESTS
>> +	tristate "FPGA KUnit tests" if !KUNIT_ALL_TESTS
>> +	depends on FPGA && FPGA_REGION && FPGA_BRIDGE && KUNIT
>> +	default KUNIT_ALL_TESTS
>> +	help
>> +	  Builds unit tests for the FPGA subsystem. This option
>> +	  is not useful for distributions or general kernels,
>> +	  but only for kernel developers working on the FPGA
>> +	  subsystem and its associated drivers.
>> +
>> +	  For more information on KUnit and unit tests in general,
>> +	  please refer to the KUnit documentation in
>> +	  Documentation/dev-tools/kunit/.
>> +
>> +	  If in doubt, say "N".
>> diff --git a/drivers/fpga/tests/Makefile b/drivers/fpga/tests/Makefile
>> new file mode 100644
>> index 000000000000..74346ae62457
>> --- /dev/null
>> +++ b/drivers/fpga/tests/Makefile
>> @@ -0,0 +1,6 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +
>> +obj-$(CONFIG_FPGA_KUNIT_TESTS) += fake-fpga-mgr.o
>> +obj-$(CONFIG_FPGA_KUNIT_TESTS) += fake-fpga-region.o
>> +obj-$(CONFIG_FPGA_KUNIT_TESTS) += fake-fpga-bridge.o
>> +obj-$(CONFIG_FPGA_KUNIT_TESTS) += fpga-tests.o
>> diff --git a/drivers/fpga/tests/fpga-tests.c b/drivers/fpga/tests/fpga-tests.c
>> new file mode 100644
>> index 000000000000..33f04079b32f
>> --- /dev/null
>> +++ b/drivers/fpga/tests/fpga-tests.c
>> @@ -0,0 +1,264 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Test suite for the FPGA subsystem
>> + *
>> + * Copyright (C) 2023 Red Hat, Inc. All rights reserved.
>> + *
>> + * Author: Marco Pagani <marpagan@redhat.com>
>> + */
>> +
>> +#include <kunit/test.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/scatterlist.h>
>> +
>> +#include <linux/fpga/fpga-mgr.h>
>> +#include <linux/fpga/fpga-region.h>
>> +#include <linux/fpga/fpga-bridge.h>
>> +
>> +#include "fake-fpga-region.h"
>> +#include "fake-fpga-bridge.h"
>> +#include "fake-fpga-mgr.h"
>> +
>> +#define FAKE_BIT_BLOCKS		16
>> +#define FAKE_BIT_SIZE		(FPGA_TEST_BIT_BLOCK * FAKE_BIT_BLOCKS)
>> +
>> +static u8 fake_bit[FAKE_BIT_SIZE];
> 
> I take it "bit" in fake_bit and sgt_bit is short for "bitstream". Initially,
> I found this confusing as I tend to think of a bit as a single bit. It might
> be better to expand that something like "fake_bitstream" or "fake_image".
> 
> - Russ


You're right. Using "bit" in the name can be confusing. I'll change it
to "fake_image" or maybe "fake_image_buf" to be consistent with the naming
convention used in the subsystem. I'll also change "test_img_info"
to "fake_img_info" to improve naming consistency.

Thanks,
Marco