firewire: ohci: add static inline functions to deserialize for Self-ID DMA operation

The SelfI-ID is one type of DMAs defined in 1394 OHCI specification. It is
operated by two registers, one interrupt, and has one format of buffer.

This commit adds some static inline functions to deserialize the data in
the buffer and registers. Some KUnit tests are also added to check their
reliability.

Link: https://lore.kernel.org/r/20240702222034.1378764-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/firewire/ohci-serdes-test.c b/drivers/firewire/ohci-serdes-test.c
new file mode 100644
index 000000000000..304a09ff528e
--- /dev/null
+++ b/drivers/firewire/ohci-serdes-test.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// ohci-serdes-test.c - An application of Kunit to check serialization/deserialization of data in
+//			buffers and registers defined in 1394 OHCI specification.
+//
+// Copyright (c) 2024 Takashi Sakamoto
+
+#include <kunit/test.h>
+
+#include "ohci.h"
+
+
+static void test_self_id_count_register_deserialization(struct kunit *test)
+{
+	const u32 expected = 0x803d0594;
+
+	bool is_error = ohci1394_self_id_count_is_error(expected);
+	u8 generation = ohci1394_self_id_count_get_generation(expected);
+	u32 size = ohci1394_self_id_count_get_size(expected);
+
+	KUNIT_EXPECT_TRUE(test, is_error);
+	KUNIT_EXPECT_EQ(test, 0x3d, generation);
+	KUNIT_EXPECT_EQ(test, 0x165, size);
+}
+
+static void test_self_id_receive_buffer_deserialization(struct kunit *test)
+{
+	const u32 buffer[] = {
+		0x0006f38b,
+		0x807fcc56,
+		0x7f8033a9,
+		0x8145cc5e,
+		0x7eba33a1,
+	};
+
+	u8 generation = ohci1394_self_id_receive_q0_get_generation(buffer[0]);
+	u16 timestamp = ohci1394_self_id_receive_q0_get_timestamp(buffer[0]);
+
+	KUNIT_EXPECT_EQ(test, 0x6, generation);
+	KUNIT_EXPECT_EQ(test, 0xf38b, timestamp);
+}
+
+static struct kunit_case ohci_serdes_test_cases[] = {
+	KUNIT_CASE(test_self_id_count_register_deserialization),
+	KUNIT_CASE(test_self_id_receive_buffer_deserialization),
+	{}
+};
+
+static struct kunit_suite ohci_serdes_test_suite = {
+	.name = "firewire-ohci-serdes",
+	.test_cases = ohci_serdes_test_cases,
+};
+kunit_test_suite(ohci_serdes_test_suite);
+
+MODULE_DESCRIPTION("FireWire buffers and registers serialization/deserialization unit test suite");
+MODULE_LICENSE("GPL");