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>

diff --git a/drivers/firewire/.kunitconfig b/drivers/firewire/.kunitconfig
index 74259204fcdd0dcba4f0f143b119eb2c5a1d7401..21b7e9eef63d1ee4f3b033a8990bdb50c30ccefc 100644 (file)
--- a/drivers/firewire/.kunitconfig
+++ b/drivers/firewire/.kunitconfig
@@ -5,3 +5,4 @@ CONFIG_FIREWIRE_KUNIT_UAPI_TEST=y
 CONFIG_FIREWIRE_KUNIT_DEVICE_ATTRIBUTE_TEST=y
 CONFIG_FIREWIRE_KUNIT_PACKET_SERDES_TEST=y
 CONFIG_FIREWIRE_KUNIT_SELF_ID_SEQUENCE_HELPER_TEST=y
+CONFIG_FIREWIRE_KUNIT_OHCI_SERDES_TEST=y

diff --git a/drivers/firewire/Kconfig b/drivers/firewire/Kconfig
index 95e72e0b592bdfca34226e105b9d7cf9ea0346eb..905c82e26ce74f381c8f8e846fe9f695802bdeff 100644 (file)
--- a/drivers/firewire/Kconfig
+++ b/drivers/firewire/Kconfig
@@ -92,6 +92,22 @@ config FIREWIRE_OHCI
          To compile this driver as a module, say M here:  The module will be
          called firewire-ohci.
 
+config FIREWIRE_KUNIT_OHCI_SERDES_TEST
+       tristate "KUnit tests for serialization/deserialization of data in buffers/registers" if !KUNIT_ALL_TESTS
+       depends on FIREWIRE && KUNIT
+       default KUNIT_ALL_TESTS
+       help
+         This builds the KUnit tests to check serialization and deserialization
+         of data in buffers and registers defined in 1394 OHCI specification.
+
+         KUnit tests run during boot and output the results to the debug
+         log in TAP format (https://testanything.org/). Only useful for
+         kernel devs running KUnit test harness and are not for inclusion
+         into a production build.
+
+         For more information on KUnit and unit tests in general, refer
+         to the KUnit documentation in Documentation/dev-tools/kunit/.
+
 config FIREWIRE_SBP2
        tristate "Storage devices (SBP-2 protocol)"
        depends on FIREWIRE && SCSI

diff --git a/drivers/firewire/Makefile b/drivers/firewire/Makefile
index 21b975e0a387a6b9229c8ed38685f62a8b0da5ae..1ff550e93a8c593dbea3a7488e8d3c181dbd293f 100644 (file)
--- a/drivers/firewire/Makefile
+++ b/drivers/firewire/Makefile
@@ -19,3 +19,4 @@ obj-$(CONFIG_PROVIDE_OHCI1394_DMA_INIT) += init_ohci1394_dma.o
 obj-$(CONFIG_FIREWIRE_KUNIT_UAPI_TEST) += uapi-test.o
 obj-$(CONFIG_FIREWIRE_KUNIT_PACKET_SERDES_TEST) += packet-serdes-test.o
 obj-$(CONFIG_FIREWIRE_KUNIT_SELF_ID_SEQUENCE_HELPER_TEST) += self-id-sequence-helper-test.o
+obj-$(CONFIG_FIREWIRE_KUNIT_OHCI_SERDES_TEST) += ohci-serdes-test.o

diff --git a/drivers/firewire/ohci-serdes-test.c b/drivers/firewire/ohci-serdes-test.c
new file mode 100644 (file)
index 0000000..304a09f
--- /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");

diff --git a/drivers/firewire/ohci.h b/drivers/firewire/ohci.h
index c4d005a9901a8a5fd655c19afb678117f796db48..d83fd4731d56e953d525140f379d311b47642f06 100644 (file)
--- a/drivers/firewire/ohci.h
+++ b/drivers/firewire/ohci.h
@@ -156,4 +156,46 @@
 
 #define OHCI1394_phy_tcode             0xe
 
+// Self-ID DMA.
+
+#define OHCI1394_SelfIDCount_selfIDError_MASK          0x80000000
+#define OHCI1394_SelfIDCount_selfIDError_SHIFT         31
+#define OHCI1394_SelfIDCount_selfIDGeneration_MASK     0x00ff0000
+#define OHCI1394_SelfIDCount_selfIDGeneration_SHIFT    16
+#define OHCI1394_SelfIDCount_selfIDSize_MASK           0x000007fc
+#define OHCI1394_SelfIDCount_selfIDSize_SHIFT          2
+
+static inline bool ohci1394_self_id_count_is_error(u32 value)
+{
+       return !!((value & OHCI1394_SelfIDCount_selfIDError_MASK) >> OHCI1394_SelfIDCount_selfIDError_SHIFT);
+}
+
+static inline u8 ohci1394_self_id_count_get_generation(u32 value)
+{
+       return (value & OHCI1394_SelfIDCount_selfIDGeneration_MASK) >> OHCI1394_SelfIDCount_selfIDGeneration_SHIFT;
+}
+
+// In 1394 OHCI specification, the maximum size of self ID stream is 504 quadlets
+// (= 63 devices * 4 self ID packets * 2 quadlets). The selfIDSize field accommodates it and its
+// additional first quadlet, since the field is 9 bits (0x1ff = 511).
+static inline u32 ohci1394_self_id_count_get_size(u32 value)
+{
+       return (value & OHCI1394_SelfIDCount_selfIDSize_MASK) >> OHCI1394_SelfIDCount_selfIDSize_SHIFT;
+}
+
+#define OHCI1394_SELF_ID_RECEIVE_Q0_GENERATION_MASK    0x00ff0000
+#define OHCI1394_SELF_ID_RECEIVE_Q0_GENERATION_SHIFT   16
+#define OHCI1394_SELF_ID_RECEIVE_Q0_TIMESTAMP_MASK     0x0000ffff
+#define OHCI1394_SELF_ID_RECEIVE_Q0_TIMESTAMP_SHIFT    0
+
+static inline u8 ohci1394_self_id_receive_q0_get_generation(u32 quadlet0)
+{
+       return (quadlet0 & OHCI1394_SELF_ID_RECEIVE_Q0_GENERATION_MASK) >> OHCI1394_SELF_ID_RECEIVE_Q0_GENERATION_SHIFT;
+}
+
+static inline u16 ohci1394_self_id_receive_q0_get_timestamp(u32 quadlet0)
+{
+       return (quadlet0 & OHCI1394_SELF_ID_RECEIVE_Q0_TIMESTAMP_MASK) >> OHCI1394_SELF_ID_RECEIVE_Q0_TIMESTAMP_SHIFT;
+}
+
 #endif /* _FIREWIRE_OHCI_H */