nvme: add enum for opcode data direction

NVMe opcodes contain a two-bit field that encodes the expected data
direction for each command.  Add an enum and a function to extract these
bits.

Change-Id: Ie214319f121cf0899c6aa5663866f2988b128dd2
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>

include/spdk/nvme_spec.h

@@ -526,6 +526,34 @@ enum spdk_nvme_nvm_opcode {
 	SPDK_NVME_OPC_RESERVATION_RELEASE		= 0x15,
 };
 
+/**
+ * Data transfer (bits 1:0) of an NVMe opcode.
+ *
+ * \sa spdk_nvme_opc_get_data_transfer
+ */
+enum spdk_nvme_data_transfer {
+	/** Opcode does not transfer data */
+	SPDK_NVME_DATA_NONE				= 0,
+	/** Opcode transfers data from host to controller (e.g. Write) */
+	SPDK_NVME_DATA_HOST_TO_CONTROLLER		= 1,
+	/** Opcode transfers data from controller to host (e.g. Read) */
+	SPDK_NVME_DATA_CONTROLLER_TO_HOST		= 2,
+	/** Opcode transfers data both directions */
+	SPDK_NVME_DATA_BIDIRECTIONAL			= 3
+};
+
+/**
+ * Extract the Data Transfer bits from an NVMe opcode.
+ *
+ * This determines whether a command requires a data buffer and
+ * which direction (host to controller or controller to host) it is
+ * transferred.
+ */
+static inline enum spdk_nvme_data_transfer spdk_nvme_opc_get_data_transfer(uint8_t opc)
+{
+	return opc & 3;
+}
+
 enum spdk_nvme_feat {
 	/* 0x00 - reserved */
 	SPDK_NVME_FEAT_ARBITRATION				= 0x01,

test/lib/nvme/nvme.sh

@@ -14,7 +14,7 @@ timing_enter nvme
 
 timing_enter unit
 $valgrind $testdir/unit/nvme_ns_cmd_c/nvme_ns_cmd_ut
-$testdir/unit/nvme_c/nvme_ut
+$valgrind $testdir/unit/nvme_c/nvme_ut
 $valgrind $testdir/unit/nvme_qpair_c/nvme_qpair_ut
 $valgrind $testdir/unit/nvme_ctrlr_c/nvme_ctrlr_ut
 $valgrind $testdir/unit/nvme_ctrlr_cmd_c/nvme_ctrlr_cmd_ut

test/lib/nvme/unit/nvme_c/nvme_ut.c

@@ -71,6 +71,24 @@ spdk_nvme_ctrlr_opts_set_defaults(struct spdk_nvme_ctrlr_opts *opts)
 	memset(opts, 0, sizeof(*opts));
 }
 
+static void
+test_opc_data_transfer(void)
+{
+	enum spdk_nvme_data_transfer xfer;
+
+	xfer = spdk_nvme_opc_get_data_transfer(SPDK_NVME_OPC_FLUSH);
+	CU_ASSERT(xfer == SPDK_NVME_DATA_NONE);
+
+	xfer = spdk_nvme_opc_get_data_transfer(SPDK_NVME_OPC_WRITE);
+	CU_ASSERT(xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER);
+
+	xfer = spdk_nvme_opc_get_data_transfer(SPDK_NVME_OPC_READ);
+	CU_ASSERT(xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST);
+
+	xfer = spdk_nvme_opc_get_data_transfer(SPDK_NVME_OPC_GET_LOG_PAGE);
+	CU_ASSERT(xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST);
+}
+
 int main(int argc, char **argv)
 {
 	CU_pSuite	suite = NULL;
@@ -86,15 +104,12 @@ int main(int argc, char **argv)
 		return CU_get_error();
 	}
 
-#if 0
 	if (
-		CU_add_test(suite, "test1", test1) == NULL
+		CU_add_test(suite, "test_opc_data_transfer", test_opc_data_transfer) == NULL
-		|| CU_add_test(suite, "test2", test2) == NULL
 	) {
 		CU_cleanup_registry();
 		return CU_get_error();
 	}
-#endif
 
 	CU_basic_set_mode(CU_BRM_VERBOSE);
 	CU_basic_run_tests();