net/dpaa2: add optional non-prefetch Rx mode

When we need particular number of packets from the rx routine,
which would change in every call, we cannot prefetch the packets
and provide previous results to the user.

User can select the mode by using devargs for non prefetch mode.

Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>

doc/guides/nics/dpaa2.rst

@@ -504,6 +504,10 @@ for details.
   driver level. Any packet received will be reflected back by the
   driver on same port. e.g. ``fslmc:dpni.1,drv_loopback=1``
 
+* Use dev arg option ``drv_no_prefetch=1`` to disable prefetching
+  of the packet pull command which is issued  in the previous cycle.
+  e.g. ``fslmc:dpni.1,drv_no_prefetch=1``
+
 Enabling logs
 -------------
 

drivers/net/dpaa2/dpaa2_ethdev.c

@@ -29,6 +29,7 @@
 #include <fsl_qbman_debug.h>
 
 #define DRIVER_LOOPBACK_MODE "drv_loopback"
+#define DRIVER_NO_PREFETCH_MODE "drv_no_prefetch"
 
 /* Supported Rx offloads */
 static uint64_t dev_rx_offloads_sup =
@@ -752,6 +753,7 @@ dpaa2_supported_ptypes_get(struct rte_eth_dev *dev)
 	};
 
 	if (dev->rx_pkt_burst == dpaa2_dev_prefetch_rx ||
+		dev->rx_pkt_burst == dpaa2_dev_rx ||
 		dev->rx_pkt_burst == dpaa2_dev_loopback_rx)
 		return ptypes;
 	return NULL;
@@ -2128,6 +2130,9 @@ dpaa2_dev_init(struct rte_eth_dev *eth_dev)
 		eth_dev->dev_ops = &dpaa2_ethdev_ops;
 		if (dpaa2_get_devargs(dev->devargs, DRIVER_LOOPBACK_MODE))
 			eth_dev->rx_pkt_burst = dpaa2_dev_loopback_rx;
+		else if (dpaa2_get_devargs(dev->devargs,
+					DRIVER_NO_PREFETCH_MODE))
+			eth_dev->rx_pkt_burst = dpaa2_dev_rx;
 		else
 			eth_dev->rx_pkt_burst = dpaa2_dev_prefetch_rx;
 		eth_dev->tx_pkt_burst = dpaa2_dev_tx;
@@ -2246,6 +2251,9 @@ dpaa2_dev_init(struct rte_eth_dev *eth_dev)
 	if (dpaa2_get_devargs(dev->devargs, DRIVER_LOOPBACK_MODE)) {
 		eth_dev->rx_pkt_burst = dpaa2_dev_loopback_rx;
 		DPAA2_PMD_INFO("Loopback mode");
+	} else if (dpaa2_get_devargs(dev->devargs, DRIVER_NO_PREFETCH_MODE)) {
+		eth_dev->rx_pkt_burst = dpaa2_dev_rx;
+		DPAA2_PMD_INFO("No Prefetch mode");
 	} else {
 		eth_dev->rx_pkt_burst = dpaa2_dev_prefetch_rx;
 	}
@@ -2405,7 +2413,8 @@ static struct rte_dpaa2_driver rte_dpaa2_pmd = {
 
 RTE_PMD_REGISTER_DPAA2(net_dpaa2, rte_dpaa2_pmd);
 RTE_PMD_REGISTER_PARAM_STRING(net_dpaa2,
-		DRIVER_LOOPBACK_MODE "=<int>");
+		DRIVER_LOOPBACK_MODE "=<int> "
+		DRIVER_NO_PREFETCH_MODE "=<int>");
 RTE_INIT(dpaa2_pmd_init_log)
 {
 	dpaa2_logtype_pmd = rte_log_register("pmd.net.dpaa2");

drivers/net/dpaa2/dpaa2_ethdev.h

@@ -149,6 +149,8 @@ int dpaa2_eth_eventq_attach(const struct rte_eth_dev *dev,
 int dpaa2_eth_eventq_detach(const struct rte_eth_dev *dev,
 		int eth_rx_queue_id);
 
+uint16_t dpaa2_dev_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts);
+
 uint16_t dpaa2_dev_loopback_rx(void *queue, struct rte_mbuf **bufs,
 				uint16_t nb_pkts);
 

drivers/net/dpaa2/dpaa2_rxtx.c

@@ -727,6 +727,111 @@ dpaa2_dev_process_ordered_event(struct qbman_swp *swp,
 	qbman_swp_dqrr_consume(swp, dq);
 }
 
+uint16_t
+dpaa2_dev_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
+{
+	/* Function receive frames for a given device and VQ */
+	struct dpaa2_queue *dpaa2_q = (struct dpaa2_queue *)queue;
+	struct qbman_result *dq_storage;
+	uint32_t fqid = dpaa2_q->fqid;
+	int ret, num_rx = 0, next_pull = nb_pkts, num_pulled;
+	uint8_t pending, status;
+	struct qbman_swp *swp;
+	const struct qbman_fd *fd, *next_fd;
+	struct qbman_pull_desc pulldesc;
+	struct rte_eth_dev_data *eth_data = dpaa2_q->eth_data;
+
+	if (unlikely(!DPAA2_PER_LCORE_DPIO)) {
+		ret = dpaa2_affine_qbman_swp();
+		if (ret) {
+			DPAA2_PMD_ERR("Failure in affining portal\n");
+			return 0;
+		}
+	}
+	swp = DPAA2_PER_LCORE_PORTAL;
+
+	do {
+		dq_storage = dpaa2_q->q_storage->dq_storage[0];
+		qbman_pull_desc_clear(&pulldesc);
+		qbman_pull_desc_set_fq(&pulldesc, fqid);
+		qbman_pull_desc_set_storage(&pulldesc, dq_storage,
+				(size_t)(DPAA2_VADDR_TO_IOVA(dq_storage)), 1);
+
+		if (next_pull > dpaa2_dqrr_size) {
+			qbman_pull_desc_set_numframes(&pulldesc,
+				dpaa2_dqrr_size);
+			next_pull -= dpaa2_dqrr_size;
+		} else {
+			qbman_pull_desc_set_numframes(&pulldesc, next_pull);
+			next_pull = 0;
+		}
+
+		while (1) {
+			if (qbman_swp_pull(swp, &pulldesc)) {
+				DPAA2_PMD_DP_DEBUG(
+					"VDQ command is not issued.QBMAN is busy\n");
+				/* Portal was busy, try again */
+				continue;
+			}
+			break;
+		}
+
+		rte_prefetch0((void *)((size_t)(dq_storage + 1)));
+		/* Check if the previous issued command is completed. */
+		while (!qbman_check_command_complete(dq_storage))
+			;
+
+		num_pulled = 0;
+		pending = 1;
+		do {
+			/* Loop until the dq_storage is updated with
+			 * new token by QBMAN
+			 */
+			while (!qbman_check_new_result(dq_storage))
+				;
+			rte_prefetch0((void *)((size_t)(dq_storage + 2)));
+			/* Check whether Last Pull command is Expired and
+			 * setting Condition for Loop termination
+			 */
+			if (qbman_result_DQ_is_pull_complete(dq_storage)) {
+				pending = 0;
+				/* Check for valid frame. */
+				status = qbman_result_DQ_flags(dq_storage);
+				if (unlikely((status &
+					QBMAN_DQ_STAT_VALIDFRAME) == 0))
+					continue;
+			}
+			fd = qbman_result_DQ_fd(dq_storage);
+
+			next_fd = qbman_result_DQ_fd(dq_storage + 1);
+			/* Prefetch Annotation address for the parse results */
+			rte_prefetch0(
+				(void *)(size_t)(DPAA2_GET_FD_ADDR(next_fd)
+					+ DPAA2_FD_PTA_SIZE + 16));
+
+			if (unlikely(DPAA2_FD_GET_FORMAT(fd) == qbman_fd_sg))
+				bufs[num_rx] = eth_sg_fd_to_mbuf(fd);
+			else
+				bufs[num_rx] = eth_fd_to_mbuf(fd);
+			bufs[num_rx]->port = eth_data->port_id;
+
+		if (eth_data->dev_conf.rxmode.offloads &
+				DEV_RX_OFFLOAD_VLAN_STRIP) {
+			rte_vlan_strip(bufs[num_rx]);
+		}
+
+			dq_storage++;
+			num_rx++;
+			num_pulled++;
+		} while (pending);
+	/* Last VDQ provided all packets and more packets are requested */
+	} while (next_pull && num_pulled == dpaa2_dqrr_size);
+
+	dpaa2_q->rx_pkts += num_rx;
+
+	return num_rx;
+}
+
 /*
  * Callback to handle sending packets through WRIOP based interface
  */