drivers: nrf_wifi: Implement TX zero-copy feature (5119f9c3) · Commits · Wenxi XU / zephyr

drivers/wifi/nrf_wifi/Kconfig.nrfwifi

+21 −0

Original line number	Diff line number	Diff line
		@@ -828,4 +828,25 @@ config NRF_WIFI_COEX_DISABLE_PRIORITY_WINDOW_FOR_SCAN
		help
		Enable this configuration to disable priority window for scan
		in the case of coexistence with Short Range radio.

		if NETWORKING
		config NRF_WIFI_ZERO_COPY_TX
		bool "Zero copy Transmit path [EXPERIMENTAL]"
		select NET_L2_ETHERNET_RESERVE_HEADER
		select EXPERIMENTAL
		# 54L has lower RAM
		default y if SOC_SERIES_NRF54LX
		help
		Enable this configuration to use zero copy Transmit path.
		The driver will use the network buffer directly for transmission
		without copying the data to the driver's buffer. This reduces the
		driver heap memory usage without much impact on the performance.

		The application should configure the network buffers to ensure that
		the whole packet fits in a single buffer, else the driver will fallback
		to the normal copy path, but the memory requirements would still match
		to the zero copy path and may be sub-optimal for the normal copy path.

		endif # NETWORKING

		endif # WIFI_NRF70

drivers/wifi/nrf_wifi/src/net_if.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -1002,6 +1002,11 @@ int nrf_wifi_if_get_config_zep(const struct device *dev,
		ETHERNET_CHECKSUM_SUPPORT_TCP \|
		ETHERNET_CHECKSUM_SUPPORT_UDP;
		}
		#endif
		#ifdef CONFIG_NRF_WIFI_ZERO_COPY_TX
		if (type == ETHERNET_CONFIG_TYPE_EXTRA_TX_PKT_HEADROOM) {
		config->extra_tx_pkt_headroom = NRF_WIFI_EXTRA_TX_HEADROOM;
		}
		#endif
		ret = 0;
		unlock:

modules/nrf_wifi/os/shim.c

+59 −0

Original line number	Diff line number	Diff line
		@@ -268,6 +268,9 @@ struct nwb {
		void (*cleanup_cb)();
		unsigned char priority;
		bool chksum_done;
		#ifdef CONFIG_NRF_WIFI_ZERO_COPY_TX
		struct net_pkt *pkt;
		#endif
		};

		static void *zep_shim_nbuf_alloc(unsigned int size)
		@@ -301,6 +304,12 @@ static void zep_shim_nbuf_free(void *nbuf)
		if (!nbuf) {
		return;
		}
		#ifdef CONFIG_NRF_WIFI_ZERO_COPY_TX
		if (((struct nwb *)nbuf)->pkt) {
		net_pkt_unref(((struct nwb *)nbuf)->pkt);
		((struct nwb *)nbuf)->pkt = NULL;
		}
		#endif /* CONFIG_NRF_WIFI_ZERO_COPY_TX */

		zep_shim_data_mem_free(((struct nwb *)nbuf)->priv);
		zep_shim_data_mem_free(nbuf);
		@@ -387,12 +396,62 @@ static void zep_shim_nbuf_set_chksum_done(void *nbuf, unsigned char chksum_done)
		#include <zephyr/net/ethernet.h>
		#include <zephyr/net/net_core.h>

		#ifdef CONFIG_NRF_WIFI_ZERO_COPY_TX
		void net_pkt_to_nbuf_zc(struct net_pkt pkt)
		{
		struct nwb *nbuff;

		if (!pkt \|\| !pkt->buffer) {
		LOG_DBG("Invalid packet, dropping");
		return NULL;
		}

		/* Check if packet has more than one fragment */
		if (pkt->buffer->frags) {
		LOG_ERR("Zero-copy only supports single buffer packets");
		return NULL;
		}

		nbuff = zep_shim_nbuf_alloc(NRF_WIFI_EXTRA_TX_HEADROOM); /* Just for headers */
		if (!nbuff) {
		return NULL;
		}

		zep_shim_nbuf_headroom_res(nbuff, NRF_WIFI_EXTRA_TX_HEADROOM);

		/* Zero-copy: point to the single data buffer */
		/* TODO: Use API for proper cursor access? */
		nbuff->data = pkt->buffer->data;
		nbuff->len = pkt->buffer->len;

		nbuff->priority = net_pkt_priority(pkt);
		nbuff->chksum_done = (bool)net_pkt_is_chksum_done(pkt);

		nbuff->pkt = pkt;
		/* Ref the packet so that it is not freed */
		net_pkt_ref(pkt);

		return nbuff;
		}
		#endif /* CONFIG_NRF_WIFI_ZERO_COPY_TX */

		void net_pkt_to_nbuf(struct net_pkt pkt)
		{
		struct nwb *nbuff;
		unsigned char *data;
		unsigned int len;

		if (!pkt) {
		return NULL;
		}

		#ifdef CONFIG_NRF_WIFI_ZERO_COPY_TX
		/* For zero-copy, check if packet has single buffer */
		if (pkt->buffer && !pkt->buffer->frags) {
		return net_pkt_to_nbuf_zc(pkt);
		}
		#endif /* CONFIG_NRF_WIFI_ZERO_COPY_TX */

		len = net_pkt_get_len(pkt);

		nbuff = zep_shim_nbuf_alloc(len + 100);

modules/nrf_wifi/os/shim.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -16,6 +16,8 @@
		#include <zephyr/drivers/gpio.h>
		#include <zephyr/net/net_pkt.h>

		#define NRF_WIFI_EXTRA_TX_HEADROOM 100

		/**
		* struct zep_shim_bus_qspi_priv - Structure to hold context information for the Linux OS
		* shim.

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