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drivers: nrf_wifi: Implement TX zero-copy feature

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This uses the network packet as is without the need for a copy all the
way till the packet is handed over to RPU.

Signed-off-by: Chaitanya Tata <Chaitanya.Tata@nordicsemi.no>
This commit is contained in:
Chaitanya Tata 2025-02-08 01:34:48 +05:30 • committed by Benjamin Cabé
commit 5119f9c379
4 changed files with 87 additions and 0 deletions
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59
modules/nrf_wifi/os/shim.c
View file

@ -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);

2
modules/nrf_wifi/os/shim.h
View file

@ -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.