[PATCH net-next 3/5] net: ipqess: Add out-of-band DSA tagging support

Maxime Chevallier
2022-04-22T18:10:34Z

On the IPQ4019, there's an 5 ports switch connected to the CPU through
the IPQESS Ethernet controller. The way the DSA tag is sent-out to that
switch is through the DMA descriptor, due to how tightly it is
integrated with the switch.

This commit uses the out-of-band tagging protocol to get the outgoing
port index for each SKB, and reports it back in the skb->shinfo on the
RX side based on information located in the descriptor.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
drivers/net/ethernet/qualcomm/ipqess/ipqess.c | 23 +++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/drivers/net/ethernet/qualcomm/ipqess/ipqess.c b/drivers/net/ethernet/qualcomm/ipqess/ipqess.c
index 4ecb8c65417b..32a5cdd1c063 100644
--- a/drivers/net/ethernet/qualcomm/ipqess/ipqess.c
+++ b/drivers/net/ethernet/qualcomm/ipqess/ipqess.c
@@ -20,6 +20,7 @@
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
#include <net/checksum.h>
+#include <net/dsa.h>
#include <net/ip6_checksum.h>

#include "ipqess.h"
@@ -399,6 +400,11 @@ static int ipqess_rx_poll(struct ipqess_rx_ring *rx_ring, int budget)
skb->protocol = eth_type_trans(skb, rx_ring->ess->netdev);
skb_record_rx_queue(skb, rx_ring->ring_id);

+ if (netdev_uses_dsa(rx_ring->ess->netdev)) {
+ skb_shinfo(skb)->dsa_tag_info.dp =
+ FIELD_GET(IPQESS_RRD_PORT_ID_MASK, rd->rrd1);
+ }
+
if (rd->rrd6 & IPQESS_RRD_CSUM_FAIL_MASK)
skb_checksum_none_assert(skb);
else
@@ -706,6 +712,21 @@ static void ipqess_rollback_tx(struct ipqess *eth,
tx_ring->head = start_index;
}

+static void ipqess_process_dsa_tag_sh(struct ipqess *ess, struct sk_buff *skb,
+ u32 *word3)
+{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+ struct dsa_tag_info *tag_info = &shinfo->dsa_tag_info;
+
+ if (!netdev_uses_dsa(ess->netdev) ||
+ tag_info->proto != DSA_TAG_PROTO_OOB)
+ return;
+
+ *word3 |= tag_info->dp << IPQESS_TPD_PORT_BITMAP_SHIFT;
+ *word3 |= BIT(IPQESS_TPD_FROM_CPU_SHIFT);
+ *word3 |= 0x3e << IPQESS_TPD_PORT_BITMAP_SHIFT;
+}
+
static int ipqess_tx_map_and_fill(struct ipqess_tx_ring *tx_ring,
struct sk_buff *skb)
{
@@ -716,6 +737,8 @@ static int ipqess_tx_map_and_fill(struct ipqess_tx_ring *tx_ring,
u16 len;
int i;

+ ipqess_process_dsa_tag_sh(tx_ring->ess, skb, &word3);
+
if (skb_is_gso(skb)) {
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) {
lso_word1 |= IPQESS_TPD_IPV4_EN;
--
2.35.1