diff mbox series

[net-next,v5,4/5] net: ipqess: Add out-of-band DSA tagging support

Message ID 20221021124556.100445-5-maxime.chevallier@bootlin.com (mailing list archive)
State New, archived
Headers show
Series net: ipqess: introduce Qualcomm IPQESS driver | expand

Commit Message

Maxime Chevallier Oct. 21, 2022, 12:45 p.m. UTC
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.

We use the out-of-band tagging protocol by getting the source
port from the descriptor, push it into the skb extensions, and have the
tagger pull it to infer the destination netdev. The reverse process is
done on the TX side, where the driver pulls the tag from the skb and
builds the descriptor accordingly.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
V4->V5:
 - Rework the CHANGEUPPER event handling
V3->V4:
 - No changes
V2->V3:
 - No changes
V1->V2:
 - Use the new tagger, and the dsa_oob_tag_* helpers
 drivers/net/ethernet/qualcomm/Kconfig         |  3 +-
 drivers/net/ethernet/qualcomm/ipqess/ipqess.c | 63 ++++++++++++++++++-
 drivers/net/ethernet/qualcomm/ipqess/ipqess.h |  4 ++
 3 files changed, 68 insertions(+), 2 deletions(-)

Comments

Vladimir Oltean Oct. 21, 2022, 2:12 p.m. UTC | #1
On Fri, Oct 21, 2022 at 02:45:55PM +0200, Maxime Chevallier wrote:
> +static int ipqess_netdevice_event(struct notifier_block *nb,
> +				  unsigned long event, void *ptr)
> +{
> +	struct ipqess *ess = container_of(nb, struct ipqess, netdev_notifier);
> +	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
> +	struct netdev_notifier_changeupper_info *info;
> +
> +	switch (event) {
> +	case NETDEV_CHANGEUPPER:
> +		info = ptr;
> +
> +		if (dev->netdev_ops != &ipqess_axi_netdev_ops)
> +			return NOTIFY_DONE;
> +
> +		if (!dsa_slave_dev_check(info->upper_dev))
> +			return NOTIFY_DONE;
> +
> +		if (info->linking)
> +			ess->dsa_ports++;
> +		else
> +			ess->dsa_ports--;

How many ipqess devices are there in a system? The netdev notifier
should be a singleton, meaning it should be registered at module_init()
and unregistered at module_exit(). You can then get the "ess" pointer as
netdev_priv(dev), once you ensure that dev->netdev_ops is what you expect.

The code is already wrong: you take *ess from the &ess->netdev_notifier
reference, then you increment ess->dsa_ports based on the sole condition
that "dev" (the interface on which the notification was already emitted)
was an ess netdevice. But the "dev" pointer could be ess1, and the "ess"
pointer could be the netdev_priv(ess0). Your logic would increment the
dsa_ports of ess0 when a DSA switch joined ess1 (because all notifier
handlers see the event).

> +
> +		return NOTIFY_DONE;
> +	}
> +	return NOTIFY_OK;
> +}
> +
> @@ -1201,12 +1255,19 @@ static int ipqess_axi_probe(struct platform_device *pdev)
>  		netif_napi_add(netdev, &ess->rx_ring[i].napi_rx, ipqess_rx_napi);
>  	}
>  
> -	err = register_netdev(netdev);
> +	ess->netdev_notifier.notifier_call = ipqess_netdevice_event;
> +	err = register_netdevice_notifier(&ess->netdev_notifier);
>  	if (err)
>  		goto err_hw_stop;
>  
> +	err = register_netdev(netdev);
> +	if (err)
> +		goto err_notifier_unregister;
> +
>  	return 0;
>  
> +err_notifier_unregister:
> +	unregister_netdevice_notifier(&ess->netdev_notifier);
>  err_hw_stop:
>  	ipqess_hw_stop(ess);
>  
> diff --git a/drivers/net/ethernet/qualcomm/ipqess/ipqess.h b/drivers/net/ethernet/qualcomm/ipqess/ipqess.h
> index 9a4ab6ce282a..33cccaf6f143 100644
> --- a/drivers/net/ethernet/qualcomm/ipqess/ipqess.h
> +++ b/drivers/net/ethernet/qualcomm/ipqess/ipqess.h
> @@ -171,6 +171,10 @@ struct ipqess {
>  	struct platform_device *pdev;
>  	struct phylink *phylink;
>  	struct phylink_config phylink_config;
> +
> +	struct notifier_block netdev_notifier;
> +	int dsa_ports;
> +
>  	struct ipqess_tx_ring tx_ring[IPQESS_NETDEV_QUEUES];
>  
>  	struct ipqess_statistics ipqess_stats;
> -- 
> 2.37.3
>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/qualcomm/Kconfig b/drivers/net/ethernet/qualcomm/Kconfig
index a723ddbea248..eeb2c608d6b9 100644
--- a/drivers/net/ethernet/qualcomm/Kconfig
+++ b/drivers/net/ethernet/qualcomm/Kconfig
@@ -62,8 +62,9 @@  config QCOM_EMAC
 
 config QCOM_IPQ4019_ESS_EDMA
 	tristate "Qualcomm Atheros IPQ4019 ESS EDMA support"
-	depends on OF
+	depends on OF && NET_DSA
 	select PHYLINK
+	select NET_DSA_TAG_OOB
 	help
 	  This driver supports the Qualcomm Atheros IPQ40xx built-in
 	  ESS EDMA ethernet controller.
diff --git a/drivers/net/ethernet/qualcomm/ipqess/ipqess.c b/drivers/net/ethernet/qualcomm/ipqess/ipqess.c
index b23e7d776cd0..8e24e599f9be 100644
--- a/drivers/net/ethernet/qualcomm/ipqess/ipqess.c
+++ b/drivers/net/ethernet/qualcomm/ipqess/ipqess.c
@@ -9,6 +9,7 @@ 
 
 #include <linux/bitfield.h>
 #include <linux/clk.h>
+#include <linux/dsa/oob.h>
 #include <linux/if_vlan.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
@@ -22,6 +23,7 @@ 
 #include <linux/skbuff.h>
 #include <linux/vmalloc.h>
 #include <net/checksum.h>
+#include <net/dsa.h>
 #include <net/ip6_checksum.h>
 
 #include "ipqess.h"
@@ -330,6 +332,7 @@  static int ipqess_rx_poll(struct ipqess_rx_ring *rx_ring, int budget)
 	tail &= IPQESS_RFD_CONS_IDX_MASK;
 
 	while (done < budget) {
+		struct dsa_oob_tag_info tag_info;
 		struct ipqess_rx_desc *rd;
 		struct sk_buff *skb;
 
@@ -409,6 +412,12 @@  static int ipqess_rx_poll(struct ipqess_rx_ring *rx_ring, int budget)
 			__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021AD),
 					       rd->rrd4);
 
+		if (rx_ring->ess->dsa_ports) {
+			tag_info.dp = FIELD_GET(IPQESS_RRD_PORT_ID_MASK, rd->rrd1);
+			tag_info.proto = DSA_TAG_PROTO_OOB;
+			dsa_oob_tag_push(skb, &tag_info);
+		}
+
 		napi_gro_receive(&rx_ring->napi_rx, skb);
 
 		rx_ring->ess->stats.rx_packets++;
@@ -709,6 +718,22 @@  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 dsa_oob_tag_info tag_info;
+
+	if (!ess->dsa_ports)
+		return;
+
+	if (dsa_oob_tag_pop(skb, &tag_info))
+		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)
 {
@@ -719,6 +744,8 @@  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;
@@ -920,6 +947,33 @@  static const struct net_device_ops ipqess_axi_netdev_ops = {
 	.ndo_tx_timeout		= ipqess_tx_timeout,
 };
 
+static int ipqess_netdevice_event(struct notifier_block *nb,
+				  unsigned long event, void *ptr)
+{
+	struct ipqess *ess = container_of(nb, struct ipqess, netdev_notifier);
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct netdev_notifier_changeupper_info *info;
+
+	switch (event) {
+	case NETDEV_CHANGEUPPER:
+		info = ptr;
+
+		if (dev->netdev_ops != &ipqess_axi_netdev_ops)
+			return NOTIFY_DONE;
+
+		if (!dsa_slave_dev_check(info->upper_dev))
+			return NOTIFY_DONE;
+
+		if (info->linking)
+			ess->dsa_ports++;
+		else
+			ess->dsa_ports--;
+
+		return NOTIFY_DONE;
+	}
+	return NOTIFY_OK;
+}
+
 static void ipqess_hw_stop(struct ipqess *ess)
 {
 	int i;
@@ -1201,12 +1255,19 @@  static int ipqess_axi_probe(struct platform_device *pdev)
 		netif_napi_add(netdev, &ess->rx_ring[i].napi_rx, ipqess_rx_napi);
 	}
 
-	err = register_netdev(netdev);
+	ess->netdev_notifier.notifier_call = ipqess_netdevice_event;
+	err = register_netdevice_notifier(&ess->netdev_notifier);
 	if (err)
 		goto err_hw_stop;
 
+	err = register_netdev(netdev);
+	if (err)
+		goto err_notifier_unregister;
+
 	return 0;
 
+err_notifier_unregister:
+	unregister_netdevice_notifier(&ess->netdev_notifier);
 err_hw_stop:
 	ipqess_hw_stop(ess);
 
diff --git a/drivers/net/ethernet/qualcomm/ipqess/ipqess.h b/drivers/net/ethernet/qualcomm/ipqess/ipqess.h
index 9a4ab6ce282a..33cccaf6f143 100644
--- a/drivers/net/ethernet/qualcomm/ipqess/ipqess.h
+++ b/drivers/net/ethernet/qualcomm/ipqess/ipqess.h
@@ -171,6 +171,10 @@  struct ipqess {
 	struct platform_device *pdev;
 	struct phylink *phylink;
 	struct phylink_config phylink_config;
+
+	struct notifier_block netdev_notifier;
+	int dsa_ports;
+
 	struct ipqess_tx_ring tx_ring[IPQESS_NETDEV_QUEUES];
 
 	struct ipqess_statistics ipqess_stats;