From 59ccdf80f8fde1ea15db4e96ec8ae40cf143090b Mon Sep 17 00:00:00 2001
From: Denis Kirjanov <denis.kirjanov@suse.com>
Date: Thu, 6 Oct 2022 13:50:00 +0300
Subject: [PATCH 01/32] net: dsa: ksz9477: port mirror sniffing limited to one
 port
Git-commit: fee34dd199384a483f84806a5cbcf8d657a481cc
References: git-fixes
Patch-mainline: v5.18-rc6

This patch limits the sniffing to only one port during the mirror add.
And during the mirror_del it checks for all the ports using the sniff,
if and only if no other ports are referring, sniffing is disabled.
The code is updated based on the review comments of LAN937x port mirror
patch.

Link: https://patchwork.kernel.org/project/netdevbpf/patch/20210422094257.1641396-8-prasanna.vengateshan@microchip.com/
Fixes: b987e98e50ab ("dsa: add DSA switch driver for Microchip KSZ9477")
Signed-off-by: Prasanna Vengateshan <prasanna.vengateshan@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Link: https://lore.kernel.org/r/20220428070709.7094-1-arun.ramadoss@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/dsa/microchip/ksz9477.c | 37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index 353b5f981740..970c587ac9b0 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -896,14 +896,31 @@ static int ksz9477_port_mirror_add(struct dsa_switch *ds, int port,
 				   bool ingress)
 {
 	struct ksz_device *dev = ds->priv;
+	u8 data;
+	int p;
+
+	/* Limit to one sniffer port
+	 * Check if any of the port is already set for sniffing
+	 * If yes, instruct the user to remove the previous entry & exit
+	 */
+	for (p = 0; p < dev->port_cnt; p++) {
+		/* Skip the current sniffing port */
+		if (p == mirror->to_local_port)
+			continue;
+
+		ksz_pread8(dev, p, P_MIRROR_CTRL, &data);
+
+		if (data & PORT_MIRROR_SNIFFER) {
+			dev_dbg(dev->dev, "Sniffer port is already configured, delete existing rules & retry");
+			return -EBUSY;
+		}
+	}
 
 	if (ingress)
 		ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_RX, true);
 	else
 		ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_TX, true);
 
-	ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_SNIFFER, false);
-
 	/* configure mirror port */
 	ksz_port_cfg(dev, mirror->to_local_port, P_MIRROR_CTRL,
 		     PORT_MIRROR_SNIFFER, true);
@@ -917,16 +934,28 @@ static void ksz9477_port_mirror_del(struct dsa_switch *ds, int port,
 				    struct dsa_mall_mirror_tc_entry *mirror)
 {
 	struct ksz_device *dev = ds->priv;
+	bool in_use = false;
 	u8 data;
+	int p;
 
 	if (mirror->ingress)
 		ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_RX, false);
 	else
 		ksz_port_cfg(dev, port, P_MIRROR_CTRL, PORT_MIRROR_TX, false);
 
-	ksz_pread8(dev, port, P_MIRROR_CTRL, &data);
 
-	if (!(data & (PORT_MIRROR_RX | PORT_MIRROR_TX)))
+	/* Check if any of the port is still referring to sniffer port */
+	for (p = 0; p < dev->port_cnt; p++) {
+		ksz_pread8(dev, p, P_MIRROR_CTRL, &data);
+
+		if ((data & (PORT_MIRROR_RX | PORT_MIRROR_TX))) {
+			in_use = true;
+			break;
+		}
+	}
+
+	/* delete sniffing if there are no other mirroring rules */
+	if (!in_use)
 		ksz_port_cfg(dev, mirror->to_local_port, P_MIRROR_CTRL,
 			     PORT_MIRROR_SNIFFER, false);
 }
-- 
2.16.4