linux: backport DSA b53 driver fixes for switch ports

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

target/linux/generic/backport-5.10/790-v5.15-0001-net-dsa-b53-Fix-calculating-number-of-switch-ports.patch

@@ -0,0 +1,39 @@
+From cdb067d31c0fe4cce98b9d15f1f2ef525acaa094 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Thu, 2 Sep 2021 10:30:50 +0200
+Subject: [PATCH] net: dsa: b53: Fix calculating number of switch ports
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+It isn't true that CPU port is always the last one. Switches BCM5301x
+have 9 ports (port 6 being inactive) and they use port 5 as CPU by
+default (depending on design some other may be CPU ports too).
+
+A more reliable way of determining number of ports is to check for the
+last set bit in the "enabled_ports" bitfield.
+
+This fixes b53 internal state, it will allow providing accurate info to
+the DSA and is required to fix BCM5301x support.
+
+Fixes: 967dd82ffc52 ("net: dsa: b53: Add support for Broadcom RoboSwitch")
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/dsa/b53/b53_common.c | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+--- a/drivers/net/dsa/b53/b53_common.c
++++ b/drivers/net/dsa/b53/b53_common.c
+@@ -2556,9 +2556,8 @@ static int b53_switch_init(struct b53_de
+ 			dev->cpu_port = 5;
+ 	}
+ 
+-	/* cpu port is always last */
+-	dev->num_ports = dev->cpu_port + 1;
+ 	dev->enabled_ports |= BIT(dev->cpu_port);
++	dev->num_ports = fls(dev->enabled_ports);
+ 
+ 	/* Include non standard CPU port built-in PHYs to be probed */
+ 	if (is539x(dev) || is531x5(dev)) {

target/linux/generic/backport-5.10/790-v5.15-0002-net-dsa-b53-Set-correct-number-of-ports-in-the-DSA-s.patch

@@ -0,0 +1,43 @@
+From d12e1c4649883e8ca5e8ff341e1948b3b6313259 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Thu, 2 Sep 2021 10:30:51 +0200
+Subject: [PATCH] net: dsa: b53: Set correct number of ports in the DSA struct
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Setting DSA_MAX_PORTS caused DSA to call b53 callbacks (e.g.
+b53_disable_port() during dsa_register_switch()) for invalid
+(non-existent) ports. That made b53 modify unrelated registers and is
+one of reasons for a broken BCM5301x support.
+
+This problem exists for years but DSA_MAX_PORTS usage has changed few
+times. It seems the most accurate to reference commit dropping
+dsa_switch_alloc() in the Fixes tag.
+
+Fixes: 7e99e3470172 ("net: dsa: remove dsa_switch_alloc helper")
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/dsa/b53/b53_common.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/drivers/net/dsa/b53/b53_common.c
++++ b/drivers/net/dsa/b53/b53_common.c
+@@ -2559,6 +2559,8 @@ static int b53_switch_init(struct b53_de
+ 	dev->enabled_ports |= BIT(dev->cpu_port);
+ 	dev->num_ports = fls(dev->enabled_ports);
+ 
++	dev->ds->num_ports = min_t(unsigned int, dev->num_ports, DSA_MAX_PORTS);
++
+ 	/* Include non standard CPU port built-in PHYs to be probed */
+ 	if (is539x(dev) || is531x5(dev)) {
+ 		for (i = 0; i < dev->num_ports; i++) {
+@@ -2603,7 +2605,6 @@ struct b53_device *b53_switch_alloc(stru
+ 		return NULL;
+ 
+ 	ds->dev = base;
+-	ds->num_ports = DSA_MAX_PORTS;
+ 
+ 	dev = devm_kzalloc(base, sizeof(*dev), GFP_KERNEL);
+ 	if (!dev)