[PATCH net 1/2] net: dsa: b53: Fix calculating number of switch ports

Subsystems: broadcom b53/sf2 ethernet switch driver, networking drivers, networking [dsa], the rest

STALE1801d

6 messages, 3 authors, 2021-09-02 · open the first message on its own page

[PATCH net 1/2] net: dsa: b53: Fix calculating number of switch ports

From: Rafał Miłecki <zajec5@gmail.com>
Date: 2021-09-01 09:22:46

From: Rafał Miłecki <rafal@milecki.pl>

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")
Cc: stable@vger.kernel.org
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 drivers/net/dsa/b53/b53_common.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index bd1417a66cbf..dcf9d7e5ae14 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -2612,9 +2612,8 @@ static int b53_switch_init(struct b53_device *dev)
 			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)) {
-- 
2.26.2

[PATCH net 2/2] net: dsa: b53: Set correct number of ports in the DSA struct

From: Rafał Miłecki <zajec5@gmail.com>
Date: 2021-09-01 09:22:52

From: Rafał Miłecki <rafal@milecki.pl>

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 so it's hard to specify a single commit this change fixes.

Cc: stable@vger.kernel.org
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 drivers/net/dsa/b53/b53_common.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index dcf9d7e5ae14..5646eb8afe38 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -2615,6 +2615,8 @@ static int b53_switch_init(struct b53_device *dev)
 	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++) {
@@ -2659,7 +2661,6 @@ struct b53_device *b53_switch_alloc(struct device *base,
 		return NULL;
 
 	ds->dev = base;
-	ds->num_ports = DSA_MAX_PORTS;
 
 	dev = devm_kzalloc(base, sizeof(*dev), GFP_KERNEL);
 	if (!dev)
-- 
2.26.2

Re: [PATCH net 1/2] net: dsa: b53: Fix calculating number of switch ports

From: Florian Fainelli <f.fainelli@gmail.com>
Date: 2021-09-01 17:16:58


On 9/1/2021 2:21 AM, Rafał Miłecki wrote:
From: Rafał Miłecki <rafal@milecki.pl>

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")
Cc: stable@vger.kernel.org
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
For a bug fix, this looks appropriate to me, and for net-next, we need 
to remove the dev->num_ports and b53_for_each_port() entirely as there 
is no need to duplicate what DSA already maintains for us. Thanks!

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Re: [PATCH net 2/2] net: dsa: b53: Set correct number of ports in the DSA struct

From: Florian Fainelli <f.fainelli@gmail.com>
Date: 2021-09-01 17:22:04


On 9/1/2021 2:21 AM, Rafał Miłecki wrote:
From: Rafał Miłecki <rafal@milecki.pl>

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 so it's hard to specify a single commit this change fixes.
You should still try to identify the relevant tags that this is fixing 
such that this gets back ported to the appropriate trees. We could use 
Fixes: 7e99e3470172 ("net: dsa: remove dsa_switch_alloc helper"), to 
minimize the amount of work doing the back port.
-- 
Florian

Re: [PATCH net 2/2] net: dsa: b53: Set correct number of ports in the DSA struct

From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-09-01 23:37:00

On Wed, 1 Sep 2021 10:21:55 -0700 Florian Fainelli wrote:
On 9/1/2021 2:21 AM, Rafał Miłecki wrote:
quoted
From: Rafał Miłecki <rafal@milecki.pl>

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 so it's hard to specify a single commit this change fixes.  
You should still try to identify the relevant tags that this is fixing 
such that this gets back ported to the appropriate trees. We could use 
Fixes: 7e99e3470172 ("net: dsa: remove dsa_switch_alloc helper"), to 
minimize the amount of work doing the back port.
To be clear are you okay with the fixes tag you provided or should we
wait for Rafał to double check?

Re: [PATCH net 2/2] net: dsa: b53: Set correct number of ports in the DSA struct

From: Florian Fainelli <f.fainelli@gmail.com>
Date: 2021-09-02 01:38:53


On 9/1/2021 4:36 PM, Jakub Kicinski wrote:
On Wed, 1 Sep 2021 10:21:55 -0700 Florian Fainelli wrote:
quoted
On 9/1/2021 2:21 AM, Rafał Miłecki wrote:
quoted
From: Rafał Miłecki <rafal@milecki.pl>

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 so it's hard to specify a single commit this change fixes.
You should still try to identify the relevant tags that this is fixing
such that this gets back ported to the appropriate trees. We could use
Fixes: 7e99e3470172 ("net: dsa: remove dsa_switch_alloc helper"), to
minimize the amount of work doing the back port.
To be clear are you okay with the fixes tag you provided or should we
wait for Rafał to double check?
That Fixes tag is correct and won't cause conflicts AFAICT with 
backports all the way down to that commit.
-- 
Florian
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