target/linux/generic/backport-5.10/792-v5.15-0001-net-dsa-b53-Fix-calculating-number-of-switch-ports.patch

   1 From cdb067d31c0fe4cce98b9d15f1f2ef525acaa094 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   3 Date: Thu, 2 Sep 2021 10:30:50 +0200
   4 Subject: [PATCH] net: dsa: b53: Fix calculating number of switch ports
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 It isn't true that CPU port is always the last one. Switches BCM5301x
  10 have 9 ports (port 6 being inactive) and they use port 5 as CPU by
  11 default (depending on design some other may be CPU ports too).
  12
  13 A more reliable way of determining number of ports is to check for the
  14 last set bit in the "enabled_ports" bitfield.
  15
  16 This fixes b53 internal state, it will allow providing accurate info to
  17 the DSA and is required to fix BCM5301x support.
  18
  19 Fixes: 967dd82ffc52 ("net: dsa: b53: Add support for Broadcom RoboSwitch")
  20 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  21 Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
  22 Signed-off-by: David S. Miller <davem@davemloft.net>
  23 ---
  24  drivers/net/dsa/b53/b53_common.c | 3 +--
  25  1 file changed, 1 insertion(+), 2 deletions(-)
  26
  27 --- a/drivers/net/dsa/b53/b53_common.c
  28 +++ b/drivers/net/dsa/b53/b53_common.c
  29 @@ -2584,9 +2584,8 @@ static int b53_switch_init(struct b53_de
  30                         dev->cpu_port = 5;
  31         }
  32
  33 -       /* cpu port is always last */
  34 -       dev->num_ports = dev->cpu_port + 1;
  35         dev->enabled_ports |= BIT(dev->cpu_port);
  36 +       dev->num_ports = fls(dev->enabled_ports);
  37
  38         /* Include non standard CPU port built-in PHYs to be probed */
  39         if (is539x(dev) || is531x5(dev)) {