| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | From 93a32fc4f43ae40a2140acd9258faada11a98ec0 Mon Sep 17 00:00:00 2001 |
| 2 | From: Vladimir Oltean <vladimir.oltean@nxp.com> |
| 3 | Date: Mon, 18 Nov 2019 20:16:57 +0200 |
| 4 | Subject: [PATCH] net: dsa: felix: Fix CPU port assignment when not last port |
| 5 | |
| 6 | On the NXP LS1028A, there are 2 Ethernet links between the Felix switch |
| 7 | and the ENETC: |
| 8 | - eno2 <-> swp4, at 2.5G |
| 9 | - eno3 <-> swp5, at 1G |
| 10 | |
| 11 | Only one of the above Ethernet port pairs can act as a DSA link for |
| 12 | tagging. |
| 13 | |
| 14 | When adding initial support for the driver, it was tested only on the 1G |
| 15 | eno3 <-> swp5 interface, due to the necessity of using PHYLIB initially |
| 16 | (which treats fixed-link interfaces as emulated C22 PHYs, so it doesn't |
| 17 | support fixed-link speeds higher than 1G). |
| 18 | |
| 19 | After making PHYLINK work, it appears that swp4 still can't act as CPU |
| 20 | port. So it looks like ocelot_set_cpu_port was being called for swp4, |
| 21 | but then it was called again for swp5, overwriting the CPU port assigned |
| 22 | in the DT. |
| 23 | |
| 24 | It appears that when you call dsa_upstream_port for a port that is not |
| 25 | defined in the device tree (such as swp5 when using swp4 as CPU port), |
| 26 | its dp->cpu_dp pointer is not initialized by dsa_tree_setup_default_cpu, |
| 27 | and this trips up the following condition in dsa_upstream_port: |
| 28 | |
| 29 | if (!cpu_dp) |
| 30 | return port; |
| 31 | |
| 32 | So the moral of the story is: don't call dsa_upstream_port for a port |
| 33 | that is not defined in the device tree, and therefore its dsa_port |
| 34 | structure is not completely initialized (ds->num_ports is still 6). |
| 35 | |
| 36 | Fixes: 56051948773e ("net: dsa: ocelot: add driver for Felix switch family") |
| 37 | Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> |
| 38 | Signed-off-by: David S. Miller <davem@davemloft.net> |
| 39 | --- |
| 40 | drivers/net/dsa/ocelot/felix.c | 2 +- |
| 41 | 1 file changed, 1 insertion(+), 1 deletion(-) |
| 42 | |
| 43 | --- a/drivers/net/dsa/ocelot/felix.c |
| 44 | +++ b/drivers/net/dsa/ocelot/felix.c |
| 45 | @@ -286,7 +286,7 @@ static int felix_setup(struct dsa_switch |
| 46 | for (port = 0; port < ds->num_ports; port++) { |
| 47 | ocelot_init_port(ocelot, port); |
| 48 | |
| 49 | - if (port == dsa_upstream_port(ds, port)) |
| 50 | + if (dsa_is_cpu_port(ds, port)) |
| 51 | ocelot_set_cpu_port(ocelot, port, |
| 52 | OCELOT_TAG_PREFIX_NONE, |
| 53 | OCELOT_TAG_PREFIX_LONG); |