Re: [PATCH net 2/2] dpaa_eth: fix usage as DSA master, try 4
From: Joakim Tjernlund <hidden>
Date: 2020-06-16 14:51:37
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On Tue, 2020-06-16 at 17:41 +0300, Vladimir Oltean wrote:
From: Vladimir Oltean <vladimir.oltean@nxp.com> The dpaa-eth driver probes on compatible string for the MAC node, and the fman/mac.c driver allocates a dpaa-ethernet platform device that triggers the probing of the dpaa-eth net device driver. All of this is fine, but the problem is that the struct device of the dpaa_eth net_device is 2 parents away from the MAC which can be referenced via of_node. So of_find_net_device_by_node can't find it, and DSA switches won't be able to probe on top of FMan ports. It would be a bit silly to modify a core function (of_find_net_device_by_node) to look for dev->parent->parent->of_node just for one driver. We're just 1 step away from implementing full recursion. On T1040, the /sys/class/net/eth0 symlink currently points to: ../../devices/platform/ffe000000.soc/ffe400000.fman/ffe4e6000.ethernet/net/eth0
Just want to point out that on 4.19.x, the above patch still exists: cd /sys find -name eth0 ./devices/platform/ffe000000.soc/ffe400000.fman/ffe4e6000.ethernet/net/eth0 ./class/net/eth
quoted hunk ↗ jump to hunk
which pretty much illustrates the problem. The closest of_node we've got is the "fsl,fman-memac" at /soc@ffe000000/fman@400000/ethernet@e6000, which is what we'd like to be able to reference from DSA as host port. For of_find_net_device_by_node to find the eth0 port, we would need the parent of the eth0 net_device to not be the "dpaa-ethernet" platform device, but to point 1 level higher, aka the "fsl,fman-memac" node directly. The new sysfs path would look like this: ../../devices/platform/ffe000000.soc/ffe400000.fman/ffe4e6000.ethernet/dpaa-ethernet.0/net/eth0 Actually this has worked before, through the SET_NETDEV_DEV mechanism, which sets the parent of the net_device as the parent of the platform device. But the device which was set as sysfs parent was inadvertently changed through commit 060ad66f9795 ("dpaa_eth: change DMA device"), which did not take into consideration the effect it would have upon of_find_net_device_by_node. So restore the old sysfs parent to make that work correctly. Fixes: 060ad66f9795 ("dpaa_eth: change DMA device") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> --- drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c index c4416a5f8816..2972244e6eb0 100644 --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c@@ -2914,7 +2914,7 @@ static int dpaa_eth_probe(struct platform_device *pdev) } /* Do this here, so we can be verbose early */ - SET_NETDEV_DEV(net_dev, dev); + SET_NETDEV_DEV(net_dev, dev->parent); dev_set_drvdata(dev, net_dev); priv = netdev_priv(net_dev); --2.25.1