On Thu, Jan 19, 2017 at 05:30:13PM +0100, Greg KH wrote: > On Thu, Jan 19, 2017 at 03:53:15PM +0100, Andrew Lunn wrote: > > > > > struct dsa_platform_data { > > > > > /* > > > > > * Reference to a Linux network interface that connects > > > > > * to the root switch chip of the tree. > > > > > */ > > > > > struct device *netdev; > > > > > > This I think is the oddest thing, why do you need to have the "root > > > switch" here? You seem to have dropped the next value in this > > > structure: > > > struct net_device *of_netdev; > > > > We are implementing platform_data for devices which don't support > > device tree. When using OF, we don't have any of these issues. We can > > go straight to the device. > > > > It is a bit convoluted, but look at > > arch/arm/mach-orion5x/rd88f5181l-ge-setup.c. It defines the start of > > the dsa_platform_data in that file. It then gets passed through > > common.c: orion5x_eth_switch_init() to > > arch/arm/plat-orion/common.c:orion_ge00_switch_init() : > > > > void __init orion_ge00_switch_init(struct dsa_platform_data *d) > > { > > int i; > > > > d->netdev = &orion_ge00.dev; > > for (i = 0; i < d->nr_chips; i++) > > d->chip[i].host_dev = &orion_ge_mvmdio.dev; > > > > platform_device_register_data(NULL, "dsa", 0, d, sizeof(d)); > > } > > > > Where we have > > > > static struct platform_device orion_ge00 = { > > .name = MV643XX_ETH_NAME, > > .id = 0, > > .num_resources = 1, > > .resource = orion_ge00_resources, > > .dev = { > > .coherent_dma_mask = DMA_BIT_MASK(32), > > }, > > }; > > > > So this is the platform device for the Ethernet device. We cannot go > > to the net_device, because it does not exist until this Ethernet > > platform device is instantiated. > > Ok, fine, but why isn't the ethernet device a child of this platform > device? Why is it floating around somewhere else? You don't see that > happening for other devices.
The ethernet device is not a child of the DSA device. I'm going to send a mail I've had queued up for a few hours redoing Andrew's ASCII art, because I think that's what's causing the confusion here, provided I haven't discarded it. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.