On Wed, Jun 27, 2018 at 12:21 PM, <honghui.zhang@xxxxxxxxxxxx> wrote:
> From: Honghui Zhang <honghui.zhang@xxxxxxxxxxxx>
>
> Mediatek's host controller have two slots, each have it's own control
> registers. The host driver need to identify which slot was connected
> in order to access the device's configuration space. There's problem
> for current host driver to find out which slot was connected to for
> a given EP device.
>
> Assuming each slot have connect with one EP device as below:
>
> host bridge
> bus 0 --> __________|_______
> | |
> | |
> slot 0 slot 1
> bus 1 -->| bus 2 --> |
> | |
> EP 0 EP 1
>
> While PCI emulation, system software will scan all the PCI device
> starting from devfn 0. So it will get the proper port for slot0 and
> slot1 device when using PCI_SLOT(devfn) for match. But it will get
> the wrong slot for EP1: The devfn will be start from 0 when scanning
> EP1 behind slot1, it will get port0 since the PCI_SLOT(EP1) is match
> for port0's slot value. So the host driver should not using EP's devfn
> but the slot's devfn(the slot which EP was connected to) for match.
>
> This patch fix the mtk_pcie_find_port's logical by using the slot's
> devfn for match.
> + list_for_each_entry(port, &pcie->ports, list) {
> + if (bus->number == 0 && port->slot == PCI_SLOT(devfn)) {
> return port;
> + } else if (bus->number != 0) {
You can do it like (no need 'else')
if (...)
return ...;
if (bus->number) {
...
}
> + pbus = bus;
> + do {
> + dev = pbus->self;
> + if (port->slot == PCI_SLOT(dev->devfn))
> + return port;
> +
> + pbus = dev->bus;
> + } while (dev->bus->number != 0);
This can be rewritten like
pbus = bus;
while (pbus->number) {
dev = ...;
...
pbus = dev->bus;
}
and no need for if (bus->number) anymore.
> + }
> + }
>
> return NULL;
> }
> --
> 2.6.4
>
--
With Best Regards,
Andy Shevchenko
