On Mon, Sep 10, 2018 at 05:50:20PM +0800, honghui.zhang@xxxxxxxxxxxx wrote:
> From: Honghui Zhang <honghui.zhang@xxxxxxxxxxxx>
>
> The Mediatek's host controller has two slots, each with 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
>
> During PCI enumeration, 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.
>
> Signed-off-by: Honghui Zhang <honghui.zhang@xxxxxxxxxxxx>
> Acked-by: Ryder Lee <ryder.lee@xxxxxxxxxxxx>
> ---
> drivers/pci/controller/pcie-mediatek.c | 19 +++++++++++++++++--
> 1 file changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> index 861dda6..20b9088 100644
> --- a/drivers/pci/controller/pcie-mediatek.c
> +++ b/drivers/pci/controller/pcie-mediatek.c
> @@ -337,11 +337,26 @@ static struct mtk_pcie_port *mtk_pcie_find_port(struct pci_bus *bus,
> {
> struct mtk_pcie *pcie = bus->sysdata;
> struct mtk_pcie_port *port;
> + struct pci_dev *dev;
> + struct pci_bus *pbus;
>
> - list_for_each_entry(port, &pcie->ports, list)
> - if (port->slot == PCI_SLOT(devfn))
> + list_for_each_entry(port, &pcie->ports, list) {
> + if (!bus->number && port->slot == PCI_SLOT(devfn))
> return port;
>
> + if (bus->number) {
> + pbus = bus;
> +
> + while (pbus->number) {
> + dev = pbus->self;
> + pbus = dev->bus;
> + }
> +
> + if (port->slot == PCI_SLOT(dev->devfn))
> + return port;
> + }
> + }
/*
* Walk the bus hierarchy to get the devfn value
* of the port in the root bus.
*/
while (bus && bus->number) {
devfn = bus->self->devfn;
bus = bus->parent;
}
list_for_each_entry(port, &pcie->ports, list) {
if (port->slot == PCI_SLOT(devfn))
return port;
return NULL;
Would it work ? Maybe it is a little easier to parse.
I think this can even be made easier by using struct device_node* as
comparison (and store it in port->slot instead of the port number), I
think that the pci_dev representing the port should have the right
of_node associated with it by core code, so it is just a matter of
finding the first pci_dev parent with an of_node set and compare it
against port->slot (that should be converted to a struct device_node*).
This ought to be tested and written but I think that's doable.
Lorenzo
