On Mon, Oct 01, 2018 at 03:36:41PM +0100, Lorenzo Pieralisi wrote:
> On Fri, Sep 28, 2018 at 06:04:32PM +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 logic by using the slot's
> > devfn for match if finding device connected to the subordinate bus.
> >
> > Signed-off-by: Honghui Zhang <honghui.zhang@xxxxxxxxxxxx>
> > ---
> > drivers/pci/controller/pcie-mediatek.c | 17 ++++++++++++++++-
> > 1 file changed, 16 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> > index 9999dae..264e03f 100644
> > --- a/drivers/pci/controller/pcie-mediatek.c
> > +++ b/drivers/pci/controller/pcie-mediatek.c
> > @@ -337,10 +337,25 @@ 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 = NULL;
> > +
> > + /*
> > + * Walk the bus hierarchy to get the devfn value
> > + * of the port in the root bus.
> > + */
> > + while (bus && bus->number) {
> > + dev = bus->self;
> > + bus = dev->bus;
>
> If you add:
>
> devfn = dev->devfn;
>
> here
>
> > + }
> > +
> > + list_for_each_entry(port, &pcie->ports, list) {
> > + /* Using slot's devfn to compare for subordinary bus. */
> > + if (dev)
> > + devfn = dev->devfn;
>
> You can remove this ugly hunk altogether (and dev initialization
> to NULL).
Hi Honghui,
if you can make this change I would merge this series, it has been
been in the mailing lists for a while, I can make that change too
just let me know please.
Thanks,
Lorenzo
