Re: [RFC PATCH 8/9] PCI/PME: Add RCEC PME handling

Jonathan Cameron
2020-08-04T09:48:41Z

On Tue, 4 Aug 2020 16:35:59 +0800
Jay Fang <f.fangjian@huawei.com> wrote:

> 在 2020/7/25 1:22, Sean V Kelley 写道:
> > The Root Complex Event Collectors(RCEC) appear as peers of Root Ports
> > and also have the PME capability. So add RCEC support to the current PME
> > service driver and attach the PME service driver to the RCEC device.
> >
> > Co-developed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
> > Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
> > Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
> > ---
> > drivers/pci/pcie/pme.c | 15 +++++++++++----
> > 1 file changed, 11 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/pci/pcie/pme.c b/drivers/pci/pcie/pme.c
> > index 6a32970bb731..87799166c96a 100644
> > --- a/drivers/pci/pcie/pme.c
> > +++ b/drivers/pci/pcie/pme.c
> > @@ -310,7 +310,10 @@ static int pcie_pme_can_wakeup(struct pci_dev *dev, void *ign)
> > static void pcie_pme_mark_devices(struct pci_dev *port)
> > {
> > pcie_pme_can_wakeup(port, NULL);
> > - if (port->subordinate)
> > +
> > + if (pci_pcie_type(port) == PCI_EXP_TYPE_RC_EC)
> > + pcie_walk_rcec(port, pcie_pme_can_wakeup, NULL);
> > + else if (port->subordinate)
> > pci_walk_bus(port->subordinate, pcie_pme_can_wakeup, NULL);
> > }
> >
> > @@ -320,10 +323,15 @@ static void pcie_pme_mark_devices(struct pci_dev *port)
> > */
> > static int pcie_pme_probe(struct pcie_device *srv)
> > {
> > - struct pci_dev *port;
> > + struct pci_dev *port = srv->port;
> > struct pcie_pme_service_data *data;
> > int ret;
> >
> > + /* Limit to Root Ports or Root Complex Event Collectors */
> > + if ((pci_pcie_type(port) != PCI_EXP_TYPE_RC_EC) &&
> > + (pci_pcie_type(port) != PCI_EXP_TYPE_ROOT_PORT))
> > + return -ENODEV;
> > +
> > data = kzalloc(sizeof(*data), GFP_KERNEL);
> > if (!data)
> > return -ENOMEM;
> > @@ -333,7 +341,6 @@ static int pcie_pme_probe(struct pcie_device *srv)
> > data->srv = srv;
> > set_service_data(srv, data);
> >
> > - port = srv->port;
> > pcie_pme_interrupt_enable(port, false);
> > pcie_clear_root_pme_status(port);
> >
> > @@ -445,7 +452,7 @@ static void pcie_pme_remove(struct pcie_device *srv)
> >
> > static struct pcie_port_service_driver pcie_pme_driver = {
> > .name = "pcie_pme",
> > - .port_type = PCI_EXP_TYPE_ROOT_PORT,
> > + .port_type = PCIE_ANY_PORT,
> Maybe we can use port_type for driver matching. There is no need
> to check the type of port in pcie_pme_probe function.
>

I walked into the same hole for the AER case.
port_type is effectively an enum so there is no way of specifying several
types unless you want to register different instances of pcie_port_service_driver
and that isn't currently possible.

The PCIE_ANY_PORT is a special case value.

https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/pci_regs.h#L477
https://elixir.bootlin.com/linux/latest/source/drivers/pci/pci-driver.c#L1651

So odd corner case, but I think this is the right solution. Anything better
would require a lot more code to change.

Jonathan

>
> Jay
>
> > .service = PCIE_PORT_SERVICE_PME,
> >
> > .probe = pcie_pme_probe,
> >