On Mon, Aug 21, 2017 at 09:53:56AM -0400, Sinan Kaya wrote:
> On 8/18/2017 5:32 PM, Bjorn Helgaas wrote:
> > + if ((*l & 0xffff) != 0x0001)
> > + return true; /* not a CRS completion */
> >
>
> This version certainly looks cleaner. However, it breaks pci_flr_wait().
>
> If some root port doesn't support CRS and returns 0xFFFFFFFF, pci_bus_wait_crs()
> function returns true. pci_flr_wait() prematurely bails out from here.
>
>
> pci_flr_wait()
> {
>
> + ret = pci_bus_wait_crs(dev->bus, dev->devfn, &id, 60000);
> + if (ret)
> + return;
>
> }
>
> We can change the return code to false above but then we break pci_bus_read_dev_vendor_id()
> function.
>
> That's why, I was interested in creating a pci_bus_crs_visibility_supported() helper
> function that would check for the magic 0x0001 value and return true. Otherwise, false.
>
> pci_bus_read_dev_vendor_id() would do this
>
> pci_bus_read_dev_vendor_id()
> {
> ...
> if (pci_bus_crs_visibility_supported())
> return pci_bus_wait_crs(dev->bus, dev->devfn, &id, 60000);
>
> return true
> }
>
> Similar pattern for pci_flr_wait().
I think that makes sense. We'd want to check for CRS SV being
enabled, e.g., maybe read PCI_EXP_RTCTL_CRSSVE back in
pci_enable_crs() and cache it somewhere. Maybe a crs_sv_enabled bit
in the root port's pci_dev, and check it with something like what
pcie_root_rcb_set() does?
--
To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
