On Thu, Jan 21, 2021 at 05:55:47PM -0600, Bjorn Helgaas wrote: > On Tue, Jan 12, 2021 at 03:36:43PM +0000, Antti Järvinen wrote: > > TI C667X does not support bus/hot reset. > > See https://e2e.ti.com/support/processors/f/791/t/954382 > > You can cite the URL as the source, but the URL will eventually become > stale, so let's include the relevant details here directly.
Thanks for trying the experiment below. I'll look for a repost that includes details from the URL directly in the commit log. > From the forum, it looks like the device doesn't respond after a > reset (config accesses return ~0). It seems somewhat surprising that > something as basic as a reset would be completely broken. I wonder if > we're not doing the reset correctly. > > It looks like we would probably be trying a Secondary Bus Reset using > the bridge leading to the C667X. Can you confirm? Wonder if you > could try doing what pci_reset_secondary_bus() does by hand: > > # BRIDGE=... # PCI address, e.g., 00:1c.0 > # C667X=... > # setpci -s$C667X VENDOR_ID.w > # setpci -s$BRIDGE BRIDGE_CONTROL.w # prints "val" > # setpci -s$BRIDGE BRIDGE_CONTROL.w= # val | 0x40 (set SBR) > # sleep 1 > # setpci -s$BRIDGE BRIDGE_CONTROL.w= # val (clear SBR) > # sleep 1 > # setpci -s$C667X VENDOR_ID.w=0 > # setpci -s$C667X VENDOR_ID.w > > If we use this quirk and avoid the reset, I assume that means > assigning the device to VMs with VFIO will leak state between VMs? > > > Signed-off-by: Antti Järvinen <antti.jarvi...@gmail.com> > > --- > > drivers/pci/quirks.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > > index 653660e3ba9e..c8fcf24c5bd0 100644 > > --- a/drivers/pci/quirks.c > > +++ b/drivers/pci/quirks.c > > @@ -3578,6 +3578,12 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, > > 0x0034, quirk_no_bus_reset); > > */ > > DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CAVIUM, 0xa100, quirk_no_bus_reset); > > > > +/* > > + * Some TI keystone C667X devices do no support bus/hot reset. > > + * https://e2e.ti.com/support/processors/f/791/t/954382 > > + */ > > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_TI, 0xb005, quirk_no_bus_reset); > > + > > static void quirk_no_pm_reset(struct pci_dev *dev) > > { > > /* > > -- > > 2.17.1 > >
