Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx> writes: > When pnv_pci_reset_secondary_bus() is called to issue reset on > the indicated secondary bus, the bus can't be root bus. So we > needn't consider root bus in the function. It took me a while to convince myself that this is correct. For the record, this is why it's correct: pnv_pci_reset_secondary_bus fills the reset_secondary_bus callback in the pci_controller_ops structure, and isn't used elsewhere. In arch/powerpc/kernel/pci.c, that callback is called (if it exists) in pcibios_reset_secondary_bus(). It's not called anywhere else. The PPC pcibios_reset_secondary_bus overrides the weak version in drivers/pci/pci.c. It's called from the same file by pci_reset_bridge_secondary_device() (and nowhere else). pci_reset_bridge_secondary_device() is nicely documented: /** * pci_reset_bridge_secondary_bus - Reset the secondary bus on a PCI bridge. * @dev: Bridge device * * Use the bridge control register to assert reset on the secondary bus. * Devices on the secondary bus are left in power-on state. */ Therefore, by the definiton of pci_reset_bridge_secondary_bus, pnv_pci_reset_secondary_bus() can only be called with a bridge device. As such, a bridge reset only is appropriate. If this breaks anything, the caller is broken. It might be worth including a condensed version of this in the commit message. Reviewed-by: Daniel Axtens <dja@xxxxxxxxxx> Regards, Daniel Axtens > > Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx> > --- > arch/powerpc/platforms/powernv/eeh-powernv.c | 12 ++---------- > 1 file changed, 2 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c > index a7d84a4..c69b6a1 100644 > --- a/arch/powerpc/platforms/powernv/eeh-powernv.c > +++ b/arch/powerpc/platforms/powernv/eeh-powernv.c > @@ -880,16 +880,8 @@ static int pnv_eeh_bridge_reset(struct pci_dev *dev, int option) > > void pnv_pci_reset_secondary_bus(struct pci_dev *dev) > { > - struct pci_controller *hose; > - > - if (pci_is_root_bus(dev->bus)) { > - hose = pci_bus_to_host(dev->bus); > - pnv_eeh_root_reset(hose, EEH_RESET_HOT); > - pnv_eeh_root_reset(hose, EEH_RESET_DEACTIVATE); > - } else { > - pnv_eeh_bridge_reset(dev, EEH_RESET_HOT); > - pnv_eeh_bridge_reset(dev, EEH_RESET_DEACTIVATE); > - } > + pnv_eeh_bridge_reset(dev, EEH_RESET_HOT); > + pnv_eeh_bridge_reset(dev, EEH_RESET_DEACTIVATE); > } > > /** > -- > 2.1.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html
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