| Message ID | 20200203083521.16549-4-oohall@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [1/6] powerpc/eeh: Add sysfs files in late probe | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (7e7c42aa339cb92ad758bd0b5e7a299fecf9f9ce) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 27 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Mon, Feb 03, 2020 at 07:35:18PM +1100, Oliver O'Halloran wrote: > The pci hotplug helper (pci_hp_add_devices()) calls > eeh_add_device_tree_early() to scan the device-tree for new PCI devices and > do the early EEH probe before the device is scanned. This early probe is a > no-op in a lot of cases because: > > a) The early init is only required to satisfy a PAPR requirement that EEH > be configured before we start doing config accesses. On PowerNV it is > a no-op. > > b) It's a no-op for devices that have already had their eeh_dev > initialised. > > There are four callers of pci_hp_add_devices(): > > 1. arch/powerpc/kernel/eeh_driver.c > Here the hotplug helper is called when re-scanning pci_devs that > were removed during an EEH recovery pass. The EEH stat for each > removed device (the eeh_dev) is retained across a recovery pass > so the early init is a no-op in this case. > > 2. drivers/pci/hotplug/pnv_php.c > This is also a no-op since the PowerNV hotplug driver is, suprisingly, > PowerNV specific. > > 3. drivers/pci/hotplug/rpaphp_core.c > 4. drivers/pci/hotplug/rpaphp_pci.c > In these two cases new devices have been hotplugged and FW has > provided new DT nodes for each. These are the only two cases where > the EEH we might have new PCI device nodes in the DT so these are > the only two cases where the early EEH probe needs to be done. > > We can move the calls to eeh_add_device_tree_early() to the locations where > it's needed and remove it from the generic path. This is preparation for > making the early EEH probe pseries specific. > > Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Makes sense to me. Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com> > --- > arch/powerpc/kernel/pci-hotplug.c | 2 -- > drivers/pci/hotplug/rpaphp_core.c | 2 ++ > drivers/pci/hotplug/rpaphp_pci.c | 4 +++- > 3 files changed, 5 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/kernel/pci-hotplug.c b/arch/powerpc/kernel/pci-hotplug.c > index d6a67f8..bf83f76 100644 > --- a/arch/powerpc/kernel/pci-hotplug.c > +++ b/arch/powerpc/kernel/pci-hotplug.c > @@ -112,8 +112,6 @@ void pci_hp_add_devices(struct pci_bus *bus) > struct pci_controller *phb; > struct device_node *dn = pci_bus_to_OF_node(bus); > > - eeh_add_device_tree_early(PCI_DN(dn)); > - > phb = pci_bus_to_host(bus); > > mode = PCI_PROBE_NORMAL; > diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c > index e408e40..9c1e43e 100644 > --- a/drivers/pci/hotplug/rpaphp_core.c > +++ b/drivers/pci/hotplug/rpaphp_core.c > @@ -494,6 +494,8 @@ static int enable_slot(struct hotplug_slot *hotplug_slot) > return retval; > > if (state == PRESENT) { > + eeh_add_device_tree_early(PCI_DN(slot->dn)); > + > pci_lock_rescan_remove(); > pci_hp_add_devices(slot->bus); > pci_unlock_rescan_remove(); > diff --git a/drivers/pci/hotplug/rpaphp_pci.c b/drivers/pci/hotplug/rpaphp_pci.c > index beca61b..61ebbd8 100644 > --- a/drivers/pci/hotplug/rpaphp_pci.c > +++ b/drivers/pci/hotplug/rpaphp_pci.c > @@ -95,8 +95,10 @@ int rpaphp_enable_slot(struct slot *slot) > return -EINVAL; > } > > - if (list_empty(&bus->devices)) > + if (list_empty(&bus->devices)) { > + eeh_add_device_tree_early(PCI_DN(slot->dn)); > pci_hp_add_devices(bus); > + } > > if (!list_empty(&bus->devices)) { > slot->state = CONFIGURED; > -- > 2.9.5 >
diff --git a/arch/powerpc/kernel/pci-hotplug.c b/arch/powerpc/kernel/pci-hotplug.c index d6a67f8..bf83f76 100644 --- a/arch/powerpc/kernel/pci-hotplug.c +++ b/arch/powerpc/kernel/pci-hotplug.c @@ -112,8 +112,6 @@ void pci_hp_add_devices(struct pci_bus *bus) struct pci_controller *phb; struct device_node *dn = pci_bus_to_OF_node(bus); - eeh_add_device_tree_early(PCI_DN(dn)); - phb = pci_bus_to_host(bus); mode = PCI_PROBE_NORMAL; diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c index e408e40..9c1e43e 100644 --- a/drivers/pci/hotplug/rpaphp_core.c +++ b/drivers/pci/hotplug/rpaphp_core.c @@ -494,6 +494,8 @@ static int enable_slot(struct hotplug_slot *hotplug_slot) return retval; if (state == PRESENT) { + eeh_add_device_tree_early(PCI_DN(slot->dn)); + pci_lock_rescan_remove(); pci_hp_add_devices(slot->bus); pci_unlock_rescan_remove(); diff --git a/drivers/pci/hotplug/rpaphp_pci.c b/drivers/pci/hotplug/rpaphp_pci.c index beca61b..61ebbd8 100644 --- a/drivers/pci/hotplug/rpaphp_pci.c +++ b/drivers/pci/hotplug/rpaphp_pci.c @@ -95,8 +95,10 @@ int rpaphp_enable_slot(struct slot *slot) return -EINVAL; } - if (list_empty(&bus->devices)) + if (list_empty(&bus->devices)) { + eeh_add_device_tree_early(PCI_DN(slot->dn)); pci_hp_add_devices(bus); + } if (!list_empty(&bus->devices)) { slot->state = CONFIGURED;
The pci hotplug helper (pci_hp_add_devices()) calls eeh_add_device_tree_early() to scan the device-tree for new PCI devices and do the early EEH probe before the device is scanned. This early probe is a no-op in a lot of cases because: a) The early init is only required to satisfy a PAPR requirement that EEH be configured before we start doing config accesses. On PowerNV it is a no-op. b) It's a no-op for devices that have already had their eeh_dev initialised. There are four callers of pci_hp_add_devices(): 1. arch/powerpc/kernel/eeh_driver.c Here the hotplug helper is called when re-scanning pci_devs that were removed during an EEH recovery pass. The EEH stat for each removed device (the eeh_dev) is retained across a recovery pass so the early init is a no-op in this case. 2. drivers/pci/hotplug/pnv_php.c This is also a no-op since the PowerNV hotplug driver is, suprisingly, PowerNV specific. 3. drivers/pci/hotplug/rpaphp_core.c 4. drivers/pci/hotplug/rpaphp_pci.c In these two cases new devices have been hotplugged and FW has provided new DT nodes for each. These are the only two cases where the EEH we might have new PCI device nodes in the DT so these are the only two cases where the early EEH probe needs to be done. We can move the calls to eeh_add_device_tree_early() to the locations where it's needed and remove it from the generic path. This is preparation for making the early EEH probe pseries specific. Signed-off-by: Oliver O'Halloran <oohall@gmail.com> --- arch/powerpc/kernel/pci-hotplug.c | 2 -- drivers/pci/hotplug/rpaphp_core.c | 2 ++ drivers/pci/hotplug/rpaphp_pci.c | 4 +++- 3 files changed, 5 insertions(+), 3 deletions(-)