From: Sam Bobroff <sbobroff@linux.ibm.com>
To: "Oliver O'Halloran" <oohall@gmail.com>
Cc: tyreld@linux.ibm.com, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 3/6] powerpc/eeh: Do early EEH init only when required
Date: Thu, 6 Feb 2020 16:22:35 +1100 [thread overview]
Message-ID: <20200206052234.GF15629@osmium> (raw)
In-Reply-To: <20200203083521.16549-4-oohall@gmail.com>
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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
>
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next prev parent reply other threads:[~2020-02-06 5:24 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 8:35 EEH init cleanup Oliver O'Halloran
2020-02-03 8:35 ` [PATCH 1/6] powerpc/eeh: Add sysfs files in late probe Oliver O'Halloran
2020-02-06 4:13 ` Sam Bobroff
2020-02-07 3:22 ` Oliver O'Halloran
2020-02-03 8:35 ` [PATCH 2/6] powerpc/eeh: Remove eeh_add_device_tree_late() Oliver O'Halloran
2020-02-06 4:23 ` Sam Bobroff
2020-02-03 8:35 ` [PATCH 3/6] powerpc/eeh: Do early EEH init only when required Oliver O'Halloran
2020-02-06 5:22 ` Sam Bobroff [this message]
2020-02-03 8:35 ` [PATCH 4/6] powerpc/eeh: Remove PHB check in probe Oliver O'Halloran
2020-02-06 5:30 ` Sam Bobroff
2020-02-03 8:35 ` [PATCH 5/6] powerpc/eeh: Make early EEH init pseries specific Oliver O'Halloran
2020-02-07 2:24 ` Sam Bobroff
2020-02-07 3:35 ` Oliver O'Halloran
2020-02-07 3:56 ` Oliver O'Halloran
2020-02-03 8:35 ` [PATCH 6/6] powerpc/eeh: Rework eeh_ops->probe() Oliver O'Halloran
2020-02-07 2:37 ` Sam Bobroff
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