On Tue, Feb 17, 2015 at 06:13:23PM +1100, Gavin Shan wrote:
> The patch intends to add standalone driver to support PCI hotplug
> for PowerPC PowerNV platform, which runs on top of skiboot firmware.
> The firmware identified hotpluggable slots and marked their device
> tree node with proper "ibm,slot-pluggable" and "ibm,reset-by-firmware".
> The driver simply scans device-tree to create/register PCI hotplug slot
> accordingly.
>
> If the skiboot firmware doesn't support slot status retrieval, the PCI
> slot device node shouldn't have property "ibm,reset-by-firmware". In
> that case, none of valid PCI slots will be detected from device tree.
> The skiboot firmware doesn't export the capability to access attention
> LEDs yet and it's something for TBD.
>
> Signed-off-by: Gavin Shan <[email protected]>
> ...
> +static int disable_slot(struct hotplug_slot *php_slot)
> +{
> + struct powernv_php_slot *slot = php_slot->private;
> +
> + if (slot->state != POWERNV_PHP_SLOT_STATE_POPULATED)
> + return 0;
> +
> + pci_lock_rescan_remove();
> + pcibios_remove_pci_devices(slot->bus);
> + pci_unlock_rescan_remove();
> + vm_unmap_aliases();
What is vm_unmap_aliases() for? I see this is probably copied from
rpaphp_core.c, where it was added by b4a26be9f6f8 ("powerpc/pseries: Flush
lazy kernel mappings after unplug operations").
But I don't know whether:
- this is something specific to powerpc,
- the lack of vm_unmap_aliases() in other hotplug paths is a bug,
- the fact that we only do this on powerpc is covering up a
powerpc bug somewhere
> +
> + /* Detach the child hotpluggable slots */
> + powernv_php_unregister(slot->dn);
> +
> + /* Update slot state */
> + slot->state = POWERNV_PHP_SLOT_STATE_REGISTER;
> + return 0;
> +}
>
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