On Thu, Jun 04, 2015 at 04:42:11PM +1000, 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 <gws...@linux.vnet.ibm.com>
Acked-by: Bjorn Helgaas <bhelg...@google.com>
But I do have a few comments (my ack is valid whether you do anything with
them or not):
> +static void slot_power_off_handler(struct powernv_php_slot *slot)
> +{
> + int ret;
> +
> + /* Release the firmware data for the child device nodes */
> + remove_child_pdn(slot->dn);
> +
> + /*
> + * Release the child device nodes. If the sub-tree was
> + * built with the help of overlay, we just need revert
> + * the changes introduced by the overlay
> + */
> + if (slot->overlay_id >= 0) {
> + ret = of_overlay_destroy(slot->overlay_id);
> + if (ret)
> + pr_warn("%s: Error %d destroying overlay %d\n",
> + __func__, ret, slot->overlay_id);
For this and similar messages: isn't there a device you can use with
dev_warn() here? I think a device name would be much better than a
function name.
> +scan:
> + switch (presence) {
> + case POWERNV_PHP_SLOT_PRESENT:
> + if (rescan) {
> + pci_lock_rescan_remove();
> + pcibios_add_pci_devices(slot->bus);
You didn't add this, but "pcibios_add_pci_devices" doesn't seem like the
right name. "pcibios" generally refers to an arch-specific hook that's
called by the generic PCI core. In this case, pcibios_add_pci_devices()
contains powerpc-specific code, and it's only called from powerpc code, so
I think using "pcibios_" in the name is a bit misleading.
> + /* Remove all devices behind the slot */
> + pci_lock_rescan_remove();
> + pcibios_remove_pci_devices(slot->bus);
Same comment for pcibios_remove_pci_devices(). It would be better if the
name didn't suggest that this was part of the pcibios_ interface between
the PCI core and the arch code, because it's not.
> + /* Slot indentifier */
s/indentifier/identifier/
> + if (!php_slot_get_id(dn, &id))
> + return NULL;
> +
> + /* PCI bus */
> + bus = pcibios_find_pci_bus(dn);
And pcibios_find_pci_bus() (it's also powerpc-specific).
Bjorn
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