PCI/hotplug: PowerPC PowerNV PCI hotplug driver

This adds standalone driver to support PCI hotplug for PowerPC PowerNV
platform that runs on top of skiboot firmware. The firmware identifies
hotpluggable slots and marked their device tree node with proper
"ibm,slot-pluggable" and "ibm,reset-by-firmware". The driver scans
device tree nodes to create/register PCI hotplug slot accordingly.

The PCI slots are organized in fashion of tree, which means one
PCI slot might have parent PCI slot and parent PCI slot possibly
contains multiple child PCI slots. At the plugging time, the parent
PCI slot is populated before its children. The child PCI slots are
removed before their parent PCI slot can be removed from the system.

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 <gwshan@linux.vnet.ibm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

MAINTAINERS

@@ -6857,6 +6857,7 @@ F:	drivers/crypto/nx/
 F:	drivers/crypto/vmx/
 F:	drivers/net/ethernet/ibm/ibmveth.*
 F:	drivers/net/ethernet/ibm/ibmvnic.*
+F:	drivers/pci/hotplug/pnv_php.c
 F:	drivers/pci/hotplug/rpa*
 F:	drivers/scsi/ibmvscsi/
 N:	opal

drivers/pci/hotplug/Kconfig

@@ -113,6 +113,19 @@ config HOTPLUG_PCI_SHPC
 
 	  When in doubt, say N.
 
+config HOTPLUG_PCI_POWERNV
+	tristate "PowerPC PowerNV PCI Hotplug driver"
+	depends on PPC_POWERNV && EEH
+	select OF_DYNAMIC
+	help
+	  Say Y here if you run PowerPC PowerNV platform that supports
+	  PCI Hotplug
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called pnv-php.
+
+	  When in doubt, say N.
+
 config HOTPLUG_PCI_RPA
 	tristate "RPA PCI Hotplug driver"
 	depends on PPC_PSERIES && EEH

drivers/pci/hotplug/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_HOTPLUG_PCI_PCIE)		+= pciehp.o
 obj-$(CONFIG_HOTPLUG_PCI_CPCI_ZT5550)	+= cpcihp_zt5550.o
 obj-$(CONFIG_HOTPLUG_PCI_CPCI_GENERIC)	+= cpcihp_generic.o
 obj-$(CONFIG_HOTPLUG_PCI_SHPC)		+= shpchp.o
+obj-$(CONFIG_HOTPLUG_PCI_POWERNV)	+= pnv-php.o
 obj-$(CONFIG_HOTPLUG_PCI_RPA)		+= rpaphp.o
 obj-$(CONFIG_HOTPLUG_PCI_RPA_DLPAR)	+= rpadlpar_io.o
 obj-$(CONFIG_HOTPLUG_PCI_SGI)		+= sgi_hotplug.o
@@ -50,6 +51,8 @@ ibmphp-objs		:=	ibmphp_core.o	\
 acpiphp-objs		:=	acpiphp_core.o	\
 				acpiphp_glue.o
 
+pnv-php-objs		:=	pnv_php.o
+
 rpaphp-objs		:=	rpaphp_core.o	\
 				rpaphp_pci.o	\
 				rpaphp_slot.o