ARM/PCI: Move to generic PCI domains

Most if not all ARM PCI host controller device drivers either ignore the
domain field in the pci_sys_data structure or just increment it every time
a host controller is probed, using it as a domain counter.

Therefore, instead of relying on pci_sys_data to stash the domain number in
a standard location, ARM pcibios code can be moved to the newly introduced
generic PCI domains code, implemented in commits:

  41e5c0f81d ("of/pci: Add pci_get_new_domain_nr() and of_get_pci_domain_nr()")
  670ba0c888 ("PCI: Add generic domain handling")

ARM code is made to select PCI_DOMAINS_GENERIC by default, which builds
core PCI code that assigns the domain number through the generic function:

  void pci_bus_assign_domain_nr(...)

that relies on a DT property to define the domain number or falls back to a
counter according to a predefined logic; its usage replaces the current
domain assignment code in PCI host controllers present in the kernel.

Tested-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Yijing Wang <wangyijing@huawei.com>
Reviewed-By: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> # mvebu
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Phil Edworthy <phil.edworthy@renesas.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
CC: Mohit Kumar <mohit.kumar@st.com>

arch/arm/Kconfig

@@ -1279,6 +1279,9 @@ config PCI_DOMAINS
 	bool
 	depends on PCI
 
+config PCI_DOMAINS_GENERIC
+	def_bool PCI_DOMAINS
+
 config PCI_NANOENGINE
 	bool "BSE nanoEngine PCI support"
 	depends on SA1100_NANOENGINE

arch/arm/include/asm/mach/pci.h

@@ -19,9 +19,6 @@ struct pci_bus;
 struct device;
 
 struct hw_pci {
-#ifdef CONFIG_PCI_DOMAINS
-	int		domain;
-#endif
 #ifdef CONFIG_PCI_MSI
 	struct msi_controller *msi_ctrl;
 #endif
@@ -45,9 +42,6 @@ struct hw_pci {
  * Per-controller structure
  */
 struct pci_sys_data {
-#ifdef CONFIG_PCI_DOMAINS
-	int		domain;
-#endif
 #ifdef CONFIG_PCI_MSI
 	struct msi_controller *msi_ctrl;
 #endif

arch/arm/include/asm/pci.h

@@ -18,13 +18,6 @@ static inline int pcibios_assign_all_busses(void)
 }
 
 #ifdef CONFIG_PCI_DOMAINS
-static inline int pci_domain_nr(struct pci_bus *bus)
-{
-	struct pci_sys_data *root = bus->sysdata;
-
-	return root->domain;
-}
-
 static inline int pci_proc_domain(struct pci_bus *bus)
 {
 	return pci_domain_nr(bus);

arch/arm/kernel/bios32.c

@@ -463,9 +463,6 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
 		if (!sys)
 			panic("PCI: unable to allocate sys data!");
 
-#ifdef CONFIG_PCI_DOMAINS
-		sys->domain  = hw->domain;
-#endif
 #ifdef CONFIG_PCI_MSI
 		sys->msi_ctrl = hw->msi_ctrl;
 #endif

drivers/pci/host/pci-mvebu.c

@@ -101,9 +101,7 @@ struct mvebu_pcie {
 	struct mvebu_pcie_port *ports;
 	struct msi_controller *msi;
 	struct resource io;
-	char io_name[30];
 	struct resource realio;
-	char mem_name[30];
 	struct resource mem;
 	struct resource busn;
 	int nports;
@@ -723,18 +721,9 @@ static int mvebu_pcie_setup(int nr, struct pci_sys_data *sys)
 {
 	struct mvebu_pcie *pcie = sys_to_pcie(sys);
 	int i;
-	int domain = 0;
 
-#ifdef CONFIG_PCI_DOMAINS
-	domain = sys->domain;
-#endif
-
-	snprintf(pcie->mem_name, sizeof(pcie->mem_name), "PCI MEM %04x",
-		 domain);
-	pcie->mem.name = pcie->mem_name;
-
-	snprintf(pcie->io_name, sizeof(pcie->io_name), "PCI I/O %04x", domain);
-	pcie->realio.name = pcie->io_name;
+	pcie->mem.name = "PCI MEM";
+	pcie->realio.name = "PCI I/O";
 
 	if (request_resource(&iomem_resource, &pcie->mem))
 		return 0;

drivers/pci/host/pcie-designware.c

@@ -508,9 +508,6 @@ int __init dw_pcie_host_init(struct pcie_port *pp)
 	dw_pci.private_data = (void **)&pp;
 
 	pci_common_init_dev(pp->dev, &dw_pci);
-#ifdef CONFIG_PCI_DOMAINS
-	dw_pci.domain++;
-#endif
 
 	return 0;
 }

drivers/pci/host/pcie-rcar.c

@@ -397,9 +397,6 @@ static void rcar_pcie_enable(struct rcar_pcie *pcie)
 #endif
 
 	pci_common_init_dev(&pdev->dev, &rcar_pci);
-#ifdef CONFIG_PCI_DOMAINS
-	rcar_pci.domain++;
-#endif
 }
 
 static int phy_wait_for_ack(struct rcar_pcie *pcie)