pci root complex: support for tile architecture

This change enables PCI root complex support for TILEPro.  Unlike
TILE-Gx, TILEPro has no support for memory-mapped I/O, so the PCI
support consists of hypervisor upcalls for PIO, DMA, etc.  However,
the performance is fine for the devices we have tested with so far
(1Gb Ethernet, SATA, etc.).

The <asm/io.h> header was tweaked to be a little bit more aggressive
about disabling attempts to map/unmap IO port space.  The hacky
<asm/pci-bridge.h> header was rolled into the <asm/pci.h> header
and the result was simplified.  Both of the latter two headers were
preliminary versions not meant for release before now - oh well.

There is one quirk for our TILEmpower platform, which accidentally
negotiates up to 5GT and needs to be kicked down to 2.5GT.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

arch/tile/Kconfig

@@ -329,6 +329,18 @@ endmenu  # Tilera-specific configuration
 
 menu "Bus options"
 
+config PCI
+	bool "PCI support"
+	default y
+	select PCI_DOMAINS
+	---help---
+	  Enable PCI root complex support, so PCIe endpoint devices can
+	  be attached to the Tile chip.  Many, but not all, PCI devices
+	  are supported under Tilera's root complex driver.
+
+config PCI_DOMAINS
+	bool
+
 config NO_IOMEM
 	def_bool !PCI
 

arch/tile/include/asm/io.h

@@ -55,9 +55,6 @@ extern void iounmap(volatile void __iomem *addr);
 #define ioremap_writethrough(physaddr, size)	ioremap(physaddr, size)
 #define ioremap_fullcache(physaddr, size)	ioremap(physaddr, size)
 
-void __iomem *ioport_map(unsigned long port, unsigned int len);
-extern inline void ioport_unmap(void __iomem *addr) {}
-
 #define mmiowb()
 
 /* Conversion between virtual and physical mappings.  */
@@ -189,12 +186,22 @@ static inline void memcpy_toio(volatile void __iomem *dst, const void *src,
  * we never run, uses them unconditionally.
  */
 
-static inline int ioport_panic(void)
+static inline long ioport_panic(void)
 {
 	panic("inb/outb and friends do not exist on tile");
 	return 0;
 }
 
+static inline void __iomem *ioport_map(unsigned long port, unsigned int len)
+{
+	return (void __iomem *) ioport_panic();
+}
+
+static inline void ioport_unmap(void __iomem *addr)
+{
+	ioport_panic();
+}
+
 static inline u8 inb(unsigned long addr)
 {
 	return ioport_panic();

arch/tile/include/asm/pci-bridge.h

-/*
- * Copyright 2010 Tilera Corporation. All Rights Reserved.
- *
- *   This program is free software; you can redistribute it and/or
- *   modify it under the terms of the GNU General Public License
- *   as published by the Free Software Foundation, version 2.
- *
- *   This program is distributed in the hope that it will be useful, but
- *   WITHOUT ANY WARRANTY; without even the implied warranty of
- *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- *   NON INFRINGEMENT.  See the GNU General Public License for
- *   more details.
- */
-
-#ifndef _ASM_TILE_PCI_BRIDGE_H
-#define _ASM_TILE_PCI_BRIDGE_H
-
-#include <linux/ioport.h>
-#include <linux/pci.h>
-
-struct device_node;
-struct pci_controller;
-
-/*
- * pci_io_base returns the memory address at which you can access
- * the I/O space for PCI bus number `bus' (or NULL on error).
- */
-extern void __iomem *pci_bus_io_base(unsigned int bus);
-extern unsigned long pci_bus_io_base_phys(unsigned int bus);
-extern unsigned long pci_bus_mem_base_phys(unsigned int bus);
-
-/* Allocate a new PCI host bridge structure */
-extern struct pci_controller *pcibios_alloc_controller(void);
-
-/* Helper function for setting up resources */
-extern void pci_init_resource(struct resource *res, unsigned long start,
-			      unsigned long end, int flags, char *name);
-
-/* Get the PCI host controller for a bus */
-extern struct pci_controller *pci_bus_to_hose(int bus);
-
-/*
- * Structure of a PCI controller (host bridge)
- */
-struct pci_controller {
-	int index;		/* PCI domain number */
-	struct pci_bus *root_bus;
-
-	int first_busno;
-	int last_busno;
-
-	int hv_cfg_fd[2];	/* config{0,1} fds for this PCIe controller */
-	int hv_mem_fd;		/* fd to Hypervisor for MMIO operations */
-
-	struct pci_ops *ops;
-
-	int irq_base;		/* Base IRQ from the Hypervisor	*/
-	int plx_gen1;		/* flag for PLX Gen 1 configuration */
-
-	/* Address ranges that are routed to this controller/bridge. */
-	struct resource mem_resources[3];
-};
-
-static inline struct pci_controller *pci_bus_to_host(struct pci_bus *bus)
-{
-	return bus->sysdata;
-}
-
-extern void setup_indirect_pci_nomap(struct pci_controller *hose,
-			       void __iomem *cfg_addr, void __iomem *cfg_data);
-extern void setup_indirect_pci(struct pci_controller *hose,
-			       u32 cfg_addr, u32 cfg_data);
-extern void setup_grackle(struct pci_controller *hose);
-
-extern unsigned char common_swizzle(struct pci_dev *, unsigned char *);
-
-/*
- *   The following code swizzles for exactly one bridge.  The routine
- *   common_swizzle below handles multiple bridges.  But there are a
- *   some boards that don't follow the PCI spec's suggestion so we
- *   break this piece out separately.
- */
-static inline unsigned char bridge_swizzle(unsigned char pin,
-		unsigned char idsel)
-{
-	return (((pin-1) + idsel) % 4) + 1;
-}
-
-/*
- * The following macro is used to lookup irqs in a standard table
- * format for those PPC systems that do not already have PCI
- * interrupts properly routed.
- */
-/* FIXME - double check this */
-#define PCI_IRQ_TABLE_LOOKUP ({ \
-	long _ctl_ = -1; \
-	if (idsel >= min_idsel && idsel <= max_idsel && pin <= irqs_per_slot) \
-		_ctl_ = pci_irq_table[idsel - min_idsel][pin-1]; \
-	_ctl_; \
-})
-
-/*
- * Scan the buses below a given PCI host bridge and assign suitable
- * resources to all devices found.
- */
-extern int pciauto_bus_scan(struct pci_controller *, int);
-
-#ifdef CONFIG_PCI
-extern unsigned long pci_address_to_pio(phys_addr_t address);
-#else
-static inline unsigned long pci_address_to_pio(phys_addr_t address)
-{
-	return (unsigned long)-1;
-}
-#endif
-
-#endif /* _ASM_TILE_PCI_BRIDGE_H */

arch/tile/include/asm/pci.h

@@ -15,7 +15,29 @@
 #ifndef _ASM_TILE_PCI_H
 #define _ASM_TILE_PCI_H
 
-#include <asm/pci-bridge.h>
+#include <linux/pci.h>
+
+/*
+ * Structure of a PCI controller (host bridge)
+ */
+struct pci_controller {
+	int index;		/* PCI domain number */
+	struct pci_bus *root_bus;
+
+	int first_busno;
+	int last_busno;
+
+	int hv_cfg_fd[2];	/* config{0,1} fds for this PCIe controller */
+	int hv_mem_fd;		/* fd to Hypervisor for MMIO operations */
+
+	struct pci_ops *ops;
+
+	int irq_base;		/* Base IRQ from the Hypervisor	*/
+	int plx_gen1;		/* flag for PLX Gen 1 configuration */
+
+	/* Address ranges that are routed to this controller/bridge. */
+	struct resource mem_resources[3];
+};
 
 /*
  * The hypervisor maps the entirety of CPA-space as bus addresses, so
@@ -24,56 +46,12 @@
  */
 #define PCI_DMA_BUS_IS_PHYS     1
 
-struct pci_controller *pci_bus_to_hose(int bus);
-unsigned char __init common_swizzle(struct pci_dev *dev, unsigned char *pinp);
 int __init tile_pci_init(void);
-void pci_iounmap(struct pci_dev *dev, void __iomem *addr);
-void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
-void __devinit pcibios_fixup_bus(struct pci_bus *bus);
 
-int __devinit _tile_cfg_read(struct pci_controller *hose,
-				    int bus,
-				    int slot,
-				    int function,
-				    int offset,
-				    int size,
-				    u32 *val);
-int __devinit _tile_cfg_write(struct pci_controller *hose,
-				     int bus,
-				     int slot,
-				     int function,
-				     int offset,
-				     int size,
-				     u32 val);
+void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
+static inline void pci_iounmap(struct pci_dev *dev, void __iomem *addr) {}
 
-/*
- * These are used to to config reads and writes in the early stages of
- * setup before the driver infrastructure has been set up enough to be
- * able to do config reads and writes.
- */
-#define early_cfg_read(where, size, value) \
-	_tile_cfg_read(controller, \
-		       current_bus, \
-		       pci_slot, \
-		       pci_fn, \
-		       where, \
-		       size, \
-		       value)
-
-#define early_cfg_write(where, size, value) \
-	_tile_cfg_write(controller, \
-		       current_bus, \
-		       pci_slot, \
-		       pci_fn, \
-		       where, \
-		       size, \
-		       value)
-
-
-
-#define PCICFG_BYTE	1
-#define PCICFG_WORD	2
-#define PCICFG_DWORD	4
+void __devinit pcibios_fixup_bus(struct pci_bus *bus);
 
 #define	TILE_NUM_PCIE	2
 
@@ -88,33 +66,33 @@ static inline int pci_proc_domain(struct pci_bus *bus)
 }
 
 /*
- * I/O space is currently not supported.
+ * pcibios_assign_all_busses() tells whether or not the bus numbers
+ * should be reassigned, in case the BIOS didn't do it correctly, or
+ * in case we don't have a BIOS and we want to let Linux do it.
  */
+static inline int pcibios_assign_all_busses(void)
+{
+	return 1;
+}
 
-#define TILE_PCIE_LOWER_IO		0x0
-#define TILE_PCIE_UPPER_IO		0x10000
-#define TILE_PCIE_PCIE_IO_SIZE		0x0000FFFF
-
-#define _PAGE_NO_CACHE		0
-#define _PAGE_GUARDED		0
-
-
-#define pcibios_assign_all_busses()    pci_assign_all_buses
-extern int pci_assign_all_buses;
-
+/*
+ * No special bus mastering setup handling.
+ */
 static inline void pcibios_set_master(struct pci_dev *dev)
 {
-	/* No special bus mastering setup handling */
 }
 
 #define PCIBIOS_MIN_MEM		0
-#define PCIBIOS_MIN_IO		TILE_PCIE_LOWER_IO
+#define PCIBIOS_MIN_IO		0
 
 /*
  * This flag tells if the platform is TILEmpower that needs
  * special configuration for the PLX switch chip.
  */
-extern int blade_pci;
+extern int tile_plx_gen1;
+
+/* Use any cpu for PCI. */
+#define cpumask_of_pcibus(bus) cpu_online_mask
 
 /* implement the pci_ DMA API in terms of the generic device dma_ one */
 #include <asm-generic/pci-dma-compat.h>
@@ -122,7 +100,4 @@ extern int blade_pci;
 /* generic pci stuff */
 #include <asm-generic/pci.h>
 
-/* Use any cpu for PCI. */
-#define cpumask_of_pcibus(bus) cpu_online_mask
-
 #endif /* _ASM_TILE_PCI_H */

arch/tile/kernel/Makefile

@@ -15,3 +15,4 @@ obj-$(CONFIG_SMP)		+= smpboot.o smp.o tlb.o
 obj-$(CONFIG_MODULES)		+= module.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
+obj-$(CONFIG_PCI)		+= pci.o

drivers/pci/Makefile

@@ -49,6 +49,7 @@ obj-$(CONFIG_MIPS) += setup-bus.o setup-irq.o
 obj-$(CONFIG_X86_VISWS) += setup-irq.o
 obj-$(CONFIG_MN10300) += setup-bus.o
 obj-$(CONFIG_MICROBLAZE) += setup-bus.o
+obj-$(CONFIG_TILE) += setup-bus.o setup-irq.o
 
 #
 # ACPI Related PCI FW Functions

drivers/pci/quirks.c

@@ -2136,6 +2136,24 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82865_HB,
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82875_HB,
 			quirk_unhide_mch_dev6);
 
+#ifdef CONFIG_TILE
+/*
+ * The Tilera TILEmpower platform needs to set the link speed
+ * to 2.5GT(Giga-Transfers)/s (Gen 1). The default link speed
+ * setting is 5GT/s (Gen 2). 0x98 is the Link Control2 PCIe
+ * capability register of the PEX8624 PCIe switch. The switch
+ * supports link speed auto negotiation, but falsely sets
+ * the link speed to 5GT/s.
+ */
+static void __devinit quirk_tile_plx_gen1(struct pci_dev *dev)
+{
+	if (tile_plx_gen1) {
+		pci_write_config_dword(dev, 0x98, 0x1);
+		mdelay(50);
+	}
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_PLX, 0x8624, quirk_tile_plx_gen1);
+#endif /* CONFIG_TILE */
 
 #ifdef CONFIG_PCI_MSI
 /* Some chipsets do not support MSI. We cannot easily rely on setting