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>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 07ec8a8..e11b5fc 100644
--- a/arch/tile/Kconfig
+++ b/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