[PATCH] x86: add write_pci_config_byte() to direct PCI access routines

Mechanism of selecting physical mode in genapic when cpu hotplug is enabled on
x86_64, broke the quirk(quirk_intel_irqbalance()) introduced for working
around the transposing interrupt message errata in E7520/E7320/E7525 (revision
ID 0x9 and below.  errata #23 in
http://download.intel.com/design/chipsets/specupdt/30304203.pdf).

This errata requires the mode to be in logical flat, so that interrupts can be
directed to more than one cpu(and thus use hardware IRQ balancing enabled by
BIOS on these platforms).

Following four patches fixes this by moving the quirk to early quirk and
forcing the x86_64 genapic selection to logical flat on these platforms.

Thanks to Shaohua for pointing out the breakage.

This patch:

Add write_pci_config_byte() to direct PCI access  routines

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: "Li, Shaohua" <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

diff --git a/arch/i386/pci/early.c b/arch/i386/pci/early.c
index 713d6c866cae0b9f8ecc56c82fc04cebde642d80..42df4b6606dfdbc6f21d2cce0cbb6e8ae3e3ea42 100644 (file)
--- a/arch/i386/pci/early.c
+++ b/arch/i386/pci/early.c
@@ -45,6 +45,13 @@ void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
        outl(val, 0xcfc);
 }
 
+void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val)
+{
+       PDprintk("%x writing to %x: %x\n", slot, offset, val);
+       outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
+       outb(val, 0xcfc);
+}
+
 int early_pci_allowed(void)
 {
        return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==

diff --git a/include/asm-x86_64/pci-direct.h b/include/asm-x86_64/pci-direct.h
index eba9cb471df38b1bee0b4893482fccb576411795..6823fa4f1afa3c8a43a17697cba5ce4ecf63cb36 100644 (file)
--- a/include/asm-x86_64/pci-direct.h
+++ b/include/asm-x86_64/pci-direct.h
@@ -10,6 +10,7 @@ extern u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset);
 extern u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset);
 extern u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset);
 extern void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset, u32 val);
+extern void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val);
 
 extern int early_pci_allowed(void);