[RFC][PATCH 1/2] show Intel QuickPath Interconnect Routing and Protocol Layer Registers in PCI config space

[Stefan Assmann <sassmann@redhat.com>]

On some machines with Intel X58 or Intel 55x0 chipset the Intel QuickPath
Interconnect Routing and Protocol Layer Registers or not exposed to PCI config
space. Access to these is necessary to disable boot interrupts in the QPI
Protocol Interrupt Control Register.
DEVHIDE1 provides a method to (un)hide the PCI config space of devices inside
the IOH and is altered to guarantee that PCI config space is accessible.
See Intel document #320838-003, sections 17.6.5.10 and 17.11.2.21.

Signed-off-by: Stefan Assmann <sassmann@redhat.com>
---
 drivers/pci/quirks.c    |   24 ++++++++++++++++++++++++
 include/linux/pci_ids.h |    1 +
 2 files changed, 25 insertions(+)

--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1612,6 +1612,30 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_IN
 DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL,   PCI_DEVICE_ID_INTEL_ESB_10, 	quirk_disable_intel_boot_interrupt);
 
 /*
+ * Show Intel QuickPath Interconnect Routing and Protocol Layer Registers
+ * in PCI config space (ensures access to QPIPINTRC).
+ * See Intel document #320838-003, sections 17.6.5.10 and 17.11.2.21.
+ */
+#define INTEL_X58_55x0_DEVHIDE1_REG	0xf2
+#define INTEL_X58_55x0_HIDE_DEV17_FUN0	(1<<12)
+#define INTEL_X58_55x0_HIDE_DEV17_FUN1	(1<<13)
+
+static void quirk_show_intel_qpi_conf_register(struct pci_dev *dev)
+{
+	u16 pci_config_word;
+
+	pci_read_config_word(dev, INTEL_X58_55x0_DEVHIDE1_REG, &pci_config_word);
+	pci_config_word &= ~(INTEL_X58_55x0_HIDE_DEV17_FUN0 |
+			     INTEL_X58_55x0_HIDE_DEV17_FUN1);
+	pci_write_config_word(dev, INTEL_X58_55x0_DEVHIDE1_REG, pci_config_word);
+
+	/* need to rescan the bus for changes to take effect */
+	pci_rescan_bus(dev->bus);
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_IOAT_TBG9,	quirk_show_intel_qpi_conf_register);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_IOAT_TBG9,	quirk_show_intel_qpi_conf_register);
+
+/*
  * disable boot interrupts on HT-1000
  */
 #define BC_HT1000_FEATURE_REG		0x64
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -2508,6 +2508,7 @@
 #define PCI_DEVICE_ID_INTEL_IOAT_TBG5	0x342a
 #define PCI_DEVICE_ID_INTEL_IOAT_TBG6	0x342b
 #define PCI_DEVICE_ID_INTEL_IOAT_TBG7	0x342c
+#define PCI_DEVICE_ID_INTEL_IOAT_TBG9	0x342e
 #define PCI_DEVICE_ID_INTEL_IOAT_TBG0	0x3430
 #define PCI_DEVICE_ID_INTEL_IOAT_TBG1	0x3431
 #define PCI_DEVICE_ID_INTEL_IOAT_TBG2	0x3432