[PATCH V2] Quirk for IVB graphics FLR errata

[Hao, Xudong]

For IvyBridge Mobile platform, a system hang may occur if a FLR(Function Level
 Reset) is asserted to internal graphics.

This quirk patch is workaround for the IVB FLR errata issue.
We are disabling the FLR reset handshake between the PCH and CPU display, 
then manually powering down the panel power sequencing and resetting the PCH display.

Signed-off-by: Xudong Hao <xudong.hao@xxxxxxxxx>
Signed-off-by: Kay, Allen M <allen.m.kay@xxxxxxxxx>
---
 drivers/pci/quirks.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 49 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 6476547..5223b80 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -29,6 +29,11 @@
 #include <asm/dma.h>	/* isa_dma_bridge_buggy */
 #include "pci.h"
 
+#include "../gpu/drm/i915/i915_reg.h"
+#include <asm/tsc.h>
+/* 10 seconds */
+#define IGD_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
+
 /*
  * This quirk function disables memory decoding and releases memory resources
  * of the device specified by kernel's boot parameter 'pci=resource_alignment='.
@@ -3069,11 +3074,55 @@ static int reset_intel_82599_sfp_virtfn(struct pci_dev *dev, int probe)
 	return 0;
 }
 
+#define MSG_CTL	0x45010
+
+static int reset_ivb_igd(struct pci_dev *dev, int probe) {
+	u8 *mmio_base;
+	u32 val;
+
+	if (probe)
+		return 0;
+
+	mmio_base = ioremap_nocache(pci_resource_start(dev, 0),
+				 pci_resource_len(dev, 0));
+	if (!mmio_base)
+		return -ENOMEM;
+
+	/* Work Around */
+	*((u32 *)(mmio_base + MSG_CTL)) = 0x00000002;
+	*((u32 *)(mmio_base + SOUTH_CHICKEN2)) = 0x00000005;
+	val = *((u32 *)(mmio_base + PCH_PP_CONTROL)) & 0xfffffffe;
+	*((u32 *)(mmio_base + PCH_PP_CONTROL)) = val;
+	do {
+		cycles_t start_time = get_cycles();
+		while (1) {
+			val = *((u32 *)(mmio_base + PCH_PP_STATUS));
+			if (((val & 0x80000000) == 0)
+				&& ((val & 0x30000000) == 0))
+				break;
+			if (IGD_OPERATION_TIMEOUT < (get_cycles() - start_time))
+				break;
+			cpu_relax();
+		}
+	} while (0);
+	*((u32 *)(mmio_base + 0xd0100)) = 0x00000002;
+
+	iounmap(pci_resource_start(dev, 0));
+	return 0;
+}
+
 #define PCI_DEVICE_ID_INTEL_82599_SFP_VF   0x10ed
+#define PCI_DEVICE_ID_INTEL_IVB_M_VGA      0x0156
+#define PCI_DEVICE_ID_INTEL_IVB_M2_VGA     0x0166
 
 static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
 	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82599_SFP_VF,
 		 reset_intel_82599_sfp_virtfn },
+	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IVB_M_VGA,
+		reset_ivb_igd },
+	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IVB_M2_VGA,
+		reset_ivb_igd },
 	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID,
 		reset_intel_generic_dev },
 	{ 0 }
--
1.6.0.rc1


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