[PATCH] Quirk for IVB graphics FLR errata

[PATCH] 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.

Signed-off-by: Xudong Hao <xudong.hao@intel.com>
Signed-off-by: Kay, Allen M <allen.m.kay@intel.com>
---
 drivers/pci/quirks.c |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 46 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 6476547..8bf5b88 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -29,6 +29,10 @@
 #include <asm/dma.h>	/* isa_dma_bridge_buggy */
 #include "pci.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 +3073,53 @@ static int reset_intel_82599_sfp_virtfn(struct pci_dev *dev, int probe)
 	return 0;
 }
 
+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 + 0x45010)) = 0x00000002;
+	*((u32 *)(mmio_base + 0xc2004)) = 0x00000005;
+	val = *((u32 *)(mmio_base + 0xc7204)) & 0xfffffffe;
+	*((u32 *)(mmio_base + 0xc7204)) = val;
+	do {
+		cycles_t start_time = get_cycles();
+		while (1) {
+			val = *((u32 *)(mmio_base + 0xc7200));
+			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

Re: [PATCH] Quirk for IVB graphics FLR errata

[Jesse Barnes]

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On Mon, 20 Feb 2012 02:27:25 +0000
"Hao, Xudong" <xudong.hao@intel.com> wrote:

> 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.
> 

Can you name the magic constants and offsets and document what the FLR
quirk is actually trying to do?  IIRC it had something to do with
waiting for the PCH acknowledge for the display portion of the reset...

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center

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