linux-kernel - [PATCH 2/2] PNP: work around Dell 1536/1546 BIOS MMCONFIG bug that breaks USB

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Date:	Thu, 05 Jan 2012 14:27:24 -0700
From:	Bjorn Helgaas <bhelgaas@...gle.com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>
Cc:	thuban@...gularity.fr, dann frazier <dann.frazier@...onical.com>,
	Lisa Salimbas <lisa.salimbas@...onical.com>,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
	stable@...nel.org#2.6.34+, Len Brown <lenb@...nel.org>
Subject: [PATCH 2/2] PNP: work around Dell 1536/1546 BIOS MMCONFIG bug that
	breaks USB

Some Dell BIOSes have MCFG tables that don't report the entire
MMCONFIG area claimed by the chipset.  If we move PCI devices into
that claimed-but-unreported area, they don't work.

This quirk reads the AMD MMCONFIG MSRs and adds PNP0C01 resources as
needed to cover the entire area.

Example problem scenario:

  BIOS-e820: 00000000cfec5400 - 00000000d4000000 (reserved)
  Fam 10h mmconf [d0000000, dfffffff]
  PCI: MMCONFIG for domain 0000 [bus 00-3f] at [mem 0xd0000000-0xd3ffffff] (base 0xd0000000)
  pnp 00:0c: [mem 0xd0000000-0xd3ffffff]
  pci 0000:00:12.0: reg 10: [mem 0xffb00000-0xffb00fff]
  pci 0000:00:12.0: no compatible bridge window for [mem 0xffb00000-0xffb00fff]
  pci 0000:00:12.0: BAR 0: assigned [mem 0xd4000000-0xd40000ff]

Reported-by: Lisa Salimbas <lisa.salimbas@...onical.com>
Reported-by: <thuban@...gularity.fr>
Tested-by: dann frazier <dann.frazier@...onical.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=31602
References: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/647043
References: https://bugzilla.redhat.com/show_bug.cgi?id=770308
Cc: stable@...nel.org	# 2.6.34+
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
---
 drivers/pnp/quirks.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/drivers/pnp/quirks.c b/drivers/pnp/quirks.c
index dfbd5a6..258fef2 100644
--- a/drivers/pnp/quirks.c
+++ b/drivers/pnp/quirks.c
@@ -295,6 +295,45 @@ static void quirk_system_pci_resources(struct pnp_dev *dev)
 	}
 }
 
+#ifdef CONFIG_AMD_NB
+
+#include <asm/amd_nb.h>
+
+static void quirk_amd_mmconfig_area(struct pnp_dev *dev)
+{
+	resource_size_t start, end;
+	struct pnp_resource *pnp_res;
+	struct resource *res;
+	struct resource mmconfig_res, *mmconfig;
+
+	mmconfig = amd_get_mmconfig_range(&mmconfig_res);
+	if (!mmconfig)
+		return;
+
+	list_for_each_entry(pnp_res, &dev->resources, list) {
+		res = &pnp_res->res;
+		if (res->end < mmconfig->start || res->start > mmconfig->end ||
+		    (res->start == mmconfig->start && res->end == mmconfig->end))
+			continue;
+
+		dev_info(&dev->dev, FW_BUG
+			 "%pR covers only part of AMD MMCONFIG area %pR; adding more reservations\n",
+			 res, mmconfig);
+		if (mmconfig->start < res->start) {
+			start = mmconfig->start;
+			end = res->start - 1;
+			pnp_add_mem_resource(dev, start, end, 0);
+		}
+		if (mmconfig->end > res->end) {
+			start = res->end + 1;
+			end = mmconfig->end;
+			pnp_add_mem_resource(dev, start, end, 0);
+		}
+		break;
+	}
+}
+#endif
+
 /*
  *  PnP Quirks
  *  Cards or devices that need some tweaking due to incomplete resource info
@@ -322,6 +361,9 @@ static struct pnp_fixup pnp_fixups[] = {
 	/* PnP resources that might overlap PCI BARs */
 	{"PNP0c01", quirk_system_pci_resources},
 	{"PNP0c02", quirk_system_pci_resources},
+#ifdef CONFIG_AMD_NB
+	{"PNP0c01", quirk_amd_mmconfig_area},
+#endif
 	{""}
 };
 

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