x86: Force enable HPET for CK804 (nForce 4) chipsets

This patch adds a quirk from LinuxBIOS to force enable HPET on
the nVidia CK804 (nForce 4) chipset.

This quirk can very likely support more than just nForce 4
(LinuxBIOS use the same code for nForce 5), and possibly nForce 3,
but I don't have those chipsets, so cannot add and test them.

Tested on an Abit KN9 (CK804).

Signed-off-by: Carlos Corbacho <cathectic@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
 Documentation/kernel-parameters.txt |    3 +-
 arch/x86/kernel/quirks.c            |   37 +++++++++++++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index b236166..a13d69b 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -422,7 +422,8 @@ and is between 256 and 4096 characters. It is defined in the file
        hpet=           [X86-32,HPET] option to control HPET usage
                        Format: { enable (default) | disable | force }
                        disable: disable HPET and use PIT instead
-                       force: allow force enabled of undocumented chips (ICH4, VIA)
+                       force: allow force enabled of undocumented chips (ICH4,
+                       VIA, nVidia)
 
        com20020=       [HW,NET] ARCnet - COM20020 chipset
                        Format:

diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c
index a4ce191..5317c40 100644 (file)
--- a/arch/x86/kernel/quirks.c
+++ b/arch/x86/kernel/quirks.c
@@ -60,7 +60,8 @@ static enum {
        NONE_FORCE_HPET_RESUME,
        OLD_ICH_FORCE_HPET_RESUME,
        ICH_FORCE_HPET_RESUME,
-       VT8237_FORCE_HPET_RESUME
+       VT8237_FORCE_HPET_RESUME,
+       NVIDIA_FORCE_HPET_RESUME,
 } force_hpet_resume_type;
 
 static void __iomem *rcba_base;
@@ -321,6 +322,37 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8235,
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237,
                         vt8237_force_enable_hpet);
 
+/*
+ * Undocumented chipset feature taken from LinuxBIOS.
+ */
+static void nvidia_force_hpet_resume(void)
+{
+       pci_write_config_dword(cached_dev, 0x44, 0xfed00001);
+       printk(KERN_DEBUG "Force enabled HPET at resume\n");
+}
+
+static void nvidia_force_enable_hpet(struct pci_dev *dev)
+{
+       u32 uninitialized_var(val);
+
+       if (!hpet_force_user || hpet_address || force_hpet_address)
+               return;
+
+       pci_write_config_dword(dev, 0x44, 0xfed00001);
+       pci_read_config_dword(dev, 0x44, &val);
+       force_hpet_address = val & 0xfffffffe;
+       force_hpet_resume_type = NVIDIA_FORCE_HPET_RESUME;
+       printk(KERN_DEBUG "Force enabled HPET at base address 0x%lx\n",
+               force_hpet_address);
+       cached_dev = dev;
+       return;
+}
+
+/* ISA Bridges */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_NVIDIA, 0x0050,
+                       nvidia_force_enable_hpet);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_NVIDIA, 0x0051,
+                       nvidia_force_enable_hpet);
 
 void force_hpet_resume(void)
 {
@@ -334,6 +366,9 @@ void force_hpet_resume(void)
            case VT8237_FORCE_HPET_RESUME:
                return vt8237_force_hpet_resume();
 
+           case NVIDIA_FORCE_HPET_RESUME:
+               return nvidia_force_hpet_resume();
+
            default:
                break;
        }