x86: enable hpet=force for AMD SB400

Add quirk to allow forced usage of HPET on ATI SB400.
I stumbled over machines where HPET is enabled but not reported
by BIOS. This patch configures the HPET base address and makes
it known to the OS.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/quirks.c

@@ -65,6 +65,7 @@ static enum {
 	ICH_FORCE_HPET_RESUME,
 	VT8237_FORCE_HPET_RESUME,
 	NVIDIA_FORCE_HPET_RESUME,
+	ATI_FORCE_HPET_RESUME,
 } force_hpet_resume_type;
 
 static void __iomem *rcba_base;
@@ -330,6 +331,31 @@ 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);
 
+static void ati_force_hpet_resume(void)
+{
+	pci_write_config_dword(cached_dev, 0x14, 0xfed00000);
+	printk(KERN_DEBUG "Force enabled HPET at resume\n");
+}
+
+static void ati_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, 0x14, 0xfed00000);
+	pci_read_config_dword(dev, 0x14, &val);
+	force_hpet_address = val;
+	force_hpet_resume_type = ATI_FORCE_HPET_RESUME;
+	dev_printk(KERN_DEBUG, &dev->dev, "Force enabled HPET at 0x%lx\n",
+		   force_hpet_address);
+	cached_dev = dev;
+	return;
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_IXP400_SMBUS,
+			 ati_force_enable_hpet);
+
 /*
  * Undocumented chipset feature taken from LinuxBIOS.
  */
@@ -397,6 +423,9 @@ void force_hpet_resume(void)
 	case NVIDIA_FORCE_HPET_RESUME:
 		nvidia_force_hpet_resume();
 		return;
+	case ATI_FORCE_HPET_RESUME:
+		ati_force_hpet_resume();
+		return;
 	default:
 		break;
 	}