Force detect and/or enable HPET on ICH chipsets. This patch just handles the
detection part and following patches use this information. Adds a function
to repeat the force enabling during resume time.
Using HPET this way, instead of PIT increases the time CPUs can
reside in C-state when system is totally idle. On my test system with
Core 2 Duo, average C-state residency goes up from ~20mS to ~80mS.
Signed-off-by: Venkatesh Pallipadi <[email protected]>
---
arch/i386/kernel/quirks.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++
include/asm-i386/hpet.h | 2
2 files changed, 103 insertions(+)
Index: linux-2.6.22-rc5/arch/i386/kernel/quirks.c
===================================================================
--- linux-2.6.22-rc5.orig/arch/i386/kernel/quirks.c 2007-06-17 08:51:58.000000000 +0200
+++ linux-2.6.22-rc5/arch/i386/kernel/quirks.c 2007-06-17 08:52:10.000000000 +0200
@@ -4,6 +4,8 @@
#include <linux/pci.h>
#include <linux/irq.h>
+#include <asm/hpet.h>
+
#if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
static void __devinit quirk_intel_irqbalance(struct pci_dev *dev)
@@ -48,3 +50,102 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_IN
DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_E7525_MCH, quirk_intel_irqbalance);
DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_E7520_MCH, quirk_intel_irqbalance);
#endif
+
+#if defined(CONFIG_HPET_TIMER)
+unsigned long force_hpet_address;
+
+static void __iomem *rcba_base;
+
+void ich_force_hpet_resume(void)
+{
+ u32 val;
+
+ if (!force_hpet_address)
+ return;
+
+ if (rcba_base == NULL)
+ BUG();
+
+ /* read the Function Disable register, dword mode only */
+ val = readl(rcba_base + 0x3404);
+ if (!(val & 0x80)) {
+ /* HPET disabled in HPTC. Trying to enable */
+ writel(val | 0x80, rcba_base + 0x3404);
+ }
+
+ val = readl(rcba_base + 0x3404);
+ if (!(val & 0x80))
+ BUG();
+ else
+ printk(KERN_DEBUG "Force enabled HPET at resume\n");
+
+ return;
+}
+
+static void ich_force_enable_hpet(struct pci_dev *dev)
+{
+ u32 val, rcba;
+ int err = 0;
+
+ if (hpet_address || force_hpet_address)
+ return;
+
+ pci_read_config_dword(dev, 0xF0, &rcba);
+ rcba &= 0xFFFFC000;
+ if (rcba == 0) {
+ printk(KERN_DEBUG "RCBA disabled. Cannot force enable HPET\n");
+ return;
+ }
+
+ /* use bits 31:14, 16 kB aligned */
+ rcba_base = ioremap_nocache(rcba, 0x4000);
+ if (rcba_base == NULL) {
+ printk(KERN_DEBUG "ioremap failed. Cannot force enable HPET\n");
+ return;
+ }
+
+ /* read the Function Disable register, dword mode only */
+ val = readl(rcba_base + 0x3404);
+
+ if (val & 0x80) {
+ /* HPET is enabled in HPTC. Just not reported by BIOS */
+ val = val & 0x3;
+ force_hpet_address = 0xFED00000 | (val << 12);
+ printk(KERN_DEBUG "Force enabled HPET at base address 0x%lx\n",
+ force_hpet_address);
+ iounmap(rcba_base);
+ return;
+ }
+
+ /* HPET disabled in HPTC. Trying to enable */
+ writel(val | 0x80, rcba_base + 0x3404);
+
+ val = readl(rcba_base + 0x3404);
+ if (!(val & 0x80)) {
+ err = 1;
+ } else {
+ val = val & 0x3;
+ force_hpet_address = 0xFED00000 | (val << 12);
+ }
+
+ if (err) {
+ force_hpet_address = 0;
+ iounmap(rcba_base);
+ printk(KERN_DEBUG "Failed to force enable HPET\n");
+ } else {
+ printk(KERN_DEBUG "Force enabled HPET at base address 0x%lx\n",
+ force_hpet_address);
+ }
+}
+
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB2_0,
+ ich_force_enable_hpet);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH6_1,
+ ich_force_enable_hpet);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH7_1,
+ ich_force_enable_hpet);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH7_31,
+ ich_force_enable_hpet);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH8_1,
+ ich_force_enable_hpet);
+#endif
Index: linux-2.6.22-rc5/include/asm-i386/hpet.h
===================================================================
--- linux-2.6.22-rc5.orig/include/asm-i386/hpet.h 2007-06-17 08:52:09.000000000 +0200
+++ linux-2.6.22-rc5/include/asm-i386/hpet.h 2007-06-17 08:52:10.000000000 +0200
@@ -72,6 +72,8 @@ extern int hpet_enable(void);
#include <asm/vsyscall.h>
#endif
+void ich_force_hpet_resume(void);
+
#ifdef CONFIG_HPET_EMULATE_RTC
#include <linux/interrupt.h>
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