x86: HPET force enable o ICH7 and later

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.

[ Build fixed from Andrew Morton ]

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 103 insertions, 0 deletions

diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c
index 6722469c2633..d3ac703867d6 100644
--- a/arch/x86/kernel/quirks.c
+++ b/arch/x86/kernel/quirks.c
@@ -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)
@@ -47,3 +49,103 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_E7320_MCH,	quir
 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;
+        u32 uninitialized_var(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
diff --git a/include/asm-x86/hpet.h b/include/asm-x86/hpet.h
index 64446a9577dc..7c933242365f 100644
--- a/include/asm-x86/hpet.h
+++ b/include/asm-x86/hpet.h
@@ -66,6 +66,7 @@ extern unsigned long hpet_address;
 extern int is_hpet_enabled(void);
 extern int hpet_enable(void);
 extern unsigned long hpet_readl(unsigned long a);
+extern void ich_force_hpet_resume(void);
 
 #ifdef CONFIG_HPET_EMULATE_RTC