x86: Provide tick counter and frequency reference for Intel core architecture

[karo-tx-uboot.git] / arch / x86 / cpu / interrupts.c

diff --git a/arch/x86/cpu/interrupts.c b/arch/x86/cpu/interrupts.c
index e7887152f7b27f73559263092b5cc09b7fefbdf4..dd30a05a9ddf54a97d69a62e29aa26c7e3bd0106 100644 (file)
--- a/arch/x86/cpu/interrupts.c
+++ b/arch/x86/cpu/interrupts.c
@@ -34,6 +34,8 @@
 #include <asm/io.h>
 #include <asm/processor-flags.h>
 #include <linux/compiler.h>
+#include <asm/msr.h>
+#include <asm/u-boot-x86.h>
 
 #define DECLARE_INTERRUPT(x) \
        ".globl irq_"#x"\n" \
@@ -615,3 +617,32 @@ asm(".globl irq_common_entry\n" \
        DECLARE_INTERRUPT(253) \
        DECLARE_INTERRUPT(254) \
        DECLARE_INTERRUPT(255));
+
+#if defined(CONFIG_INTEL_CORE_ARCH)
+/*
+ * Get the number of CPU time counter ticks since it was read first time after
+ * restart. This yields a free running counter guaranteed to take almost 6
+ * years to wrap around even at 100GHz clock rate.
+ */
+u64 get_ticks(void)
+{
+       static u64 tick_base;
+       u64 now_tick = rdtsc();
+
+       if (!tick_base)
+               tick_base = now_tick;
+
+       return now_tick - tick_base;
+}
+
+#define PLATFORM_INFO_MSR 0xce
+
+unsigned long get_tbclk(void)
+{
+       u32 ratio;
+       u64 platform_info = native_read_msr(PLATFORM_INFO_MSR);
+
+       ratio = (platform_info >> 8) & 0xff;
+       return 100 * 1000 * 1000 * ratio; /* 100MHz times Max Non Turbo ratio */
+}
+#endif