x86/apb_timer: Drop unused TSC calibration

Drop the APB-timer TSC calibration, which hasn't been used since the
removal of Moorestown support by commit

  1a8359e411eb ("x86/mid: Remove Intel Moorestown").

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200513100944.9171-1-johan@kernel.org

diff --git a/arch/x86/include/asm/apb_timer.h b/arch/x86/include/asm/apb_timer.h
index 99bb207..0a9bf8b 100644 (file)
--- a/arch/x86/include/asm/apb_timer.h
+++ b/arch/x86/include/asm/apb_timer.h
@@ -28,7 +28,6 @@
 #define APBT_DEV_USED  1
 
 extern void apbt_time_init(void);
-extern unsigned long apbt_quick_calibrate(void);
 extern int arch_setup_apbt_irqs(int irq, int trigger, int mask, int cpu);
 extern void apbt_setup_secondary_clock(void);
 
@@ -38,7 +37,6 @@ extern int sfi_mtimer_num;
 
 #else /* CONFIG_APB_TIMER */
 
-static inline unsigned long apbt_quick_calibrate(void) {return 0; }
 static inline void apbt_time_init(void) { }
 
 #endif

diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c
index fe698f9..263eead 100644 (file)
--- a/arch/x86/kernel/apb_timer.c
+++ b/arch/x86/kernel/apb_timer.c
@@ -345,56 +345,3 @@ out_noapbt:
        apb_timer_block_enabled = 0;
        panic("failed to enable APB timer\n");
 }
-
-/* called before apb_timer_enable, use early map */
-unsigned long apbt_quick_calibrate(void)
-{
-       int i, scale;
-       u64 old, new;
-       u64 t1, t2;
-       unsigned long khz = 0;
-       u32 loop, shift;
-
-       apbt_set_mapping();
-       dw_apb_clocksource_start(clocksource_apbt);
-
-       /* check if the timer can count down, otherwise return */
-       old = dw_apb_clocksource_read(clocksource_apbt);
-       i = 10000;
-       while (--i) {
-               if (old != dw_apb_clocksource_read(clocksource_apbt))
-                       break;
-       }
-       if (!i)
-               goto failed;
-
-       /* count 16 ms */
-       loop = (apbt_freq / 1000) << 4;
-
-       /* restart the timer to ensure it won't get to 0 in the calibration */
-       dw_apb_clocksource_start(clocksource_apbt);
-
-       old = dw_apb_clocksource_read(clocksource_apbt);
-       old += loop;
-
-       t1 = rdtsc();
-
-       do {
-               new = dw_apb_clocksource_read(clocksource_apbt);
-       } while (new < old);
-
-       t2 = rdtsc();
-
-       shift = 5;
-       if (unlikely(loop >> shift == 0)) {
-               printk(KERN_INFO
-                      "APBT TSC calibration failed, not enough resolution\n");
-               return 0;
-       }
-       scale = (int)div_u64((t2 - t1), loop >> shift);
-       khz = (scale * (apbt_freq / 1000)) >> shift;
-       printk(KERN_INFO "TSC freq calculated by APB timer is %lu khz\n", khz);
-       return khz;
-failed:
-       return 0;
-}