x86/apb_timer: Drop unused TSC calibration (003d8053) · Commits · 戴 / test

arch/x86/include/asm/apb_timer.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -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

+0 −53

Original line number	Diff line number	Diff line
		@@ -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;
		}