gmac get mac form eeprom

hc

2024-05-10 37f49e37ab4cb5d0bc4c60eb5c6d4dd57db767bb

 kernel/arch/x86/kernel/i8253.c
..
..
@@ -8,6 +8,7 @@
8
8
 #include <linux/timex.h>
9
9
 #include <linux/i8253.h>
10
10
 
11
+#include <asm/apic.h>
11
12
 #include <asm/hpet.h>
12
13
 #include <asm/time.h>
13
14
 #include <asm/smp.h>
..
..
@@ -18,10 +19,32 @@
18
19
  */
19
20
 struct clock_event_device *global_clock_event;
20
21
 
21
-void __init setup_pit_timer(void)
22
+/*
23
+ * Modern chipsets can disable the PIT clock which makes it unusable. It
24
+ * would be possible to enable the clock but the registers are chipset
25
+ * specific and not discoverable. Avoid the whack a mole game.
26
+ *
27
+ * These platforms have discoverable TSC/CPU frequencies but this also
28
+ * requires to know the local APIC timer frequency as it normally is
29
+ * calibrated against the PIT interrupt.
30
+ */
31
+static bool __init use_pit(void)
22
32
 {
33
+	if (!IS_ENABLED(CONFIG_X86_TSC) || !boot_cpu_has(X86_FEATURE_TSC))
34
+		return true;
35
+
36
+	/* This also returns true when APIC is disabled */
37
+	return apic_needs_pit();
38
+}
39
+
40
+bool __init pit_timer_init(void)
41
+{
42
+	if (!use_pit())
43
+		return false;
44
+
23
45
 	clockevent_i8253_init(true);
24
46
 	global_clock_event = &i8253_clockevent;
47
+	return true;
25
48
 }
26
49
 
27
50
 #ifndef CONFIG_X86_64