x86/ACPI: Move ACPI_FADT_NO_CMOS_RTC check to ACPI boot code

This moves the ACPI specific check into the ACPI boot code,
it also takes advantage of the x86_platform.legacy.rtc which
is checked for already on the RTC initialization code. This
lets us remove the nasty #ifdefery and consolidate the checks
to use only one toggle to disable the RTC init code.

The works as RTC is initialized by device_initcall(add_rtc_cmos),
this will run late in boot on start_kernel() during rest_init(),
acpi_parse_fadt() gets called earlier during setup_arch().

Signed-off-by: Luis R. Rodriguez <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
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Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

2 files changed, 4 insertions, 8 deletions

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 8c2f1ef6ca23..8c9c2bdba092 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -913,6 +913,10 @@ late_initcall(hpet_insert_resource);
 
 static int __init acpi_parse_fadt(struct acpi_table_header *table)
 {
+	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
+		pr_debug("ACPI: not registering RTC platform device\n");
+		x86_platform.legacy.rtc = 0;
+	}
 
 #ifdef CONFIG_X86_PM_TIMER
 	/* detect the location of the ACPI PM Timer */
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index 62c48da3889d..ff4f4180fefd 100644
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -189,14 +189,6 @@ static __init int add_rtc_cmos(void)
 	if (of_have_populated_dt())
 		return 0;
 
-#ifdef CONFIG_ACPI
-	if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
-		/* This warning can likely go away again in a year or two. */
-		pr_info("ACPI: not registering RTC platform device\n");
-		return -ENODEV;
-	}
-#endif
-
 	if (!x86_platform.legacy.rtc)
 		return -ENODEV;