linux-kernel - [PATCH 6/7] ARM: rtc: update CMOS RTC to support MMIO and private lock

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Date:	Fri, 25 Apr 2014 10:31:14 +0100
From:	Marc Zyngier <marc.zyngier@....com>
To:	linux-kernel@...r.kernel.org, rtc-linux@...glegroups.com
Cc:	Russell King <linux@....linux.org.uk>,
	Will Deacon <will.deacon@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Alessandro Zummo <a.zummo@...ertech.it>
Subject: [PATCH 6/7] ARM: rtc: update CMOS RTC to support MMIO and private lock

So far, the CMOS RTC (PC-style mc146818) has always been used
through an ISA I/O port of some sort, with each platform configuring
the address in a static way.

Some platforms (KVM with kvmtools, for example) offer a MMIO version
of the CMOS RTC, which requires a different access method.

This patch select the RTC_DRV_CMOS_MMIO configuration in order to
support MMIO accesses as well as the older IO port method.

While we're at it, switch to RTC_DRV_CMOS_PRIV_LOCK and remove the
ancient rtc_lock.

Tested on Cortex-A7 with KVM and kvmtools.

Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
 arch/arm/kernel/time.c | 7 -------
 drivers/rtc/Kconfig    | 2 ++
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c
index 829a96d..38c8718 100644
--- a/arch/arm/kernel/time.c
+++ b/arch/arm/kernel/time.c
@@ -32,13 +32,6 @@
 #include <asm/stacktrace.h>
 #include <asm/thread_info.h>
 
-#if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || \
-    defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE)
-/* this needs a better home */
-DEFINE_SPINLOCK(rtc_lock);
-EXPORT_SYMBOL(rtc_lock);
-#endif	/* pc-style 'CMOS' RTC support */
-
 /* change this if you have some constant time drift */
 #define USECS_PER_JIFFY	(1000000/HZ)
 
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 12bc27d..b2a512e 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -662,6 +662,8 @@ config RTC_DRV_CMOS
 	tristate "PC-style 'CMOS'"
 	depends on X86 || ARM || M32R || PPC || MIPS || SPARC64
 	default y if X86
+	select RTC_DRV_CMOS_MMIO if ARM
+	select RTC_DRV_CMOS_PRIV_LOCK if ARM
 	help
 	  Say "yes" here to get direct support for the real time clock
 	  found in every PC or ACPI-based system, and some other boards.
-- 
1.8.3.4

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