ARM: 7413/1: move read_{boot,persistent}_clock to the architecture level

At the moment, read_persistent_clock is implemented at the
platform level, which makes it impossible to compile these
platforms in a single kernel.

Implement these two functions at the architecture level, and
provide a thin registration interface for both read_boot_clock
and read_persistent_clock. The two affected platforms (OMAP and
Tegra) are converted at the same time.

Reported-by: Jeff Ohlstein <johlstei@codeaurora.org>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 36 insertions, 0 deletions

diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c
index fe31b22f18fd..af2afb019672 100644
--- a/arch/arm/kernel/time.c
+++ b/arch/arm/kernel/time.c
@@ -110,6 +110,42 @@ void timer_tick(void)
 }
 #endif
 
+static void dummy_clock_access(struct timespec *ts)
+{
+        ts->tv_sec = 0;
+        ts->tv_nsec = 0;
+}
+
+static clock_access_fn __read_persistent_clock = dummy_clock_access;
+static clock_access_fn __read_boot_clock = dummy_clock_access;;
+
+void read_persistent_clock(struct timespec *ts)
+{
+        __read_persistent_clock(ts);
+}
+
+void read_boot_clock(struct timespec *ts)
+{
+        __read_boot_clock(ts);
+}
+
+int __init register_persistent_clock(clock_access_fn read_boot,
+                                     clock_access_fn read_persistent)
+{
+        /* Only allow the clockaccess functions to be registered once */
+        if (__read_persistent_clock == dummy_clock_access &&
+            __read_boot_clock == dummy_clock_access) {
+                if (read_boot)
+                        __read_boot_clock = read_boot;
+                if (read_persistent)
+                        __read_persistent_clock = read_persistent;
+
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
 #if defined(CONFIG_PM) && !defined(CONFIG_GENERIC_CLOCKEVENTS)
 static int timer_suspend(void)
 {