i.MXC family: Adding timer support

This patch adds timer support for the i.MX machine family. This code can
be used on the following machs:

 - i.MX1 (tested)
 - i.MX2 (i.MX21 (to be tested), i.MX27 (tested))
 - i.MX3 (i.MX31 (tested))

TODO: It seems impossible to build a kernel for more than one CPU because the
timer do not follow the platform device rules. So it does only work if
timer 1 can be accessed on all CPUs at the same address.

Signed-off-by: Juergen Beisert <j.beisert@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/Kconfig

@@ -367,6 +367,8 @@ config ARCH_NS9XXX
 
 config ARCH_MXC
 	bool "Freescale MXC/iMX-based"
+	select GENERIC_TIME
+	select GENERIC_CLOCKEVENTS
 	select ARCH_MTD_XIP
 	select GENERIC_GPIO
 	select HAVE_GPIO_LIB

arch/arm/mach-mx3/Makefile

@@ -4,5 +4,5 @@
 
 # Object file lists.
 
-obj-y			:= mm.o time.o clock.o devices.o iomux.o
+obj-y			:= mm.o clock.o devices.o iomux.o
 obj-$(CONFIG_MACH_MX31ADS)	+= mx31ads.o

arch/arm/mach-mx3/mx31ads.c

@@ -26,6 +26,7 @@
 #include <asm/hardware.h>
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
+#include <asm/mach/time.h>
 #include <asm/memory.h>
 #include <asm/mach/map.h>
 #include <asm/arch/common.h>
@@ -127,6 +128,16 @@ static void __init mxc_board_init(void)
 	mxc_init_extuart();
 }
 
+static void __init mx31ads_timer_init(void)
+{
+	mxc_clocks_init(26000000);
+	mxc_timer_init("ipg_clk.0");
+}
+
+struct sys_timer mx31ads_timer = {
+	.init	= mx31ads_timer_init,
+};
+
 /*
  * The following uses standard kernel macros defined in arch.h in order to
  * initialize __mach_desc_MX31ADS data structure.
@@ -139,5 +150,5 @@ MACHINE_START(MX31ADS, "Freescale MX31ADS")
 	.map_io         = mx31ads_map_io,
 	.init_irq       = mxc_init_irq,
 	.init_machine   = mxc_board_init,
-	.timer          = &mxc_timer,
+	.timer          = &mx31ads_timer,
 MACHINE_END

arch/arm/plat-mxc/Makefile

@@ -3,4 +3,4 @@
 #
 
 # Common support
-obj-y := irq.o clock.o gpio.o
+obj-y := irq.o clock.o gpio.o time.o