2 files changed, 93 insertions, 1 deletions

diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index 346fd26f3aa6..4b773fd56978 100644
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -24,6 +24,9 @@ config ARCH_OMAP2PLUS_TYPICAL
 config SOC_HAS_OMAP2_SDRC
         bool "OMAP2 SDRAM Controller support"
 
+config SOC_HAS_REALTIME_COUNTER
+        bool "Real time free running counter"
+
 config ARCH_OMAP2
         bool "TI OMAP2"
         depends on ARCH_OMAP2PLUS
@@ -70,6 +73,7 @@ config SOC_OMAP5
         select ARM_GIC
         select HAVE_SMP
         select ARM_CPU_SUSPEND if PM
+        select SOC_HAS_REALTIME_COUNTER
 
 comment "OMAP Core Type"
         depends on ARCH_OMAP2
diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 2ba4f57dda86..026fcfff6698 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -69,6 +69,11 @@
 #define OMAP3_SECURE_TIMER      1
 #endif
 
+#define REALTIME_COUNTER_BASE                           0x48243200
+#define INCREMENTER_NUMERATOR_OFFSET                    0x10
+#define INCREMENTER_DENUMERATOR_RELOAD_OFFSET           0x14
+#define NUMERATOR_DENUMERATOR_MASK                      0xfffff000
+
 /* Clockevent code */
 
 static struct omap_dm_timer clkev;
@@ -346,6 +351,84 @@ static void __init omap2_clocksource_init(int gptimer_id,
                 omap2_gptimer_clocksource_init(gptimer_id, fck_source);
 }
 
+#ifdef CONFIG_SOC_HAS_REALTIME_COUNTER
+/*
+ * The realtime counter also called master counter, is a free-running
+ * counter, which is related to real time. It produces the count used
+ * by the CPU local timer peripherals in the MPU cluster. The timer counts
+ * at a rate of 6.144 MHz. Because the device operates on different clocks
+ * in different power modes, the master counter shifts operation between
+ * clocks, adjusting the increment per clock in hardware accordingly to
+ * maintain a constant count rate.
+ */
+static void __init realtime_counter_init(void)
+{
+        void __iomem *base;
+        static struct clk *sys_clk;
+        unsigned long rate;
+        unsigned int reg, num, den;
+
+        base = ioremap(REALTIME_COUNTER_BASE, SZ_32);
+        if (!base) {
+                pr_err("%s: ioremap failed\n", __func__);
+                return;
+        }
+        sys_clk = clk_get(NULL, "sys_clkin_ck");
+        if (!sys_clk) {
+                pr_err("%s: failed to get system clock handle\n", __func__);
+                iounmap(base);
+                return;
+        }
+
+        rate = clk_get_rate(sys_clk);
+        /* Numerator/denumerator values refer TRM Realtime Counter section */
+        switch (rate) {
+        case 1200000:
+                num = 64;
+                den = 125;
+                break;
+        case 1300000:
+                num = 768;
+                den = 1625;
+                break;
+        case 19200000:
+                num = 8;
+                den = 25;
+                break;
+        case 2600000:
+                num = 384;
+                den = 1625;
+                break;
+        case 2700000:
+                num = 256;
+                den = 1125;
+                break;
+        case 38400000:
+        default:
+                /* Program it for 38.4 MHz */
+                num = 4;
+                den = 25;
+                break;
+        }
+
+        /* Program numerator and denumerator registers */
+        reg = __raw_readl(base + INCREMENTER_NUMERATOR_OFFSET) &
+                        NUMERATOR_DENUMERATOR_MASK;
+        reg |= num;
+        __raw_writel(reg, base + INCREMENTER_NUMERATOR_OFFSET);
+
+        reg = __raw_readl(base + INCREMENTER_NUMERATOR_OFFSET) &
+                        NUMERATOR_DENUMERATOR_MASK;
+        reg |= den;
+        __raw_writel(reg, base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET);
+
+        iounmap(base);
+}
+#else
+static inline void __init realtime_counter_init(void)
+{}
+#endif
+
 #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src,                  \
                                 clksrc_nr, clksrc_src)                  \
 static void __init omap##name##_timer_init(void)                        \
@@ -403,7 +486,12 @@ OMAP_SYS_TIMER(4)
 #endif
 
 #ifdef CONFIG_SOC_OMAP5
-OMAP_SYS_TIMER_INIT(5, 1, OMAP4_CLKEV_SOURCE, 2, OMAP4_MPU_SOURCE)
+static void __init omap5_timer_init(void)
+{
+        omap2_gp_clockevent_init(1, OMAP4_CLKEV_SOURCE);
+        omap2_clocksource_init(2, OMAP4_MPU_SOURCE);
+        realtime_counter_init();
+}
 OMAP_SYS_TIMER(5)
 #endif