1 files changed, 93 insertions, 25 deletions

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index 1b7835865c83..840929bd9dae 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -90,7 +90,7 @@ static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id)
 }
 
 static struct irqaction omap2_gp_timer_irq = {
-        .name           = "gp timer",
+        .name           = "gp_timer",
         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
         .handler        = omap2_gp_timer_interrupt,
 };
@@ -132,7 +132,7 @@ static void omap2_gp_timer_set_mode(enum clock_event_mode mode,
 }
 
 static struct clock_event_device clockevent_gpt = {
-        .name           = "gp timer",
+        .name           = "gp_timer",
         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
         .shift          = 32,
         .set_next_event = omap2_gp_timer_set_next_event,
@@ -236,22 +236,8 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 }
 
 /* Clocksource code */
-
-#ifdef CONFIG_OMAP_32K_TIMER
-/*
- * When 32k-timer is enabled, don't use GPTimer for clocksource
- * instead, just leave default clocksource which uses the 32k
- * sync counter.  See clocksource setup in plat-omap/counter_32k.c
- */
-
-static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
-{
-        omap_init_clocksource_32k();
-}
-
-#else
-
 static struct omap_dm_timer clksrc;
+static bool use_gptimer_clksrc;
 
 /*
  * clocksource
@@ -262,7 +248,7 @@ static cycle_t clocksource_read_cycles(struct clocksource *cs)
 }
 
 static struct clocksource clocksource_gpt = {
-        .name           = "gp timer",
+        .name           = "gp_timer",
         .rating         = 300,
         .read           = clocksource_read_cycles,
         .mask           = CLOCKSOURCE_MASK(32),
@@ -278,7 +264,46 @@ static u32 notrace dmtimer_read_sched_clock(void)
 }
 
 /* Setup free-running counter for clocksource */
-static void __init omap2_gp_clocksource_init(int gptimer_id,
+static int __init omap2_sync32k_clocksource_init(void)
+{
+        int ret;
+        struct omap_hwmod *oh;
+        void __iomem *vbase;
+        const char *oh_name = "counter_32k";
+
+        /*
+         * First check hwmod data is available for sync32k counter
+         */
+        oh = omap_hwmod_lookup(oh_name);
+        if (!oh || oh->slaves_cnt == 0)
+                return -ENODEV;
+
+        omap_hwmod_setup_one(oh_name);
+
+        vbase = omap_hwmod_get_mpu_rt_va(oh);
+        if (!vbase) {
+                pr_warn("%s: failed to get counter_32k resource\n", __func__);
+                return -ENXIO;
+        }
+
+        ret = omap_hwmod_enable(oh);
+        if (ret) {
+                pr_warn("%s: failed to enable counter_32k module (%d)\n",
+                                                        __func__, ret);
+                return ret;
+        }
+
+        ret = omap_init_clocksource_32k(vbase);
+        if (ret) {
+                pr_warn("%s: failed to initialize counter_32k as a clocksource (%d)\n",
+                                                        __func__, ret);
+                omap_hwmod_idle(oh);
+        }
+
+        return ret;
+}
+
+static void __init omap2_gptimer_clocksource_init(int gptimer_id,
                                                 const char *fck_source)
 {
         int res;
@@ -286,9 +311,6 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
         res = omap_dm_timer_init_one(&clksrc, gptimer_id, fck_source);
         BUG_ON(res);
 
-        pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
-                gptimer_id, clksrc.rate);
-
         __omap_dm_timer_load_start(&clksrc,
                         OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);
         setup_sched_clock(dmtimer_read_sched_clock, 32, clksrc.rate);
@@ -296,15 +318,36 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
         if (clocksource_register_hz(&clocksource_gpt, clksrc.rate))
                 pr_err("Could not register clocksource %s\n",
                         clocksource_gpt.name);
+        else
+                pr_info("OMAP clocksource: GPTIMER%d at %lu Hz\n",
+                        gptimer_id, clksrc.rate);
+}
+
+static void __init omap2_clocksource_init(int gptimer_id,
+                                                const char *fck_source)
+{
+        /*
+         * First give preference to kernel parameter configuration
+         * by user (clocksource="gp_timer").
+         *
+         * In case of missing kernel parameter for clocksource,
+         * first check for availability for 32k-sync timer, in case
+         * of failure in finding 32k_counter module or registering
+         * it as clocksource, execution will fallback to gp-timer.
+         */
+        if (use_gptimer_clksrc == true)
+                omap2_gptimer_clocksource_init(gptimer_id, fck_source);
+        else if (omap2_sync32k_clocksource_init())
+                /* Fall back to gp-timer code */
+                omap2_gptimer_clocksource_init(gptimer_id, fck_source);
 }
-#endif
 
 #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src,                  \
                                 clksrc_nr, clksrc_src)                  \
 static void __init omap##name##_timer_init(void)                        \
 {                                                                       \
         omap2_gp_clockevent_init((clkev_nr), clkev_src);                \
-        omap2_gp_clocksource_init((clksrc_nr), clksrc_src);             \
+        omap2_clocksource_init((clksrc_nr), clksrc_src);                \
 }
 
 #define OMAP_SYS_TIMER(name)                                            \
@@ -335,7 +378,7 @@ static DEFINE_TWD_LOCAL_TIMER(twd_local_timer,
 static void __init omap4_timer_init(void)
 {
         omap2_gp_clockevent_init(1, OMAP4_CLKEV_SOURCE);
-        omap2_gp_clocksource_init(2, OMAP4_MPU_SOURCE);
+        omap2_clocksource_init(2, OMAP4_MPU_SOURCE);
 #ifdef CONFIG_LOCAL_TIMERS
         /* Local timers are not supprted on OMAP4430 ES1.0 */
         if (omap_rev() != OMAP4430_REV_ES1_0) {
@@ -503,3 +546,28 @@ static int __init omap2_dm_timer_init(void)
         return 0;
 }
 arch_initcall(omap2_dm_timer_init);
+
+/**
+ * omap2_override_clocksource - clocksource override with user configuration
+ *
+ * Allows user to override default clocksource, using kernel parameter
+ *   clocksource="gp_timer"     (For all OMAP2PLUS architectures)
+ *
+ * Note that, here we are using same standard kernel parameter "clocksource=",
+ * and not introducing any OMAP specific interface.
+ */
+static int __init omap2_override_clocksource(char *str)
+{
+        if (!str)
+                return 0;
+        /*
+         * For OMAP architecture, we only have two options
+         *    - sync_32k (default)
+         *    - gp_timer (sys_clk based)
+         */
+        if (!strcmp(str, "gp_timer"))
+                use_gptimer_clksrc = true;
+
+        return 0;
+}
+early_param("clocksource", omap2_override_clocksource);