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path: root/drivers/clocksource/dw_apb_timer_of.c
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Diffstat (limited to 'drivers/clocksource/dw_apb_timer_of.c')
-rw-r--r--drivers/clocksource/dw_apb_timer_of.c95
1 files changed, 63 insertions, 32 deletions
diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index ab09ed3742ee..cef554432a33 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -20,6 +20,7 @@
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
+#include <linux/clk.h>
#include <asm/mach/time.h>
#include <asm/sched_clock.h>
@@ -27,14 +28,37 @@
static void timer_get_base_and_rate(struct device_node *np,
void __iomem **base, u32 *rate)
{
+ struct clk *timer_clk;
+ struct clk *pclk;
+
*base = of_iomap(np, 0);
if (!*base)
panic("Unable to map regs for %s", np->name);
+ /*
+ * Not all implementations use a periphal clock, so don't panic
+ * if it's not present
+ */
+ pclk = of_clk_get_by_name(np, "pclk");
+ if (!IS_ERR(pclk))
+ if (clk_prepare_enable(pclk))
+ pr_warn("pclk for %s is present, but could not be activated\n",
+ np->name);
+
+ timer_clk = of_clk_get_by_name(np, "timer");
+ if (IS_ERR(timer_clk))
+ goto try_clock_freq;
+
+ if (!clk_prepare_enable(timer_clk)) {
+ *rate = clk_get_rate(timer_clk);
+ return;
+ }
+
+try_clock_freq:
if (of_property_read_u32(np, "clock-freq", rate) &&
of_property_read_u32(np, "clock-frequency", rate))
- panic("No clock-frequency property for %s", np->name);
+ panic("No clock nor clock-frequency property for %s", np->name);
}
static void add_clockevent(struct device_node *event_timer)
@@ -57,6 +81,9 @@ static void add_clockevent(struct device_node *event_timer)
dw_apb_clockevent_register(ced);
}
+static void __iomem *sched_io_base;
+static u32 sched_rate;
+
static void add_clocksource(struct device_node *source_timer)
{
void __iomem *iobase;
@@ -71,9 +98,15 @@ static void add_clocksource(struct device_node *source_timer)
dw_apb_clocksource_start(cs);
dw_apb_clocksource_register(cs);
-}
-static void __iomem *sched_io_base;
+ /*
+ * Fallback to use the clocksource as sched_clock if no separate
+ * timer is found. sched_io_base then points to the current_value
+ * register of the clocksource timer.
+ */
+ sched_io_base = iobase + 0x04;
+ sched_rate = rate;
+}
static u32 read_sched_clock(void)
{
@@ -89,39 +122,37 @@ static const struct of_device_id sptimer_ids[] __initconst = {
static void init_sched_clock(void)
{
struct device_node *sched_timer;
- u32 rate;
sched_timer = of_find_matching_node(NULL, sptimer_ids);
- if (!sched_timer)
- panic("No RTC for sched clock to use");
+ if (sched_timer) {
+ timer_get_base_and_rate(sched_timer, &sched_io_base,
+ &sched_rate);
+ of_node_put(sched_timer);
+ }
- timer_get_base_and_rate(sched_timer, &sched_io_base, &rate);
- of_node_put(sched_timer);
-
- setup_sched_clock(read_sched_clock, 32, rate);
+ setup_sched_clock(read_sched_clock, 32, sched_rate);
}
-static const struct of_device_id osctimer_ids[] __initconst = {
- { .compatible = "picochip,pc3x2-timer" },
- { .compatible = "snps,dw-apb-timer-osc" },
- {},
-};
-
-void __init dw_apb_timer_init(void)
+static int num_called;
+static void __init dw_apb_timer_init(struct device_node *timer)
{
- struct device_node *event_timer, *source_timer;
-
- event_timer = of_find_matching_node(NULL, osctimer_ids);
- if (!event_timer)
- panic("No timer for clockevent");
- add_clockevent(event_timer);
-
- source_timer = of_find_matching_node(event_timer, osctimer_ids);
- if (!source_timer)
- panic("No timer for clocksource");
- add_clocksource(source_timer);
-
- of_node_put(source_timer);
-
- init_sched_clock();
+ switch (num_called) {
+ case 0:
+ pr_debug("%s: found clockevent timer\n", __func__);
+ add_clockevent(timer);
+ of_node_put(timer);
+ break;
+ case 1:
+ pr_debug("%s: found clocksource timer\n", __func__);
+ add_clocksource(timer);
+ of_node_put(timer);
+ init_sched_clock();
+ break;
+ default:
+ break;
+ }
+
+ num_called++;
}
+CLOCKSOURCE_OF_DECLARE(pc3x2_timer, "picochip,pc3x2-timer", dw_apb_timer_init);
+CLOCKSOURCE_OF_DECLARE(apb_timer, "snps,dw-apb-timer-osc", dw_apb_timer_init);