clocksource/drivers/tcb_clksrc: Use tcb as sched_clock

Now that the driver is registered early enough, use the TCB as the
sched_clock which is much more accurate than the jiffies implementation.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
index bf68504da94a..9de8c10ab546 100644
--- a/drivers/clocksource/tcb_clksrc.c
+++ b/drivers/clocksource/tcb_clksrc.c
@@ -11,6 +11,7 @@
 #include <linux/io.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/sched_clock.h>
 #include <linux/syscore_ops.h>
 #include <soc/at91/atmel_tcb.h>
 
@@ -114,6 +115,16 @@ static struct clocksource clksrc = {
         .resume         = tc_clksrc_resume,
 };
 
+static u64 notrace tc_sched_clock_read(void)
+{
+        return tc_get_cycles(&clksrc);
+}
+
+static u64 notrace tc_sched_clock_read32(void)
+{
+        return tc_get_cycles32(&clksrc);
+}
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 
 struct tc_clkevt_device {
@@ -335,6 +346,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
         struct atmel_tc tc;
         struct clk *t0_clk;
         const struct of_device_id *match;
+        u64 (*tc_sched_clock)(void);
         u32 rate, divided_rate = 0;
         int best_divisor_idx = -1;
         int clk32k_divisor_idx = -1;
@@ -419,6 +431,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
                 clksrc.read = tc_get_cycles32;
                 /* setup ony channel 0 */
                 tcb_setup_single_chan(&tc, best_divisor_idx);
+                tc_sched_clock = tc_sched_clock_read32;
         } else {
                 /* we have three clocks no matter what the
                  * underlying platform supports.
@@ -430,6 +443,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
                 }
                 /* setup both channel 0 & 1 */
                 tcb_setup_dual_chan(&tc, best_divisor_idx);
+                tc_sched_clock = tc_sched_clock_read;
         }
 
         /* and away we go! */
@@ -442,6 +456,8 @@ static int __init tcb_clksrc_init(struct device_node *node)
         if (ret)
                 goto err_unregister_clksrc;
 
+        sched_clock_register(tc_sched_clock, 32, divided_rate);
+
         return 0;
 
 err_unregister_clksrc: