x86: timer: tsc: Allow specifying clock rate from device tree again

[u-boot] / drivers / timer / tsc_timer.c

diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c
index cf869998bf9cc1da3e3d5f1a28c732996bbc8f63..747f190d3845a60fac6d1e1e5d90071525d9b028 100644 (file)
--- a/drivers/timer/tsc_timer.c
+++ b/drivers/timer/tsc_timer.c
@@ -377,14 +377,23 @@ static int tsc_timer_probe(struct udevice *dev)
 {
        struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
 
-       tsc_timer_ensure_setup();
-       uc_priv->clock_rate = gd->arch.clock_rate;
+       if (!uc_priv->clock_rate) {
+               tsc_timer_ensure_setup();
+               uc_priv->clock_rate = gd->arch.clock_rate;
+       } else {
+               gd->arch.tsc_base = rdtsc();
+       }
 
        return 0;
 }
 
 unsigned long notrace timer_early_get_rate(void)
 {
+       /*
+        * When TSC timer is used as the early timer, be warned that the timer
+        * clock rate can only be calibrated via some hardware ways. Specifying
+        * it in the device tree won't work for the early timer.
+        */
        tsc_timer_ensure_setup();
 
        return gd->arch.clock_rate;