x86: Sync up tsc_timer with Linux
Since we are using the code from Linux, update it to the newer version
in v6.11
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c
index 2f2c2f2..dd16ab3 100644
--- a/drivers/timer/tsc_timer.c
+++ b/drivers/timer/tsc_timer.c
@@ -83,7 +83,7 @@
if (cpuid_eax(0) < 0x16)
return 0;
- return cpuid_eax(0x16);
+ return cpuid_eax(0x15);
}
/*
@@ -299,10 +299,19 @@
if (!pit_expect_msb(0xff-i, &delta, &d2))
break;
+ delta -= tsc;
+
+ /*
+ * Extrapolate the error and fail fast if the error will
+ * never be below 500 ppm.
+ */
+ if (i == 1 &&
+ d1 + d2 >= (delta * MAX_QUICK_PIT_ITERATIONS) >> 11)
+ return 0;
+
/*
* Iterate until the error is less than 500 ppm
*/
- delta -= tsc;
if (d1+d2 >= delta >> 11)
continue;