From: Simon Glass <sjg@chromium.org>
Date: Fri, 10 Mar 2023 20:47:15 +0000 (-0800)
Subject: efi: Use a fixed value for the timer clock
X-Git-Url: http://git.dujemihanovic.xyz/html/static/%7B%7B%20.RelPermalink%20%7D%7D?a=commitdiff_plain;h=4f9a8f33f0ab5acdcfa7fafc29bb2a16883e9801;p=u-boot.git

efi: Use a fixed value for the timer clock

It is not yet clear how to read the timer via EFI. The current value seems
much too high on a Framework laptop I tried. Adjust it to a lower
hard-coded value for now.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c
index 192c7b71a5..f86a0b8692 100644
--- a/drivers/timer/tsc_timer.c
+++ b/drivers/timer/tsc_timer.c
@@ -404,6 +404,15 @@ static void tsc_timer_ensure_setup(bool early)
 	if (!gd->arch.clock_rate) {
 		unsigned long fast_calibrate;
 
+		/**
+		 * There is no obvious way to obtain this information from EFI
+		 * boot services. This value was measured on a Framework Laptop
+		 * which has a 12th Gen Intel Core
+		 */
+		if (IS_ENABLED(CONFIG_EFI_APP)) {
+			fast_calibrate = 2750;
+			goto done;
+		}
 		fast_calibrate = native_calibrate_tsc();
 		if (fast_calibrate)
 			goto done;