From 7c97e1255c9cdff4f0cf64f5215b4fe2dfa4b37e Mon Sep 17 00:00:00 2001
From: Tim Wawrzynczak <twawrzynczak@chromium.org>
Date: Tue, 28 Jun 2022 12:06:22 -0600
Subject: mb/google/brya/acpi: Update GPIO polling method

The preferred way of polling in ACPI I've seen is usually to just
divide the sleep into N chunks, and ignore the time taken in between.
This works in practice (validated with Timer calls before and after).

Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Change-Id: I4a2cd82cea05c539eff30b9b9d6ef18550d17686
Reviewed-on: https://review.coreboot.org/c/coreboot/+/65484
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Robert Zieba <robertzieba@google.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
---
 src/mainboard/google/brya/acpi/utility.asl | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

(limited to 'src/mainboard')

diff --git a/src/mainboard/google/brya/acpi/utility.asl b/src/mainboard/google/brya/acpi/utility.asl
index 4fc03e83e1..1999d33348 100644
--- a/src/mainboard/google/brya/acpi/utility.asl
+++ b/src/mainboard/google/brya/acpi/utility.asl
@@ -8,14 +8,22 @@
  */
 Method (GPPL, 3, Serialized)
 {
-	Local0 = GRXS (Arg0)
-	Local7 = Arg2 * 10000
-	Local7 = Timer + Local7
-	While (Local0 != Arg1 && Timer < Local7)
+	Local0 = 0
+	While (Local0 < Arg2)
 	{
-		Stall (10)
-		Local0 = \_SB.PCI0.GRXS (Arg0)
+		If (\_SB.PCI0.GRXS (Arg0) == Arg1) {
+			Return (0)
+		} Else {
+			Local0++
+		}
+		Sleep (1)
 	}
+
+	If (Local0 == Arg2) {
+		Printf("[ERROR] GPPL for %o timed out", Arg0)
+	}
+
+	Return (0xFF)
 }
 
 /* Convert from 32-bit integer to 4-byte buffer (little-endian) */
-- 
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