From 52aeb078ce69479c0efa852ba9ee7c97a09dfbc7 Mon Sep 17 00:00:00 2001
From: Cliff Huang <cliff.huang@intel.com>
Date: Wed, 19 Nov 2025 17:50:39 -0800
Subject: [PATCH] soc/intel/common/acpi: Add IOST device
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Add ACPI device for Intel's IO Self-Testing Software (IOST), which is an
OS tool for performing electrical margining analysis on USB4 Host and
Device Routers, DP2.1 displays, memory, UFS, and PCIe Gen4+ devices.
This ACPI device provides the necessary P2SB access interface to enable
IOST to interact with hardware registers for comprehensive IO testing
and validation. The ASL file should be included in the SoC's
southbridge.asl.

BUG=none
TEST=Build coreboot with this ASL file included in the SoC's
southbridge.asl. Boot to OS and verify IOST objects appear correctly in
the DSDT tables.

Signed-off-by: Cliff Huang <cliff.huang@intel.com>
Change-Id: I9417da8322931c2afbf75aa9062bceb52b8320d6
Reviewed-on: https://review.coreboot.org/c/coreboot/+/90128
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Alicja Michalska <ahplka19@gmail.com>
---
 src/soc/intel/common/acpi/iost.asl | 81 ++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 src/soc/intel/common/acpi/iost.asl

diff --git a/src/soc/intel/common/acpi/iost.asl b/src/soc/intel/common/acpi/iost.asl
new file mode 100644
index 0000000000..51d934ca7a
--- /dev/null
+++ b/src/soc/intel/common/acpi/iost.asl
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Device: Intel's IO Self-Testing Software (IOST)
+ * NOTE: The IOSE Name object is used to enable IOST. It is set to 0 by default,
+ * and its value can be updated in the SSDT.
+ */
+Device (IOST)
+{
+	//
+	// Intel IO Self Testing Device
+	//
+	Name (_UID, "IOST")
+	Name (_HID, "IOS0001")
+	Name (IVER, 0x00010000)
+	Name (IOSE, 0x00)
+	Method (_STA, 0, NotSerialized)
+	{
+		If (IOSE > Zero) {
+			Return (0xf)
+		}
+		Return (Zero)
+	}
+
+	/*
+	 * _DSM Device Specific Method
+	 *
+	 * Arg0: UUID : 893f00a6-660c-494e-bcfd-3043f4fb67c0
+	 * Arg1: Integer Revision Level
+	 * Arg2: Integer Function Index (0 = Return Supported Functions)
+	 * Arg3: Package Parameters
+	 */
+	Method (_DSM, 4, Serialized)
+	{
+		If ( (IOSE > Zero) && LEqual (Arg0, ToUUID ("893f00a6-660c-494e-bcfd-3043f4fb67c0")))
+		{
+			If (LEqual (0, ToInteger (Arg1)))
+			{
+				Switch (ToInteger (Arg2))
+				{
+					/* Function 0: returns a buffer containing one bit for each function index, starting with zero.
+					 * Bit 0 indicates whether there is support for any function other than function 0
+					 */
+					Case (0)
+					{
+						Return (Buffer(){0x07})
+					}
+					/* Function 1: P2SB Read
+					 * Package Details
+					 * Idx0 = PortID
+					 * Idx1 = Offset
+					 */
+					Case (1)
+					{
+						Local0 = DeRefOf (Index (Arg3, 0)) /* PordID */
+						Local1 = DeRefOf (Index (Arg3, 1)) /* offset */
+
+						Local3 = PCRR(Local0, Local1)
+						Printf ("[IOST] P2B Read: PortID: %o  Offset: %o read = %o", ToHexString(Local0), ToHexString(Local1), ToHexString(Local3))
+						Return(Local3)
+					}
+					/* Function 2: P2SB Write
+					 * Package Details
+					 * Idx0 = PortID
+					 * Idx1 = Offset
+					 * Idx2 = DataToWrite
+					 */
+					Case (2)
+					{
+						Local0 = DeRefOf (Index (Arg3, 0)) /* PordID */
+						Local1 = DeRefOf (Index (Arg3, 1)) /* offset */
+						Local2 = DeRefOf (Index (Arg3, 2)) /* data to Write */
+						Printf ("[IOST] P2B Write: PortID: %o Offset: %o with %o", ToHexString(Local0), ToHexString(Local1), ToHexString(Local2))
+						PCRW(Local0, Local1, Local2)
+						Return (0x00)
+					}
+				}
+			}
+		}
+		Return (Buffer () {0x00})
+	}
+}