drvs/intel/gma/acpi: Add methods to use MBOX3

* Add Mailbox 3 driver
* Request brightness change through Mailbox 3
* Return Ones on error or if unsupported
* Mark existing code as legacy
  (still required if no GMA driver is running)
* Call legacy code if Mailbox 3 is unsupported, on error or
  if gma driver isn't running

Tested on Lenovo T430:
* Brightness control still works
* Brightness is the same on S3 resume

Change-Id: I51554c819148336b204d28972cbf775a10c3fb8a
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/27711
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Nathaniel Roach <nroach44@gmail.com>
Reviewed-by: Nicola Corna <nicola@corna.info>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/drivers/intel/gma/acpi/common.asl

@@ -44,8 +44,11 @@
 		Store (And(Arg0, 7), DSEN)
 	}
 
-	/* Using Notify is the right way. But Windows doesn't handle
-	   it well. So use both method in a way to avoid double action.
+	/*
+	 * Decrement display brightness.
+	 *
+	 * Using Notify is the right way. But Windows doesn't handle
+	 * it well. So use both method in a way to avoid double action.
 	 */
 	Method (DECB, 0, NotSerialized)
 	{
@@ -62,6 +65,9 @@
 		}
 	}
 
+	/*
+	 * Increment display brightness.
+	 */
 	Method (INCB, 0, NotSerialized)
 	{
 		If (BRCT)

src/drivers/intel/gma/acpi/configure_brightness_levels.asl

@@ -1,3 +1,132 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2015 Nico Huber <nico.huber@secunet.com>
+ * Copyright (C) 2018 Patrick Rudolph
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+	/*
+	 * Pseudo device that contains methods to modify Opregion
+	 * "Mailbox 3 BIOS to Driver Notification"
+	 * The BIOS to Driver Notification mailbox is intended to support
+	 * BIOS to Driver event notification or data storage for BIOS to
+	 * Driver data synchronization purpose.
+	*/
+	Device (BOX3)
+	{
+		Name (_ADR, 0)
+
+		OperationRegion (OPRG, SystemMemory, ASLS, 0x2000)
+		Field (OPRG, DWordAcc, NoLock, Preserve)
+		{
+			// OpRegion Header
+			Offset (0x58),
+			MBOX, 32,
+
+			// Mailbox 3
+			Offset (0x300),
+			ARDY, 1,	/* Offset 0   Driver readiness */
+			, 31,
+			ASLC, 32,	/* Offset 4   ASLE interrupt command / status */
+			TCHE, 32,	/* Offset 8   Technology enabled indicator */
+			ALSI, 32,	/* Offset 12  Current ALS illuminance reading */
+			BCLP, 32,	/* Offset 16  Backlight britness to set */
+			PFIT, 32,	/* Offset 20  Panel fitting Request */
+			CBLV, 32,	/* Offset 24  Brightness Current State */
+		}
+
+		/*
+		 * Request back-light brightness change through mailbox 3
+		 *
+		 * @param Arg0 The brightness level to set in percent
+		 * @Return Zero on success, Ones on failure
+		 * Errors: * ASLS is zero
+		 *         * Mailbox 3 support not advertised
+		 *         * Driver not loaded or not ready
+		 *         * Driver reported an error during ASLE IRQ
+		 */
+		Method (XBCM, 1, NotSerialized)
+		{
+			If (LEqual(ASLS, Zero))
+			{
+				Return (Ones)
+			}
+			If (LEqual(And(MBOX, 0x4), Zero))
+			{
+				Return (Ones)
+			}
+			If (LEqual(ARDY, Zero))
+			{
+				Return (Ones)
+			}
+
+			Store (Or (Arg0, 0x80000000), BCLP)
+			/* Request back-light change */
+			Store (0x2, ASLC)
+			/* Trigger IRQ */
+			Store (0x1, ASLE)
+
+			Store (0x20, Local0)
+			While (LGreater(Local0, Zero))
+			{
+				Sleep (1)
+				If (LEqual(And(ShiftRight(ASLC, 12), 0x3), Zero))
+				{
+					Return (Zero)
+				}
+				Decrement (Local0)
+			}
+
+			Return (Ones)
+		}
+
+		/*
+		 * Get current back-light brightness through mailbox 3
+		 *
+		 * @Return The current brightness or Ones on error
+		 * Errors: * ASLS is zero
+		 *         * Mailbox 3 support not advertised
+		 *         * Driver not loaded or not ready
+		 *         * CBLV is not marked valid
+		 */
+		Method (XBQC, 0, NotSerialized)
+		{
+			If (LEqual(ASLS, Zero))
+			{
+				Return (Ones)
+			}
+			If (LEqual(And(MBOX, 0x4), Zero))
+			{
+				Return (Ones)
+			}
+			If (LEqual(ARDY, Zero))
+			{
+				Return (Ones)
+			}
+			If (LEqual(And (CBLV, 0x80000000), Zero))
+			{
+				Return (Ones)
+			}
+			Return (And (CBLV, 0xff))
+		}
+	}
+
+	/*
+	 * Pseudo device that contains methods to operate on GTT memory
+	 */
+	Device (LEGA)
+	{
+		Name (_ADR, 0)
+
 		Method (XBCM, 1, NotSerialized)
 		{
 			Store (Divide (Multiply (Arg0, BCLM), 100), BCLV)
@@ -22,3 +151,23 @@
 			/* Didn't find greater/equal value: use the last */
 			Return (DeRefOf (Index (BRIG, Local2)))
 		}
+	}
+
+	Method (XBCM, 1, NotSerialized)
+	{
+		If (LEqual(^BOX3.XBCM (Arg0), Ones))
+		{
+			^LEGA.XBCM (Arg0)
+		}
+	}
+
+	Method (XBQC, 0, NotSerialized)
+	{
+		Store (^BOX3.XBQC (), Local0)
+		If (LEqual(Local0, Ones))
+		{
+			Store (^LEGA.XBQC (), Local0)
+		}
+
+		Return (Local0)
+	}

src/drivers/intel/gma/acpi/non-pch.asl

@@ -22,7 +22,11 @@ Device (GFX0)
 	Field (GFXC, DWordAcc, NoLock, Preserve)
 	{
 		Offset (0x10),
-		BAR0, 64
+		BAR0, 64,
+		Offset (0xe4),
+		ASLE, 32,
+		Offset (0xfc),
+		ASLS, 32,
 	}
 
 	OperationRegion (GFRG, SystemMemory, And (BAR0, 0xfffffffffffffff0), 0x400000)

src/drivers/intel/gma/acpi/pch.asl

@@ -22,7 +22,11 @@ Device (GFX0)
 	Field (GFXC, DWordAcc, NoLock, Preserve)
 	{
 		Offset (0x10),
-		BAR0, 64
+		BAR0, 64,
+		Offset (0xe4),
+		ASLE, 32,
+		Offset (0xfc),
+		ASLS, 32,
 	}
 
 	OperationRegion (GFRG, SystemMemory, And (BAR0, 0xfffffffffffffff0), 0x400000)