soc/intel/cannonlake: Add ASL functions to manipulate RX/TX buffers

Add a function in gpio ASL library to enable/disable pad Rx/Tx Buffers.

BUG=b:123350329

Change-Id: I6c40d79debb61b0c4e96e485b410d446b77d9cf6
Signed-off-by: Rizwan Qureshi <rizwan.qureshi@intel.com>
Reviewed-on: https://review.coreboot.org/c/31619
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/soc/intel/cannonlake/acpi/gpio_op.asl

@@ -94,3 +94,47 @@ Method (GPMO, 2, Serialized)
 	And (ShiftLeft (Arg1, GPIOPADMODE_SHIFT, Arg1), GPIOPADMODE_MASK, Arg1)
 	Or (Local0, Arg1, VAL0)
 }
+
+/*
+ * Enable/Disable Tx buffer
+ * Arg0 - GPIO Number
+ * Arg1 - TxBuffer state
+ *     0 = Disable Tx Buffer
+ *     1 = Enable Tx Buffer
+ */
+Method (GTXE, 2, Serialized)
+{
+	OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
+	Field (PREG, AnyAcc, NoLock, Preserve)
+	{
+		VAL0, 32
+	}
+
+	If (LEqual (Arg1, 1)) {
+		And (Not (GPIOTXBUFDIS_MASK), VAL0, VAL0)
+	} ElseIf (LEqual (Arg1, 0)){
+		Or (GPIOTXBUFDIS_MASK, VAL0, VAL0)
+	}
+}
+
+/*
+ * Enable/Disable Rx buffer
+ * Arg0 - GPIO Number
+ * Arg1 - RxBuffer state
+ *     0 = Disable Rx Buffer
+ *     1 = Enable Rx Buffer
+ */
+Method (GRXE, 2, Serialized)
+{
+	OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
+	Field (PREG, AnyAcc, NoLock, Preserve)
+	{
+		VAL0, 32
+	}
+
+	If (LEqual (Arg1, 1)) {
+		And (Not (GPIORXBUFDIS_MASK), VAL0, VAL0)
+	} ElseIf (LEqual (Arg1, 0)){
+		Or (GPIORXBUFDIS_MASK, VAL0, VAL0)
+	}
+}

src/soc/intel/cannonlake/include/soc/gpio_defs.h

@@ -255,4 +255,8 @@
 #define GPIOTXSTATE_MASK			0x1
 #define GPIOPADMODE_MASK			0xC00
 #define GPIOPADMODE_SHIFT			10
+#define GPIOTXBUFDIS_MASK			0x100
+#define GPIOTXBUFDIS_SHIFT			8
+#define GPIORXBUFDIS_MASK			0x200
+#define GPIORXBUFDIS_SHIFT			9
 #endif

src/soc/intel/cannonlake/include/soc/gpio_defs_cnp_h.h

@@ -329,4 +329,8 @@
 #define GPIOTXSTATE_MASK			0x1
 #define GPIOPADMODE_MASK			0xC00
 #define GPIOPADMODE_SHIFT			10
+#define GPIOTXBUFDIS_MASK			0x100
+#define GPIOTXBUFDIS_SHIFT			8
+#define GPIORXBUFDIS_MASK			0x200
+#define GPIORXBUFDIS_SHIFT			9
 #endif