lenovo/t420: Add new port

This is based on t420s. Tested on a T420 without discrete GPU.
There is no support for nvidia gpu and optimus.

Signed-off-by: Nicolas Reinecke <nr@das-labor.org>
Tested-by: Iru Cai <mytbk920423@gmail.com>
Change-Id: Ie9405966e56180ac1c43a3c5b83181ee500177c8
Reviewed-on: https://review.coreboot.org/11765
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/mainboard/lenovo/t420/smihandler.c b/src/mainboard/lenovo/t420/smihandler.c
new file mode 100644
index 0000000..23a98dd
--- /dev/null
+++ b/src/mainboard/lenovo/t420/smihandler.c
@@ -0,0 +1,101 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2008-2009 coresystems GmbH
+ * Copyright (C) 2014 Vladimir Serbinenko
+ *
+ * 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.
+ */
+
+#include <arch/io.h>
+#include <console/console.h>
+#include <cpu/x86/smm.h>
+#include <ec/acpi/ec.h>
+#include <ec/lenovo/h8/h8.h>
+#include <southbridge/intel/bd82x6x/pch.h>
+
+#define GPE_EC_SCI	1
+#define GPE_EC_WAKE	13
+
+static void mainboard_smm_init(void)
+{
+	printk(BIOS_DEBUG, "initializing SMI\n");
+	/* Enable 0x1600/0x1600 register pair */
+	ec_set_bit(0x00, 0x05);
+}
+
+int mainboard_io_trap_handler(int smif)
+{
+	static int smm_initialized;
+
+	if (!smm_initialized) {
+		mainboard_smm_init();
+		smm_initialized = 1;
+	}
+
+	return 0;
+}
+
+static void mainboard_smi_handle_ec_sci(void)
+{
+	u8 status = inb(EC_SC);
+	u8 event;
+
+	if (!(status & EC_SCI_EVT))
+		return;
+
+	event = ec_query();
+	printk(BIOS_DEBUG, "EC event %02x\n", event);
+}
+
+void mainboard_smi_gpi(u32 gpi_sts)
+{
+	if (gpi_sts & (1 << GPE_EC_SCI))
+		mainboard_smi_handle_ec_sci();
+}
+
+int mainboard_smi_apmc(u8 data)
+{
+	switch (data) {
+		case APM_CNT_ACPI_ENABLE:
+			/* use 0x1600/0x1604 to prevent races with userspace */
+			ec_set_ports(0x1604, 0x1600);
+			/* route EC_SCI to SCI */
+			gpi_route_interrupt(GPE_EC_SCI, GPI_IS_SCI);
+			/* discard all events, and enable attention */
+			ec_write(0x80, 0x01);
+			break;
+		case APM_CNT_ACPI_DISABLE:
+			/* we have to use port 0x62/0x66, as 0x1600/0x1604 doesn't
+			   provide a EC query function */
+			ec_set_ports(0x66, 0x62);
+			/* route EC_SCI to SMI */
+			gpi_route_interrupt(GPE_EC_SCI, GPI_IS_SMI);
+			/* discard all events, and enable attention */
+			ec_write(0x80, 0x01);
+			break;
+		default:
+			break;
+	}
+	return 0;
+}
+
+void mainboard_smi_sleep(u8 slp_typ)
+{
+	if (slp_typ == 3) {
+		u8 ec_wake = ec_read(0x32);
+		/* If EC wake events are enabled, enable wake on EC WAKE GPE. */
+		if (ec_wake & 0x14) {
+			/* Redirect EC WAKE GPE to SCI. */
+			gpi_route_interrupt(GPE_EC_WAKE, GPI_IS_SCI);
+		}
+	}
+}