superio/fintek/f81866d: Add support for UART 3/4

Pins for UART 3/4 are by default GPIO pins.
This patch sets the pins in UART mode.
Since UART 1/3 and 2/4 share the same interrupt line,
the patch needs to enable also shared interrupts.
Datasheet: Name: F81866D/A-I, Release Date: Jan 2012, Version: V0.12P
Link: http://www.alldatasheet.com/datasheet-pdf/pdf/459085/FINTEK/F81866AD-I.html

Change-Id: Ief5d70c8b25a2fb6cd787c45a52410e20b0eaf2e
Signed-off-by: Fabian Kunkel <fabi@adv.bruhnspace.com>
Reviewed-on: https://review.coreboot.org/15564
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/superio/fintek/f81866d/Makefile.inc

@@ -16,5 +16,5 @@
 ## GNU General Public License for more details.
 ##
 
-ramstage-$(CONFIG_SUPERIO_FINTEK_F81866D) += f81866d_hwm.c
+ramstage-$(CONFIG_SUPERIO_FINTEK_F81866D) += f81866d_hwm.c f81866d_uart.c
 ramstage-$(CONFIG_SUPERIO_FINTEK_F81866D) += superio.c

src/superio/fintek/f81866d/f81866d_uart.c

@@ -0,0 +1,74 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2015 BAP - Bruhnspace Advanced Projects
+ * (Written by Fabian Kunkel <fabi@adv.bruhnspace.com> for BAP)
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 <device/device.h>
+#include <device/pnp.h>
+#include "fintek_internal.h"
+#include "f81866d.h"
+
+#define LDN_REG			0x07
+#define PORT_SELECT_REGISTER	0x27
+#define MULTI_FUNC_SEL3_REG	0x29
+#define IRQ_SHARE_REGISTER	0xF0
+#define FIFO_SEL_MODE		0xF6
+
+/*
+ * f81866d_uart_init enables all necessary registers for UART 3/4
+ * Fintek needs to know if pins are used as GPIO or UART pins
+ * Share interrupt usage needs to be enabled
+ */
+void f81866d_uart_init(struct device *dev)
+{
+	struct resource *res = find_resource(dev, PNP_IDX_IO0);
+	u8 tmp;
+
+	if (!res) {
+		printk(BIOS_WARNING, "%s: No UART resource found.\n", __func__);
+		return;
+	}
+
+	pnp_enter_conf_mode(dev);
+
+	// Set Port Select Register (Bit 0) = 0
+	// before accessing Multi Function Select 3 Register
+	tmp = pnp_read_config(dev, PORT_SELECT_REGISTER);
+	pnp_write_config(dev, PORT_SELECT_REGISTER, tmp & 0xFE);
+
+	// Set UART 3 function (Bit 4/5), otherwise pin 36-43 are GPIO
+	if (dev->path.pnp.device ==  F81866D_SP3) {
+		tmp = pnp_read_config(dev, MULTI_FUNC_SEL3_REG);
+		pnp_write_config(dev, MULTI_FUNC_SEL3_REG, tmp | 0x30);
+	}
+
+	// Set UART 4 function (Bit 6/7), otherwise pin 44-51 are GPIO
+	if (dev->path.pnp.device ==  F81866D_SP4) {
+		tmp = pnp_read_config(dev, MULTI_FUNC_SEL3_REG);
+		pnp_write_config(dev, MULTI_FUNC_SEL3_REG, tmp | 0xC0);
+	}
+
+	// Select UART X in LDN register
+	pnp_write_config(dev, LDN_REG, dev->path.pnp.device & 0xff);
+	// Set IRQ trigger mode from active low to high (Bit 3)
+	tmp = pnp_read_config(dev, FIFO_SEL_MODE);
+	pnp_write_config(dev, FIFO_SEL_MODE, tmp | 0x8);
+	// Enable share interrupt (Bit 0)
+	pnp_write_config(dev, IRQ_SHARE_REGISTER, 0x01);
+
+	pnp_exit_conf_mode(dev);
+}

src/superio/fintek/f81866d/fintek_internal.h

@@ -23,5 +23,6 @@
 #include <device/pnp.h>
 
 void f81866d_hwm_init(struct device *dev);
+void f81866d_uart_init(struct device *dev);
 
 #endif /* SUPERIO_FINTEK_F81866D_INTERNAL_H */

src/superio/fintek/f81866d/superio.c

@@ -40,6 +40,22 @@ static void f81866d_init(struct device *dev)
 		// Fixing temp sensor read out and init Fan control
 		f81866d_hwm_init(dev);
 		break;
+	case F81866D_SP1:
+		// Enable Uart1 and IRQ share register
+		f81866d_uart_init(dev);
+		break;
+	case F81866D_SP2:
+		// Enable Uart2 and IRQ share register
+		f81866d_uart_init(dev);
+		break;
+	case F81866D_SP3:
+		// Enable Uart3 and IRQ share register
+		f81866d_uart_init(dev);
+		break;
+	case F81866D_SP4:
+		// Enable Uart4 and IRQ share register
+		f81866d_uart_init(dev);
+		break;
 	}
 }