1 files changed, 51 insertions, 0 deletions
diff --git a/src/southbridge/via/common/early_smbus_read_byte.c b/src/southbridge/via/common/early_smbus_read_byte.c
new file mode 100644
index 0000000000..de76ac9175
--- /dev/null
+++ b/src/southbridge/via/common/early_smbus_read_byte.c
@@ -0,0 +1,51 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2013  Alexandru Gagniuc <mr.nuke.me@gmail.com>
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "via_early_smbus.h"
+
+/**
+ * \brief Read a byte from the SMBus.
+ *
+ * @param smbus_dev The base SMBus IO port
+ * @param addr The address location of the DIMM on the SMBus.
+ * @param offset The offset the data is located at.
+ */
+u8 smbus_read_byte(u32 smbus_dev, u8 addr, u8 offset)
+{
+	u8 val;
+
+	/* Initialize SMBus sequence */
+	smbus_reset(smbus_dev);
+	/* Clear host data port. */
+	outb(0x00, SMBHSTDAT0(smbus_dev));
+
+	smbus_wait_until_ready(smbus_dev);
+
+	/* Actual addr to reg format. */
+	addr = (addr << 1);
+	addr |= 1;		/* read command */
+	outb(addr, SMBXMITADD(smbus_dev));
+	outb(offset, SMBHSTCMD(smbus_dev));
+	/* Start transaction, byte data read. */
+	outb(0x48, SMBHSTCTL(smbus_dev));
+	smbus_wait_until_ready(smbus_dev);
+
+	val = inb(SMBHSTDAT0(smbus_dev));
+	return val;
+}