1 files changed, 94 insertions, 0 deletions
diff --git a/src/soc/intel/sch/smbus.h b/src/soc/intel/sch/smbus.h
new file mode 100644
index 0000000000..e34ca52cb0
--- /dev/null
+++ b/src/soc/intel/sch/smbus.h
@@ -0,0 +1,94 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2005 Yinghai Lu <yinghailu@gmail.com>
+ * Copyright (C) 2009 coresystems GmbH
+ *
+ * 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 <device/smbus_def.h>
+
+static void smbus_delay(void)
+{
+	inb(0x80);
+}
+
+static int smbus_wait_until_ready(u16 smbus_base)
+{
+	unsigned loops = SMBUS_TIMEOUT;
+	unsigned char byte;
+	do {
+		smbus_delay();
+		if (--loops == 0)
+			break;
+		byte = inb(smbus_base + SMBHSTSTAT);
+	} while (byte & 1);
+	return loops ? 0 : -1;
+}
+
+static int smbus_wait_until_done(u16 smbus_base)
+{
+	unsigned loops = SMBUS_TIMEOUT;
+	unsigned char byte;
+	do {
+		smbus_delay();
+		if (--loops == 0)
+			break;
+		byte = inb(smbus_base + SMBHSTSTAT);
+	} while ((byte & 1) || (byte & ~((1 << 6) | (1 << 0))) == 0);
+	return loops ? 0 : -1;
+}
+
+static int do_smbus_read_byte(unsigned smbus_base, unsigned device,
+			      unsigned address)
+{
+	unsigned char global_status_register;
+	unsigned char byte;
+
+	if (smbus_wait_until_ready(smbus_base) < 0) {
+		return SMBUS_WAIT_UNTIL_READY_TIMEOUT;
+	}
+	/* Setup transaction */
+	/* Disable interrupts */
+	outb(inb(smbus_base + SMBHSTCTL) & (~1), smbus_base + SMBHSTCTL);
+	/* Set the device I'm talking too */
+	outb(((device & 0x7f) << 1) | 1, smbus_base + SMBXMITADD);
+	/* Set the command/address... */
+	outb(address & 0xff, smbus_base + SMBHSTCMD);
+	/* Set up for a byte data read */
+	outb((inb(smbus_base + SMBHSTCTL) & 0xe3) | (0x2 << 2),
+	     (smbus_base + SMBHSTCTL));
+	/* Clear any lingering errors, so the transaction will run */
+	outb(inb(smbus_base + SMBHSTSTAT), smbus_base + SMBHSTSTAT);
+
+	/* Clear the data byte... */
+	outb(0, smbus_base + SMBHSTDAT0);
+
+	/* Start the command */
+	outb((inb(smbus_base + SMBHSTCTL) | 0x40), smbus_base + SMBHSTCTL);
+
+	/* Poll for transaction completion */
+	if (smbus_wait_until_done(smbus_base) < 0) {
+		return SMBUS_WAIT_UNTIL_DONE_TIMEOUT;
+	}
+
+	global_status_register = inb(smbus_base + SMBHSTSTAT);
+
+	/* Ignore the "In Use" status... */
+	global_status_register &= ~(3 << 5);
+
+	/* Read results of transaction */
+	byte = inb(smbus_base + SMBHSTDAT0);
+	if (global_status_register != (1 << 1)) {
+		return SMBUS_ERROR;
+	}
+	return byte;
+}