1 files changed, 105 insertions, 0 deletions
diff --git a/src/southbridge/intel/i82801dx/smbus.c b/src/southbridge/intel/i82801dx/smbus.c
new file mode 100644
index 0000000000..1f7e47be95
--- /dev/null
+++ b/src/southbridge/intel/i82801dx/smbus.c
@@ -0,0 +1,105 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2004 Ronald G. Minnich
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "i82801dx.h"
+#include <smbus.h>
+#include <pci.h>
+#include <arch/io.h>
+
+#define PM_BUS 0
+#define PM_DEVFN PCI_DEVFN(0x1f,3)
+
+void smbus_enable(void)
+{
+	unsigned char byte;
+	/* iobase addr */
+	pcibios_write_config_dword(PM_BUS, PM_DEVFN, 0x20, SMBUS_IO_BASE | 1);
+	/* smbus enable */
+	pcibios_write_config_byte(PM_BUS, PM_DEVFN, 0x40, 1);
+	/* iospace enable */
+	pcibios_write_config_word(PM_BUS, PM_DEVFN, 0x4, 1);
+
+	/* Disable interrupt generation */
+	outb(0, SMBUS_IO_BASE + SMBHSTCTL);
+
+}
+
+void smbus_setup(void)
+{
+	outb(0, SMBUS_IO_BASE + SMBHSTSTAT);
+}
+
+static void smbus_wait_until_ready(void)
+{
+	while ((inb(SMBUS_IO_BASE + SMBHSTSTAT) & 1) == 1) {
+		/* nop */
+	}
+}
+
+static void smbus_wait_until_done(void)
+{
+	unsigned char byte;
+	do {
+		byte = inb(SMBUS_IO_BASE + SMBHSTSTAT);
+	}
+	while ((byte & 1) == 1);
+	while ((byte & ~1) == 0) {
+		byte = inb(SMBUS_IO_BASE + SMBHSTSTAT);
+	}
+}
+
+int smbus_read_byte(unsigned device, unsigned address, unsigned char *result)
+{
+	unsigned char host_status_register;
+	unsigned char byte;
+
+	smbus_wait_until_ready();
+
+	/* setup transaction */
+	/* disable interrupts */
+	outb(inb(SMBUS_IO_BASE + SMBHSTCTL) & (~1), SMBUS_IO_BASE + SMBHSTCTL);
+	/* set the device I'm talking too */
+	outb(((device & 0x7f) << 1) | 1, SMBUS_IO_BASE + SMBHSTADD);
+	/* set the command/address... */
+	outb(address & 0xFF, SMBUS_IO_BASE + SMBHSTCMD);
+	/* set up for a byte data read */
+	outb((inb(SMBUS_IO_BASE + SMBHSTCTL) & 0xE3) | (0x2 << 2),
+	     SMBUS_IO_BASE + SMBHSTCTL);
+
+	/* clear any lingering errors, so the transaction will run */
+	outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), SMBUS_IO_BASE + SMBHSTSTAT);
+
+	/* clear the data byte... */
+	outb(0, SMBUS_IO_BASE + SMBHSTDAT0);
+
+	/* start the command */
+	outb((inb(SMBUS_IO_BASE + SMBHSTCTL) | 0x40),
+	     SMBUS_IO_BASE + SMBHSTCTL);
+
+	/* poll for transaction completion */
+	smbus_wait_until_done();
+
+	host_status_register = inb(SMBUS_IO_BASE + SMBHSTSTAT);
+
+	/* read results of transaction */
+	byte = inb(SMBUS_IO_BASE + SMBHSTDAT0);
+
+	*result = byte;
+	return host_status_register != 0x02;
+}