soc/intel/common/block: Add Intel common SMBus code

Add below code support under intel/common/block:

* SMBus read/write byte APIs
* Common SMBus initialization code

Change-Id: I936143a334c31937d557c6828e5876d35b133567
Signed-off-by: Aamir Bohra <aamir.bohra@intel.com>
Reviewed-on: https://review.coreboot.org/19372
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

1 files changed, 137 insertions, 0 deletions

diff --git a/src/soc/intel/common/block/smbus/smbuslib.c b/src/soc/intel/common/block/smbus/smbuslib.c
new file mode 100644
index 000000000000..a865abfc304b
--- /dev/null
+++ b/src/soc/intel/common/block/smbus/smbuslib.c
@@ -0,0 +1,137 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2017 Intel Corporation.
+ *
+ * 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 <device/smbus_def.h>
+#include <timer.h>
+#include "smbuslib.h"
+
+static int smbus_wait_till_ready(u16 smbus_base)
+{
+	struct stopwatch sw;
+	unsigned char byte;
+
+	stopwatch_init_msecs_expire(&sw, SMBUS_TIMEOUT);
+	do {
+		byte = inb(smbus_base + SMBHSTSTAT);
+		if (!(byte & 1))
+			return 0;
+	} while (!stopwatch_expired(&sw));
+	return -1;
+}
+
+static int smbus_wait_till_done(u16 smbus_base)
+{
+	struct stopwatch sw;
+	unsigned char byte;
+
+	stopwatch_init_msecs_expire(&sw, SMBUS_TIMEOUT);
+	do {
+		byte = inb(smbus_base + SMBHSTSTAT);
+		if (!((byte & 1) || (byte & ~((1 << 6) | (1 << 0))) == 0))
+			return 0;
+	} while (!stopwatch_expired(&sw));
+	return -1;
+}
+
+int smbus_read8(unsigned int smbus_base, unsigned int device,
+	unsigned int address)
+{
+	unsigned char global_status_register;
+	unsigned char byte;
+
+	if (smbus_wait_till_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_till_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;
+}
+
+int smbus_write8(unsigned int smbus_base, unsigned int device,
+			unsigned int address, unsigned int data)
+{
+	unsigned char global_status_register;
+
+	if (smbus_wait_till_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) & ~0x01, 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(data, smbus_base + SMBHSTDAT0);
+
+	/* Start the command */
+	outb((inb(smbus_base + SMBHSTCTL) | 0x40),
+	     smbus_base + SMBHSTCTL);
+
+	/* Poll for transaction completion */
+	if (smbus_wait_till_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 */
+	if (global_status_register != (1 << 1))
+		return SMBUS_ERROR;
+
+	return 0;
+}