1 files changed, 50 insertions, 0 deletions
diff --git a/roms/skiboot/libstb/drivers/tpm_i2c_interface.c b/roms/skiboot/libstb/drivers/tpm_i2c_interface.c
new file mode 100644
index 000000000..84cbab5bb
--- /dev/null
+++ b/roms/skiboot/libstb/drivers/tpm_i2c_interface.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+/* Copyright 2013-2018 IBM Corp. */
+
+#include <skiboot.h>
+#include <opal-api.h>
+#include <i2c.h>
+
+#include "tpm_i2c_interface.h"
+#include "../status_codes.h"
+
+/* TPMs can clock strech I2C operations for a LOOOOOOONG */
+#define I2C_BYTE_TIMEOUT_MS		2000  /* 2000ms/byte timeout */
+
+/**
+ * tpm_i2c_request_send - send request to i2c bus
+ * @tpm_bus_id: i2c bus id
+ * @tpm_dev_addr: address of the tpm device
+ * @read_write: SMBUS_READ or SMBUS_WRITE
+ * @offset: any of the I2C interface offset defined
+ * @offset_bytes: offset size in bytes
+ * @buf: data to be read or written
+ * @buflen: buf length
+ *
+ * This interacts with skiboot i2c API to send an I2C request to the tpm
+ * device
+ *
+ * Returns: Zero on success otherwise a negative error code
+ */
+int tpm_i2c_request_send(struct tpm_dev *tpm_device, int read_write,
+			 uint32_t offset, uint32_t offset_bytes, void* buf,
+			 size_t buflen)
+{
+	int rc, timeout;
+
+	/*
+	 * Set the request timeout to 30ms per byte. Otherwise, we get
+	 * an I2C master timeout for all requests sent to the device
+	 * since the I2C master's timeout is too short (1ms per byte).
+	 */
+	timeout = (buflen + offset_bytes + 2) * I2C_BYTE_TIMEOUT_MS;
+
+	rc = i2c_request_send(tpm_device->bus_id, tpm_device->i2c_addr,
+				read_write, offset, offset_bytes, buf, buflen,
+				timeout);
+	if (rc == OPAL_PARAMETER)
+		return STB_ARG_ERROR;
+	else if (rc < 0)
+		return STB_DRIVER_ERROR;
+	return 0;
+}