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/* Copyright 2013-2016 IBM Corp.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#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;
}
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