1 /* Copyright 2013-2016 IBM Corp.
2 *
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
12 * implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <skiboot.h>
18 #include <opal-api.h>
19 #include <i2c.h>
20
21 #include "tpm_i2c_interface.h"
22 #include "../status_codes.h"
23
24 #define I2C_BYTE_TIMEOUT_MS 30 /* 30ms/byte timeout */
25
26 /**
27 * tpm_i2c_request_send - send request to i2c bus
28 * @tpm_bus_id: i2c bus id
29 * @tpm_dev_addr: address of the tpm device
30 * @read_write: SMBUS_READ or SMBUS_WRITE
31 * @offset: any of the I2C interface offset defined
32 * @offset_bytes: offset size in bytes
33 * @buf: data to be read or written
34 * @buflen: buf length
35 *
36 * This interacts with skiboot i2c API to send an I2C request to the tpm
37 * device
38 *
39 * Returns: Zero on success otherwise a negative error code
40 */
tpm_i2c_request_send(int bus_id,int dev_addr,int read_write,uint32_t offset,uint32_t offset_bytes,void * buf,size_t buflen)41 int tpm_i2c_request_send(int bus_id, int dev_addr, int read_write,
42 uint32_t offset, uint32_t offset_bytes, void* buf,
43 size_t buflen)
44 {
45 int rc, timeout;
46
47 /*
48 * Set the request timeout to 30ms per byte. Otherwise, we get
49 * an I2C master timeout for all requests sent to the device
50 * since the I2C master's timeout is too short (1ms per byte).
51 */
52 timeout = (buflen + offset_bytes + 2) * I2C_BYTE_TIMEOUT_MS;
53
54 rc = i2c_request_send(bus_id, dev_addr, read_write, offset,
55 offset_bytes, buf, buflen, timeout);
56 if (rc == OPAL_PARAMETER)
57 return STB_ARG_ERROR;
58 else if (rc < 0)
59 return STB_DRIVER_ERROR;
60 return 0;
61 }
62