| /* 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 <timebase.h> |
| #include <opal-api.h> |
| #include <i2c.h> |
| |
| #include "tpm_i2c_interface.h" |
| #include "../status_codes.h" |
| |
| //#define DBG(fmt, ...) prlog(PR_DEBUG, fmt, ##__VA_ARGS__) |
| #define DBG(fmt, ...) |
| |
| #define I2C_BYTE_TIMEOUT_MS 30 /* 30ms/byte timeout */ |
| #define TPM_MAX_NACK_RETRIES 2 |
| #define REQ_COMPLETE_POLLING 5 /* Check if req is complete |
| in 5ms interval */ |
| |
| struct tpm_i2c_userdata { |
| int rc; |
| bool done; |
| }; |
| |
| void tpm_i2c_request_complete(int rc, struct i2c_request *req) |
| { |
| struct tpm_i2c_userdata *ud = req->user_data; |
| ud->rc = rc; |
| ud->done = true; |
| } |
| |
| /** |
| * 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(int tpm_bus_id, int tpm_dev_addr, int read_write, |
| uint32_t offset, uint32_t offset_bytes, void* buf, |
| size_t buflen) |
| { |
| int rc, waited, retries, timeout; |
| struct i2c_request *req; |
| struct i2c_bus *bus; |
| uint64_t time_to_wait = 0; |
| struct tpm_i2c_userdata ud; |
| |
| bus = i2c_find_bus_by_id(tpm_bus_id); |
| if (!bus) { |
| /** |
| * @fwts-label TPMI2CInvalidBusID |
| * @fwts-advice tpm_i2c_request_send was passed an invalid bus |
| * ID. This indicates a tb_init() bug. |
| */ |
| prlog(PR_ERR, "TPM: Invalid bus_id=%x\n", tpm_bus_id); |
| rc = STB_ARG_ERROR; |
| goto out; |
| } |
| |
| req = i2c_alloc_req(bus); |
| if (!req) { |
| /** |
| * @fwts-label TPMI2CAllocationFailed |
| * @fwts-advice OPAL failed to allocate memory for an |
| * i2c_request. This points to an OPAL bug as OPAL run out of |
| * memory and this should never happen. |
| */ |
| prlog(PR_ERR, "TPM: i2c_alloc_req failed\n"); |
| rc = STB_DRIVER_ERROR; |
| goto out; |
| } |
| |
| req->dev_addr = tpm_dev_addr; |
| req->op = read_write; |
| req->offset = offset; |
| req->offset_bytes = offset_bytes; |
| req->rw_buf = (void*) buf; |
| req->rw_len = buflen; |
| req->completion = tpm_i2c_request_complete; |
| ud.done = false; |
| req->user_data = &ud; |
| |
| /* |
| * Set the request timeout to 10ms per byte. Otherwise, we get |
| * an I2C master timeout for all requests sent to the TPM device |
| * since the I2C master's timeout is too short (1ms per byte). |
| */ |
| timeout = (buflen + offset_bytes + 2) * I2C_BYTE_TIMEOUT_MS; |
| |
| for (retries = 0; retries <= TPM_MAX_NACK_RETRIES; retries++) { |
| waited = 0; |
| i2c_set_req_timeout(req, timeout); |
| i2c_queue_req(req); |
| |
| do { |
| time_to_wait = i2c_run_req(req); |
| if (!time_to_wait) |
| time_to_wait = REQ_COMPLETE_POLLING; |
| time_wait(time_to_wait); |
| waited += time_to_wait; |
| } while (!ud.done); |
| |
| rc = ud.rc; |
| |
| if (rc == OPAL_I2C_NACK_RCVD) |
| continue; |
| else |
| /* error or success */ |
| break; |
| } |
| |
| DBG("%s tpm req op=%x offset=%x buf=%016llx buflen=%d delay=%lu/%d," |
| "rc=%d\n", |
| (rc) ? "!!!!" : "----", req->op, req->offset, |
| *(uint64_t*) buf, req->rw_len, tb_to_msecs(waited), timeout, rc); |
| |
| i2c_free_req(req); |
| if (rc) |
| rc = STB_DRIVER_ERROR; |
| out: |
| return rc; |
| } |