/* Copyright 2013-2014 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 #include #include #include #include #include #include #include static LIST_HEAD(i2c_bus_list); /* Used to assign OPAL IDs */ static uint32_t i2c_next_bus; void i2c_add_bus(struct i2c_bus *bus) { bus->opal_id = ++i2c_next_bus; dt_add_property_cells(bus->dt_node, "ibm,opal-id", bus->opal_id); list_add_tail(&i2c_bus_list, &bus->link); } struct i2c_bus *i2c_find_bus_by_id(uint32_t opal_id) { struct i2c_bus *bus; list_for_each(&i2c_bus_list, bus, link) { if (bus->opal_id == opal_id) return bus; } return NULL; } static void opal_i2c_request_complete(int rc, struct i2c_request *req) { uint64_t token = (uint64_t)(unsigned long)req->user_data; opal_queue_msg(OPAL_MSG_ASYNC_COMP, NULL, NULL, token, rc); free(req); } static int opal_i2c_request(uint64_t async_token, uint32_t bus_id, struct opal_i2c_request *oreq) { struct i2c_bus *bus = NULL; struct i2c_request *req; int rc; if (!opal_addr_valid(oreq)) return OPAL_PARAMETER; if (oreq->flags & OPAL_I2C_ADDR_10) return OPAL_UNSUPPORTED; bus = i2c_find_bus_by_id(bus_id); if (!bus) { /** * @fwts-label I2CInvalidBusID * @fwts-advice opal_i2c_request was passed an invalid bus * ID. This has likely come from the OS rather than OPAL * and thus could indicate an OS bug rather than an OPAL * bug. */ prlog(PR_ERR, "I2C: Invalid 'bus_id' passed to the OPAL\n"); return OPAL_PARAMETER; } req = zalloc(sizeof(*req)); if (!req) { /** * @fwts-label I2CFailedAllocation * @fwts-advice OPAL failed to allocate memory for an * i2c_request. This points to an OPAL bug as OPAL ran * out of memory and this should never happen. */ prlog(PR_ERR, "I2C: Failed to allocate 'i2c_request'\n"); return OPAL_NO_MEM; } switch(oreq->type) { case OPAL_I2C_RAW_READ: req->op = I2C_READ; break; case OPAL_I2C_RAW_WRITE: req->op = I2C_WRITE; break; case OPAL_I2C_SM_READ: req->op = SMBUS_READ; req->offset = be32_to_cpu(oreq->subaddr); req->offset_bytes = oreq->subaddr_sz; break; case OPAL_I2C_SM_WRITE: req->op = SMBUS_WRITE; req->offset = be32_to_cpu(oreq->subaddr); req->offset_bytes = oreq->subaddr_sz; break; default: free(req); return OPAL_PARAMETER; } req->dev_addr = be16_to_cpu(oreq->addr); req->rw_len = be32_to_cpu(oreq->size); req->rw_buf = (void *)be64_to_cpu(oreq->buffer_ra); req->completion = opal_i2c_request_complete; req->user_data = (void *)(unsigned long)async_token; req->bus = bus; if (i2c_check_quirk(req, &rc)) { free(req); return rc; } /* Finally, queue the OPAL i2c request and return */ rc = i2c_queue_req(req); if (rc) { free(req); return rc; } return OPAL_ASYNC_COMPLETION; } opal_call(OPAL_I2C_REQUEST, opal_i2c_request, 3); #define MAX_NACK_RETRIES 2 #define REQ_COMPLETE_POLLING 5 /* Check if req is complete in 5ms interval */ int64_t i2c_request_sync(struct i2c_request *req) { uint64_t timer_period = msecs_to_tb(5), timer_count; uint64_t time_to_wait = 0; int64_t rc, waited, retries; for (retries = 0; retries <= MAX_NACK_RETRIES; retries++) { waited = 0; timer_count = 0; 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; timer_count += time_to_wait; if (timer_count > timer_period) { /* * The above request may be relying on * timers to complete, yet there may * not be called, especially during * opal init. We could be looping here * forever. So explicitly check the * timers once in a while */ check_timers(false); timer_count = 0; } } while (req->req_state != i2c_req_done); lwsync(); rc = req->result; /* retry on NACK, otherwise exit */ if (rc != OPAL_I2C_NACK_RCVD) break; req->req_state = i2c_req_new; } prlog(PR_DEBUG, "I2C: %s req op=%x offset=%x buf=%016llx buflen=%d " "delay=%lu/%lld rc=%lld\n", (rc) ? "!!!!" : "----", req->op, req->offset, *(uint64_t*) req->rw_buf, req->rw_len, tb_to_msecs(waited), req->timeout, rc); return rc; } /** * i2c_request_send - send request to i2c bus synchronously * @bus_id: i2c bus id * @dev_addr: address of the 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 * @timeout: request timeout in milliseconds * * Send an I2C request to a device synchronously * * Returns: Zero on success otherwise a negative error code */ int64_t i2c_request_send(int bus_id, int dev_addr, int read_write, uint32_t offset, uint32_t offset_bytes, void* buf, size_t buflen, int timeout) { struct i2c_request *req; struct i2c_bus *bus; int64_t rc; bus = i2c_find_bus_by_id(bus_id); if (!bus) { /** * @fwts-label I2CInvalidBusID * @fwts-advice i2c_request_send was passed an invalid bus * ID. This indicates a bug. */ prlog(PR_ERR, "I2C: Invalid bus_id=%x\n", bus_id); return OPAL_PARAMETER; } req = zalloc(sizeof(*req)); if (!req) { /** * @fwts-label I2CAllocationFailed * @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, "I2C: allocating i2c_request failed\n"); return OPAL_INTERNAL_ERROR; } req->bus = bus; req->dev_addr = dev_addr; req->op = read_write; req->offset = offset; req->offset_bytes = offset_bytes; req->rw_buf = (void*) buf; req->rw_len = buflen; req->timeout = timeout; rc = i2c_request_sync(req); free(req); if (rc) return OPAL_HARDWARE; return OPAL_SUCCESS; }