| // SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later |
| /* |
| * I2C |
| * |
| * Copyright 2013-2019 IBM Corp. |
| */ |
| |
| #include <skiboot.h> |
| #include <i2c.h> |
| #include <opal.h> |
| #include <device.h> |
| #include <opal-msg.h> |
| #include <timebase.h> |
| #include <processor.h> |
| #include <timer.h> |
| |
| 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, |
| cpu_to_be64(token), |
| cpu_to_be64(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; |
| size_t i, count; |
| char buf[17]; /* 8 bytes in hex + NUL */ |
| |
| 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; |
| } |
| |
| count = 0; |
| for (i = 0; i < req->rw_len && count < sizeof(buf); i++) { |
| count += snprintf(buf+count, sizeof(buf)-count, "%02x", |
| *(unsigned char *)(req->rw_buf+i)); |
| } |
| |
| prlog(PR_DEBUG, "I2C: %s req op=%x offset=%x buf=%s buflen=%d " |
| "delay=%lu/%lld rc=%lld\n", |
| (rc) ? "!!!!" : "----", req->op, req->offset, |
| 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; |
| } |