| // SPDX-License-Identifier: GPL-2.0 |
| // ChromeOS EC communication protocol helper functions |
| // |
| // Copyright (C) 2015 Google, Inc |
| |
| #include <linux/mfd/cros_ec.h> |
| #include <linux/delay.h> |
| #include <linux/device.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <asm/unaligned.h> |
| |
| #include "cros_ec_trace.h" |
| |
| #define EC_COMMAND_RETRIES 50 |
| |
| static int prepare_packet(struct cros_ec_device *ec_dev, |
| struct cros_ec_command *msg) |
| { |
| struct ec_host_request *request; |
| u8 *out; |
| int i; |
| u8 csum = 0; |
| |
| BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION); |
| BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size); |
| |
| out = ec_dev->dout; |
| request = (struct ec_host_request *)out; |
| request->struct_version = EC_HOST_REQUEST_VERSION; |
| request->checksum = 0; |
| request->command = msg->command; |
| request->command_version = msg->version; |
| request->reserved = 0; |
| request->data_len = msg->outsize; |
| |
| for (i = 0; i < sizeof(*request); i++) |
| csum += out[i]; |
| |
| /* Copy data and update checksum */ |
| memcpy(out + sizeof(*request), msg->data, msg->outsize); |
| for (i = 0; i < msg->outsize; i++) |
| csum += msg->data[i]; |
| |
| request->checksum = -csum; |
| |
| return sizeof(*request) + msg->outsize; |
| } |
| |
| static int send_command(struct cros_ec_device *ec_dev, |
| struct cros_ec_command *msg) |
| { |
| int ret; |
| int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg); |
| |
| trace_cros_ec_cmd(msg); |
| |
| if (ec_dev->proto_version > 2) |
| xfer_fxn = ec_dev->pkt_xfer; |
| else |
| xfer_fxn = ec_dev->cmd_xfer; |
| |
| if (!xfer_fxn) { |
| /* |
| * This error can happen if a communication error happened and |
| * the EC is trying to use protocol v2, on an underlying |
| * communication mechanism that does not support v2. |
| */ |
| dev_err_once(ec_dev->dev, |
| "missing EC transfer API, cannot send command\n"); |
| return -EIO; |
| } |
| |
| ret = (*xfer_fxn)(ec_dev, msg); |
| if (msg->result == EC_RES_IN_PROGRESS) { |
| int i; |
| struct cros_ec_command *status_msg; |
| struct ec_response_get_comms_status *status; |
| |
| status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status), |
| GFP_KERNEL); |
| if (!status_msg) |
| return -ENOMEM; |
| |
| status_msg->version = 0; |
| status_msg->command = EC_CMD_GET_COMMS_STATUS; |
| status_msg->insize = sizeof(*status); |
| status_msg->outsize = 0; |
| |
| /* |
| * Query the EC's status until it's no longer busy or |
| * we encounter an error. |
| */ |
| for (i = 0; i < EC_COMMAND_RETRIES; i++) { |
| usleep_range(10000, 11000); |
| |
| ret = (*xfer_fxn)(ec_dev, status_msg); |
| if (ret == -EAGAIN) |
| continue; |
| if (ret < 0) |
| break; |
| |
| msg->result = status_msg->result; |
| if (status_msg->result != EC_RES_SUCCESS) |
| break; |
| |
| status = (struct ec_response_get_comms_status *) |
| status_msg->data; |
| if (!(status->flags & EC_COMMS_STATUS_PROCESSING)) |
| break; |
| } |
| |
| kfree(status_msg); |
| } |
| |
| return ret; |
| } |
| |
| int cros_ec_prepare_tx(struct cros_ec_device *ec_dev, |
| struct cros_ec_command *msg) |
| { |
| u8 *out; |
| u8 csum; |
| int i; |
| |
| if (ec_dev->proto_version > 2) |
| return prepare_packet(ec_dev, msg); |
| |
| BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE); |
| out = ec_dev->dout; |
| out[0] = EC_CMD_VERSION0 + msg->version; |
| out[1] = msg->command; |
| out[2] = msg->outsize; |
| csum = out[0] + out[1] + out[2]; |
| for (i = 0; i < msg->outsize; i++) |
| csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i]; |
| out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum; |
| |
| return EC_MSG_TX_PROTO_BYTES + msg->outsize; |
| } |
| EXPORT_SYMBOL(cros_ec_prepare_tx); |
| |
| int cros_ec_check_result(struct cros_ec_device *ec_dev, |
| struct cros_ec_command *msg) |
| { |
| switch (msg->result) { |
| case EC_RES_SUCCESS: |
| return 0; |
| case EC_RES_IN_PROGRESS: |
| dev_dbg(ec_dev->dev, "command 0x%02x in progress\n", |
| msg->command); |
| return -EAGAIN; |
| default: |
| dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n", |
| msg->command, msg->result); |
| return 0; |
| } |
| } |
| EXPORT_SYMBOL(cros_ec_check_result); |
| |
| /* |
| * cros_ec_get_host_event_wake_mask |
| * |
| * Get the mask of host events that cause wake from suspend. |
| * |
| * @ec_dev: EC device to call |
| * @msg: message structure to use |
| * @mask: result when function returns >=0. |
| * |
| * LOCKING: |
| * the caller has ec_dev->lock mutex, or the caller knows there is |
| * no other command in progress. |
| */ |
| static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev, |
| struct cros_ec_command *msg, |
| uint32_t *mask) |
| { |
| struct ec_response_host_event_mask *r; |
| int ret; |
| |
| msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK; |
| msg->version = 0; |
| msg->outsize = 0; |
| msg->insize = sizeof(*r); |
| |
| ret = send_command(ec_dev, msg); |
| if (ret > 0) { |
| r = (struct ec_response_host_event_mask *)msg->data; |
| *mask = r->mask; |
| } |
| |
| return ret; |
| } |
| |
| static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev, |
| int devidx, |
| struct cros_ec_command *msg) |
| { |
| /* |
| * Try using v3+ to query for supported protocols. If this |
| * command fails, fall back to v2. Returns the highest protocol |
| * supported by the EC. |
| * Also sets the max request/response/passthru size. |
| */ |
| int ret; |
| |
| if (!ec_dev->pkt_xfer) |
| return -EPROTONOSUPPORT; |
| |
| memset(msg, 0, sizeof(*msg)); |
| msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO; |
| msg->insize = sizeof(struct ec_response_get_protocol_info); |
| |
| ret = send_command(ec_dev, msg); |
| |
| if (ret < 0) { |
| dev_dbg(ec_dev->dev, |
| "failed to check for EC[%d] protocol version: %d\n", |
| devidx, ret); |
| return ret; |
| } |
| |
| if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND) |
| return -ENODEV; |
| else if (msg->result != EC_RES_SUCCESS) |
| return msg->result; |
| |
| return 0; |
| } |
| |
| static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev) |
| { |
| struct cros_ec_command *msg; |
| struct ec_params_hello *hello_params; |
| struct ec_response_hello *hello_response; |
| int ret; |
| int len = max(sizeof(*hello_params), sizeof(*hello_response)); |
| |
| msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL); |
| if (!msg) |
| return -ENOMEM; |
| |
| msg->version = 0; |
| msg->command = EC_CMD_HELLO; |
| hello_params = (struct ec_params_hello *)msg->data; |
| msg->outsize = sizeof(*hello_params); |
| hello_response = (struct ec_response_hello *)msg->data; |
| msg->insize = sizeof(*hello_response); |
| |
| hello_params->in_data = 0xa0b0c0d0; |
| |
| ret = send_command(ec_dev, msg); |
| |
| if (ret < 0) { |
| dev_dbg(ec_dev->dev, |
| "EC failed to respond to v2 hello: %d\n", |
| ret); |
| goto exit; |
| } else if (msg->result != EC_RES_SUCCESS) { |
| dev_err(ec_dev->dev, |
| "EC responded to v2 hello with error: %d\n", |
| msg->result); |
| ret = msg->result; |
| goto exit; |
| } else if (hello_response->out_data != 0xa1b2c3d4) { |
| dev_err(ec_dev->dev, |
| "EC responded to v2 hello with bad result: %u\n", |
| hello_response->out_data); |
| ret = -EBADMSG; |
| goto exit; |
| } |
| |
| ret = 0; |
| |
| exit: |
| kfree(msg); |
| return ret; |
| } |
| |
| /* |
| * cros_ec_get_host_command_version_mask |
| * |
| * Get the version mask of a given command. |
| * |
| * @ec_dev: EC device to call |
| * @msg: message structure to use |
| * @cmd: command to get the version of. |
| * @mask: result when function returns 0. |
| * |
| * @return 0 on success, error code otherwise |
| * |
| * LOCKING: |
| * the caller has ec_dev->lock mutex or the caller knows there is |
| * no other command in progress. |
| */ |
| static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev, |
| u16 cmd, u32 *mask) |
| { |
| struct ec_params_get_cmd_versions *pver; |
| struct ec_response_get_cmd_versions *rver; |
| struct cros_ec_command *msg; |
| int ret; |
| |
| msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)), |
| GFP_KERNEL); |
| if (!msg) |
| return -ENOMEM; |
| |
| msg->version = 0; |
| msg->command = EC_CMD_GET_CMD_VERSIONS; |
| msg->insize = sizeof(*rver); |
| msg->outsize = sizeof(*pver); |
| |
| pver = (struct ec_params_get_cmd_versions *)msg->data; |
| pver->cmd = cmd; |
| |
| ret = send_command(ec_dev, msg); |
| if (ret > 0) { |
| rver = (struct ec_response_get_cmd_versions *)msg->data; |
| *mask = rver->version_mask; |
| } |
| |
| kfree(msg); |
| |
| return ret; |
| } |
| |
| int cros_ec_query_all(struct cros_ec_device *ec_dev) |
| { |
| struct device *dev = ec_dev->dev; |
| struct cros_ec_command *proto_msg; |
| struct ec_response_get_protocol_info *proto_info; |
| u32 ver_mask = 0; |
| int ret; |
| |
| proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info), |
| GFP_KERNEL); |
| if (!proto_msg) |
| return -ENOMEM; |
| |
| /* First try sending with proto v3. */ |
| ec_dev->proto_version = 3; |
| ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg); |
| |
| if (ret == 0) { |
| proto_info = (struct ec_response_get_protocol_info *) |
| proto_msg->data; |
| ec_dev->max_request = proto_info->max_request_packet_size - |
| sizeof(struct ec_host_request); |
| ec_dev->max_response = proto_info->max_response_packet_size - |
| sizeof(struct ec_host_response); |
| ec_dev->proto_version = |
| min(EC_HOST_REQUEST_VERSION, |
| fls(proto_info->protocol_versions) - 1); |
| dev_dbg(ec_dev->dev, |
| "using proto v%u\n", |
| ec_dev->proto_version); |
| |
| ec_dev->din_size = ec_dev->max_response + |
| sizeof(struct ec_host_response) + |
| EC_MAX_RESPONSE_OVERHEAD; |
| ec_dev->dout_size = ec_dev->max_request + |
| sizeof(struct ec_host_request) + |
| EC_MAX_REQUEST_OVERHEAD; |
| |
| /* |
| * Check for PD |
| */ |
| ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg); |
| |
| if (ret) { |
| dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret); |
| ec_dev->max_passthru = 0; |
| } else { |
| dev_dbg(ec_dev->dev, "found PD chip\n"); |
| ec_dev->max_passthru = |
| proto_info->max_request_packet_size - |
| sizeof(struct ec_host_request); |
| } |
| } else { |
| /* Try querying with a v2 hello message. */ |
| ec_dev->proto_version = 2; |
| ret = cros_ec_host_command_proto_query_v2(ec_dev); |
| |
| if (ret == 0) { |
| /* V2 hello succeeded. */ |
| dev_dbg(ec_dev->dev, "falling back to proto v2\n"); |
| |
| ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE; |
| ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE; |
| ec_dev->max_passthru = 0; |
| ec_dev->pkt_xfer = NULL; |
| ec_dev->din_size = EC_PROTO2_MSG_BYTES; |
| ec_dev->dout_size = EC_PROTO2_MSG_BYTES; |
| } else { |
| /* |
| * It's possible for a test to occur too early when |
| * the EC isn't listening. If this happens, we'll |
| * test later when the first command is run. |
| */ |
| ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN; |
| dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret); |
| goto exit; |
| } |
| } |
| |
| devm_kfree(dev, ec_dev->din); |
| devm_kfree(dev, ec_dev->dout); |
| |
| ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL); |
| if (!ec_dev->din) { |
| ret = -ENOMEM; |
| goto exit; |
| } |
| |
| ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL); |
| if (!ec_dev->dout) { |
| devm_kfree(dev, ec_dev->din); |
| ret = -ENOMEM; |
| goto exit; |
| } |
| |
| /* Probe if MKBP event is supported */ |
| ret = cros_ec_get_host_command_version_mask(ec_dev, |
| EC_CMD_GET_NEXT_EVENT, |
| &ver_mask); |
| if (ret < 0 || ver_mask == 0) |
| ec_dev->mkbp_event_supported = 0; |
| else |
| ec_dev->mkbp_event_supported = 1; |
| |
| /* Probe if host sleep v1 is supported for S0ix failure detection. */ |
| ret = cros_ec_get_host_command_version_mask(ec_dev, |
| EC_CMD_HOST_SLEEP_EVENT, |
| &ver_mask); |
| ec_dev->host_sleep_v1 = (ret >= 0 && (ver_mask & EC_VER_MASK(1))); |
| |
| /* |
| * Get host event wake mask, assume all events are wake events |
| * if unavailable. |
| */ |
| ret = cros_ec_get_host_event_wake_mask(ec_dev, proto_msg, |
| &ec_dev->host_event_wake_mask); |
| if (ret < 0) |
| ec_dev->host_event_wake_mask = U32_MAX; |
| |
| ret = 0; |
| |
| exit: |
| kfree(proto_msg); |
| return ret; |
| } |
| EXPORT_SYMBOL(cros_ec_query_all); |
| |
| int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev, |
| struct cros_ec_command *msg) |
| { |
| int ret; |
| |
| mutex_lock(&ec_dev->lock); |
| if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) { |
| ret = cros_ec_query_all(ec_dev); |
| if (ret) { |
| dev_err(ec_dev->dev, |
| "EC version unknown and query failed; aborting command\n"); |
| mutex_unlock(&ec_dev->lock); |
| return ret; |
| } |
| } |
| |
| if (msg->insize > ec_dev->max_response) { |
| dev_dbg(ec_dev->dev, "clamping message receive buffer\n"); |
| msg->insize = ec_dev->max_response; |
| } |
| |
| if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) { |
| if (msg->outsize > ec_dev->max_request) { |
| dev_err(ec_dev->dev, |
| "request of size %u is too big (max: %u)\n", |
| msg->outsize, |
| ec_dev->max_request); |
| mutex_unlock(&ec_dev->lock); |
| return -EMSGSIZE; |
| } |
| } else { |
| if (msg->outsize > ec_dev->max_passthru) { |
| dev_err(ec_dev->dev, |
| "passthru rq of size %u is too big (max: %u)\n", |
| msg->outsize, |
| ec_dev->max_passthru); |
| mutex_unlock(&ec_dev->lock); |
| return -EMSGSIZE; |
| } |
| } |
| ret = send_command(ec_dev, msg); |
| mutex_unlock(&ec_dev->lock); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(cros_ec_cmd_xfer); |
| |
| int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev, |
| struct cros_ec_command *msg) |
| { |
| int ret; |
| |
| ret = cros_ec_cmd_xfer(ec_dev, msg); |
| if (ret < 0) { |
| dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret); |
| } else if (msg->result != EC_RES_SUCCESS) { |
| dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result); |
| return -EPROTO; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(cros_ec_cmd_xfer_status); |
| |
| static int get_next_event_xfer(struct cros_ec_device *ec_dev, |
| struct cros_ec_command *msg, |
| int version, uint32_t size) |
| { |
| int ret; |
| |
| msg->version = version; |
| msg->command = EC_CMD_GET_NEXT_EVENT; |
| msg->insize = size; |
| msg->outsize = 0; |
| |
| ret = cros_ec_cmd_xfer(ec_dev, msg); |
| if (ret > 0) { |
| ec_dev->event_size = ret - 1; |
| memcpy(&ec_dev->event_data, msg->data, ret); |
| } |
| |
| return ret; |
| } |
| |
| static int get_next_event(struct cros_ec_device *ec_dev) |
| { |
| u8 buffer[sizeof(struct cros_ec_command) + sizeof(ec_dev->event_data)]; |
| struct cros_ec_command *msg = (struct cros_ec_command *)&buffer; |
| static int cmd_version = 1; |
| int ret; |
| |
| if (ec_dev->suspended) { |
| dev_dbg(ec_dev->dev, "Device suspended.\n"); |
| return -EHOSTDOWN; |
| } |
| |
| if (cmd_version == 1) { |
| ret = get_next_event_xfer(ec_dev, msg, cmd_version, |
| sizeof(struct ec_response_get_next_event_v1)); |
| if (ret < 0 || msg->result != EC_RES_INVALID_VERSION) |
| return ret; |
| |
| /* Fallback to version 0 for future send attempts */ |
| cmd_version = 0; |
| } |
| |
| ret = get_next_event_xfer(ec_dev, msg, cmd_version, |
| sizeof(struct ec_response_get_next_event)); |
| |
| return ret; |
| } |
| |
| static int get_keyboard_state_event(struct cros_ec_device *ec_dev) |
| { |
| u8 buffer[sizeof(struct cros_ec_command) + |
| sizeof(ec_dev->event_data.data)]; |
| struct cros_ec_command *msg = (struct cros_ec_command *)&buffer; |
| |
| msg->version = 0; |
| msg->command = EC_CMD_MKBP_STATE; |
| msg->insize = sizeof(ec_dev->event_data.data); |
| msg->outsize = 0; |
| |
| ec_dev->event_size = cros_ec_cmd_xfer(ec_dev, msg); |
| ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX; |
| memcpy(&ec_dev->event_data.data, msg->data, |
| sizeof(ec_dev->event_data.data)); |
| |
| return ec_dev->event_size; |
| } |
| |
| int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event) |
| { |
| u8 event_type; |
| u32 host_event; |
| int ret; |
| |
| if (!ec_dev->mkbp_event_supported) { |
| ret = get_keyboard_state_event(ec_dev); |
| if (ret <= 0) |
| return ret; |
| |
| if (wake_event) |
| *wake_event = true; |
| |
| return ret; |
| } |
| |
| ret = get_next_event(ec_dev); |
| if (ret <= 0) |
| return ret; |
| |
| if (wake_event) { |
| event_type = ec_dev->event_data.event_type; |
| host_event = cros_ec_get_host_event(ec_dev); |
| |
| /* |
| * Sensor events need to be parsed by the sensor sub-device. |
| * Defer them, and don't report the wakeup here. |
| */ |
| if (event_type == EC_MKBP_EVENT_SENSOR_FIFO) |
| *wake_event = false; |
| /* Masked host-events should not count as wake events. */ |
| else if (host_event && |
| !(host_event & ec_dev->host_event_wake_mask)) |
| *wake_event = false; |
| /* Consider all other events as wake events. */ |
| else |
| *wake_event = true; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(cros_ec_get_next_event); |
| |
| u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev) |
| { |
| u32 host_event; |
| |
| BUG_ON(!ec_dev->mkbp_event_supported); |
| |
| if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT) |
| return 0; |
| |
| if (ec_dev->event_size != sizeof(host_event)) { |
| dev_warn(ec_dev->dev, "Invalid host event size\n"); |
| return 0; |
| } |
| |
| host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event); |
| |
| return host_event; |
| } |
| EXPORT_SYMBOL(cros_ec_get_host_event); |