diff options
Diffstat (limited to 'drivers/greybus/operation.c')
| -rw-r--r-- | drivers/greybus/operation.c | 1264 |
1 files changed, 1264 insertions, 0 deletions
diff --git a/drivers/greybus/operation.c b/drivers/greybus/operation.c new file mode 100644 index 000000000..8459e9bc0 --- /dev/null +++ b/drivers/greybus/operation.c @@ -0,0 +1,1264 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Greybus operations + * + * Copyright 2014-2015 Google Inc. + * Copyright 2014-2015 Linaro Ltd. + */ + +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/wait.h> +#include <linux/workqueue.h> +#include <linux/greybus.h> + +#include "greybus_trace.h" + +static struct kmem_cache *gb_operation_cache; +static struct kmem_cache *gb_message_cache; + +/* Workqueue to handle Greybus operation completions. */ +static struct workqueue_struct *gb_operation_completion_wq; + +/* Wait queue for synchronous cancellations. */ +static DECLARE_WAIT_QUEUE_HEAD(gb_operation_cancellation_queue); + +/* + * Protects updates to operation->errno. + */ +static DEFINE_SPINLOCK(gb_operations_lock); + +static int gb_operation_response_send(struct gb_operation *operation, + int errno); + +/* + * Increment operation active count and add to connection list unless the + * connection is going away. + * + * Caller holds operation reference. + */ +static int gb_operation_get_active(struct gb_operation *operation) +{ + struct gb_connection *connection = operation->connection; + unsigned long flags; + + spin_lock_irqsave(&connection->lock, flags); + switch (connection->state) { + case GB_CONNECTION_STATE_ENABLED: + break; + case GB_CONNECTION_STATE_ENABLED_TX: + if (gb_operation_is_incoming(operation)) + goto err_unlock; + break; + case GB_CONNECTION_STATE_DISCONNECTING: + if (!gb_operation_is_core(operation)) + goto err_unlock; + break; + default: + goto err_unlock; + } + + if (operation->active++ == 0) + list_add_tail(&operation->links, &connection->operations); + + trace_gb_operation_get_active(operation); + + spin_unlock_irqrestore(&connection->lock, flags); + + return 0; + +err_unlock: + spin_unlock_irqrestore(&connection->lock, flags); + + return -ENOTCONN; +} + +/* Caller holds operation reference. */ +static void gb_operation_put_active(struct gb_operation *operation) +{ + struct gb_connection *connection = operation->connection; + unsigned long flags; + + spin_lock_irqsave(&connection->lock, flags); + + trace_gb_operation_put_active(operation); + + if (--operation->active == 0) { + list_del(&operation->links); + if (atomic_read(&operation->waiters)) + wake_up(&gb_operation_cancellation_queue); + } + spin_unlock_irqrestore(&connection->lock, flags); +} + +static bool gb_operation_is_active(struct gb_operation *operation) +{ + struct gb_connection *connection = operation->connection; + unsigned long flags; + bool ret; + + spin_lock_irqsave(&connection->lock, flags); + ret = operation->active; + spin_unlock_irqrestore(&connection->lock, flags); + + return ret; +} + +/* + * Set an operation's result. + * + * Initially an outgoing operation's errno value is -EBADR. + * If no error occurs before sending the request message the only + * valid value operation->errno can be set to is -EINPROGRESS, + * indicating the request has been (or rather is about to be) sent. + * At that point nobody should be looking at the result until the + * response arrives. + * + * The first time the result gets set after the request has been + * sent, that result "sticks." That is, if two concurrent threads + * race to set the result, the first one wins. The return value + * tells the caller whether its result was recorded; if not the + * caller has nothing more to do. + * + * The result value -EILSEQ is reserved to signal an implementation + * error; if it's ever observed, the code performing the request has + * done something fundamentally wrong. It is an error to try to set + * the result to -EBADR, and attempts to do so result in a warning, + * and -EILSEQ is used instead. Similarly, the only valid result + * value to set for an operation in initial state is -EINPROGRESS. + * Attempts to do otherwise will also record a (successful) -EILSEQ + * operation result. + */ +static bool gb_operation_result_set(struct gb_operation *operation, int result) +{ + unsigned long flags; + int prev; + + if (result == -EINPROGRESS) { + /* + * -EINPROGRESS is used to indicate the request is + * in flight. It should be the first result value + * set after the initial -EBADR. Issue a warning + * and record an implementation error if it's + * set at any other time. + */ + spin_lock_irqsave(&gb_operations_lock, flags); + prev = operation->errno; + if (prev == -EBADR) + operation->errno = result; + else + operation->errno = -EILSEQ; + spin_unlock_irqrestore(&gb_operations_lock, flags); + WARN_ON(prev != -EBADR); + + return true; + } + + /* + * The first result value set after a request has been sent + * will be the final result of the operation. Subsequent + * attempts to set the result are ignored. + * + * Note that -EBADR is a reserved "initial state" result + * value. Attempts to set this value result in a warning, + * and the result code is set to -EILSEQ instead. + */ + if (WARN_ON(result == -EBADR)) + result = -EILSEQ; /* Nobody should be setting -EBADR */ + + spin_lock_irqsave(&gb_operations_lock, flags); + prev = operation->errno; + if (prev == -EINPROGRESS) + operation->errno = result; /* First and final result */ + spin_unlock_irqrestore(&gb_operations_lock, flags); + + return prev == -EINPROGRESS; +} + +int gb_operation_result(struct gb_operation *operation) +{ + int result = operation->errno; + + WARN_ON(result == -EBADR); + WARN_ON(result == -EINPROGRESS); + + return result; +} +EXPORT_SYMBOL_GPL(gb_operation_result); + +/* + * Looks up an outgoing operation on a connection and returns a refcounted + * pointer if found, or NULL otherwise. + */ +static struct gb_operation * +gb_operation_find_outgoing(struct gb_connection *connection, u16 operation_id) +{ + struct gb_operation *operation; + unsigned long flags; + bool found = false; + + spin_lock_irqsave(&connection->lock, flags); + list_for_each_entry(operation, &connection->operations, links) + if (operation->id == operation_id && + !gb_operation_is_incoming(operation)) { + gb_operation_get(operation); + found = true; + break; + } + spin_unlock_irqrestore(&connection->lock, flags); + + return found ? operation : NULL; +} + +static int gb_message_send(struct gb_message *message, gfp_t gfp) +{ + struct gb_connection *connection = message->operation->connection; + + trace_gb_message_send(message); + return connection->hd->driver->message_send(connection->hd, + connection->hd_cport_id, + message, + gfp); +} + +/* + * Cancel a message we have passed to the host device layer to be sent. + */ +static void gb_message_cancel(struct gb_message *message) +{ + struct gb_host_device *hd = message->operation->connection->hd; + + hd->driver->message_cancel(message); +} + +static void gb_operation_request_handle(struct gb_operation *operation) +{ + struct gb_connection *connection = operation->connection; + int status; + int ret; + + if (connection->handler) { + status = connection->handler(operation); + } else { + dev_err(&connection->hd->dev, + "%s: unexpected incoming request of type 0x%02x\n", + connection->name, operation->type); + + status = -EPROTONOSUPPORT; + } + + ret = gb_operation_response_send(operation, status); + if (ret) { + dev_err(&connection->hd->dev, + "%s: failed to send response %d for type 0x%02x: %d\n", + connection->name, status, operation->type, ret); + return; + } +} + +/* + * Process operation work. + * + * For incoming requests, call the protocol request handler. The operation + * result should be -EINPROGRESS at this point. + * + * For outgoing requests, the operation result value should have + * been set before queueing this. The operation callback function + * allows the original requester to know the request has completed + * and its result is available. + */ +static void gb_operation_work(struct work_struct *work) +{ + struct gb_operation *operation; + int ret; + + operation = container_of(work, struct gb_operation, work); + + if (gb_operation_is_incoming(operation)) { + gb_operation_request_handle(operation); + } else { + ret = del_timer_sync(&operation->timer); + if (!ret) { + /* Cancel request message if scheduled by timeout. */ + if (gb_operation_result(operation) == -ETIMEDOUT) + gb_message_cancel(operation->request); + } + + operation->callback(operation); + } + + gb_operation_put_active(operation); + gb_operation_put(operation); +} + +static void gb_operation_timeout(struct timer_list *t) +{ + struct gb_operation *operation = from_timer(operation, t, timer); + + if (gb_operation_result_set(operation, -ETIMEDOUT)) { + /* + * A stuck request message will be cancelled from the + * workqueue. + */ + queue_work(gb_operation_completion_wq, &operation->work); + } +} + +static void gb_operation_message_init(struct gb_host_device *hd, + struct gb_message *message, + u16 operation_id, + size_t payload_size, u8 type) +{ + struct gb_operation_msg_hdr *header; + + header = message->buffer; + + message->header = header; + message->payload = payload_size ? header + 1 : NULL; + message->payload_size = payload_size; + + /* + * The type supplied for incoming message buffers will be + * GB_REQUEST_TYPE_INVALID. Such buffers will be overwritten by + * arriving data so there's no need to initialize the message header. + */ + if (type != GB_REQUEST_TYPE_INVALID) { + u16 message_size = (u16)(sizeof(*header) + payload_size); + + /* + * For a request, the operation id gets filled in + * when the message is sent. For a response, it + * will be copied from the request by the caller. + * + * The result field in a request message must be + * zero. It will be set just prior to sending for + * a response. + */ + header->size = cpu_to_le16(message_size); + header->operation_id = 0; + header->type = type; + header->result = 0; + } +} + +/* + * Allocate a message to be used for an operation request or response. + * Both types of message contain a common header. The request message + * for an outgoing operation is outbound, as is the response message + * for an incoming operation. The message header for an outbound + * message is partially initialized here. + * + * The headers for inbound messages don't need to be initialized; + * they'll be filled in by arriving data. + * + * Our message buffers have the following layout: + * message header \_ these combined are + * message payload / the message size + */ +static struct gb_message * +gb_operation_message_alloc(struct gb_host_device *hd, u8 type, + size_t payload_size, gfp_t gfp_flags) +{ + struct gb_message *message; + struct gb_operation_msg_hdr *header; + size_t message_size = payload_size + sizeof(*header); + + if (message_size > hd->buffer_size_max) { + dev_warn(&hd->dev, "requested message size too big (%zu > %zu)\n", + message_size, hd->buffer_size_max); + return NULL; + } + + /* Allocate the message structure and buffer. */ + message = kmem_cache_zalloc(gb_message_cache, gfp_flags); + if (!message) + return NULL; + + message->buffer = kzalloc(message_size, gfp_flags); + if (!message->buffer) + goto err_free_message; + + /* Initialize the message. Operation id is filled in later. */ + gb_operation_message_init(hd, message, 0, payload_size, type); + + return message; + +err_free_message: + kmem_cache_free(gb_message_cache, message); + + return NULL; +} + +static void gb_operation_message_free(struct gb_message *message) +{ + kfree(message->buffer); + kmem_cache_free(gb_message_cache, message); +} + +/* + * Map an enum gb_operation_status value (which is represented in a + * message as a single byte) to an appropriate Linux negative errno. + */ +static int gb_operation_status_map(u8 status) +{ + switch (status) { + case GB_OP_SUCCESS: + return 0; + case GB_OP_INTERRUPTED: + return -EINTR; + case GB_OP_TIMEOUT: + return -ETIMEDOUT; + case GB_OP_NO_MEMORY: + return -ENOMEM; + case GB_OP_PROTOCOL_BAD: + return -EPROTONOSUPPORT; + case GB_OP_OVERFLOW: + return -EMSGSIZE; + case GB_OP_INVALID: + return -EINVAL; + case GB_OP_RETRY: + return -EAGAIN; + case GB_OP_NONEXISTENT: + return -ENODEV; + case GB_OP_MALFUNCTION: + return -EILSEQ; + case GB_OP_UNKNOWN_ERROR: + default: + return -EIO; + } +} + +/* + * Map a Linux errno value (from operation->errno) into the value + * that should represent it in a response message status sent + * over the wire. Returns an enum gb_operation_status value (which + * is represented in a message as a single byte). + */ +static u8 gb_operation_errno_map(int errno) +{ + switch (errno) { + case 0: + return GB_OP_SUCCESS; + case -EINTR: + return GB_OP_INTERRUPTED; + case -ETIMEDOUT: + return GB_OP_TIMEOUT; + case -ENOMEM: + return GB_OP_NO_MEMORY; + case -EPROTONOSUPPORT: + return GB_OP_PROTOCOL_BAD; + case -EMSGSIZE: + return GB_OP_OVERFLOW; /* Could be underflow too */ + case -EINVAL: + return GB_OP_INVALID; + case -EAGAIN: + return GB_OP_RETRY; + case -EILSEQ: + return GB_OP_MALFUNCTION; + case -ENODEV: + return GB_OP_NONEXISTENT; + case -EIO: + default: + return GB_OP_UNKNOWN_ERROR; + } +} + +bool gb_operation_response_alloc(struct gb_operation *operation, + size_t response_size, gfp_t gfp) +{ + struct gb_host_device *hd = operation->connection->hd; + struct gb_operation_msg_hdr *request_header; + struct gb_message *response; + u8 type; + + type = operation->type | GB_MESSAGE_TYPE_RESPONSE; + response = gb_operation_message_alloc(hd, type, response_size, gfp); + if (!response) + return false; + response->operation = operation; + + /* + * Size and type get initialized when the message is + * allocated. The errno will be set before sending. All + * that's left is the operation id, which we copy from the + * request message header (as-is, in little-endian order). + */ + request_header = operation->request->header; + response->header->operation_id = request_header->operation_id; + operation->response = response; + + return true; +} +EXPORT_SYMBOL_GPL(gb_operation_response_alloc); + +/* + * Create a Greybus operation to be sent over the given connection. + * The request buffer will be big enough for a payload of the given + * size. + * + * For outgoing requests, the request message's header will be + * initialized with the type of the request and the message size. + * Outgoing operations must also specify the response buffer size, + * which must be sufficient to hold all expected response data. The + * response message header will eventually be overwritten, so there's + * no need to initialize it here. + * + * Request messages for incoming operations can arrive in interrupt + * context, so they must be allocated with GFP_ATOMIC. In this case + * the request buffer will be immediately overwritten, so there is + * no need to initialize the message header. Responsibility for + * allocating a response buffer lies with the incoming request + * handler for a protocol. So we don't allocate that here. + * + * Returns a pointer to the new operation or a null pointer if an + * error occurs. + */ +static struct gb_operation * +gb_operation_create_common(struct gb_connection *connection, u8 type, + size_t request_size, size_t response_size, + unsigned long op_flags, gfp_t gfp_flags) +{ + struct gb_host_device *hd = connection->hd; + struct gb_operation *operation; + + operation = kmem_cache_zalloc(gb_operation_cache, gfp_flags); + if (!operation) + return NULL; + operation->connection = connection; + + operation->request = gb_operation_message_alloc(hd, type, request_size, + gfp_flags); + if (!operation->request) + goto err_cache; + operation->request->operation = operation; + + /* Allocate the response buffer for outgoing operations */ + if (!(op_flags & GB_OPERATION_FLAG_INCOMING)) { + if (!gb_operation_response_alloc(operation, response_size, + gfp_flags)) { + goto err_request; + } + + timer_setup(&operation->timer, gb_operation_timeout, 0); + } + + operation->flags = op_flags; + operation->type = type; + operation->errno = -EBADR; /* Initial value--means "never set" */ + + INIT_WORK(&operation->work, gb_operation_work); + init_completion(&operation->completion); + kref_init(&operation->kref); + atomic_set(&operation->waiters, 0); + + return operation; + +err_request: + gb_operation_message_free(operation->request); +err_cache: + kmem_cache_free(gb_operation_cache, operation); + + return NULL; +} + +/* + * Create a new operation associated with the given connection. The + * request and response sizes provided are the number of bytes + * required to hold the request/response payload only. Both of + * these are allowed to be 0. Note that 0x00 is reserved as an + * invalid operation type for all protocols, and this is enforced + * here. + */ +struct gb_operation * +gb_operation_create_flags(struct gb_connection *connection, + u8 type, size_t request_size, + size_t response_size, unsigned long flags, + gfp_t gfp) +{ + struct gb_operation *operation; + + if (WARN_ON_ONCE(type == GB_REQUEST_TYPE_INVALID)) + return NULL; + if (WARN_ON_ONCE(type & GB_MESSAGE_TYPE_RESPONSE)) + type &= ~GB_MESSAGE_TYPE_RESPONSE; + + if (WARN_ON_ONCE(flags & ~GB_OPERATION_FLAG_USER_MASK)) + flags &= GB_OPERATION_FLAG_USER_MASK; + + operation = gb_operation_create_common(connection, type, + request_size, response_size, + flags, gfp); + if (operation) + trace_gb_operation_create(operation); + + return operation; +} +EXPORT_SYMBOL_GPL(gb_operation_create_flags); + +struct gb_operation * +gb_operation_create_core(struct gb_connection *connection, + u8 type, size_t request_size, + size_t response_size, unsigned long flags, + gfp_t gfp) +{ + struct gb_operation *operation; + + flags |= GB_OPERATION_FLAG_CORE; + + operation = gb_operation_create_common(connection, type, + request_size, response_size, + flags, gfp); + if (operation) + trace_gb_operation_create_core(operation); + + return operation; +} + +/* Do not export this function. */ + +size_t gb_operation_get_payload_size_max(struct gb_connection *connection) +{ + struct gb_host_device *hd = connection->hd; + + return hd->buffer_size_max - sizeof(struct gb_operation_msg_hdr); +} +EXPORT_SYMBOL_GPL(gb_operation_get_payload_size_max); + +static struct gb_operation * +gb_operation_create_incoming(struct gb_connection *connection, u16 id, + u8 type, void *data, size_t size) +{ + struct gb_operation *operation; + size_t request_size; + unsigned long flags = GB_OPERATION_FLAG_INCOMING; + + /* Caller has made sure we at least have a message header. */ + request_size = size - sizeof(struct gb_operation_msg_hdr); + + if (!id) + flags |= GB_OPERATION_FLAG_UNIDIRECTIONAL; + + operation = gb_operation_create_common(connection, type, + request_size, + GB_REQUEST_TYPE_INVALID, + flags, GFP_ATOMIC); + if (!operation) + return NULL; + + operation->id = id; + memcpy(operation->request->header, data, size); + trace_gb_operation_create_incoming(operation); + + return operation; +} + +/* + * Get an additional reference on an operation. + */ +void gb_operation_get(struct gb_operation *operation) +{ + kref_get(&operation->kref); +} +EXPORT_SYMBOL_GPL(gb_operation_get); + +/* + * Destroy a previously created operation. + */ +static void _gb_operation_destroy(struct kref *kref) +{ + struct gb_operation *operation; + + operation = container_of(kref, struct gb_operation, kref); + + trace_gb_operation_destroy(operation); + + if (operation->response) + gb_operation_message_free(operation->response); + gb_operation_message_free(operation->request); + + kmem_cache_free(gb_operation_cache, operation); +} + +/* + * Drop a reference on an operation, and destroy it when the last + * one is gone. + */ +void gb_operation_put(struct gb_operation *operation) +{ + if (WARN_ON(!operation)) + return; + + kref_put(&operation->kref, _gb_operation_destroy); +} +EXPORT_SYMBOL_GPL(gb_operation_put); + +/* Tell the requester we're done */ +static void gb_operation_sync_callback(struct gb_operation *operation) +{ + complete(&operation->completion); +} + +/** + * gb_operation_request_send() - send an operation request message + * @operation: the operation to initiate + * @callback: the operation completion callback + * @timeout: operation timeout in milliseconds, or zero for no timeout + * @gfp: the memory flags to use for any allocations + * + * The caller has filled in any payload so the request message is ready to go. + * The callback function supplied will be called when the response message has + * arrived, a unidirectional request has been sent, or the operation is + * cancelled, indicating that the operation is complete. The callback function + * can fetch the result of the operation using gb_operation_result() if + * desired. + * + * Return: 0 if the request was successfully queued in the host-driver queues, + * or a negative errno. + */ +int gb_operation_request_send(struct gb_operation *operation, + gb_operation_callback callback, + unsigned int timeout, + gfp_t gfp) +{ + struct gb_connection *connection = operation->connection; + struct gb_operation_msg_hdr *header; + unsigned int cycle; + int ret; + + if (gb_connection_is_offloaded(connection)) + return -EBUSY; + + if (!callback) + return -EINVAL; + + /* + * Record the callback function, which is executed in + * non-atomic (workqueue) context when the final result + * of an operation has been set. + */ + operation->callback = callback; + + /* + * Assign the operation's id, and store it in the request header. + * Zero is a reserved operation id for unidirectional operations. + */ + if (gb_operation_is_unidirectional(operation)) { + operation->id = 0; + } else { + cycle = (unsigned int)atomic_inc_return(&connection->op_cycle); + operation->id = (u16)(cycle % U16_MAX + 1); + } + + header = operation->request->header; + header->operation_id = cpu_to_le16(operation->id); + + gb_operation_result_set(operation, -EINPROGRESS); + + /* + * Get an extra reference on the operation. It'll be dropped when the + * operation completes. + */ + gb_operation_get(operation); + ret = gb_operation_get_active(operation); + if (ret) + goto err_put; + + ret = gb_message_send(operation->request, gfp); + if (ret) + goto err_put_active; + + if (timeout) { + operation->timer.expires = jiffies + msecs_to_jiffies(timeout); + add_timer(&operation->timer); + } + + return 0; + +err_put_active: + gb_operation_put_active(operation); +err_put: + gb_operation_put(operation); + + return ret; +} +EXPORT_SYMBOL_GPL(gb_operation_request_send); + +/* + * Send a synchronous operation. This function is expected to + * block, returning only when the response has arrived, (or when an + * error is detected. The return value is the result of the + * operation. + */ +int gb_operation_request_send_sync_timeout(struct gb_operation *operation, + unsigned int timeout) +{ + int ret; + + ret = gb_operation_request_send(operation, gb_operation_sync_callback, + timeout, GFP_KERNEL); + if (ret) + return ret; + + ret = wait_for_completion_interruptible(&operation->completion); + if (ret < 0) { + /* Cancel the operation if interrupted */ + gb_operation_cancel(operation, -ECANCELED); + } + + return gb_operation_result(operation); +} +EXPORT_SYMBOL_GPL(gb_operation_request_send_sync_timeout); + +/* + * Send a response for an incoming operation request. A non-zero + * errno indicates a failed operation. + * + * If there is any response payload, the incoming request handler is + * responsible for allocating the response message. Otherwise the + * it can simply supply the result errno; this function will + * allocate the response message if necessary. + */ +static int gb_operation_response_send(struct gb_operation *operation, + int errno) +{ + struct gb_connection *connection = operation->connection; + int ret; + + if (!operation->response && + !gb_operation_is_unidirectional(operation)) { + if (!gb_operation_response_alloc(operation, 0, GFP_KERNEL)) + return -ENOMEM; + } + + /* Record the result */ + if (!gb_operation_result_set(operation, errno)) { + dev_err(&connection->hd->dev, "request result already set\n"); + return -EIO; /* Shouldn't happen */ + } + + /* Sender of request does not care about response. */ + if (gb_operation_is_unidirectional(operation)) + return 0; + + /* Reference will be dropped when message has been sent. */ + gb_operation_get(operation); + ret = gb_operation_get_active(operation); + if (ret) + goto err_put; + + /* Fill in the response header and send it */ + operation->response->header->result = gb_operation_errno_map(errno); + + ret = gb_message_send(operation->response, GFP_KERNEL); + if (ret) + goto err_put_active; + + return 0; + +err_put_active: + gb_operation_put_active(operation); +err_put: + gb_operation_put(operation); + + return ret; +} + +/* + * This function is called when a message send request has completed. + */ +void greybus_message_sent(struct gb_host_device *hd, + struct gb_message *message, int status) +{ + struct gb_operation *operation = message->operation; + struct gb_connection *connection = operation->connection; + + /* + * If the message was a response, we just need to drop our + * reference to the operation. If an error occurred, report + * it. + * + * For requests, if there's no error and the operation in not + * unidirectional, there's nothing more to do until the response + * arrives. If an error occurred attempting to send it, or if the + * operation is unidrectional, record the result of the operation and + * schedule its completion. + */ + if (message == operation->response) { + if (status) { + dev_err(&connection->hd->dev, + "%s: error sending response 0x%02x: %d\n", + connection->name, operation->type, status); + } + + gb_operation_put_active(operation); + gb_operation_put(operation); + } else if (status || gb_operation_is_unidirectional(operation)) { + if (gb_operation_result_set(operation, status)) { + queue_work(gb_operation_completion_wq, + &operation->work); + } + } +} +EXPORT_SYMBOL_GPL(greybus_message_sent); + +/* + * We've received data on a connection, and it doesn't look like a + * response, so we assume it's a request. + * + * This is called in interrupt context, so just copy the incoming + * data into the request buffer and handle the rest via workqueue. + */ +static void gb_connection_recv_request(struct gb_connection *connection, + const struct gb_operation_msg_hdr *header, + void *data, size_t size) +{ + struct gb_operation *operation; + u16 operation_id; + u8 type; + int ret; + + operation_id = le16_to_cpu(header->operation_id); + type = header->type; + + operation = gb_operation_create_incoming(connection, operation_id, + type, data, size); + if (!operation) { + dev_err(&connection->hd->dev, + "%s: can't create incoming operation\n", + connection->name); + return; + } + + ret = gb_operation_get_active(operation); + if (ret) { + gb_operation_put(operation); + return; + } + trace_gb_message_recv_request(operation->request); + + /* + * The initial reference to the operation will be dropped when the + * request handler returns. + */ + if (gb_operation_result_set(operation, -EINPROGRESS)) + queue_work(connection->wq, &operation->work); +} + +/* + * We've received data that appears to be an operation response + * message. Look up the operation, and record that we've received + * its response. + * + * This is called in interrupt context, so just copy the incoming + * data into the response buffer and handle the rest via workqueue. + */ +static void gb_connection_recv_response(struct gb_connection *connection, + const struct gb_operation_msg_hdr *header, + void *data, size_t size) +{ + struct gb_operation *operation; + struct gb_message *message; + size_t message_size; + u16 operation_id; + int errno; + + operation_id = le16_to_cpu(header->operation_id); + + if (!operation_id) { + dev_err_ratelimited(&connection->hd->dev, + "%s: invalid response id 0 received\n", + connection->name); + return; + } + + operation = gb_operation_find_outgoing(connection, operation_id); + if (!operation) { + dev_err_ratelimited(&connection->hd->dev, + "%s: unexpected response id 0x%04x received\n", + connection->name, operation_id); + return; + } + + errno = gb_operation_status_map(header->result); + message = operation->response; + message_size = sizeof(*header) + message->payload_size; + if (!errno && size > message_size) { + dev_err_ratelimited(&connection->hd->dev, + "%s: malformed response 0x%02x received (%zu > %zu)\n", + connection->name, header->type, + size, message_size); + errno = -EMSGSIZE; + } else if (!errno && size < message_size) { + if (gb_operation_short_response_allowed(operation)) { + message->payload_size = size - sizeof(*header); + } else { + dev_err_ratelimited(&connection->hd->dev, + "%s: short response 0x%02x received (%zu < %zu)\n", + connection->name, header->type, + size, message_size); + errno = -EMSGSIZE; + } + } + + /* We must ignore the payload if a bad status is returned */ + if (errno) + size = sizeof(*header); + + /* The rest will be handled in work queue context */ + if (gb_operation_result_set(operation, errno)) { + memcpy(message->buffer, data, size); + + trace_gb_message_recv_response(message); + + queue_work(gb_operation_completion_wq, &operation->work); + } + + gb_operation_put(operation); +} + +/* + * Handle data arriving on a connection. As soon as we return the + * supplied data buffer will be reused (so unless we do something + * with, it's effectively dropped). + */ +void gb_connection_recv(struct gb_connection *connection, + void *data, size_t size) +{ + struct gb_operation_msg_hdr header; + struct device *dev = &connection->hd->dev; + size_t msg_size; + + if (connection->state == GB_CONNECTION_STATE_DISABLED || + gb_connection_is_offloaded(connection)) { + dev_warn_ratelimited(dev, "%s: dropping %zu received bytes\n", + connection->name, size); + return; + } + + if (size < sizeof(header)) { + dev_err_ratelimited(dev, "%s: short message received\n", + connection->name); + return; + } + + /* Use memcpy as data may be unaligned */ + memcpy(&header, data, sizeof(header)); + msg_size = le16_to_cpu(header.size); + if (size < msg_size) { + dev_err_ratelimited(dev, + "%s: incomplete message 0x%04x of type 0x%02x received (%zu < %zu)\n", + connection->name, + le16_to_cpu(header.operation_id), + header.type, size, msg_size); + return; /* XXX Should still complete operation */ + } + + if (header.type & GB_MESSAGE_TYPE_RESPONSE) { + gb_connection_recv_response(connection, &header, data, + msg_size); + } else { + gb_connection_recv_request(connection, &header, data, + msg_size); + } +} + +/* + * Cancel an outgoing operation synchronously, and record the given error to + * indicate why. + */ +void gb_operation_cancel(struct gb_operation *operation, int errno) +{ + if (WARN_ON(gb_operation_is_incoming(operation))) + return; + + if (gb_operation_result_set(operation, errno)) { + gb_message_cancel(operation->request); + queue_work(gb_operation_completion_wq, &operation->work); + } + trace_gb_message_cancel_outgoing(operation->request); + + atomic_inc(&operation->waiters); + wait_event(gb_operation_cancellation_queue, + !gb_operation_is_active(operation)); + atomic_dec(&operation->waiters); +} +EXPORT_SYMBOL_GPL(gb_operation_cancel); + +/* + * Cancel an incoming operation synchronously. Called during connection tear + * down. + */ +void gb_operation_cancel_incoming(struct gb_operation *operation, int errno) +{ + if (WARN_ON(!gb_operation_is_incoming(operation))) + return; + + if (!gb_operation_is_unidirectional(operation)) { + /* + * Make sure the request handler has submitted the response + * before cancelling it. + */ + flush_work(&operation->work); + if (!gb_operation_result_set(operation, errno)) + gb_message_cancel(operation->response); + } + trace_gb_message_cancel_incoming(operation->response); + + atomic_inc(&operation->waiters); + wait_event(gb_operation_cancellation_queue, + !gb_operation_is_active(operation)); + atomic_dec(&operation->waiters); +} + +/** + * gb_operation_sync_timeout() - implement a "simple" synchronous operation + * @connection: the Greybus connection to send this to + * @type: the type of operation to send + * @request: pointer to a memory buffer to copy the request from + * @request_size: size of @request + * @response: pointer to a memory buffer to copy the response to + * @response_size: the size of @response. + * @timeout: operation timeout in milliseconds + * + * This function implements a simple synchronous Greybus operation. It sends + * the provided operation request and waits (sleeps) until the corresponding + * operation response message has been successfully received, or an error + * occurs. @request and @response are buffers to hold the request and response + * data respectively, and if they are not NULL, their size must be specified in + * @request_size and @response_size. + * + * If a response payload is to come back, and @response is not NULL, + * @response_size number of bytes will be copied into @response if the operation + * is successful. + * + * If there is an error, the response buffer is left alone. + */ +int gb_operation_sync_timeout(struct gb_connection *connection, int type, + void *request, int request_size, + void *response, int response_size, + unsigned int timeout) +{ + struct gb_operation *operation; + int ret; + + if ((response_size && !response) || + (request_size && !request)) + return -EINVAL; + + operation = gb_operation_create(connection, type, + request_size, response_size, + GFP_KERNEL); + if (!operation) + return -ENOMEM; + + if (request_size) + memcpy(operation->request->payload, request, request_size); + + ret = gb_operation_request_send_sync_timeout(operation, timeout); + if (ret) { + dev_err(&connection->hd->dev, + "%s: synchronous operation id 0x%04x of type 0x%02x failed: %d\n", + connection->name, operation->id, type, ret); + } else { + if (response_size) { + memcpy(response, operation->response->payload, + response_size); + } + } + + gb_operation_put(operation); + + return ret; +} +EXPORT_SYMBOL_GPL(gb_operation_sync_timeout); + +/** + * gb_operation_unidirectional_timeout() - initiate a unidirectional operation + * @connection: connection to use + * @type: type of operation to send + * @request: memory buffer to copy the request from + * @request_size: size of @request + * @timeout: send timeout in milliseconds + * + * Initiate a unidirectional operation by sending a request message and + * waiting for it to be acknowledged as sent by the host device. + * + * Note that successful send of a unidirectional operation does not imply that + * the request as actually reached the remote end of the connection. + */ +int gb_operation_unidirectional_timeout(struct gb_connection *connection, + int type, void *request, + int request_size, + unsigned int timeout) +{ + struct gb_operation *operation; + int ret; + + if (request_size && !request) + return -EINVAL; + + operation = gb_operation_create_flags(connection, type, + request_size, 0, + GB_OPERATION_FLAG_UNIDIRECTIONAL, + GFP_KERNEL); + if (!operation) + return -ENOMEM; + + if (request_size) + memcpy(operation->request->payload, request, request_size); + + ret = gb_operation_request_send_sync_timeout(operation, timeout); + if (ret) { + dev_err(&connection->hd->dev, + "%s: unidirectional operation of type 0x%02x failed: %d\n", + connection->name, type, ret); + } + + gb_operation_put(operation); + + return ret; +} +EXPORT_SYMBOL_GPL(gb_operation_unidirectional_timeout); + +int __init gb_operation_init(void) +{ + gb_message_cache = kmem_cache_create("gb_message_cache", + sizeof(struct gb_message), 0, 0, + NULL); + if (!gb_message_cache) + return -ENOMEM; + + gb_operation_cache = kmem_cache_create("gb_operation_cache", + sizeof(struct gb_operation), 0, + 0, NULL); + if (!gb_operation_cache) + goto err_destroy_message_cache; + + gb_operation_completion_wq = alloc_workqueue("greybus_completion", + 0, 0); + if (!gb_operation_completion_wq) + goto err_destroy_operation_cache; + + return 0; + +err_destroy_operation_cache: + kmem_cache_destroy(gb_operation_cache); + gb_operation_cache = NULL; +err_destroy_message_cache: + kmem_cache_destroy(gb_message_cache); + gb_message_cache = NULL; + + return -ENOMEM; +} + +void gb_operation_exit(void) +{ + destroy_workqueue(gb_operation_completion_wq); + gb_operation_completion_wq = NULL; + kmem_cache_destroy(gb_operation_cache); + gb_operation_cache = NULL; + kmem_cache_destroy(gb_message_cache); + gb_message_cache = NULL; +} |