| /* |
| * Greybus operations |
| * |
| * Copyright 2014 Google Inc. |
| * Copyright 2014 Linaro Ltd. |
| * |
| * Released under the GPLv2 only. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| #include <linux/module.h> |
| #include <linux/workqueue.h> |
| |
| #include "greybus.h" |
| |
| /* The default amount of time a request is given to complete */ |
| #define OPERATION_TIMEOUT_DEFAULT 1000 /* milliseconds */ |
| |
| /* |
| * XXX This needs to be coordinated with host driver parameters |
| * XXX May need to reduce to allow for message header within a page |
| */ |
| #define GB_OPERATION_MESSAGE_SIZE_MAX 4096 |
| |
| static struct kmem_cache *gb_operation_cache; |
| static struct kmem_cache *gb_simple_message_cache; |
| |
| /* Workqueue to handle Greybus operation completions. */ |
| static struct workqueue_struct *gb_operation_workqueue; |
| |
| /* Protects the cookie representing whether a message is in flight */ |
| static DEFINE_MUTEX(gb_message_mutex); |
| |
| /* |
| * All operation messages (both requests and responses) begin with |
| * a header that encodes the size of the message (header included). |
| * This header also contains a unique identifier, that associates a |
| * response message with its operation. The header contains an |
| * operation type field, whose interpretation is dependent on what |
| * type of protocol is used over the connection. The high bit |
| * (0x80) of the operation type field is used to indicate whether |
| * the message is a request (clear) or a response (set). |
| * |
| * Response messages include an additional status byte, which |
| * communicates the result of the corresponding request. A zero |
| * status value means the operation completed successfully. Any |
| * other value indicates an error; in this case, the payload of the |
| * response message (if any) is ignored. The status byte must be |
| * zero in the header for a request message. |
| * |
| * The wire format for all numeric fields in the header is little |
| * endian. Any operation-specific data begins immediately after the |
| * header, and is 64-bit aligned. |
| */ |
| struct gb_operation_msg_hdr { |
| __le16 size; /* Size in bytes of header + payload */ |
| __le16 operation_id; /* Operation unique id */ |
| __u8 type; /* E.g GB_I2C_TYPE_* or GB_GPIO_TYPE_* */ |
| __u8 result; /* Result of request (in responses only) */ |
| /* 2 bytes pad, must be zero (ignore when read) */ |
| } __aligned(sizeof(u64)); |
| |
| /* |
| * Protects access to connection operations lists, as well as |
| * updates to operation->errno. |
| */ |
| static DEFINE_SPINLOCK(gb_operations_lock); |
| |
| /* |
| * 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 |
| * reponse 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) |
| { |
| 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_irq(&gb_operations_lock); |
| prev = operation->errno; |
| if (prev == -EBADR) |
| operation->errno = result; |
| else |
| operation->errno = -EILSEQ; |
| spin_unlock_irq(&gb_operations_lock); |
| 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_irq(&gb_operations_lock); |
| prev = operation->errno; |
| if (prev == -EINPROGRESS) |
| operation->errno = result; /* First and final result */ |
| spin_unlock_irq(&gb_operations_lock); |
| |
| 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; |
| } |
| |
| static struct gb_operation * |
| gb_operation_find(struct gb_connection *connection, u16 operation_id) |
| { |
| struct gb_operation *operation; |
| bool found = false; |
| |
| spin_lock_irq(&gb_operations_lock); |
| list_for_each_entry(operation, &connection->operations, links) |
| if (operation->id == operation_id) { |
| found = true; |
| break; |
| } |
| spin_unlock_irq(&gb_operations_lock); |
| |
| return found ? operation : NULL; |
| } |
| |
| static int gb_message_send(struct gb_message *message) |
| { |
| size_t message_size = sizeof(*message->header) + message->payload_size; |
| struct gb_connection *connection = message->operation->connection; |
| int ret = 0; |
| void *cookie; |
| |
| mutex_lock(&gb_message_mutex); |
| cookie = connection->hd->driver->buffer_send(connection->hd, |
| connection->hd_cport_id, |
| message->header, |
| message_size, |
| GFP_KERNEL); |
| if (IS_ERR(cookie)) |
| ret = PTR_ERR(cookie); |
| else |
| message->cookie = cookie; |
| mutex_unlock(&gb_message_mutex); |
| |
| return ret; |
| } |
| |
| /* |
| * Cancel a message whose buffer we have passed to the host device |
| * layer to be sent. |
| */ |
| static void gb_message_cancel(struct gb_message *message) |
| { |
| mutex_lock(&gb_message_mutex); |
| if (message->cookie) { |
| struct greybus_host_device *hd; |
| |
| hd = message->operation->connection->hd; |
| hd->driver->buffer_cancel(message->cookie); |
| } |
| mutex_unlock(&gb_message_mutex); |
| } |
| |
| static void gb_operation_request_handle(struct gb_operation *operation) |
| { |
| struct gb_protocol *protocol = operation->connection->protocol; |
| |
| if (!protocol) |
| return; |
| |
| /* |
| * If the protocol has no incoming request handler, report |
| * an error and mark the request bad. |
| */ |
| if (protocol->request_recv) { |
| protocol->request_recv(operation->type, operation); |
| return; |
| } |
| |
| gb_connection_err(operation->connection, |
| "unexpected incoming request type 0x%02hhx\n", operation->type); |
| if (gb_operation_result_set(operation, -EPROTONOSUPPORT)) |
| queue_work(gb_operation_workqueue, &operation->work); |
| else |
| WARN(true, "failed to mark request bad\n"); |
| } |
| |
| /* |
| * Complete an operation in non-atomic context. For incoming |
| * requests, the callback function is the request handler, and |
| * 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; |
| |
| operation = container_of(work, struct gb_operation, work); |
| if (operation->callback) { |
| operation->callback(operation); |
| operation->callback = NULL; |
| } |
| gb_operation_put(operation); |
| } |
| |
| |
| /* |
| * Given a pointer to the header in a message sent on a given host |
| * device, return the associated message structure. (This "header" |
| * is just the buffer pointer we supply to the host device for |
| * sending.) |
| */ |
| static struct gb_message * |
| gb_hd_message_find(struct greybus_host_device *hd, void *header) |
| { |
| struct gb_message *message; |
| u8 *result; |
| |
| result = (u8 *)header - hd->buffer_headroom - sizeof(*message); |
| message = (struct gb_message *)result; |
| |
| return message; |
| } |
| |
| static void gb_operation_message_init(struct greybus_host_device *hd, |
| struct gb_message *message, u16 operation_id, |
| size_t payload_size, u8 type) |
| { |
| struct gb_operation_msg_hdr *header; |
| u8 *buffer; |
| |
| buffer = &message->buffer[0]; |
| header = (struct gb_operation_msg_hdr *)(buffer + hd->buffer_headroom); |
| |
| message->header = header; |
| message->payload = payload_size ? header + 1 : NULL; |
| message->payload_size = payload_size; |
| |
| /* |
| * The type supplied for incoming message buffers will be |
| * 0x00. Such buffers will be overwritten by arriving data |
| * so there's no need to initialize the message header. |
| */ |
| if (type != GB_OPERATION_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 structure consists of: |
| * message structure |
| * headroom |
| * message header \_ these combined are |
| * message payload / the message size |
| */ |
| static struct gb_message * |
| gb_operation_message_alloc(struct greybus_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); |
| size_t size; |
| |
| if (hd->buffer_size_max > GB_OPERATION_MESSAGE_SIZE_MAX) { |
| pr_warn("limiting buffer size to %u\n", |
| GB_OPERATION_MESSAGE_SIZE_MAX); |
| hd->buffer_size_max = GB_OPERATION_MESSAGE_SIZE_MAX; |
| } |
| |
| /* Allocate the message. Use the slab cache for simple messages */ |
| if (payload_size) { |
| if (message_size > hd->buffer_size_max) { |
| pr_warn("requested message size too big (%zu > %zu)\n", |
| message_size, hd->buffer_size_max); |
| return NULL; |
| } |
| |
| size = sizeof(*message) + hd->buffer_headroom + message_size; |
| message = kzalloc(size, gfp_flags); |
| } else { |
| message = kmem_cache_zalloc(gb_simple_message_cache, gfp_flags); |
| } |
| if (!message) |
| return NULL; |
| |
| /* Initialize the message. Operation id is filled in later. */ |
| gb_operation_message_init(hd, message, 0, payload_size, type); |
| |
| return message; |
| } |
| |
| static void gb_operation_message_free(struct gb_message *message) |
| { |
| if (message->payload_size) |
| kfree(message); |
| else |
| kmem_cache_free(gb_simple_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) |
| { |
| struct greybus_host_device *hd = operation->connection->hd; |
| struct gb_operation_msg_hdr *request_header; |
| struct gb_message *response; |
| u8 type; |
| |
| type = operation->type | GB_OPERATION_TYPE_RESPONSE; |
| response = gb_operation_message_alloc(hd, type, response_size, |
| GFP_KERNEL); |
| 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; |
| } |
| |
| /* |
| * 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) |
| { |
| struct greybus_host_device *hd = connection->hd; |
| struct gb_operation *operation; |
| gfp_t gfp_flags; |
| |
| /* |
| * An incoming request will pass an invalid operation type, |
| * because the header will get overwritten anyway. These |
| * occur in interrupt context, so we must use GFP_ATOMIC. |
| */ |
| if (type == GB_OPERATION_TYPE_INVALID) |
| gfp_flags = GFP_ATOMIC; |
| else |
| gfp_flags = GFP_KERNEL; |
| 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 (type != GB_OPERATION_TYPE_INVALID) { |
| if (!gb_operation_response_alloc(operation, response_size)) |
| goto err_request; |
| operation->type = type; |
| } |
| operation->errno = -EBADR; /* Initial value--means "never set" */ |
| |
| INIT_WORK(&operation->work, gb_operation_work); |
| operation->callback = NULL; /* set at submit time */ |
| init_completion(&operation->completion); |
| kref_init(&operation->kref); |
| |
| spin_lock_irq(&gb_operations_lock); |
| list_add_tail(&operation->links, &connection->operations); |
| spin_unlock_irq(&gb_operations_lock); |
| |
| 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(struct gb_connection *connection, |
| u8 type, size_t request_size, |
| size_t response_size) |
| { |
| if (WARN_ON_ONCE(type == GB_OPERATION_TYPE_INVALID)) |
| return NULL; |
| if (WARN_ON_ONCE(type & GB_OPERATION_TYPE_RESPONSE)) |
| type &= ~GB_OPERATION_TYPE_RESPONSE; |
| |
| return gb_operation_create_common(connection, type, |
| request_size, response_size); |
| } |
| EXPORT_SYMBOL_GPL(gb_operation_create); |
| |
| static struct gb_operation * |
| gb_operation_create_incoming(struct gb_connection *connection, u16 id, |
| u8 type, void *data, size_t request_size) |
| { |
| struct gb_operation *operation; |
| |
| operation = gb_operation_create_common(connection, |
| GB_OPERATION_TYPE_INVALID, |
| request_size, 0); |
| if (operation) { |
| operation->id = id; |
| operation->type = type; |
| memcpy(operation->request->header, data, request_size); |
| } |
| |
| return operation; |
| } |
| |
| /* |
| * Get an additional reference on an operation. |
| */ |
| void gb_operation_get(struct gb_operation *operation) |
| { |
| kref_get(&operation->kref); |
| } |
| |
| /* |
| * 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); |
| |
| /* XXX Make sure it's not in flight */ |
| spin_lock_irq(&gb_operations_lock); |
| list_del(&operation->links); |
| spin_unlock_irq(&gb_operations_lock); |
| |
| 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)) |
| 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); |
| } |
| |
| /* |
| * Send an operation request message. The caller has filled in |
| * any payload so the request message is ready to go. If non-null, |
| * the callback function supplied will be called when the response |
| * message has arrived indicating the operation is complete. In |
| * that case, the callback function is responsible for fetching the |
| * result of the operation using gb_operation_result() if desired, |
| * and dropping the final reference to (i.e., destroying) the |
| * operation. A null callback function is used for a synchronous |
| * request; in that case return from this function won't occur until |
| * the operation is complete. |
| */ |
| int gb_operation_request_send(struct gb_operation *operation, |
| gb_operation_callback callback) |
| { |
| struct gb_connection *connection = operation->connection; |
| struct gb_operation_msg_hdr *header; |
| unsigned int cycle; |
| |
| if (connection->state != GB_CONNECTION_STATE_ENABLED) |
| return -ENOTCONN; |
| |
| /* |
| * First, get an extra reference on the operation. |
| * It'll be dropped when the operation completes. |
| */ |
| gb_operation_get(operation); |
| |
| /* |
| * 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. |
| */ |
| 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); |
| |
| /* All set, send the request */ |
| gb_operation_result_set(operation, -EINPROGRESS); |
| |
| return gb_message_send(operation->request); |
| } |
| |
| /* |
| * 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(struct gb_operation *operation) |
| { |
| int ret; |
| unsigned long timeout; |
| |
| ret = gb_operation_request_send(operation, gb_operation_sync_callback); |
| if (ret) |
| return ret; |
| |
| timeout = msecs_to_jiffies(OPERATION_TIMEOUT_DEFAULT); |
| ret = wait_for_completion_interruptible_timeout(&operation->completion, timeout); |
| if (ret < 0) { |
| /* Cancel the operation if interrupted */ |
| gb_operation_cancel(operation, -ECANCELED); |
| } else if (ret == 0) { |
| /* Cancel the operation if op timed out */ |
| gb_operation_cancel(operation, -ETIMEDOUT); |
| } |
| |
| return gb_operation_result(operation); |
| } |
| EXPORT_SYMBOL_GPL(gb_operation_request_send_sync); |
| |
| /* |
| * 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. |
| */ |
| int gb_operation_response_send(struct gb_operation *operation, int errno) |
| { |
| /* Record the result */ |
| if (!gb_operation_result_set(operation, errno)) { |
| pr_err("request result already set\n"); |
| return -EIO; /* Shouldn't happen */ |
| } |
| |
| if (!operation->response) { |
| if (!gb_operation_response_alloc(operation, 0)) { |
| pr_err("error allocating response\n"); |
| /* XXX Respond with pre-allocated -ENOMEM? */ |
| return -ENOMEM; |
| } |
| } |
| |
| /* FIXME operation->response could still be NULL here */ |
| /* Fill in the response header and send it */ |
| operation->response->header->result = gb_operation_errno_map(errno); |
| |
| return gb_message_send(operation->response); |
| } |
| |
| /* |
| * This function is called when a buffer send request has completed. |
| * The "header" is the message header--the beginning of what we |
| * asked to have sent. |
| */ |
| void |
| greybus_data_sent(struct greybus_host_device *hd, void *header, int status) |
| { |
| struct gb_message *message; |
| struct gb_operation *operation; |
| |
| /* Get the message and record that it is no longer in flight */ |
| message = gb_hd_message_find(hd, header); |
| message->cookie = NULL; |
| |
| /* |
| * 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, there's nothing more |
| * to do until the response arrives. If an error occurred |
| * attempting to send it, record that as the result of |
| * the operation and schedule its completion. |
| */ |
| operation = message->operation; |
| if (message == operation->response) { |
| if (status) |
| pr_err("error %d sending response\n", status); |
| gb_operation_put(operation); |
| } else if (status) { |
| if (gb_operation_result_set(operation, status)) |
| queue_work(gb_operation_workqueue, &operation->work); |
| } |
| } |
| EXPORT_SYMBOL_GPL(greybus_data_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, |
| u16 operation_id, u8 type, |
| void *data, size_t size) |
| { |
| struct gb_operation *operation; |
| |
| operation = gb_operation_create_incoming(connection, operation_id, |
| type, data, size); |
| if (!operation) { |
| gb_connection_err(connection, "can't create operation"); |
| return; /* XXX Respond with pre-allocated ENOMEM */ |
| } |
| |
| /* |
| * Incoming requests are handled by arranging for the |
| * request handler to be the operation's callback function. |
| * |
| * The last thing the handler does is send a response |
| * message. The callback function is then cleared (in |
| * gb_operation_work()). The original reference to the |
| * operation will be dropped when the response has been |
| * sent. |
| */ |
| operation->callback = gb_operation_request_handle; |
| if (gb_operation_result_set(operation, -EINPROGRESS)) |
| queue_work(gb_operation_workqueue, &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, |
| u16 operation_id, u8 result, void *data, size_t size) |
| { |
| struct gb_operation *operation; |
| struct gb_message *message; |
| int errno = gb_operation_status_map(result); |
| size_t message_size; |
| |
| operation = gb_operation_find(connection, operation_id); |
| if (!operation) { |
| gb_connection_err(connection, "operation not found"); |
| return; |
| } |
| |
| message = operation->response; |
| message_size = sizeof(*message->header) + message->payload_size; |
| if (!errno && size != message_size) { |
| gb_connection_err(connection, "bad message size (%zu != %zu)", |
| size, message_size); |
| errno = -EMSGSIZE; |
| } |
| |
| /* We must ignore the payload if a bad status is returned */ |
| if (errno) |
| size = sizeof(*message->header); |
| memcpy(message->header, data, size); |
| |
| /* The rest will be handled in work queue context */ |
| if (gb_operation_result_set(operation, errno)) |
| queue_work(gb_operation_workqueue, &operation->work); |
| } |
| |
| /* |
| * 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; |
| size_t msg_size; |
| u16 operation_id; |
| |
| if (connection->state != GB_CONNECTION_STATE_ENABLED) { |
| gb_connection_err(connection, "dropping %zu received bytes", |
| size); |
| return; |
| } |
| |
| if (size < sizeof(*header)) { |
| gb_connection_err(connection, "message too small"); |
| return; |
| } |
| |
| header = data; |
| msg_size = (size_t)le16_to_cpu(header->size); |
| if (msg_size > size) { |
| gb_connection_err(connection, "incomplete message"); |
| return; /* XXX Should still complete operation */ |
| } |
| |
| operation_id = le16_to_cpu(header->operation_id); |
| if (header->type & GB_OPERATION_TYPE_RESPONSE) |
| gb_connection_recv_response(connection, operation_id, |
| header->result, data, msg_size); |
| else |
| gb_connection_recv_request(connection, operation_id, |
| header->type, data, msg_size); |
| } |
| |
| /* |
| * Cancel an operation, and record the given error to indicate why. |
| */ |
| void gb_operation_cancel(struct gb_operation *operation, int errno) |
| { |
| if (gb_operation_result_set(operation, errno)) { |
| gb_message_cancel(operation->request); |
| gb_message_cancel(operation->response); |
| } |
| gb_operation_put(operation); |
| } |
| |
| /** |
| * gb_operation_sync: implement a "simple" synchronous gb 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. |
| * |
| * 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(struct gb_connection *connection, int type, |
| void *request, int request_size, |
| void *response, int response_size) |
| { |
| 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); |
| if (!operation) |
| return -ENOMEM; |
| |
| if (request_size) |
| memcpy(operation->request->payload, request, request_size); |
| |
| ret = gb_operation_request_send_sync(operation); |
| if (ret) |
| pr_err("synchronous operation failed (%d)\n", ret); |
| else |
| if (response_size) |
| memcpy(response, operation->response->payload, |
| response_size); |
| gb_operation_destroy(operation); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(gb_operation_sync); |
| |
| int gb_operation_init(void) |
| { |
| size_t size; |
| |
| BUILD_BUG_ON(GB_OPERATION_MESSAGE_SIZE_MAX > |
| U16_MAX - sizeof(struct gb_operation_msg_hdr)); |
| |
| /* |
| * A message structure with consists of: |
| * - the message structure itself |
| * - the headroom set aside for the host device |
| * - the message header |
| * - space for the message payload |
| * Messages with no payload are a fairly common case and |
| * have a known fixed maximum size, so we use a slab cache |
| * for them. |
| */ |
| size = sizeof(struct gb_message) + GB_BUFFER_HEADROOM_MAX + |
| sizeof(struct gb_operation_msg_hdr); |
| gb_simple_message_cache = kmem_cache_create("gb_simple_message_cache", |
| size, 0, 0, NULL); |
| if (!gb_simple_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_simple; |
| |
| gb_operation_workqueue = alloc_workqueue("greybus_operation", 0, 1); |
| if (!gb_operation_workqueue) |
| goto err_operation; |
| |
| return 0; |
| err_operation: |
| kmem_cache_destroy(gb_operation_cache); |
| gb_operation_cache = NULL; |
| err_simple: |
| kmem_cache_destroy(gb_simple_message_cache); |
| gb_simple_message_cache = NULL; |
| |
| return -ENOMEM; |
| } |
| |
| void gb_operation_exit(void) |
| { |
| destroy_workqueue(gb_operation_workqueue); |
| gb_operation_workqueue = NULL; |
| kmem_cache_destroy(gb_operation_cache); |
| gb_operation_cache = NULL; |
| kmem_cache_destroy(gb_simple_message_cache); |
| gb_simple_message_cache = NULL; |
| } |