| /* |
| * Greybus operations |
| * |
| * Copyright 2014 Google Inc. |
| * |
| * 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 top bit of the type in an operation message header indicates |
| * whether the message is a request (bit clear) or response (bit set) |
| */ |
| #define GB_OPERATION_TYPE_RESPONSE 0x80 |
| |
| #define OPERATION_TIMEOUT_DEFAULT 1000 /* milliseconds */ |
| |
| /* |
| * XXX This needs to be coordinated with host driver parameters |
| */ |
| #define GB_OPERATION_MESSAGE_SIZE_MAX 4096 |
| |
| static struct kmem_cache *gb_operation_cache; |
| |
| /* Workqueue to handle Greybus operation completions. */ |
| static struct workqueue_struct *gb_operation_recv_workqueue; |
| |
| /* |
| * All operation messages (both requests and responses) begin with |
| * a common header that encodes the size of the data (header |
| * included). This header also contains a unique identifier, which |
| * is used to keep track of in-flight operations. Finally, the |
| * header contains a operation type field, whose interpretation is |
| * dependent on what type of device lies on the other end of the |
| * connection. Response messages are distinguished from request |
| * messages by setting the high bit (0x80) in the operation type |
| * value. |
| * |
| * 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 id; /* Operation unique id */ |
| __u8 type; /* E.g GB_I2C_TYPE_* or GB_GPIO_TYPE_* */ |
| /* 3 bytes pad, must be zero (ignore when read) */ |
| } __aligned(sizeof(u64)); |
| |
| /* XXX Could be per-host device, per-module, or even per-connection */ |
| static DEFINE_SPINLOCK(gb_operations_lock); |
| |
| static void gb_operation_insert(struct gb_operation *operation) |
| { |
| struct gb_connection *connection = operation->connection; |
| struct rb_root *root = &connection->pending; |
| struct rb_node *node = &operation->node; |
| struct rb_node **link = &root->rb_node; |
| struct rb_node *above = NULL; |
| struct gb_operation_msg_hdr *header; |
| unsigned long timeout; |
| bool start_timer; |
| __le16 wire_id; |
| |
| /* |
| * Assign the operation's id, and store it in the header of |
| * both request and response message headers. |
| */ |
| operation->id = gb_connection_operation_id(connection); |
| wire_id = cpu_to_le16(operation->id); |
| header = operation->request->transfer_buffer; |
| header->id = wire_id; |
| |
| /* OK, insert the operation into its connection's tree */ |
| spin_lock_irq(&gb_operations_lock); |
| |
| /* |
| * We impose a time limit for requests to complete. If |
| * there are no requests pending there is no need for a |
| * timer. So if this will be the only one in flight we'll |
| * need to start the timer. Otherwise we just update the |
| * existing one to give this request a full timeout period |
| * to complete. |
| */ |
| start_timer = RB_EMPTY_ROOT(root); |
| |
| while (*link) { |
| struct gb_operation *other; |
| |
| above = *link; |
| other = rb_entry(above, struct gb_operation, node); |
| header = other->request->transfer_buffer; |
| if (other->id > operation->id) |
| link = &above->rb_left; |
| else if (other->id < operation->id) |
| link = &above->rb_right; |
| } |
| rb_link_node(node, above, link); |
| rb_insert_color(node, root); |
| spin_unlock_irq(&gb_operations_lock); |
| |
| timeout = msecs_to_jiffies(OPERATION_TIMEOUT_DEFAULT); |
| if (start_timer) |
| schedule_delayed_work(&operation->timeout_work, timeout); |
| else |
| mod_delayed_work(system_wq, &operation->timeout_work, timeout); |
| } |
| |
| static void gb_operation_remove(struct gb_operation *operation) |
| { |
| struct gb_connection *connection = operation->connection; |
| |
| /* Shut down our timeout timer */ |
| cancel_delayed_work(&operation->timeout_work); |
| |
| /* Take us off of the list of pending operations */ |
| spin_lock_irq(&gb_operations_lock); |
| rb_erase(&operation->node, &connection->pending); |
| spin_unlock_irq(&gb_operations_lock); |
| |
| } |
| |
| static struct gb_operation * |
| gb_operation_find(struct gb_connection *connection, u16 id) |
| { |
| struct gb_operation *operation = NULL; |
| struct rb_node *node; |
| bool found = false; |
| |
| spin_lock_irq(&gb_operations_lock); |
| node = connection->pending.rb_node; |
| while (node && !found) { |
| operation = rb_entry(node, struct gb_operation, node); |
| if (operation->id > id) |
| node = node->rb_left; |
| else if (operation->id < id) |
| node = node->rb_right; |
| else |
| found = true; |
| } |
| spin_unlock_irq(&gb_operations_lock); |
| |
| return found ? operation : NULL; |
| } |
| |
| /* |
| * An operations's response message has arrived. If no callback was |
| * supplied it was submitted for asynchronous completion, so we notify |
| * any waiters. Otherwise we assume calling the completion is enough |
| * and nobody else will be waiting. |
| */ |
| static void gb_operation_complete(struct gb_operation *operation) |
| { |
| if (operation->callback) |
| operation->callback(operation); |
| else |
| complete_all(&operation->completion); |
| } |
| |
| /* Wait for a submitted operation to complete */ |
| int gb_operation_wait(struct gb_operation *operation) |
| { |
| int ret; |
| |
| ret = wait_for_completion_interruptible(&operation->completion); |
| /* If interrupted, cancel the in-flight buffer */ |
| if (ret < 0) |
| greybus_kill_gbuf(operation->request); |
| return ret; |
| |
| } |
| |
| static void gb_operation_request_handle(struct gb_operation *operation) |
| { |
| struct gb_protocol *protocol = operation->connection->protocol; |
| struct gb_operation_msg_hdr *header; |
| |
| /* |
| * If the protocol has no incoming request handler, report |
| * an error and mark the request bad. |
| */ |
| if (protocol->request_recv) { |
| protocol->request_recv(operation); |
| goto out; |
| } |
| |
| header = operation->request->transfer_buffer; |
| gb_connection_err(operation->connection, |
| "unexpected incoming request type 0x%02hhx\n", header->type); |
| operation->result = GB_OP_PROTOCOL_BAD; |
| out: |
| gb_operation_complete(operation); |
| } |
| |
| /* |
| * Either this operation contains an incoming request, or its |
| * response has arrived. An incoming request will have a null |
| * response buffer pointer (it is the responsibility of the request |
| * handler to allocate and fill in the response buffer). |
| */ |
| static void gb_operation_recv_work(struct work_struct *recv_work) |
| { |
| struct gb_operation *operation; |
| bool incoming_request; |
| |
| operation = container_of(recv_work, struct gb_operation, recv_work); |
| incoming_request = operation->response == NULL; |
| if (incoming_request) |
| gb_operation_request_handle(operation); |
| gb_operation_complete(operation); |
| |
| /* We're finished with the buffer we read into */ |
| if (incoming_request) |
| greybus_gbuf_finished(operation->request); |
| else |
| greybus_gbuf_finished(operation->response); |
| } |
| |
| /* |
| * Timeout call for the operation. |
| * |
| * If this fires, something went wrong, so mark the result as timed out, and |
| * run the completion handler, which (hopefully) should clean up the operation |
| * properly. |
| */ |
| static void operation_timeout(struct work_struct *work) |
| { |
| struct gb_operation *operation; |
| |
| operation = container_of(work, struct gb_operation, timeout_work.work); |
| printk("timeout!\n"); |
| |
| operation->result = GB_OP_TIMEOUT; |
| gb_operation_complete(operation); |
| } |
| |
| /* |
| * Buffer completion function. We get notified whenever any buffer |
| * completes. For outbound messages, this tells us that the message |
| * has been sent. For inbound messages, it means the data has |
| * landed in the buffer and is ready to be processed. |
| * |
| * Either way, we don't do anything. We don't really care when an |
| * outbound message has been sent, and for incoming messages we |
| * we'll be done with everything we need to do before we mark it |
| * finished. |
| * |
| * XXX We may want to record that a request is (or is no longer) in flight. |
| */ |
| static void gb_operation_gbuf_complete(struct gbuf *gbuf) |
| { |
| if (gbuf->status) { |
| struct gb_operation *operation = gbuf->context; |
| struct gb_operation_msg_hdr *header; |
| int id; |
| int type; |
| |
| if (gbuf == operation->request) |
| header = operation->request->transfer_buffer; |
| else if (gbuf == operation->response) |
| header = operation->response->transfer_buffer; |
| else |
| header = NULL; |
| |
| if (header) { |
| id = le16_to_cpu(header->id); |
| type = header->type; |
| } else { |
| id = -1; |
| type = -1; |
| } |
| |
| gb_connection_err(operation->connection, |
| "operation %d type %d gbuf error %d", |
| id, type, gbuf->status); |
| } |
| return; |
| } |
| |
| /* |
| * Allocate a buffer to be used for an operation request or response |
| * message. For outgoing messages, both types of message contain a |
| * common header, which is filled in here. Incoming requests or |
| * responses also contain the same header, but there's no need to |
| * initialize it here (it'll be overwritten by the incoming |
| * message). |
| */ |
| static struct gbuf *gb_operation_gbuf_create(struct gb_operation *operation, |
| u8 type, size_t size, |
| bool data_out) |
| { |
| struct gb_connection *connection = operation->connection; |
| struct gb_operation_msg_hdr *header; |
| struct gbuf *gbuf; |
| gfp_t gfp_flags = data_out ? GFP_KERNEL : GFP_ATOMIC; |
| |
| size += sizeof(*header); |
| gbuf = greybus_alloc_gbuf(connection, gb_operation_gbuf_complete, |
| size, data_out, gfp_flags, operation); |
| if (!gbuf) |
| return NULL; |
| |
| /* Fill in the header structure */ |
| header = (struct gb_operation_msg_hdr *)gbuf->transfer_buffer; |
| header->size = cpu_to_le16(size); |
| header->id = 0; /* Filled in when submitted */ |
| header->type = type; |
| |
| return gbuf; |
| } |
| |
| /* |
| * Create a Greybus operation to be sent over the given connection. |
| * The request buffer will big enough for a payload of the given |
| * size. Outgoing requests must specify the size of the response |
| * buffer size, which must be sufficient to hold all expected |
| * response data. |
| * |
| * Incoming requests will supply a response size of 0, and in that |
| * case no response buffer is allocated. (A response always |
| * includes a status byte, so 0 is not a valid size.) Whatever |
| * handles the operation request is responsible for allocating the |
| * response buffer. |
| * |
| * Returns a pointer to the new operation or a null pointer if an |
| * error occurs. |
| */ |
| struct gb_operation *gb_operation_create(struct gb_connection *connection, |
| u8 type, size_t request_size, |
| size_t response_size) |
| { |
| struct gb_operation *operation; |
| gfp_t gfp_flags = response_size ? GFP_KERNEL : GFP_ATOMIC; |
| bool outgoing = response_size != 0; |
| |
| operation = kmem_cache_zalloc(gb_operation_cache, gfp_flags); |
| if (!operation) |
| return NULL; |
| operation->connection = connection; |
| |
| operation->request = gb_operation_gbuf_create(operation, type, |
| request_size, |
| outgoing); |
| if (!operation->request) |
| goto err_cache; |
| operation->request_payload = operation->request->transfer_buffer + |
| sizeof(struct gb_operation_msg_hdr); |
| |
| if (outgoing) { |
| type |= GB_OPERATION_TYPE_RESPONSE; |
| operation->response = gb_operation_gbuf_create(operation, |
| type, response_size, |
| false); |
| if (!operation->response) |
| goto err_request; |
| operation->response_payload = |
| operation->response->transfer_buffer + |
| sizeof(struct gb_operation_msg_hdr); |
| } |
| |
| INIT_WORK(&operation->recv_work, gb_operation_recv_work); |
| operation->callback = NULL; /* set at submit time */ |
| init_completion(&operation->completion); |
| INIT_DELAYED_WORK(&operation->timeout_work, operation_timeout); |
| |
| spin_lock_irq(&gb_operations_lock); |
| list_add_tail(&operation->links, &connection->operations); |
| spin_unlock_irq(&gb_operations_lock); |
| |
| return operation; |
| |
| err_request: |
| greybus_free_gbuf(operation->request); |
| err_cache: |
| kmem_cache_free(gb_operation_cache, operation); |
| |
| return NULL; |
| } |
| |
| /* |
| * Destroy a previously created operation. |
| */ |
| void gb_operation_destroy(struct gb_operation *operation) |
| { |
| if (WARN_ON(!operation)) |
| return; |
| |
| /* XXX Make sure it's not in flight */ |
| spin_lock_irq(&gb_operations_lock); |
| list_del(&operation->links); |
| spin_unlock_irq(&gb_operations_lock); |
| |
| greybus_free_gbuf(operation->response); |
| greybus_free_gbuf(operation->request); |
| |
| kmem_cache_free(gb_operation_cache, operation); |
| } |
| |
| /* |
| * 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. A null |
| * callback function is used for a synchronous request; return from |
| * this function won't occur until the operation is complete (or an |
| * interrupt occurs). |
| */ |
| int gb_operation_request_send(struct gb_operation *operation, |
| gb_operation_callback callback) |
| { |
| int ret; |
| |
| if (operation->connection->state != GB_CONNECTION_STATE_ENABLED) |
| return -ENOTCONN; |
| |
| /* |
| * XXX |
| * I think the order of operations is going to be |
| * significant, and if so, we may need a mutex to surround |
| * setting the operation id and submitting the gbuf. |
| */ |
| operation->callback = callback; |
| gb_operation_insert(operation); |
| ret = greybus_submit_gbuf(operation->request, GFP_KERNEL); |
| if (ret) |
| return ret; |
| if (!callback) |
| ret = gb_operation_wait(operation); |
| |
| return ret; |
| } |
| |
| /* |
| * Send a response for an incoming operation request. |
| */ |
| int gb_operation_response_send(struct gb_operation *operation) |
| { |
| gb_operation_remove(operation); |
| gb_operation_destroy(operation); |
| |
| return 0; |
| } |
| |
| /* |
| * Handle data arriving on a connection. This is called in |
| * interrupt context, so just copy the incoming data into a buffer |
| * and do remaining handling via a work queue. |
| */ |
| void gb_connection_operation_recv(struct gb_connection *connection, |
| void *data, size_t size) |
| { |
| struct gb_operation_msg_hdr *header; |
| struct gb_operation *operation; |
| struct gbuf *gbuf; |
| u16 msg_size; |
| |
| if (connection->state != GB_CONNECTION_STATE_ENABLED) |
| return; |
| |
| if (size > GB_OPERATION_MESSAGE_SIZE_MAX) { |
| gb_connection_err(connection, "message too big"); |
| return; |
| } |
| |
| header = data; |
| msg_size = le16_to_cpu(header->size); |
| if (header->type & GB_OPERATION_TYPE_RESPONSE) { |
| u16 id = le16_to_cpu(header->id); |
| |
| operation = gb_operation_find(connection, id); |
| if (!operation) { |
| gb_connection_err(connection, "operation not found"); |
| return; |
| } |
| gb_operation_remove(operation); |
| gbuf = operation->response; |
| gbuf->status = GB_OP_SUCCESS; /* If we got here we're good */ |
| if (size > gbuf->transfer_buffer_length) { |
| gb_connection_err(connection, "recv buffer too small"); |
| return; |
| } |
| } else { |
| WARN_ON(msg_size != size); |
| operation = gb_operation_create(connection, header->type, |
| msg_size, 0); |
| if (!operation) { |
| gb_connection_err(connection, "can't create operation"); |
| return; |
| } |
| gbuf = operation->request; |
| } |
| |
| memcpy(gbuf->transfer_buffer, data, msg_size); |
| |
| /* The rest will be handled in work queue context */ |
| queue_work(gb_operation_recv_workqueue, &operation->recv_work); |
| } |
| |
| /* |
| * Cancel an operation. |
| */ |
| void gb_operation_cancel(struct gb_operation *operation) |
| { |
| operation->canceled = true; |
| greybus_kill_gbuf(operation->request); |
| if (operation->response) |
| greybus_kill_gbuf(operation->response); |
| } |
| |
| int gb_operation_init(void) |
| { |
| gb_operation_cache = kmem_cache_create("gb_operation_cache", |
| sizeof(struct gb_operation), 0, 0, NULL); |
| if (!gb_operation_cache) |
| return -ENOMEM; |
| |
| gb_operation_recv_workqueue = alloc_workqueue("greybus_recv", 0, 1); |
| if (!gb_operation_recv_workqueue) { |
| kmem_cache_destroy(gb_operation_cache); |
| gb_operation_cache = NULL; |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| void gb_operation_exit(void) |
| { |
| kmem_cache_destroy(gb_operation_cache); |
| gb_operation_cache = NULL; |
| destroy_workqueue(gb_operation_recv_workqueue); |
| gb_operation_recv_workqueue = NULL; |
| } |