#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
+ * 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;
+
+/* 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.
+ * a 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. 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 id; /* Operation unique id */
- __u8 type; /* E.g GB_I2C_TYPE_* or GB_GPIO_TYPE_* */
- /* 3 bytes pad, must be zero (ignore when read) */
+ __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));
/* XXX Could be per-host device, per-module, or even per-connection */
static DEFINE_SPINLOCK(gb_operations_lock);
+static void gb_pending_operation_insert(struct gb_operation *operation)
+{
+ struct gb_connection *connection = operation->connection;
+ struct gb_operation_msg_hdr *header;
+
+ /*
+ * Assign the operation's id and move it into its
+ * connection's pending list.
+ */
+ spin_lock_irq(&gb_operations_lock);
+ operation->id = ++connection->op_cycle;
+ list_move_tail(&operation->links, &connection->pending);
+ spin_unlock_irq(&gb_operations_lock);
+
+ /* Store the operation id in the request header */
+ header = operation->request->header;
+ header->operation_id = cpu_to_le16(operation->id);
+}
+
+static void gb_pending_operation_remove(struct gb_operation *operation)
+{
+ struct gb_connection *connection = operation->connection;
+
+ /* Take us off of the list of pending operations */
+ spin_lock_irq(&gb_operations_lock);
+ list_move_tail(&operation->links, &connection->operations);
+ spin_unlock_irq(&gb_operations_lock);
+}
+
+static struct gb_operation *
+gb_pending_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->pending, 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, gfp_t gfp_mask)
+{
+ struct gb_connection *connection = message->operation->connection;
+ u16 dest_cport_id = connection->interface_cport_id;
+ int ret = 0;
+
+ message->cookie = connection->hd->driver->buffer_send(connection->hd,
+ dest_cport_id,
+ message->header,
+ message->size,
+ gfp_mask);
+ if (IS_ERR(message->cookie)) {
+ ret = PTR_ERR(message->cookie);
+ message->cookie = NULL;
+ }
+ return ret;
+}
+
/*
- * An operations's response message has arrived. If no callback was
+ * 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)
+{
+ struct greybus_host_device *hd;
+
+ if (!message->cookie)
+ return; /* Don't bother if the message isn't in flight */
+
+ hd = message->operation->connection->hd;
+ hd->driver->buffer_cancel(message->cookie);
+}
+
+/*
+ * An operation'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.
*/
-void gb_operation_complete(struct gb_operation *operation)
+static void gb_operation_complete(struct gb_operation *operation)
{
if (operation->callback)
operation->callback(operation);
complete_all(&operation->completion);
}
-/*
- * Wait for a submitted operatnoi to complete */
+/* 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)
- ret = greybus_kill_gbuf(operation->gbuf);
+ gb_message_cancel(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;
+
+ header = operation->request->header;
+
+ /*
+ * If the protocol has no incoming request handler, report
+ * an error and mark the request bad.
+ */
+ if (protocol->request_recv) {
+ protocol->request_recv(header->type, operation);
+ return;
+ }
+
+ gb_connection_err(operation->connection,
+ "unexpected incoming request type 0x%02hhx\n", header->type);
+ operation->result = GB_OP_PROTOCOL_BAD;
+}
+
+/*
+ * 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->header == NULL;
+ if (incoming_request)
+ gb_operation_request_handle(operation);
+ gb_operation_complete(operation);
+}
+
+/*
+ * 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);
+ pr_debug("%s: timeout!\n", __func__);
+
+ operation->result = GB_OP_TIMEOUT;
+ gb_operation_complete(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;
+}
+
+/*
+ * Allocate a message to be used for an operation request or
+ * response. 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).
+ *
+ * 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;
+ u8 *buffer;
+
+ if (message_size > hd->buffer_size_max)
+ return NULL;
+
+ size = sizeof(*message) + hd->buffer_headroom + message_size;
+ message = kzalloc(size, gfp_flags);
+ if (!message)
+ return NULL;
+ buffer = &message->buffer[0];
+ header = (struct gb_operation_msg_hdr *)(buffer + hd->buffer_headroom);
+
+ /* Fill in the header structure */
+ header->size = cpu_to_le16(message_size);
+ header->operation_id = 0; /* Filled in when submitted */
+ header->type = type;
+
+ message->header = header;
+ message->payload = header + 1;
+ message->size = message_size;
+
+ return message;
+}
+
+static void gb_operation_message_free(struct gb_message *message)
+{
+ kfree(message);
+}
+
+/*
+ * Map an enum gb_operation_status value (which is represented in a
+ * message as a single byte) to an appropriate Linux negative errno.
+ */
+int gb_operation_status_map(u8 status)
+{
+ switch (status) {
+ case GB_OP_SUCCESS:
+ return 0;
+ case GB_OP_INVALID:
+ return -EINVAL;
+ case GB_OP_NO_MEMORY:
+ return -ENOMEM;
+ case GB_OP_INTERRUPTED:
+ return -EINTR;
+ case GB_OP_RETRY:
+ return -EAGAIN;
+ case GB_OP_PROTOCOL_BAD:
+ return -EPROTONOSUPPORT;
+ case GB_OP_OVERFLOW:
+ return -E2BIG;
+ case GB_OP_TIMEOUT:
+ return -ETIMEDOUT;
+ default:
+ return -EIO;
+ }
+}
+
+/*
+ * 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. 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.
+ */
+static struct gb_operation *
+gb_operation_create_common(struct gb_connection *connection, bool outgoing,
+ 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 = response_size ? GFP_KERNEL : GFP_ATOMIC;
+
+ 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;
+
+ if (outgoing) {
+ type |= GB_OPERATION_TYPE_RESPONSE;
+ operation->response = gb_operation_message_alloc(hd, type,
+ response_size, GFP_KERNEL);
+ if (!operation->response)
+ goto err_request;
+ operation->response->operation = operation;
+ }
+
+ 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);
+ 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;
+}
+
+struct gb_operation *gb_operation_create(struct gb_connection *connection,
+ u8 type, size_t request_size,
+ size_t response_size)
+{
+ return gb_operation_create_common(connection, true, type,
+ request_size, response_size);
+}
+
+static struct gb_operation *
+gb_operation_create_incoming(struct gb_connection *connection,
+ u8 type, size_t request_size,
+ size_t response_size)
+{
+ return gb_operation_create_common(connection, false, type,
+ request_size, response_size);
+}
+
+/*
+ * 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);
+}
+
+void gb_operation_put(struct gb_operation *operation)
+{
+ if (!WARN_ON(!operation))
+ kref_put(&operation->kref, _gb_operation_destroy);
}
/*
- * Submit an outbound operation. The caller has filled in any
- * payload so the request message is ready to go. If non-null,
+ * 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_submit(struct gb_operation *operation,
- gb_operation_callback callback)
+int gb_operation_request_send(struct gb_operation *operation,
+ gb_operation_callback callback)
{
+ unsigned long timeout;
int ret;
- /* XXX
- * gfp is probably GFP_ATOMIC but really I think
- * the gfp mask should go away.
+ 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 buffer.
*/
operation->callback = callback;
- ret = greybus_submit_gbuf(operation->gbuf, GFP_KERNEL);
+ gb_pending_operation_insert(operation);
+
+ /*
+ * We impose a time limit for requests to complete. We need
+ * to set the timer before we send the request though, so we
+ * don't lose a race with the receipt of the resposne.
+ */
+ timeout = msecs_to_jiffies(OPERATION_TIMEOUT_DEFAULT);
+ schedule_delayed_work(&operation->timeout_work, timeout);
+
+ /* All set, send the request */
+ ret = gb_message_send(operation->request, GFP_KERNEL);
if (ret)
return ret;
+
if (!callback)
ret = gb_operation_wait(operation);
}
/*
- * Called when a greybus request message has actually been sent.
+ * Send a response for an incoming operation request.
*/
-static void gbuf_out_callback(struct gbuf *gbuf)
+int gb_operation_response_send(struct gb_operation *operation)
{
- /* Record it's been submitted; need response now */
+ gb_operation_destroy(operation);
+
+ return 0;
}
/*
- * Create a Greybus operation having a buffer big enough for an
- * outgoing payload of the given size to be sent over the given
- * connection.
+ * 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.
*
- * Returns a pointer to the new operation or a null pointer if a
- * failure occurs due to memory exhaustion.
+ * XXX Mismatch between errno here and operation result code
*/
-struct gb_operation *gb_operation_create(struct gb_connection *connection,
- size_t size)
+void
+greybus_data_sent(struct greybus_host_device *hd, void *header, int status)
{
+ struct gb_message *message;
struct gb_operation *operation;
- struct gb_operation_msg_hdr *header;
- struct gbuf *gbuf;
- /* XXX Use a slab cache */
- operation = kzalloc(sizeof(*operation), GFP_KERNEL);
- if (!operation)
- return NULL;
+ /* If there's no error, there's really nothing to do */
+ if (!status)
+ return; /* Mark it complete? */
- /* Our buffer holds a header in addition to the requested payload */
- size += sizeof(*header);
- gbuf = greybus_alloc_gbuf(connection->interface->gmod,
- connection->hd_cport_id,
- gbuf_out_callback, size,
- GFP_KERNEL, operation);
- if (gbuf) {
- kfree(operation);
- return NULL;
+ /* XXX Right now we assume we're an outgoing request */
+ message = gb_hd_message_find(hd, header);
+ operation = message->operation;
+ gb_connection_err(operation->connection, "send error %d\n", status);
+ operation->result = status; /* XXX */
+ gb_operation_complete(operation);
+}
+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.
+ */
+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, type, size, 0);
+ if (!operation) {
+ gb_connection_err(connection, "can't create operation");
+ return; /* XXX Respond with pre-allocated ENOMEM */
}
+ operation->id = operation_id;
+ memcpy(operation->request->header, data, size);
- operation->connection = connection; /* XXX refcount? */
+ /* The rest will be handled in work queue context */
+ queue_work(gb_operation_recv_workqueue, &operation->recv_work);
+}
- /* Fill in the header structure and payload pointer */
- operation->gbuf = gbuf;
- header = (struct gb_operation_msg_hdr *)&gbuf->transfer_buffer;
- header->id = 0;
- header->size = cpu_to_le16(size);
- operation->payload = (char *)header + sizeof(*header);
+/*
+ * 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, void *data, size_t size)
+{
+ struct gb_operation *operation;
+ struct gb_message *message;
+ struct gb_operation_msg_hdr *header;
- operation->callback = NULL; /* set at submit time */
- init_completion(&operation->completion);
+ operation = gb_pending_operation_find(connection, operation_id);
+ if (!operation) {
+ gb_connection_err(connection, "operation not found");
+ return;
+ }
- spin_lock_irq(&gb_operations_lock);
- list_add_tail(&operation->links, &connection->operations);
- spin_unlock_irq(&gb_operations_lock);
+ cancel_delayed_work(&operation->timeout_work);
+ gb_pending_operation_remove(operation);
- return operation;
+ message = operation->response;
+ if (size <= message->size) {
+ /* Transfer the operation result from the response header */
+ header = message->header;
+ operation->result = header->result;
+ } else {
+ gb_connection_err(connection, "recv buffer too small");
+ operation->result = GB_OP_OVERFLOW;
+ }
+
+ /* We must ignore the payload if a bad status is returned */
+ if (operation->result == GB_OP_SUCCESS)
+ memcpy(message->header, data, size);
+
+ /* The rest will be handled in work queue context */
+ queue_work(gb_operation_recv_workqueue, &operation->recv_work);
}
/*
- * Destroy a previously created 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_operation_destroy(struct gb_operation *operation)
+void gb_connection_recv(struct gb_connection *connection,
+ void *data, size_t size)
{
- if (WARN_ON(!operation))
+ 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;
+ }
- /* XXX Make sure it's not in flight */
- spin_lock_irq(&gb_operations_lock);
- list_del(&operation->links);
- spin_unlock_irq(&gb_operations_lock);
+ if (size < sizeof(*header)) {
+ gb_connection_err(connection, "message too small");
+ return;
+ }
- greybus_free_gbuf(operation->gbuf);
+ 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 */
+ }
- kfree(operation);
+ operation_id = le16_to_cpu(header->operation_id);
+ if (header->type & GB_OPERATION_TYPE_RESPONSE)
+ gb_connection_recv_response(connection, operation_id,
+ data, msg_size);
+ else
+ gb_connection_recv_request(connection, operation_id,
+ header->type, data, msg_size);
+}
+
+/*
+ * Cancel an operation.
+ */
+void gb_operation_cancel(struct gb_operation *operation)
+{
+ operation->canceled = true;
+ gb_message_cancel(operation->request);
+ if (operation->response->header)
+ gb_message_cancel(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)
+{
+ destroy_workqueue(gb_operation_recv_workqueue);
+ gb_operation_recv_workqueue = NULL;
+ kmem_cache_destroy(gb_operation_cache);
+ gb_operation_cache = NULL;
}
projects / karo-tx-linux.git / blobdiff