[patch 03/32] greybus: operations logic
From: Greg KH
Date: Fri Sep 16 2016 - 09:22:53 EST
This is the Greybus operations code, handling the logic for them.
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/greybus/operation.c | 1239 ++++++++++++++++++++++++++++++++++++++++++++
drivers/greybus/operation.h | 210 +++++++
2 files changed, 1449 insertions(+)
--- /dev/null
+++ b/drivers/greybus/operation.c
@@ -0,0 +1,1239 @@
+/*
+ * Greybus operations
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#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 "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;
+
+ operation = container_of(work, struct gb_operation, work);
+
+ if (gb_operation_is_incoming(operation))
+ gb_operation_request_handle(operation);
+ else
+ operation->callback(operation);
+
+ gb_operation_put_active(operation);
+ gb_operation_put(operation);
+}
+
+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;
+ }
+ }
+
+ 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
+ * @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,
+ 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;
+
+ 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;
+ unsigned long timeout_jiffies;
+
+ ret = gb_operation_request_send(operation, gb_operation_sync_callback,
+ GFP_KERNEL);
+ if (ret)
+ return ret;
+
+ if (timeout)
+ timeout_jiffies = msecs_to_jiffies(timeout);
+ else
+ timeout_jiffies = MAX_SCHEDULE_TIMEOUT;
+
+ ret = wait_for_completion_interruptible_timeout(&operation->completion,
+ timeout_jiffies);
+ 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_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;
+}
--- /dev/null
+++ b/drivers/greybus/operation.h
@@ -0,0 +1,210 @@
+/*
+ * Greybus operations
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __OPERATION_H
+#define __OPERATION_H
+
+#include <linux/completion.h>
+
+struct gb_operation;
+
+/* The default amount of time a request is given to complete */
+#define GB_OPERATION_TIMEOUT_DEFAULT 1000 /* milliseconds */
+
+/*
+ * 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_MESSAGE_TYPE_RESPONSE ((u8)0x80)
+
+enum gb_operation_result {
+ GB_OP_SUCCESS = 0x00,
+ GB_OP_INTERRUPTED = 0x01,
+ GB_OP_TIMEOUT = 0x02,
+ GB_OP_NO_MEMORY = 0x03,
+ GB_OP_PROTOCOL_BAD = 0x04,
+ GB_OP_OVERFLOW = 0x05,
+ GB_OP_INVALID = 0x06,
+ GB_OP_RETRY = 0x07,
+ GB_OP_NONEXISTENT = 0x08,
+ GB_OP_UNKNOWN_ERROR = 0xfe,
+ GB_OP_MALFUNCTION = 0xff,
+};
+
+#define GB_OPERATION_MESSAGE_SIZE_MIN sizeof(struct gb_operation_msg_hdr)
+#define GB_OPERATION_MESSAGE_SIZE_MAX U16_MAX
+
+/*
+ * Protocol code should only examine the payload and payload_size fields, and
+ * host-controller drivers may use the hcpriv field. All other fields are
+ * intended to be private to the operations core code.
+ */
+struct gb_message {
+ struct gb_operation *operation;
+ struct gb_operation_msg_hdr *header;
+
+ void *payload;
+ size_t payload_size;
+
+ void *buffer;
+
+ void *hcpriv;
+};
+
+#define GB_OPERATION_FLAG_INCOMING BIT(0)
+#define GB_OPERATION_FLAG_UNIDIRECTIONAL BIT(1)
+#define GB_OPERATION_FLAG_SHORT_RESPONSE BIT(2)
+#define GB_OPERATION_FLAG_CORE BIT(3)
+
+#define GB_OPERATION_FLAG_USER_MASK (GB_OPERATION_FLAG_SHORT_RESPONSE | \
+ GB_OPERATION_FLAG_UNIDIRECTIONAL)
+
+/*
+ * A Greybus operation is a remote procedure call performed over a
+ * connection between two UniPro interfaces.
+ *
+ * Every operation consists of a request message sent to the other
+ * end of the connection coupled with a reply message returned to
+ * the sender. Every operation has a type, whose interpretation is
+ * dependent on the protocol associated with the connection.
+ *
+ * Only four things in an operation structure are intended to be
+ * directly usable by protocol handlers: the operation's connection
+ * pointer; the operation type; the request message payload (and
+ * size); and the response message payload (and size). Note that a
+ * message with a 0-byte payload has a null message payload pointer.
+ *
+ * In addition, every operation has a result, which is an errno
+ * value. Protocol handlers access the operation result using
+ * gb_operation_result().
+ */
+typedef void (*gb_operation_callback)(struct gb_operation *);
+struct gb_operation {
+ struct gb_connection *connection;
+ struct gb_message *request;
+ struct gb_message *response;
+
+ unsigned long flags;
+ u8 type;
+ u16 id;
+ int errno; /* Operation result */
+
+ struct work_struct work;
+ gb_operation_callback callback;
+ struct completion completion;
+
+ struct kref kref;
+ atomic_t waiters;
+
+ int active;
+ struct list_head links; /* connection->operations */
+};
+
+static inline bool
+gb_operation_is_incoming(struct gb_operation *operation)
+{
+ return operation->flags & GB_OPERATION_FLAG_INCOMING;
+}
+
+static inline bool
+gb_operation_is_unidirectional(struct gb_operation *operation)
+{
+ return operation->flags & GB_OPERATION_FLAG_UNIDIRECTIONAL;
+}
+
+static inline bool
+gb_operation_short_response_allowed(struct gb_operation *operation)
+{
+ return operation->flags & GB_OPERATION_FLAG_SHORT_RESPONSE;
+}
+
+static inline bool gb_operation_is_core(struct gb_operation *operation)
+{
+ return operation->flags & GB_OPERATION_FLAG_CORE;
+}
+
+void gb_connection_recv(struct gb_connection *connection,
+ void *data, size_t size);
+
+int gb_operation_result(struct gb_operation *operation);
+
+size_t gb_operation_get_payload_size_max(struct gb_connection *connection);
+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);
+
+static inline struct gb_operation *
+gb_operation_create(struct gb_connection *connection,
+ u8 type, size_t request_size,
+ size_t response_size, gfp_t gfp)
+{
+ return gb_operation_create_flags(connection, type, request_size,
+ response_size, 0, gfp);
+}
+
+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);
+
+void gb_operation_get(struct gb_operation *operation);
+void gb_operation_put(struct gb_operation *operation);
+
+bool gb_operation_response_alloc(struct gb_operation *operation,
+ size_t response_size, gfp_t gfp);
+
+int gb_operation_request_send(struct gb_operation *operation,
+ gb_operation_callback callback,
+ gfp_t gfp);
+int gb_operation_request_send_sync_timeout(struct gb_operation *operation,
+ unsigned int timeout);
+static inline int
+gb_operation_request_send_sync(struct gb_operation *operation)
+{
+ return gb_operation_request_send_sync_timeout(operation,
+ GB_OPERATION_TIMEOUT_DEFAULT);
+}
+
+void gb_operation_cancel(struct gb_operation *operation, int errno);
+void gb_operation_cancel_incoming(struct gb_operation *operation, int errno);
+
+void greybus_message_sent(struct gb_host_device *hd,
+ struct gb_message *message, int status);
+
+int gb_operation_sync_timeout(struct gb_connection *connection, int type,
+ void *request, int request_size,
+ void *response, int response_size,
+ unsigned int timeout);
+int gb_operation_unidirectional_timeout(struct gb_connection *connection,
+ int type, void *request, int request_size,
+ unsigned int timeout);
+
+static inline int gb_operation_sync(struct gb_connection *connection, int type,
+ void *request, int request_size,
+ void *response, int response_size)
+{
+ return gb_operation_sync_timeout(connection, type,
+ request, request_size, response, response_size,
+ GB_OPERATION_TIMEOUT_DEFAULT);
+}
+
+static inline int gb_operation_unidirectional(struct gb_connection *connection,
+ int type, void *request, int request_size)
+{
+ return gb_operation_unidirectional_timeout(connection, type,
+ request, request_size, GB_OPERATION_TIMEOUT_DEFAULT);
+}
+
+int gb_operation_init(void);
+void gb_operation_exit(void);
+
+#endif /* !__OPERATION_H */