drivers/staging/greybus/operation.h

   1 /*
   2  * Greybus operations
   3  *
   4  * Copyright 2014 Google Inc.
   5  * Copyright 2014 Linaro Ltd.
   6  *
   7  * Released under the GPLv2 only.
   8  */
   9
  10 #ifndef __OPERATION_H
  11 #define __OPERATION_H
  12
  13 #include <linux/completion.h>
  14
  15 struct gb_operation;
  16
  17 /* The default amount of time a request is given to complete */
  18 #define GB_OPERATION_TIMEOUT_DEFAULT    1000    /* milliseconds */
  19
  20 /*
  21  * The top bit of the type in an operation message header indicates
  22  * whether the message is a request (bit clear) or response (bit set)
  23  */
  24 #define GB_MESSAGE_TYPE_RESPONSE        ((u8)0x80)
  25
  26 enum gb_operation_result {
  27         GB_OP_SUCCESS           = 0x00,
  28         GB_OP_INTERRUPTED       = 0x01,
  29         GB_OP_TIMEOUT           = 0x02,
  30         GB_OP_NO_MEMORY         = 0x03,
  31         GB_OP_PROTOCOL_BAD      = 0x04,
  32         GB_OP_OVERFLOW          = 0x05,
  33         GB_OP_INVALID           = 0x06,
  34         GB_OP_RETRY             = 0x07,
  35         GB_OP_NONEXISTENT       = 0x08,
  36         GB_OP_UNKNOWN_ERROR     = 0xfe,
  37         GB_OP_MALFUNCTION       = 0xff,
  38 };
  39
  40 #define GB_OPERATION_MESSAGE_SIZE_MIN   sizeof(struct gb_operation_msg_hdr)
  41 #define GB_OPERATION_MESSAGE_SIZE_MAX   U16_MAX
  42
  43 /*
  44  * Protocol code should only examine the payload and payload_size fields, and
  45  * host-controller drivers may use the hcpriv field. All other fields are
  46  * intended to be private to the operations core code.
  47  */
  48 struct gb_message {
  49         struct gb_operation             *operation;
  50         struct gb_operation_msg_hdr     *header;
  51
  52         void                            *payload;
  53         size_t                          payload_size;
  54
  55         void                            *buffer;
  56
  57         void                            *hcpriv;
  58 };
  59
  60 #define GB_OPERATION_FLAG_INCOMING              BIT(0)
  61 #define GB_OPERATION_FLAG_UNIDIRECTIONAL        BIT(1)
  62 #define GB_OPERATION_FLAG_SHORT_RESPONSE        BIT(2)
  63 #define GB_OPERATION_FLAG_CORE                  BIT(3)
  64
  65 #define GB_OPERATION_FLAG_USER_MASK     (GB_OPERATION_FLAG_SHORT_RESPONSE | \
  66                                          GB_OPERATION_FLAG_UNIDIRECTIONAL)
  67
  68 /*
  69  * A Greybus operation is a remote procedure call performed over a
  70  * connection between two UniPro interfaces.
  71  *
  72  * Every operation consists of a request message sent to the other
  73  * end of the connection coupled with a reply message returned to
  74  * the sender.  Every operation has a type, whose interpretation is
  75  * dependent on the protocol associated with the connection.
  76  *
  77  * Only four things in an operation structure are intended to be
  78  * directly usable by protocol handlers:  the operation's connection
  79  * pointer; the operation type; the request message payload (and
  80  * size); and the response message payload (and size).  Note that a
  81  * message with a 0-byte payload has a null message payload pointer.
  82  *
  83  * In addition, every operation has a result, which is an errno
  84  * value.  Protocol handlers access the operation result using
  85  * gb_operation_result().
  86  */
  87 typedef void (*gb_operation_callback)(struct gb_operation *);
  88 struct gb_operation {
  89         struct gb_connection    *connection;
  90         struct gb_message       *request;
  91         struct gb_message       *response;
  92
  93         unsigned long           flags;
  94         u8                      type;
  95         u16                     id;
  96         int                     errno;          /* Operation result */
  97
  98         struct work_struct      work;
  99         gb_operation_callback   callback;
 100         struct completion       completion;
 101
 102         struct kref             kref;
 103         atomic_t                waiters;
 104
 105         int                     active;
 106         struct list_head        links;          /* connection->operations */
 107 };
 108
 109 static inline bool
 110 gb_operation_is_incoming(struct gb_operation *operation)
 111 {
 112         return operation->flags & GB_OPERATION_FLAG_INCOMING;
 113 }
 114
 115 static inline bool
 116 gb_operation_is_unidirectional(struct gb_operation *operation)
 117 {
 118         return operation->flags & GB_OPERATION_FLAG_UNIDIRECTIONAL;
 119 }
 120
 121 static inline bool
 122 gb_operation_short_response_allowed(struct gb_operation *operation)
 123 {
 124         return operation->flags & GB_OPERATION_FLAG_SHORT_RESPONSE;
 125 }
 126
 127 static inline bool gb_operation_is_core(struct gb_operation *operation)
 128 {
 129         return operation->flags & GB_OPERATION_FLAG_CORE;
 130 }
 131
 132 void gb_connection_recv(struct gb_connection *connection,
 133                                         void *data, size_t size);
 134
 135 int gb_operation_result(struct gb_operation *operation);
 136
 137 size_t gb_operation_get_payload_size_max(struct gb_connection *connection);
 138 struct gb_operation *
 139 gb_operation_create_flags(struct gb_connection *connection,
 140                                 u8 type, size_t request_size,
 141                                 size_t response_size, unsigned long flags,
 142                                 gfp_t gfp);
 143
 144 static inline struct gb_operation *
 145 gb_operation_create(struct gb_connection *connection,
 146                                 u8 type, size_t request_size,
 147                                 size_t response_size, gfp_t gfp)
 148 {
 149         return gb_operation_create_flags(connection, type, request_size,
 150                                                 response_size, 0, gfp);
 151 }
 152
 153 struct gb_operation *
 154 gb_operation_create_core(struct gb_connection *connection,
 155                                 u8 type, size_t request_size,
 156                                 size_t response_size, unsigned long flags,
 157                                 gfp_t gfp);
 158
 159 void gb_operation_get(struct gb_operation *operation);
 160 void gb_operation_put(struct gb_operation *operation);
 161
 162 bool gb_operation_response_alloc(struct gb_operation *operation,
 163                                         size_t response_size, gfp_t gfp);
 164
 165 int gb_operation_request_send(struct gb_operation *operation,
 166                                 gb_operation_callback callback,
 167                                 gfp_t gfp);
 168 int gb_operation_request_send_sync_timeout(struct gb_operation *operation,
 169                                                 unsigned int timeout);
 170 static inline int
 171 gb_operation_request_send_sync(struct gb_operation *operation)
 172 {
 173         return gb_operation_request_send_sync_timeout(operation,
 174                         GB_OPERATION_TIMEOUT_DEFAULT);
 175 }
 176
 177 void gb_operation_cancel(struct gb_operation *operation, int errno);
 178 void gb_operation_cancel_incoming(struct gb_operation *operation, int errno);
 179
 180 void greybus_message_sent(struct gb_host_device *hd,
 181                                 struct gb_message *message, int status);
 182
 183 int gb_operation_sync_timeout(struct gb_connection *connection, int type,
 184                                 void *request, int request_size,
 185                                 void *response, int response_size,
 186                                 unsigned int timeout);
 187 int gb_operation_unidirectional_timeout(struct gb_connection *connection,
 188                                 int type, void *request, int request_size,
 189                                 unsigned int timeout);
 190
 191 static inline int gb_operation_sync(struct gb_connection *connection, int type,
 192                       void *request, int request_size,
 193                       void *response, int response_size)
 194 {
 195         return gb_operation_sync_timeout(connection, type,
 196                         request, request_size, response, response_size,
 197                         GB_OPERATION_TIMEOUT_DEFAULT);
 198 }
 199
 200 static inline int gb_operation_unidirectional(struct gb_connection *connection,
 201                                 int type, void *request, int request_size)
 202 {
 203         return gb_operation_unidirectional_timeout(connection, type,
 204                         request, request_size, GB_OPERATION_TIMEOUT_DEFAULT);
 205 }
 206
 207 int gb_operation_init(void);
 208 void gb_operation_exit(void);
 209
 210 #endif /* !__OPERATION_H */