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         struct timer_list       timer;
 102
 103         struct kref             kref;
 104         atomic_t                waiters;
 105
 106         int                     active;
 107         struct list_head        links;          /* connection->operations */
 108 };
 109
 110 static inline bool
 111 gb_operation_is_incoming(struct gb_operation *operation)
 112 {
 113         return operation->flags & GB_OPERATION_FLAG_INCOMING;
 114 }
 115
 116 static inline bool
 117 gb_operation_is_unidirectional(struct gb_operation *operation)
 118 {
 119         return operation->flags & GB_OPERATION_FLAG_UNIDIRECTIONAL;
 120 }
 121
 122 static inline bool
 123 gb_operation_short_response_allowed(struct gb_operation *operation)
 124 {
 125         return operation->flags & GB_OPERATION_FLAG_SHORT_RESPONSE;
 126 }
 127
 128 static inline bool gb_operation_is_core(struct gb_operation *operation)
 129 {
 130         return operation->flags & GB_OPERATION_FLAG_CORE;
 131 }
 132
 133 void gb_connection_recv(struct gb_connection *connection,
 134                                         void *data, size_t size);
 135
 136 int gb_operation_result(struct gb_operation *operation);
 137
 138 size_t gb_operation_get_payload_size_max(struct gb_connection *connection);
 139 struct gb_operation *
 140 gb_operation_create_flags(struct gb_connection *connection,
 141                                 u8 type, size_t request_size,
 142                                 size_t response_size, unsigned long flags,
 143                                 gfp_t gfp);
 144
 145 static inline struct gb_operation *
 146 gb_operation_create(struct gb_connection *connection,
 147                                 u8 type, size_t request_size,
 148                                 size_t response_size, gfp_t gfp)
 149 {
 150         return gb_operation_create_flags(connection, type, request_size,
 151                                                 response_size, 0, gfp);
 152 }
 153
 154 struct gb_operation *
 155 gb_operation_create_core(struct gb_connection *connection,
 156                                 u8 type, size_t request_size,
 157                                 size_t response_size, unsigned long flags,
 158                                 gfp_t gfp);
 159
 160 void gb_operation_get(struct gb_operation *operation);
 161 void gb_operation_put(struct gb_operation *operation);
 162
 163 bool gb_operation_response_alloc(struct gb_operation *operation,
 164                                         size_t response_size, gfp_t gfp);
 165
 166 int gb_operation_request_send(struct gb_operation *operation,
 167                                 gb_operation_callback callback,
 168                                 unsigned int timeout,
 169                                 gfp_t gfp);
 170 int gb_operation_request_send_sync_timeout(struct gb_operation *operation,
 171                                                 unsigned int timeout);
 172 static inline int
 173 gb_operation_request_send_sync(struct gb_operation *operation)
 174 {
 175         return gb_operation_request_send_sync_timeout(operation,
 176                         GB_OPERATION_TIMEOUT_DEFAULT);
 177 }
 178
 179 void gb_operation_cancel(struct gb_operation *operation, int errno);
 180 void gb_operation_cancel_incoming(struct gb_operation *operation, int errno);
 181
 182 void greybus_message_sent(struct gb_host_device *hd,
 183                                 struct gb_message *message, int status);
 184
 185 int gb_operation_sync_timeout(struct gb_connection *connection, int type,
 186                                 void *request, int request_size,
 187                                 void *response, int response_size,
 188                                 unsigned int timeout);
 189 int gb_operation_unidirectional_timeout(struct gb_connection *connection,
 190                                 int type, void *request, int request_size,
 191                                 unsigned int timeout);
 192
 193 static inline int gb_operation_sync(struct gb_connection *connection, int type,
 194                       void *request, int request_size,
 195                       void *response, int response_size)
 196 {
 197         return gb_operation_sync_timeout(connection, type,
 198                         request, request_size, response, response_size,
 199                         GB_OPERATION_TIMEOUT_DEFAULT);
 200 }
 201
 202 static inline int gb_operation_unidirectional(struct gb_connection *connection,
 203                                 int type, void *request, int request_size)
 204 {
 205         return gb_operation_unidirectional_timeout(connection, type,
 206                         request, request_size, GB_OPERATION_TIMEOUT_DEFAULT);
 207 }
 208
 209 int gb_operation_init(void);
 210 void gb_operation_exit(void);
 211
 212 #endif /* !__OPERATION_H */