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/*
* 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 */
/*
* No protocol may define an operation that has numeric value 0x00.
* It is reserved as an explicitly invalid value.
*/
#define GB_OPERATION_TYPE_INVALID ((u8)0x00)
/*
* 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,
};
/*
* All operation messages (both requests and responses) begin with
* a header that encodes the size of the message (header included).
* This header also contains a unique identifier, that associates a
* response message with its operation. 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 result byte, which
* communicates the result of the corresponding request. A zero
* result 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 result 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 operation_id; /* Operation unique id */
__u8 type; /* E.g GB_I2C_TYPE_* or GB_GPIO_TYPE_* */
__u8 result; /* Result of request (in responses only) */
__u8 pad[2]; /* must be zero (ignore when read) */
} __aligned(sizeof(u64));
#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)
/*
* 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;
}
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(struct gb_connection *connection,
u8 type, size_t request_size,
size_t response_size,
gfp_t gfp);
void gb_operation_get(struct gb_operation *operation);
void gb_operation_put(struct gb_operation *operation);
static inline void gb_operation_destroy(struct gb_operation *operation)
{
gb_operation_put(operation);
}
bool gb_operation_response_alloc(struct gb_operation *operation,
size_t response_size);
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 greybus_host_device *hd,
struct gb_message *message, int status);
int gb_operation_sync(struct gb_connection *connection, int type,
void *request, int request_size,
void *response, int response_size);
int gb_operation_init(void);
void gb_operation_exit(void);
#endif /* !__OPERATION_H */
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