\devsec{DVB SEC API}

The DVB SEC device controls the Satellite Equipment Control of 
the DVB hardware, i.e. DiSEqC and V-SEC.
It is accessed through \texttt{/dev/ost/sec}.

\devsubsec{SEC Data Types}

\devsubsubsec{secDiseqcCmd}
\label{secdiseqccmd}

\begin{verbatim}
struct secDiseqcCmd {
        uint8_t addr;
        uint8_t cmd;
        uint8_t numParams;
        uint8_t params[SEC_MAX_DISEQC_PARAMS];
};
\end{verbatim}


\devsubsubsec{secVoltage}
\label{secvoltage}

\begin{verbatim}
typedef uint32_t secVoltage;
\end{verbatim}
\begin{verbatim}
enum {
        SEC_VOLTAGE_OFF,
        SEC_VOLTAGE_LT, 
        SEC_VOLTAGE_13, 
        SEC_VOLTAGE_13_5,
        SEC_VOLTAGE_18,  
        SEC_VOLTAGE_18_5
};
\end{verbatim}


\devsubsubsec{secToneMode}
\label{sectonemode}

\begin{verbatim}
typedef uint32_t secToneMode;
\end{verbatim}
\begin{verbatim}
typedef enum {
        SEC_TONE_ON,
        SEC_TONE_OFF
} secToneMode_t;
\end{verbatim}


\devsubsubsec{secMiniCmd}
\label{secminicmd}

\begin{verbatim}
typedef uint32_t secMiniCmd;
\end{verbatim}
\begin{verbatim}
typedef enum {
        SEC_MINI_NONE,
        SEC_MINI_A,    
        SEC_MINI_B
} secMiniCmd_t;
\end{verbatim}
\begin{verbatim}
struct secStatus {
        int32_t     busMode;
        secVoltage  selVolt;
        secToneMode contTone;
};
\end{verbatim}

\begin{verbatim}
enum {
        SEC_BUS_IDLE,
        SEC_BUS_BUSY,
        SEC_BUS_OFF,
        SEC_BUS_OVERLOAD
};
\end{verbatim}


\devsubsubsec{secCommand}
\label{seccommand}

\begin{verbatim}
struct secCommand {
        int32_t type;
        union {
                struct secDiseqcCmd diseqc;
                uint8_t vsec;
                uint32_t pause;
        } u;
};
\end{verbatim}


\devsubsubsec{secCmdSequence}
\label{seccmdsequence}

\begin{verbatim}
struct secCmdSequence {
        secVoltage voltage;
        secMiniCmd miniCommand;
        secToneMode continuousTone;
        
        uint32_t numCommands;
        struct secCommand* commands;
};
\end{verbatim}

\begin{verbatim}
enum {
        SEC_CMDTYPE_DISEQC,
        SEC_CMDTYPE_VSEC,
        SEC_CMDTYPE_PAUSE
};
\end{verbatim}

\begin{verbatim}
typedef enum {
        SEC_DISEQC_SENT,
        SEC_VSEC_SENT,
        SEC_PAUSE_COMPLETE,
        SEC_CALLBACK_ERROR
} secCallback_t;                
\end{verbatim}

\clearpage

\devsubsec{SEC Function Calls}

\function{open()}{
  int open(const char *deviceName, int flags);}{
  This system call opens a named SEC device for subsequent use.
  If the device is opened in read-only mode, only status and statistics 
  monitoring is allowed. If the device is opened in read/write mode, all
  types of operations can be performed.
  Any number of applications can have simultaneous access to the device.
  }{
  const char *deviceName & Name of specific SEC device.\\
  int flags & A bit-wise OR of the following flags:\\
            & \hspace{1em} O\_RDONLY read-only access\\
            & \hspace{1em} O\_RDWR read/write access\\
            & The optional flag O\_NONBLOCK is not supported. If O\_NONBLOCK is set, 
            open() and most other subsequent calls to the device will return -1 and 
            set errno to EWOULDBLOCK.
            The communication with the peripheral devices is sequential by nature, 
            so it is probably preferable to use the device in synchronous mode. 
            This is the motivation for not going through the extra effort of 
            implementing asynchronous operation of the device.
  }{
  ENODEV    & Device driver not loaded/available.\\
  EFAULT    & deviceName does not refer to a valid memory area.\\
  EBUSY     & Device or resource busy.\\
  EINVAL    & Invalid argument.\\
}

\function{close()}{
  int close(int fd);}{
  This system call closes a previously opened SEC device.
  }{
  int fd & File descriptor returned by a previous call to open().\\
  }{
  EBADF & fd is not a valid open file descriptor.\\
}

\ifunction{SEC\_GET\_STATUS}{
  int ioctl(int fd, int request = SEC\_GET\_STATUS, struct secStatus* status);}{
  This call gets the status of the device.
  }{
  int fd & File descriptor returned by a previous call to open().\\
  int request & Equals SEC\_GET\_STATUS for this command.\\
  struct secStatus* status & The status of the device.\\
  }{
  ENODEV     & Device driver not loaded/available.\\
  EFAULT     & status is an invalid pointer.\\
  EBUSY      & Device or resource busy.\\
  EINVAL     & Invalid argument.\\
  EPERM      & File not opened with read permissions.\\
  EINTERNAL  & Internal error in the device driver.\\
}

\ifunction{SEC\_RESET\_OVERLOAD}{
  int ioctl(int fd, int request = SEC\_RESET\_OVERLOAD);}{
  If the bus has been automatically powered off due to power overload, this
  ioctl call restores the power to the bus. The call requires read/write 
  access to the device.
  This call has no effect if the device is manually powered off.
  }{
  int fd & File descriptor returned by a previous call to open().\\
  int request & Equals SEC\_RESET\_OVERLOAD for this command.\\
  }{
  EBADF      & fd is not a valid file descriptor.\\
  EPERM      & Permission denied (needs read/write access).\\
  EINTERNAL  & Internal error in the device driver.\\
}

\ifunction{SEC\_SEND\_SEQUENCE}{
int ioctl(int fd, int request = SEC\_SEND\_SEQUENCE, struct secCmdSequence *seq);
}{
This ioctl call is used to send a sequence of DiSEqCTM and/or V-SEC 
commands. The first version of the SEC device does not support V-SEC 
signaling and it aborts the operation with an error code if a V-SEC 
command is detected in the input data.\\
\begin{itemize}
\item[$\bullet$] The call will fail with errno set to EBUSOVERLOAD if the bus is 
overloaded. If the bus is overloaded, SEC\_RESET\_OVERLOAD can be 
called and the operation can be retried.
\item[$\bullet$] If seq.numCommands equals 0 and seq.miniCommand equals SEC\_MINI\_NONE,
the bus voltage will be switched and the continuous 22kHz tone 
generation enabled/disabled immediately.
\end{itemize}\\
This operation is atomic. If several processes calls this ioctl 
simultaneously, the operations will be serialized so a complete sequence
is sent at a time.
  }{
  int fd & File descriptor returned by a previous call to open().\\
  int request & Equals SEC\_SEND\_SEQUENCE for this command.\\
  struct secCmdSequence *seq & Pointer to the command sequence to be transmitted.\\
  }{
  EBADF      & fd is not a valid file descriptor.\\
  EFAULT     & Seq points to an invalid address.\\
  EINVAL     & The data structure referred to by seq is invalid in some way.\\
  EPERM      & Permission denied (needs read/write access).\\
  EINTERNAL  & Internal error in the device driver.\\
  EBUSMODE   & The device is not prepared for transmission 
  (e.g. it might be manually powered off).\\
  EBUSOVERLOAD & Bus overload has occurred.\\
}


\ifunction{SEC\_SET\_TONE}{
int ioctl(int fd, int request = SEC\_SET\_TONE, secToneMode tone);
}{
This call is used to set the generation of the continuous 22kHz tone. 
The possibility to just change the tone mode is already provided by 
ioctl SEC\_SEND\_SEQUENCE, but SEC\_SET\_TONE is an easier to use interface.
To keep the transmission of a command sequence as 
an atomic operation, SEC\_SET\_TONE will block if a transmission is in 
progress. This call requires read/write permissions.
}{
int fd & File descriptor returned by a previous call to open().\\
int request & Equals SEC\_SET\_TONE for this command.\\
secToneMode tone & The requested tone generation mode (on/off).\\
}{
ENODEV    & Device driver not loaded/available.\\
EBUSY     & Device or resource busy.\\
EINVAL    & Invalid argument.\\
EPERM     & File not opened with read permissions.\\
EINTERNAL & Internal error in the device driver.\\
}


\ifunction{SEC\_SET\_VOLTAGE}{
int ioctl(int fd, int request = SEC\_SET\_VOLTAGE, secVoltage voltage);
}{
This call is used to set the bus voltage. The possibility to just change
the bus voltage is already provided by ioctl SEC\_SEND\_SEQUENCE, but 
SEC\_SET\_VOLTAGE is an easier to use interface.
To keep the transmission of a command sequence as
an atomic operation, SEC\_SET\_VOLTAGE will block if a transmission is in 
progress.
This call requires read/write permissions.
}{
int fd & File descriptor returned by a previous call to open().\\
int request & Equals SEC\_SET\_VOLTAGE for this command.\\
secVoltage voltage & The requested bus voltage.\\
}{
ENODEV    & Device driver not loaded/available.\\
EBUSY     & Device or resource busy.\\
EINVAL    & Invalid argument.\\
EPERM     & File not opened with read permissions.\\
EINTERNAL & Internal error in the device driver.\\
}

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