TTY Driver - Revision history

Agember at 19:58, 23 May 2008

2008-05-23T19:58:22Z

Agember at 19:58, 23 May 2008

2008-05-23T19:58:08Z

Agember at 19:56, 23 May 2008

2008-05-23T19:56:55Z

Agember: Added Update template

2007-08-28T22:03:17Z

Added Update template

Agember at 20:30, 11 July 2007

2007-07-11T20:30:10Z

Agember at 20:30, 11 July 2007

2007-07-11T20:30:01Z

Agember at 20:26, 11 July 2007

2007-07-11T20:26:50Z

Agember at 20:18, 11 July 2007

2007-07-11T20:18:07Z

Agember at 16:34, 11 July 2007

2007-07-11T16:34:42Z

Agember: /* Functionality */

2007-06-21T16:14:50Z

Functionality

← Older revision		Revision as of 19:58, 23 May 2008
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−	~~{{Update}}~~
	[[Image:TtyDriver.png\|right\|450px]]The TTY driver serves as an intermediary device between hardware device drivers and user applications to provide line buffering of input and cooking of input and output. The driver is purely software oriented and makes no direct communication with physical hardware. Instead, the TTY driver relies on an underlying device driver to communicate directly with the hardware. The [[Shell\|XINU Shell]] utilizes a TTY device to line buffer and cook user input read from the [[UART_Driver\|UART]].		[[Image:TtyDriver.png\|right\|450px]]The TTY driver serves as an intermediary device between hardware device drivers and user applications to provide line buffering of input and cooking of input and output. The driver is purely software oriented and makes no direct communication with physical hardware. Instead, the TTY driver relies on an underlying device driver to communicate directly with the hardware. The [[Shell\|XINU Shell]] utilizes a TTY device to line buffer and cook user input read from the [[UART_Driver\|UART]].

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 * <code>TTY_ONLCR</code> - converts '\n' to '\r\n'
 * <code>TTY_OCRNL</code> - converts '\r' to '\n'
 == See also ==
 * [[UART Driver]]

@@ Line 1: / Line 1: @@
 {{Update}}
-[[Image:TtyDriver.png|right|450px]]The TTY driver is built on top of the UART driver (or another appropriate char-oriented device).  The driver is responsible for sending and receiving character input between a user level application, such as the [[Shell|XINU Shell]], and a char-oriented hardware driver.  The TTY driver uses a line disciple that reads and provides input in lines.  When not in raw mode, the TTY driver also cooks both input and output.
+[[Image:TtyDriver.png|right|450px]]The TTY driver serves as an intermediary device between hardware device drivers and user applications to provide line buffering of input and cooking of input and output.  The driver is purely software oriented and makes no direct communication with physical hardware.  Instead, the TTY driver relies on an underlying device driver to communicate directly with the hardware.  The [[Shell|XINU Shell]] utilizes a TTY device to line buffer and cook user input read from the [[UART_Driver|UART]].
 == Open & Close ==
-Open associates a TTY with an underlying char-oriented hardware driver.  The underlying device should already be initialized.  A TTY is allocated from the available TTY devices and its circular buffers are initialized.
+Open associates a TTY with an underlying char-oriented hardware device.  The underlying device driver must provide both getc and putc functions for the TTY to obtain input and send output character by character.  The device should already be opened and initialized before the TTY is opened.  When a TTY is opened, its device control block, input buffer, and flags are initialized.  No input flags are set when a TTY device is opened.  The TTY_ONLCR output flag is set when a TTY device is opened.
-Close disasociates a TTY from its underlying device.  It also makes the TTY available to be allocated to other processes.
+Close disassociates a TTY from its underlying device and resets the TTY's device control block.
 == Read ==
-The TTY driver reads characters from an underlying device driver, normally a [[UART Driver|UART]].  Input is read from the underlying device in lines and buffered in the TTY's input buffer.  Lines may be terminated with the line feed (LF or '\n') or carriage return (CR or <code>'\r'</code>) characters.  Read requests are not satsified until a full line has been read, or the TTY's buffer is full.
+The TTY driver reads characters from an underlying device driver using the devices getc function.  Input is first buffered in the TTY driver's circular  buffer before being copied to the user buffer supplied as a parameter in the <code>ttyRead</code> function call.
-When the end of file (Control+D)  character is read, the tty stops reading from the underlying device.  Subsquent calls to <code>ttyRead</code> will attempt to staisfy the request from the TTY's input buffer, otherwise <code>EOF</code> will be returned.  The TTY driver sets a flag if EOF (EOT or Control-D) or CBREAK (ETX or Control-C) are seen in the input that satisfies the read request. The flags can be checked using <code>control(''device id'', TTY_IOC_EOF, NULL NULL)</code> or <code>control(''device id'', TTY_IOC_CBREAK, NULL NULL)</code> for EOF and CBREAK, respectively.
+The <code>ttyRead</code> function begins by checking the <code>ieof</code> flag to determine if the EOF character (Control+D) was read during the last call to <code>ttyRead</code>  If the <code>ieof</code> flag is set, the function returns the <code>EOF</code> constant, defined in <code>stddef.h</code>.  <code>EOF</code> is only returned once for each EOF character read by the TTY driver.  A call made to <code>ttyRead</code> after <code>EOF</code> was returned, will result in an attempt to read more characters from the underlying device driver.
 == Write ==
-The TTY driver does not buffer output; it writes characters to an underlying device driver.  When not in RAW output mode, the TTY driver cooks line feeds (LF or <code>'\n'</code>) and carriage returns (CR or <code>'\r'</code>). The <code>ttyWrite</code> function always ensures CRLF is written to the output buffer when any of the following escape sequences are to be written: <code>'\r'</code>, <code>'\n'</code>, or <code>'\r\n'</code>.  Backspace and delete are cooked to <code>'\b\0\b'</code> to remove the last character output.  Null characters are ignored.  When in RAW mode, set using <code>control(device id, TTC_ORAW, TRUE, NULL)</code>, no output is cooked
+The TTY driver does not buffer output; it writes characters directly to an underlying device driver.  The TTY driver cooks newlines (LF or <code>'\n'</code>) and carriage returns (CR or <code>'\r'</code>) if certain output flags are set.
 == See also ==
 * [[UART Driver]]

← Older revision		Revision as of 22:03, 28 August 2007
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		+	{{Update}}
	[[Image:TtyDriver.png\|right\|450px]]The TTY driver is built on top of the UART driver (or another appropriate char-oriented device). The driver is responsible for sending and receiving character input between a user level application, such as the [[Shell\|XINU Shell]], and a char-oriented hardware driver. The TTY driver uses a line disciple that reads and provides input in lines. When not in raw mode, the TTY driver also cooks both input and output.		[[Image:TtyDriver.png\|right\|450px]]The TTY driver is built on top of the UART driver (or another appropriate char-oriented device). The driver is responsible for sending and receiving character input between a user level application, such as the [[Shell\|XINU Shell]], and a char-oriented hardware driver. The TTY driver uses a line disciple that reads and provides input in lines. When not in raw mode, the TTY driver also cooks both input and output.

← Older revision		Revision as of 20:30, 11 July 2007
Line 1:		Line 1:
−	~~{{Update}}~~
	[[Image:TtyDriver.png\|right\|450px]]The TTY driver is built on top of the UART driver (or another appropriate char-oriented device). The driver is responsible for sending and receiving character input between a user level application, such as the [[Shell\|XINU Shell]], and a char-oriented hardware driver. The TTY driver uses a line disciple that reads and provides input in lines. When not in raw mode, the TTY driver also cooks both input and output.		[[Image:TtyDriver.png\|right\|450px]]The TTY driver is built on top of the UART driver (or another appropriate char-oriented device). The driver is responsible for sending and receiving character input between a user level application, such as the [[Shell\|XINU Shell]], and a char-oriented hardware driver. The TTY driver uses a line disciple that reads and provides input in lines. When not in raw mode, the TTY driver also cooks both input and output.

@@ Line 8: / Line 8: @@
 == Read ==
-The TTY driver reads input in lines. Input is buffered in a secondary buffer and cooked (if not in RAW mode) until the secondary buffer is full or a carriage return (CR or '\r') or line feed (LF or '\n') is encountered. When pressing the 'Enter' key on the keyboard, xinu-console is configured to send '\n' to the backend.
+The TTY driver reads characters from an underlying device, normally a [[UART Driver|UART]].  Input is read from the underlying device in lines and buffered in the TTY's input buffer.  Lines may be terminated with the line feed (LF or '\n') or carriage return (CR or <code>'\r'</code>) characters.  Read requests are not satsified until a full line has been read, or the TTY's buffer is full.
-When not in RAW input mode, the TTY driver cooks backspace (BS or '\b') and delete (DEL or ASCII character 0x7F). BS and DEL remove the last character from the secondary buffer, and decrease the secondary buffer count by one. When in RAW mode, set using "control(device id, TTC_IRAW, TRUE, NULL)," and BS and DEL are ignored.
+When the end of file (Control+D)  character is read, the tty stops reading from the underlying device.  Subsquent calls to <code>ttyRead</code> will attempt to staisfy the request from the TTY's input buffer, otherwise <code>EOF</code> will be returned.  The TTY driver sets a flag if EOF (EOT or Control-D) or CBREAK (ETX or Control-C) are seen in the input that satisfies the read request. The flags can be checked using <code>control(''device id'', TTY_IOC_EOF, NULL NULL)</code> or <code>control(''device id'', TTY_IOC_CBREAK, NULL NULL)</code> for EOF and CBREAK, respectively.
 == Write ==

← Older revision		Revision as of 16:34, 11 July 2007
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		+	{{Update}}
		+
	[[Image:TtyUartInteraction.png\|frame\|Diagram of the interaction between hardware, UART driver, TTY driver, and user application.]]The TTY driver is built on top of the UART driver (or other TTY appropriate hardware). The driver is responsible for sending and receiving character input between a user level application, such as the XINU [[Shell]], and a char-oriented hardware driver. Line buffering and cooking are the two primary responsibilities for the new TTY driver.		[[Image:TtyUartInteraction.png\|frame\|Diagram of the interaction between hardware, UART driver, TTY driver, and user application.]]The TTY driver is built on top of the UART driver (or other TTY appropriate hardware). The driver is responsible for sending and receiving character input between a user level application, such as the XINU [[Shell]], and a char-oriented hardware driver. Line buffering and cooking are the two primary responsibilities for the new TTY driver.

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 === Open ===
 Open associates a TTY with an underlying char-oriented hardware driver.  The underlying device should already be initialized.  A TTY is allocated from the available TTY devices and its circular buffers are initialized.
 === Close ===
 Close disasociates a TTY from its underlying device.  It also makes the TTY available to be allocated to other processes.
@@ Line 34: / Line 29: @@
 === Control ===
    /* TTY input flags */
    #define	TTY_IFLAG_RAW		0x0001  /* do raw input                 */