Message-Id: <20170323210304.2181-3-nicolas.pitre@linaro.org>
Date:   Thu, 23 Mar 2017 17:03:03 -0400
From:   Nicolas Pitre <nicolas.pitre@...aro.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>
Cc:     Russell King <linux@...linux.org.uk>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH 2/3] tty: move baudrate handling code to a file of its own

To allow reuse without the rest of the tty_ioctl code.

Signed-off-by: Nicolas Pitre <nico@...aro.org>
---
 drivers/tty/Makefile       |   2 +-
 drivers/tty/tty_baudrate.c | 232 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/tty/tty_ioctl.c    | 222 -------------------------------------------
 3 files changed, 233 insertions(+), 223 deletions(-)
 create mode 100644 drivers/tty/tty_baudrate.c

diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile
index b95bed92da..1461be6b90 100644
--- a/drivers/tty/Makefile
+++ b/drivers/tty/Makefile
@@ -1,5 +1,5 @@
 obj-$(CONFIG_TTY)		+= tty_io.o n_tty.o tty_ioctl.o tty_ldisc.o \
-				   tty_buffer.o tty_port.o tty_mutex.o tty_ldsem.o
+				   tty_buffer.o tty_port.o tty_mutex.o tty_ldsem.o tty_baudrate.o
 obj-$(CONFIG_LEGACY_PTYS)	+= pty.o
 obj-$(CONFIG_UNIX98_PTYS)	+= pty.o
 obj-$(CONFIG_AUDIT)		+= tty_audit.o
diff --git a/drivers/tty/tty_baudrate.c b/drivers/tty/tty_baudrate.c
new file mode 100644
index 0000000000..5c33fd2567
--- /dev/null
+++ b/drivers/tty/tty_baudrate.c
@@ -0,0 +1,232 @@
+/*
+ *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/termios.h>
+#include <linux/tty.h>
+#include <linux/export.h>
+
+
+/*
+ * Routine which returns the baud rate of the tty
+ *
+ * Note that the baud_table needs to be kept in sync with the
+ * include/asm/termbits.h file.
+ */
+static const speed_t baud_table[] = {
+	0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
+	9600, 19200, 38400, 57600, 115200, 230400, 460800,
+#ifdef __sparc__
+	76800, 153600, 307200, 614400, 921600
+#else
+	500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
+	2500000, 3000000, 3500000, 4000000
+#endif
+};
+
+#ifndef __sparc__
+static const tcflag_t baud_bits[] = {
+	B0, B50, B75, B110, B134, B150, B200, B300, B600,
+	B1200, B1800, B2400, B4800, B9600, B19200, B38400,
+	B57600, B115200, B230400, B460800, B500000, B576000,
+	B921600, B1000000, B1152000, B1500000, B2000000, B2500000,
+	B3000000, B3500000, B4000000
+};
+#else
+static const tcflag_t baud_bits[] = {
+	B0, B50, B75, B110, B134, B150, B200, B300, B600,
+	B1200, B1800, B2400, B4800, B9600, B19200, B38400,
+	B57600, B115200, B230400, B460800, B76800, B153600,
+	B307200, B614400, B921600
+};
+#endif
+
+static int n_baud_table = ARRAY_SIZE(baud_table);
+
+/**
+ *	tty_termios_baud_rate
+ *	@termios: termios structure
+ *
+ *	Convert termios baud rate data into a speed. This should be called
+ *	with the termios lock held if this termios is a terminal termios
+ *	structure. May change the termios data. Device drivers can call this
+ *	function but should use ->c_[io]speed directly as they are updated.
+ *
+ *	Locking: none
+ */
+
+speed_t tty_termios_baud_rate(struct ktermios *termios)
+{
+	unsigned int cbaud;
+
+	cbaud = termios->c_cflag & CBAUD;
+
+#ifdef BOTHER
+	/* Magic token for arbitrary speed via c_ispeed/c_ospeed */
+	if (cbaud == BOTHER)
+		return termios->c_ospeed;
+#endif
+	if (cbaud & CBAUDEX) {
+		cbaud &= ~CBAUDEX;
+
+		if (cbaud < 1 || cbaud + 15 > n_baud_table)
+			termios->c_cflag &= ~CBAUDEX;
+		else
+			cbaud += 15;
+	}
+	return baud_table[cbaud];
+}
+EXPORT_SYMBOL(tty_termios_baud_rate);
+
+/**
+ *	tty_termios_input_baud_rate
+ *	@termios: termios structure
+ *
+ *	Convert termios baud rate data into a speed. This should be called
+ *	with the termios lock held if this termios is a terminal termios
+ *	structure. May change the termios data. Device drivers can call this
+ *	function but should use ->c_[io]speed directly as they are updated.
+ *
+ *	Locking: none
+ */
+
+speed_t tty_termios_input_baud_rate(struct ktermios *termios)
+{
+#ifdef IBSHIFT
+	unsigned int cbaud = (termios->c_cflag >> IBSHIFT) & CBAUD;
+
+	if (cbaud == B0)
+		return tty_termios_baud_rate(termios);
+
+	/* Magic token for arbitrary speed via c_ispeed*/
+	if (cbaud == BOTHER)
+		return termios->c_ispeed;
+
+	if (cbaud & CBAUDEX) {
+		cbaud &= ~CBAUDEX;
+
+		if (cbaud < 1 || cbaud + 15 > n_baud_table)
+			termios->c_cflag &= ~(CBAUDEX << IBSHIFT);
+		else
+			cbaud += 15;
+	}
+	return baud_table[cbaud];
+#else
+	return tty_termios_baud_rate(termios);
+#endif
+}
+EXPORT_SYMBOL(tty_termios_input_baud_rate);
+
+/**
+ *	tty_termios_encode_baud_rate
+ *	@termios: ktermios structure holding user requested state
+ *	@ispeed: input speed
+ *	@ospeed: output speed
+ *
+ *	Encode the speeds set into the passed termios structure. This is
+ *	used as a library helper for drivers so that they can report back
+ *	the actual speed selected when it differs from the speed requested
+ *
+ *	For maximal back compatibility with legacy SYS5/POSIX *nix behaviour
+ *	we need to carefully set the bits when the user does not get the
+ *	desired speed. We allow small margins and preserve as much of possible
+ *	of the input intent to keep compatibility.
+ *
+ *	Locking: Caller should hold termios lock. This is already held
+ *	when calling this function from the driver termios handler.
+ *
+ *	The ifdefs deal with platforms whose owners have yet to update them
+ *	and will all go away once this is done.
+ */
+
+void tty_termios_encode_baud_rate(struct ktermios *termios,
+				  speed_t ibaud, speed_t obaud)
+{
+	int i = 0;
+	int ifound = -1, ofound = -1;
+	int iclose = ibaud/50, oclose = obaud/50;
+	int ibinput = 0;
+
+	if (obaud == 0)			/* CD dropped 		  */
+		ibaud = 0;		/* Clear ibaud to be sure */
+
+	termios->c_ispeed = ibaud;
+	termios->c_ospeed = obaud;
+
+#ifdef BOTHER
+	/* If the user asked for a precise weird speed give a precise weird
+	   answer. If they asked for a Bfoo speed they may have problems
+	   digesting non-exact replies so fuzz a bit */
+
+	if ((termios->c_cflag & CBAUD) == BOTHER)
+		oclose = 0;
+	if (((termios->c_cflag >> IBSHIFT) & CBAUD) == BOTHER)
+		iclose = 0;
+	if ((termios->c_cflag >> IBSHIFT) & CBAUD)
+		ibinput = 1;	/* An input speed was specified */
+#endif
+	termios->c_cflag &= ~CBAUD;
+
+	/*
+	 *	Our goal is to find a close match to the standard baud rate
+	 *	returned. Walk the baud rate table and if we get a very close
+	 *	match then report back the speed as a POSIX Bxxxx value by
+	 *	preference
+	 */
+
+	do {
+		if (obaud - oclose <= baud_table[i] &&
+		    obaud + oclose >= baud_table[i]) {
+			termios->c_cflag |= baud_bits[i];
+			ofound = i;
+		}
+		if (ibaud - iclose <= baud_table[i] &&
+		    ibaud + iclose >= baud_table[i]) {
+			/* For the case input == output don't set IBAUD bits
+			   if the user didn't do so */
+			if (ofound == i && !ibinput)
+				ifound  = i;
+#ifdef IBSHIFT
+			else {
+				ifound = i;
+				termios->c_cflag |= (baud_bits[i] << IBSHIFT);
+			}
+#endif
+		}
+	} while (++i < n_baud_table);
+
+	/*
+	 *	If we found no match then use BOTHER if provided or warn
+	 *	the user their platform maintainer needs to wake up if not.
+	 */
+#ifdef BOTHER
+	if (ofound == -1)
+		termios->c_cflag |= BOTHER;
+	/* Set exact input bits only if the input and output differ or the
+	   user already did */
+	if (ifound == -1 && (ibaud != obaud || ibinput))
+		termios->c_cflag |= (BOTHER << IBSHIFT);
+#else
+	if (ifound == -1 || ofound == -1)
+		pr_warn_once("tty: Unable to return correct speed data as your architecture needs updating.\n");
+#endif
+}
+EXPORT_SYMBOL_GPL(tty_termios_encode_baud_rate);
+
+/**
+ *	tty_encode_baud_rate		-	set baud rate of the tty
+ *	@ibaud: input baud rate
+ *	@obad: output baud rate
+ *
+ *	Update the current termios data for the tty with the new speed
+ *	settings. The caller must hold the termios_rwsem for the tty in
+ *	question.
+ */
+
+void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, speed_t obaud)
+{
+	tty_termios_encode_baud_rate(&tty->termios, ibaud, obaud);
+}
+EXPORT_SYMBOL_GPL(tty_encode_baud_rate);
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index a9a978731c..efa96e6c4c 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -258,228 +258,6 @@ static void unset_locked_termios(struct tty_struct *tty, struct ktermios *old)
 	/* FIXME: What should we do for i/ospeed */
 }
 
-/*
- * Routine which returns the baud rate of the tty
- *
- * Note that the baud_table needs to be kept in sync with the
- * include/asm/termbits.h file.
- */
-static const speed_t baud_table[] = {
-	0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
-	9600, 19200, 38400, 57600, 115200, 230400, 460800,
-#ifdef __sparc__
-	76800, 153600, 307200, 614400, 921600
-#else
-	500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
-	2500000, 3000000, 3500000, 4000000
-#endif
-};
-
-#ifndef __sparc__
-static const tcflag_t baud_bits[] = {
-	B0, B50, B75, B110, B134, B150, B200, B300, B600,
-	B1200, B1800, B2400, B4800, B9600, B19200, B38400,
-	B57600, B115200, B230400, B460800, B500000, B576000,
-	B921600, B1000000, B1152000, B1500000, B2000000, B2500000,
-	B3000000, B3500000, B4000000
-};
-#else
-static const tcflag_t baud_bits[] = {
-	B0, B50, B75, B110, B134, B150, B200, B300, B600,
-	B1200, B1800, B2400, B4800, B9600, B19200, B38400,
-	B57600, B115200, B230400, B460800, B76800, B153600,
-	B307200, B614400, B921600
-};
-#endif
-
-static int n_baud_table = ARRAY_SIZE(baud_table);
-
-/**
- *	tty_termios_baud_rate
- *	@termios: termios structure
- *
- *	Convert termios baud rate data into a speed. This should be called
- *	with the termios lock held if this termios is a terminal termios
- *	structure. May change the termios data. Device drivers can call this
- *	function but should use ->c_[io]speed directly as they are updated.
- *
- *	Locking: none
- */
-
-speed_t tty_termios_baud_rate(struct ktermios *termios)
-{
-	unsigned int cbaud;
-
-	cbaud = termios->c_cflag & CBAUD;
-
-#ifdef BOTHER
-	/* Magic token for arbitrary speed via c_ispeed/c_ospeed */
-	if (cbaud == BOTHER)
-		return termios->c_ospeed;
-#endif
-	if (cbaud & CBAUDEX) {
-		cbaud &= ~CBAUDEX;
-
-		if (cbaud < 1 || cbaud + 15 > n_baud_table)
-			termios->c_cflag &= ~CBAUDEX;
-		else
-			cbaud += 15;
-	}
-	return baud_table[cbaud];
-}
-EXPORT_SYMBOL(tty_termios_baud_rate);
-
-/**
- *	tty_termios_input_baud_rate
- *	@termios: termios structure
- *
- *	Convert termios baud rate data into a speed. This should be called
- *	with the termios lock held if this termios is a terminal termios
- *	structure. May change the termios data. Device drivers can call this
- *	function but should use ->c_[io]speed directly as they are updated.
- *
- *	Locking: none
- */
-
-speed_t tty_termios_input_baud_rate(struct ktermios *termios)
-{
-#ifdef IBSHIFT
-	unsigned int cbaud = (termios->c_cflag >> IBSHIFT) & CBAUD;
-
-	if (cbaud == B0)
-		return tty_termios_baud_rate(termios);
-
-	/* Magic token for arbitrary speed via c_ispeed*/
-	if (cbaud == BOTHER)
-		return termios->c_ispeed;
-
-	if (cbaud & CBAUDEX) {
-		cbaud &= ~CBAUDEX;
-
-		if (cbaud < 1 || cbaud + 15 > n_baud_table)
-			termios->c_cflag &= ~(CBAUDEX << IBSHIFT);
-		else
-			cbaud += 15;
-	}
-	return baud_table[cbaud];
-#else
-	return tty_termios_baud_rate(termios);
-#endif
-}
-EXPORT_SYMBOL(tty_termios_input_baud_rate);
-
-/**
- *	tty_termios_encode_baud_rate
- *	@termios: ktermios structure holding user requested state
- *	@ispeed: input speed
- *	@ospeed: output speed
- *
- *	Encode the speeds set into the passed termios structure. This is
- *	used as a library helper for drivers so that they can report back
- *	the actual speed selected when it differs from the speed requested
- *
- *	For maximal back compatibility with legacy SYS5/POSIX *nix behaviour
- *	we need to carefully set the bits when the user does not get the
- *	desired speed. We allow small margins and preserve as much of possible
- *	of the input intent to keep compatibility.
- *
- *	Locking: Caller should hold termios lock. This is already held
- *	when calling this function from the driver termios handler.
- *
- *	The ifdefs deal with platforms whose owners have yet to update them
- *	and will all go away once this is done.
- */
-
-void tty_termios_encode_baud_rate(struct ktermios *termios,
-				  speed_t ibaud, speed_t obaud)
-{
-	int i = 0;
-	int ifound = -1, ofound = -1;
-	int iclose = ibaud/50, oclose = obaud/50;
-	int ibinput = 0;
-
-	if (obaud == 0)			/* CD dropped 		  */
-		ibaud = 0;		/* Clear ibaud to be sure */
-
-	termios->c_ispeed = ibaud;
-	termios->c_ospeed = obaud;
-
-#ifdef BOTHER
-	/* If the user asked for a precise weird speed give a precise weird
-	   answer. If they asked for a Bfoo speed they may have problems
-	   digesting non-exact replies so fuzz a bit */
-
-	if ((termios->c_cflag & CBAUD) == BOTHER)
-		oclose = 0;
-	if (((termios->c_cflag >> IBSHIFT) & CBAUD) == BOTHER)
-		iclose = 0;
-	if ((termios->c_cflag >> IBSHIFT) & CBAUD)
-		ibinput = 1;	/* An input speed was specified */
-#endif
-	termios->c_cflag &= ~CBAUD;
-
-	/*
-	 *	Our goal is to find a close match to the standard baud rate
-	 *	returned. Walk the baud rate table and if we get a very close
-	 *	match then report back the speed as a POSIX Bxxxx value by
-	 *	preference
-	 */
-
-	do {
-		if (obaud - oclose <= baud_table[i] &&
-		    obaud + oclose >= baud_table[i]) {
-			termios->c_cflag |= baud_bits[i];
-			ofound = i;
-		}
-		if (ibaud - iclose <= baud_table[i] &&
-		    ibaud + iclose >= baud_table[i]) {
-			/* For the case input == output don't set IBAUD bits
-			   if the user didn't do so */
-			if (ofound == i && !ibinput)
-				ifound  = i;
-#ifdef IBSHIFT
-			else {
-				ifound = i;
-				termios->c_cflag |= (baud_bits[i] << IBSHIFT);
-			}
-#endif
-		}
-	} while (++i < n_baud_table);
-
-	/*
-	 *	If we found no match then use BOTHER if provided or warn
-	 *	the user their platform maintainer needs to wake up if not.
-	 */
-#ifdef BOTHER
-	if (ofound == -1)
-		termios->c_cflag |= BOTHER;
-	/* Set exact input bits only if the input and output differ or the
-	   user already did */
-	if (ifound == -1 && (ibaud != obaud || ibinput))
-		termios->c_cflag |= (BOTHER << IBSHIFT);
-#else
-	if (ifound == -1 || ofound == -1)
-		pr_warn_once("tty: Unable to return correct speed data as your architecture needs updating.\n");
-#endif
-}
-EXPORT_SYMBOL_GPL(tty_termios_encode_baud_rate);
-
-/**
- *	tty_encode_baud_rate		-	set baud rate of the tty
- *	@ibaud: input baud rate
- *	@obad: output baud rate
- *
- *	Update the current termios data for the tty with the new speed
- *	settings. The caller must hold the termios_rwsem for the tty in
- *	question.
- */
-
-void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, speed_t obaud)
-{
-	tty_termios_encode_baud_rate(&tty->termios, ibaud, obaud);
-}
-EXPORT_SYMBOL_GPL(tty_encode_baud_rate);
-
 /**
  *	tty_termios_copy_hw	-	copy hardware settings
  *	@new: New termios
-- 
2.9.3

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