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[PATCH] tty: switch to ktermios and new framework
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This is the core of the switch to the new framework.  I've split it from the
driver patches which are mostly search/replace and would encourage people to
give this one a good hard stare.

The references to BOTHER and ISHIFT are the termios values that must be
defined by a platform once it wants to turn on "new style" ioctl support.  The
code patches here ensure that providing

1. The termios overlays the ktermios in memory
2. The only new kernel only fields are c_ispeed/c_ospeed (or none)

the existing behaviour is retained.  This is true for the patches at this
point in time.

Future patches will define BOTHER, ISHIFT and enable newer termios structures
for each architecture, and once they are all done some of the ifdefs also
vanish.

[akpm@osdl.org: warning fix]
[akpm@osdl.org: IRDA fix]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@Alan-Cox
Alan-Cox authored and Linus Torvalds committed Dec 8, 2006
1 parent be90038 commit edc6afc
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Showing 7 changed files with 297 additions and 127 deletions.
137 changes: 38 additions & 99 deletions drivers/char/tty_io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -109,13 +109,15 @@
#define TTY_PARANOIA_CHECK 1
#define CHECK_TTY_COUNT 1

struct termios tty_std_termios = { /* for the benefit of tty drivers */
struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
.c_iflag = ICRNL | IXON,
.c_oflag = OPOST | ONLCR,
.c_cflag = B38400 | CS8 | CREAD | HUPCL,
.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
ECHOCTL | ECHOKE | IEXTEN,
.c_cc = INIT_C_CC
.c_cc = INIT_C_CC,
.c_ispeed = 38400,
.c_ospeed = 38400
};

EXPORT_SYMBOL(tty_std_termios);
Expand Down Expand Up @@ -1239,6 +1241,22 @@ void tty_ldisc_flush(struct tty_struct *tty)
}

EXPORT_SYMBOL_GPL(tty_ldisc_flush);

/**
* tty_reset_termios - reset terminal state
* @tty: tty to reset
*
* Restore a terminal to the driver default state
*/

static void tty_reset_termios(struct tty_struct *tty)
{
mutex_lock(&tty->termios_mutex);
*tty->termios = tty->driver->init_termios;
tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
mutex_unlock(&tty->termios_mutex);
}

/**
* do_tty_hangup - actual handler for hangup events
Expand Down Expand Up @@ -1327,11 +1345,7 @@ static void do_tty_hangup(struct work_struct *work)
* N_TTY.
*/
if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
{
mutex_lock(&tty->termios_mutex);
*tty->termios = tty->driver->init_termios;
mutex_unlock(&tty->termios_mutex);
}
tty_reset_termios(tty);

/* Defer ldisc switch */
/* tty_deferred_ldisc_switch(N_TTY);
Expand Down Expand Up @@ -1870,8 +1884,8 @@ static int init_dev(struct tty_driver *driver, int idx,
struct tty_struct **ret_tty)
{
struct tty_struct *tty, *o_tty;
struct termios *tp, **tp_loc, *o_tp, **o_tp_loc;
struct termios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc;
struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
int retval = 0;

/* check whether we're reopening an existing tty */
Expand Down Expand Up @@ -1918,19 +1932,19 @@ static int init_dev(struct tty_driver *driver, int idx,
}

if (!*tp_loc) {
tp = (struct termios *) kmalloc(sizeof(struct termios),
tp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
GFP_KERNEL);
if (!tp)
goto free_mem_out;
*tp = driver->init_termios;
}

if (!*ltp_loc) {
ltp = (struct termios *) kmalloc(sizeof(struct termios),
ltp = (struct ktermios *) kmalloc(sizeof(struct ktermios),
GFP_KERNEL);
if (!ltp)
goto free_mem_out;
memset(ltp, 0, sizeof(struct termios));
memset(ltp, 0, sizeof(struct ktermios));
}

if (driver->type == TTY_DRIVER_TYPE_PTY) {
Expand All @@ -1951,19 +1965,19 @@ static int init_dev(struct tty_driver *driver, int idx,
}

if (!*o_tp_loc) {
o_tp = (struct termios *)
kmalloc(sizeof(struct termios), GFP_KERNEL);
o_tp = (struct ktermios *)
kmalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!o_tp)
goto free_mem_out;
*o_tp = driver->other->init_termios;
}

if (!*o_ltp_loc) {
o_ltp = (struct termios *)
kmalloc(sizeof(struct termios), GFP_KERNEL);
o_ltp = (struct ktermios *)
kmalloc(sizeof(struct ktermios), GFP_KERNEL);
if (!o_ltp)
goto free_mem_out;
memset(o_ltp, 0, sizeof(struct termios));
memset(o_ltp, 0, sizeof(struct ktermios));
}

/*
Expand Down Expand Up @@ -2002,6 +2016,9 @@ static int init_dev(struct tty_driver *driver, int idx,
*ltp_loc = ltp;
tty->termios = *tp_loc;
tty->termios_locked = *ltp_loc;
/* Compatibility until drivers always set this */
tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
driver->refcount++;
tty->count++;

Expand Down Expand Up @@ -2104,7 +2121,7 @@ static int init_dev(struct tty_driver *driver, int idx,
static void release_mem(struct tty_struct *tty, int idx)
{
struct tty_struct *o_tty;
struct termios *tp;
struct ktermios *tp;
int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM;

if ((o_tty = tty->link) != NULL) {
Expand Down Expand Up @@ -3458,84 +3475,6 @@ static void flush_to_ldisc(struct work_struct *work)
tty_ldisc_deref(disc);
}

/*
* 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 int 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
};

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.
*
* Locking: none
*/

int tty_termios_baud_rate(struct termios *termios)
{
unsigned int cbaud;

cbaud = termios->c_cflag & CBAUD;

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_get_baud_rate - get tty bit rates
* @tty: tty to query
*
* Returns the baud rate as an integer for this terminal. The
* termios lock must be held by the caller and the terminal bit
* flags may be updated.
*
* Locking: none
*/

int tty_get_baud_rate(struct tty_struct *tty)
{
int baud = tty_termios_baud_rate(tty->termios);

if (baud == 38400 && tty->alt_speed) {
if (!tty->warned) {
printk(KERN_WARNING "Use of setserial/setrocket to "
"set SPD_* flags is deprecated\n");
tty->warned = 1;
}
baud = tty->alt_speed;
}

return baud;
}

EXPORT_SYMBOL(tty_get_baud_rate);

/**
* tty_flip_buffer_push - terminal
* @tty: tty to push
Expand Down Expand Up @@ -3758,8 +3697,8 @@ int tty_register_driver(struct tty_driver *driver)

if (p) {
driver->ttys = (struct tty_struct **)p;
driver->termios = (struct termios **)(p + driver->num);
driver->termios_locked = (struct termios **)(p + driver->num * 2);
driver->termios = (struct ktermios **)(p + driver->num);
driver->termios_locked = (struct ktermios **)(p + driver->num * 2);
} else {
driver->ttys = NULL;
driver->termios = NULL;
Expand Down Expand Up @@ -3798,7 +3737,7 @@ EXPORT_SYMBOL(tty_register_driver);
int tty_unregister_driver(struct tty_driver *driver)
{
int i;
struct termios *tp;
struct ktermios *tp;
void *p;

if (driver->refcount)
Expand Down
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