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Link signal lines (CTS,RTS etc.) together properly.
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Increment interrupt counts when the lines change state and actually wake up
the wait queue so that tiocmiwait will be triggered.
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@rhulme
rhulme committed Jun 25, 2020
1 parent 55c9095 commit 1b541ae
Showing 1 changed file with 56 additions and 61 deletions.
117 changes: 56 additions & 61 deletions module/tty0tty.c
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Original file line number Diff line number Diff line change
Expand Up @@ -91,9 +91,52 @@ struct tty0tty_serial {
static struct tty0tty_serial *tty0tty_table[TTY0TTY_MINORS]; /* initially all NULL */


static struct tty0tty_serial *get_shadow_tty(int index)
{
struct tty0tty_serial *shadow = NULL;
int shadow_idx = index ^ 1;

if ((index < TTY0TTY_MINORS) &&
(tty0tty_table[shadow_idx] != NULL) &&
(tty0tty_table[shadow_idx]->open_count > 0)) {
shadow = tty0tty_table[shadow_idx];
#ifdef SCULL_DEBUG
printk(KERN_DEBUG "%s - shadow idx: %d\n", __FUNCTION__, shadow_idx);
#endif
}

return shadow;
}

static void update_shadow_msr(int index, int msr)
{
struct tty0tty_serial *shadow;

#ifdef SCULL_DEBUG
printk(KERN_DEBUG "%s - 0x%02x\n", __FUNCTION__, msr);
#endif

if ((shadow = get_shadow_tty(index)) != NULL) {
if((shadow->msr & MSR_CTS) != (msr & MSR_CTS))
shadow->icount.cts++;

if((shadow->msr & MSR_DSR) != (msr & MSR_DSR))
shadow->icount.dsr++;

if((shadow->msr & MSR_CD) != (msr & MSR_CD))
shadow->icount.dcd++;

if (msr != shadow->msr) {
shadow->msr = msr;
wake_up_interruptible(&shadow->wait);
}
}
}

static int tty0tty_open(struct tty_struct *tty, struct file *file)
{
struct tty0tty_serial *tty0tty;
struct tty0tty_serial *shadow;
int index;
int msr=0;
int mcr=0;
Expand Down Expand Up @@ -123,18 +166,8 @@ static int tty0tty_open(struct tty_struct *tty, struct file *file)
tport[index].tty=tty;
tty->port = &tport[index];

if( (index % 2) == 0)
{
if(tty0tty_table[index+1] != NULL)
if (tty0tty_table[index+1]->open_count > 0)
mcr=tty0tty_table[index+1]->mcr;
}
else
{
if(tty0tty_table[index-1] != NULL)
if (tty0tty_table[index-1]->open_count > 0)
mcr=tty0tty_table[index-1]->mcr;
}
if ((shadow = get_shadow_tty(index)) != NULL)
mcr = shadow->mcr;

//null modem connection

Expand All @@ -151,7 +184,9 @@ static int tty0tty_open(struct tty_struct *tty, struct file *file)

tty0tty->msr = msr;
tty0tty->mcr = 0;
memset(&tty0tty->icount, 0, sizeof(tty0tty->icount));

init_waitqueue_head(&tty0tty->wait);

/* register the tty driver */

Expand All @@ -174,18 +209,7 @@ static void do_close(struct tty0tty_serial *tty0tty)
#ifdef SCULL_DEBUG
printk(KERN_DEBUG "%s - tnt%i\n", __FUNCTION__,tty0tty->tty->index);
#endif
if( (tty0tty->tty->index % 2) == 0)
{
if(tty0tty_table[tty0tty->tty->index+1] != NULL)
if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0)
tty0tty_table[tty0tty->tty->index+1]->msr=msr;
}
else
{
if(tty0tty_table[tty0tty->tty->index-1] != NULL)
if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0)
tty0tty_table[tty0tty->tty->index-1]->msr=msr;
}
update_shadow_msr(tty0tty->tty->index, msr);

down(&tty0tty->sem);
if (!tty0tty->open_count) {
Expand Down Expand Up @@ -215,6 +239,7 @@ static void tty0tty_close(struct tty_struct *tty, struct file *file)
static int tty0tty_write(struct tty_struct *tty, const unsigned char *buffer, int count)
{
struct tty0tty_serial *tty0tty = tty->driver_data;
struct tty0tty_serial *shadow;
int retval = -EINVAL;
struct tty_struct *ttyx = NULL;

Expand All @@ -234,18 +259,8 @@ static int tty0tty_write(struct tty_struct *tty, const unsigned char *buffer, in
/* port was not opened */
goto exit;

if( (tty0tty->tty->index % 2) == 0)
{
if(tty0tty_table[tty0tty->tty->index+1] != NULL)
if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0)
ttyx=tty0tty_table[tty0tty->tty->index+1]->tty;
}
else
{
if(tty0tty_table[tty0tty->tty->index-1] != NULL)
if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0)
ttyx=tty0tty_table[tty0tty->tty->index-1]->tty;
}
if ((shadow = get_shadow_tty(tty0tty->tty->index)) != NULL)
ttyx = shadow->tty;

// tty->low_latency=1;

Expand Down Expand Up @@ -413,25 +428,15 @@ static int tty0tty_tiocmset(struct tty_struct *tty,
unsigned int set, unsigned int clear)
{
struct tty0tty_serial *tty0tty = tty->driver_data;
struct tty0tty_serial *shadow;
unsigned int mcr = tty0tty->mcr;
unsigned int msr=0;

#ifdef SCULL_DEBUG
printk(KERN_DEBUG "%s - tnt%i set=0x%08X clear=0x%08X \n", __FUNCTION__,tty->index, set ,clear);
#endif

if( (tty0tty->tty->index % 2) == 0)
{
if(tty0tty_table[tty0tty->tty->index+1] != NULL)
if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0)
msr=tty0tty_table[tty0tty->tty->index+1]->msr;
}
else
{
if(tty0tty_table[tty0tty->tty->index-1] != NULL)
if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0)
msr=tty0tty_table[tty0tty->tty->index-1]->msr;
}
if ((shadow = get_shadow_tty(tty0tty->tty->index)) != NULL)
msr = shadow->msr;

//null modem connection

Expand Down Expand Up @@ -465,18 +470,8 @@ static int tty0tty_tiocmset(struct tty_struct *tty,
/* set the new MCR value in the device */
tty0tty->mcr = mcr;

if( (tty0tty->tty->index % 2) == 0)
{
if(tty0tty_table[tty0tty->tty->index+1] != NULL)
if (tty0tty_table[tty0tty->tty->index+1]->open_count > 0)
tty0tty_table[tty0tty->tty->index+1]->msr=msr;
}
else
{
if(tty0tty_table[tty0tty->tty->index-1] != NULL)
if (tty0tty_table[tty0tty->tty->index-1]->open_count > 0)
tty0tty_table[tty0tty->tty->index-1]->msr=msr;
}
update_shadow_msr(tty0tty->tty->index, msr);

return 0;
}

Expand Down

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