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sc16is7xx: Handle modem status lines 

The uart_handle_cts_change() and uart_handle_dcd_change() must be called
with port lock being held. Acquire the lock after reading MSR register.
Do not acquire spin lock when reading MSR register because I2C/SPI port
functions cannot be called with spinlocks held.

Update rng and dsr counters. Wake up delta_msr_wait to allow tty notice
modem status change.

Co-developed-by: Lech Perczak <l.perczak@camlintechnologies.com>
Co-developed-by: Tomasz Moń <tomasz.mon@camlingroup.com>
Signed-off-by: Lech Perczak <l.perczak@camlintechnologies.com>
Signed-off-by: Tomasz Moń <tomasz.mon@camlingroup.com>
Link: https://lore.kernel.org/r/20220301060332.2561851-3-tomasz.mon@camlingroup.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tomasz Moń 2022-03-01 07:03:31 +01:00 committed by Greg Kroah-Hartman
parent cc4c1d05eb
commit 21144bab4f
1 changed files with 114 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

120
drivers/tty/serial/sc16is7xx.c
View File

@ -324,8 +324,10 @@ struct sc16is7xx_one {
u8 line;
struct kthread_work tx_work;
struct kthread_work reg_work;
struct kthread_delayed_work ms_work;
struct sc16is7xx_one_config config;
bool irda_mode;
unsigned int old_mctrl;
};
struct sc16is7xx_port {
@ -705,12 +707,56 @@ static void sc16is7xx_handle_tx(struct uart_port *port)
spin_unlock_irqrestore(&port->lock, flags);
}
static unsigned int sc16is7xx_get_hwmctrl(struct uart_port *port)
{
u8 msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
unsigned int mctrl = 0;
mctrl |= (msr & SC16IS7XX_MSR_CTS_BIT) ? TIOCM_CTS : 0;
mctrl |= (msr & SC16IS7XX_MSR_DSR_BIT) ? TIOCM_DSR : 0;
mctrl |= (msr & SC16IS7XX_MSR_CD_BIT) ? TIOCM_CAR : 0;
mctrl |= (msr & SC16IS7XX_MSR_RI_BIT) ? TIOCM_RNG : 0;
return mctrl;
}
static void sc16is7xx_update_mlines(struct sc16is7xx_one *one)
{
struct uart_port *port = &one->port;
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
unsigned long flags;
unsigned int status, changed;
lockdep_assert_held_once(&s->efr_lock);
status = sc16is7xx_get_hwmctrl(port);
changed = status ^ one->old_mctrl;
if (changed == 0)
return;
one->old_mctrl = status;
spin_lock_irqsave(&port->lock, flags);
if ((changed & TIOCM_RNG) && (status & TIOCM_RNG))
port->icount.rng++;
if (changed & TIOCM_DSR)
port->icount.dsr++;
if (changed & TIOCM_CAR)
uart_handle_dcd_change(port, status & TIOCM_CAR);
if (changed & TIOCM_CTS)
uart_handle_cts_change(port, status & TIOCM_CTS);
wake_up_interruptible(&port->state->port.delta_msr_wait);
spin_unlock_irqrestore(&port->lock, flags);
}
static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
{
struct uart_port *port = &s->p[portno].port;
do {
unsigned int iir, rxlen;
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
if (iir & SC16IS7XX_IIR_NO_INT_BIT)
@ -727,6 +773,11 @@ static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
if (rxlen)
sc16is7xx_handle_rx(port, rxlen, iir);
break;
/* CTSRTS interrupt comes only when CTS goes inactive */
case SC16IS7XX_IIR_CTSRTS_SRC:
case SC16IS7XX_IIR_MSI_SRC:
sc16is7xx_update_mlines(one);
break;
case SC16IS7XX_IIR_THRI_SRC:
sc16is7xx_handle_tx(port);
break;
@ -874,6 +925,30 @@ static void sc16is7xx_stop_rx(struct uart_port *port)
sc16is7xx_ier_clear(port, SC16IS7XX_IER_RDI_BIT);
}
static void sc16is7xx_ms_proc(struct kthread_work *ws)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(ws, ms_work.work);
struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
if (one->port.state) {
mutex_lock(&s->efr_lock);
sc16is7xx_update_mlines(one);
mutex_unlock(&s->efr_lock);
kthread_queue_delayed_work(&s->kworker, &one->ms_work, HZ);
}
}
static void sc16is7xx_enable_ms(struct uart_port *port)
{
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
lockdep_assert_held_once(&port->lock);
kthread_queue_delayed_work(&s->kworker, &one->ms_work, 0);
}
static void sc16is7xx_start_tx(struct uart_port *port)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
@ -893,10 +968,10 @@ static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
{
/* DCD and DSR are not wired and CTS/RTS is handled automatically
* so just indicate DSR and CAR asserted
*/
return TIOCM_DSR | TIOCM_CAR;
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
/* Called with port lock taken so we can only return cached value */
return one->old_mctrl;
}
static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
@ -920,8 +995,12 @@ static void sc16is7xx_set_termios(struct uart_port *port,
struct ktermios *old)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
unsigned int lcr, flow = 0;
int baud;
unsigned long flags;
kthread_cancel_delayed_work_sync(&one->ms_work);
/* Mask termios capabilities we don't support */
termios->c_cflag &= ~CMSPAR;
@ -1010,8 +1089,15 @@ static void sc16is7xx_set_termios(struct uart_port *port,
/* Setup baudrate generator */
baud = sc16is7xx_set_baud(port, baud);
spin_lock_irqsave(&port->lock, flags);
/* Update timeout according to new baud rate */
uart_update_timeout(port, termios->c_cflag, baud);
if (UART_ENABLE_MS(port, termios->c_cflag))
sc16is7xx_enable_ms(port);
spin_unlock_irqrestore(&port->lock, flags);
}
static int sc16is7xx_config_rs485(struct uart_port *port,
@ -1052,6 +1138,7 @@ static int sc16is7xx_startup(struct uart_port *port)
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
unsigned int val;
unsigned long flags;
sc16is7xx_power(port, 1);
@ -1102,16 +1189,25 @@ static int sc16is7xx_startup(struct uart_port *port)
SC16IS7XX_EFCR_TXDISABLE_BIT,
0);
/* Enable RX interrupt */
val = SC16IS7XX_IER_RDI_BIT;
/* Enable RX, CTS change and modem lines interrupts */
val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_CTSI_BIT |
SC16IS7XX_IER_MSI_BIT;
sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
/* Enable modem status polling */
spin_lock_irqsave(&port->lock, flags);
sc16is7xx_enable_ms(port);
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
static void sc16is7xx_shutdown(struct uart_port *port)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
kthread_cancel_delayed_work_sync(&one->ms_work);
/* Disable all interrupts */
sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
@ -1175,6 +1271,7 @@ static const struct uart_ops sc16is7xx_ops = {
.stop_tx = sc16is7xx_stop_tx,
.start_tx = sc16is7xx_start_tx,
.stop_rx = sc16is7xx_stop_rx,
.enable_ms = sc16is7xx_enable_ms,
.break_ctl = sc16is7xx_break_ctl,
.startup = sc16is7xx_startup,
.shutdown = sc16is7xx_shutdown,
@ -1341,7 +1438,9 @@ static int sc16is7xx_probe(struct device *dev,
s->p[i].port.uartclk = freq;
s->p[i].port.rs485_config = sc16is7xx_config_rs485;
s->p[i].port.ops = &sc16is7xx_ops;
s->p[i].old_mctrl = 0;
s->p[i].port.line = sc16is7xx_alloc_line();
if (s->p[i].port.line >= SC16IS7XX_MAX_DEVS) {
ret = -ENOMEM;
goto out_ports;
@ -1353,9 +1452,17 @@ static int sc16is7xx_probe(struct device *dev,
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
SC16IS7XX_EFCR_RXDISABLE_BIT |
SC16IS7XX_EFCR_TXDISABLE_BIT);
/* Use GPIO lines as modem status registers */
if (devtype->has_mctrl)
sc16is7xx_port_write(&s->p[i].port,
SC16IS7XX_IOCONTROL_REG,
SC16IS7XX_IOCONTROL_MODEM_BIT);
/* Initialize kthread work structs */
kthread_init_work(&s->p[i].tx_work, sc16is7xx_tx_proc);
kthread_init_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
kthread_init_delayed_work(&s->p[i].ms_work, sc16is7xx_ms_proc);
/* Register port */
uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
@ -1439,6 +1546,7 @@ static void sc16is7xx_remove(struct device *dev)
#endif
for (i = 0; i < s->devtype->nr_uart; i++) {
kthread_cancel_delayed_work_sync(&s->p[i].ms_work);
uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
clear_bit(s->p[i].port.line, &sc16is7xx_lines);
sc16is7xx_power(&s->p[i].port, 0);