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Commit d07e43d7 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'omap-serial' of git://git.linaro.org/people/rmk/linux-arm 

Pull ARM OMAP serial updates from Russell King:
 "This series is a major reworking of the OMAP serial driver code fixing
  various bugs in the hardware-assisted flow control, extending up into
  serial_core for a couple of issues.  These fixes have been done as a
  set of progressive changes and transformations in the hope that no new
  bugs will be introduced by this series.

  The problems are many-fold, from the driver not being informed about
  updated settings, to the driver not knowing what the intentions of the
  upper layers are.

  The first four patches tackle the serial_core layer, allowing it to
  provide the necessary information to drivers, and the remaining
  patches allow the OMAP serial driver to take advantage of this.

  This brings hardware assisted RTS/CTS and XON/OFF flow control into a
  useful state.

  These patches have been in linux-next for most of the last cycle;
  indeed they predate the previous merge window.  They've also been
  posted to the OMAP people."

* 'omap-serial' of git://git.linaro.org/people/rmk/linux-arm: (21 commits)
  SERIAL: omap: fix hardware assisted flow control
  SERIAL: omap: simplify (2)
  SERIAL: omap: move xon/xoff setting earlier
  SERIAL: omap: always set TCR
  SERIAL: omap: simplify
  SERIAL: omap: don't read back LCR/MCR/EFR
  SERIAL: omap: serial_omap_configure_xonxoff() contents into set_termios
  SERIAL: omap: configure xon/xoff before setting modem control lines
  SERIAL: omap: remove OMAP_UART_SYSC_RESET and OMAP_UART_FIFO_CLR
  SERIAL: omap: move driver private definitions and structures to driver
  SERIAL: omap: remove 'irq_pending' bitfield
  SERIAL: omap: fix MCR TCRTLR bit handling
  SERIAL: omap: fix set_mctrl() breakage
  SERIAL: omap: no need to re-read EFR
  SERIAL: omap: remove setting of EFR SCD bit
  SERIAL: omap: allow hardware assisted IXANY mode to be disabled
  SERIAL: omap: allow hardware assisted rts/cts modes to be disabled
  SERIAL: core: add throttle/unthrottle callbacks for hardware assisted flow control
  SERIAL: core: add hardware assisted h/w flow control support
  SERIAL: core: add hardware assisted s/w flow control support
  ...

Conflicts:
	drivers/tty/serial/omap-serial.c
parents 1ebaf4f4 3af08bd7

arch/arm/plat-omap/include/plat/omap-serial.h

+0 −55
Original line number Diff line number Diff line
@@ -30,35 +30,6 @@ 
 */

#define OMAP_SERIAL_NAME	"ttyO"



#define OMAP_MODE13X_SPEED	230400



#define OMAP_UART_SCR_TX_EMPTY	0x08



/* WER = 0x7F

 * Enable module level wakeup in WER reg

 */

#define OMAP_UART_WER_MOD_WKUP	0X7F



/* Enable XON/XOFF flow control on output */

#define OMAP_UART_SW_TX		0x04



/* Enable XON/XOFF flow control on input */

#define OMAP_UART_SW_RX		0x04



#define OMAP_UART_SYSC_RESET	0X07

#define OMAP_UART_TCR_TRIG	0X0F

#define OMAP_UART_SW_CLR	0XF0

#define OMAP_UART_FIFO_CLR	0X06



#define OMAP_UART_DMA_CH_FREE	-1



#define OMAP_MAX_HSUART_PORTS	6



#define MSR_SAVE_FLAGS		UART_MSR_ANY_DELTA



#define UART_ERRATA_i202_MDR1_ACCESS	BIT(0)

#define UART_ERRATA_i291_DMA_FORCEIDLE	BIT(1)



struct omap_uart_port_info {

	bool			dma_enabled;	/* To specify DMA Mode */

	unsigned int		uartclk;	/* UART clock rate */
@@ -77,30 +48,4 @@ struct omap_uart_port_info { 
	void (*enable_wakeup)(struct device *, bool);

};



struct uart_omap_dma {

	u8			uart_dma_tx;

	u8			uart_dma_rx;

	int			rx_dma_channel;

	int			tx_dma_channel;

	dma_addr_t		rx_buf_dma_phys;

	dma_addr_t		tx_buf_dma_phys;

	unsigned int		uart_base;

	/*

	 * Buffer for rx dma.It is not required for tx because the buffer

	 * comes from port structure.

	 */

	unsigned char		*rx_buf;

	unsigned int		prev_rx_dma_pos;

	int			tx_buf_size;

	int			tx_dma_used;

	int			rx_dma_used;

	spinlock_t		tx_lock;

	spinlock_t		rx_lock;

	/* timer to poll activity on rx dma */

	struct timer_list	rx_timer;

	unsigned int		rx_buf_size;

	unsigned int		rx_poll_rate;

	unsigned int		rx_timeout;

};



#endif /* __OMAP_SERIAL_H__ */

drivers/tty/serial/omap-serial.c

+150 −81
Original line number Diff line number Diff line
@@ -44,6 +44,8 @@ 


#include <plat/omap-serial.h>



#define OMAP_MAX_HSUART_PORTS	6



#define UART_BUILD_REVISION(x, y)	(((x) << 8) | (y))



#define OMAP_UART_REV_42 0x0402
@@ -51,10 +53,14 @@ 
#define OMAP_UART_REV_52 0x0502

#define OMAP_UART_REV_63 0x0603



#define UART_ERRATA_i202_MDR1_ACCESS	BIT(0)

#define UART_ERRATA_i291_DMA_FORCEIDLE	BIT(1)



#define DEFAULT_CLK_SPEED 48000000 /* 48Mhz*/



/* SCR register bitmasks */

#define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK		(1 << 7)

#define OMAP_UART_SCR_TX_EMPTY			(1 << 3)



/* FCR register bitmasks */

#define OMAP_UART_FCR_RX_FIFO_TRIG_MASK			(0x3 << 6)
@@ -71,6 +77,52 @@ 
#define OMAP_UART_MVR_MAJ_SHIFT		8

#define OMAP_UART_MVR_MIN_MASK		0x3f



#define OMAP_UART_DMA_CH_FREE	-1



#define MSR_SAVE_FLAGS		UART_MSR_ANY_DELTA

#define OMAP_MODE13X_SPEED	230400



/* WER = 0x7F

 * Enable module level wakeup in WER reg

 */

#define OMAP_UART_WER_MOD_WKUP	0X7F



/* Enable XON/XOFF flow control on output */

#define OMAP_UART_SW_TX		0x08



/* Enable XON/XOFF flow control on input */

#define OMAP_UART_SW_RX		0x02



#define OMAP_UART_SW_CLR	0xF0



#define OMAP_UART_TCR_TRIG	0x0F



struct uart_omap_dma {

	u8			uart_dma_tx;

	u8			uart_dma_rx;

	int			rx_dma_channel;

	int			tx_dma_channel;

	dma_addr_t		rx_buf_dma_phys;

	dma_addr_t		tx_buf_dma_phys;

	unsigned int		uart_base;

	/*

	 * Buffer for rx dma.It is not required for tx because the buffer

	 * comes from port structure.

	 */

	unsigned char		*rx_buf;

	unsigned int		prev_rx_dma_pos;

	int			tx_buf_size;

	int			tx_dma_used;

	int			rx_dma_used;

	spinlock_t		tx_lock;

	spinlock_t		rx_lock;

	/* timer to poll activity on rx dma */

	struct timer_list	rx_timer;

	unsigned int		rx_buf_size;

	unsigned int		rx_poll_rate;

	unsigned int		rx_timeout;

};



struct uart_omap_port {

	struct uart_port	port;

	struct uart_omap_dma	uart_dma;
@@ -99,7 +151,6 @@ struct uart_omap_port { 
	int			context_loss_cnt;

	u32			errata;

	u8			wakeups_enabled;

	unsigned int		irq_pending:1;



	int			DTR_gpio;

	int			DTR_inverted;
@@ -303,6 +354,34 @@ static void serial_omap_start_tx(struct uart_port *port) 
	pm_runtime_put_autosuspend(up->dev);

}



static void serial_omap_throttle(struct uart_port *port)

{

	struct uart_omap_port *up = to_uart_omap_port(port);

	unsigned long flags;



	pm_runtime_get_sync(up->dev);

	spin_lock_irqsave(&up->port.lock, flags);

	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);

	serial_out(up, UART_IER, up->ier);

	spin_unlock_irqrestore(&up->port.lock, flags);

	pm_runtime_mark_last_busy(up->dev);

	pm_runtime_put_autosuspend(up->dev);

}



static void serial_omap_unthrottle(struct uart_port *port)

{

	struct uart_omap_port *up = to_uart_omap_port(port);

	unsigned long flags;



	pm_runtime_get_sync(up->dev);

	spin_lock_irqsave(&up->port.lock, flags);

	up->ier |= UART_IER_RLSI | UART_IER_RDI;

	serial_out(up, UART_IER, up->ier);

	spin_unlock_irqrestore(&up->port.lock, flags);

	pm_runtime_mark_last_busy(up->dev);

	pm_runtime_put_autosuspend(up->dev);

}



static unsigned int check_modem_status(struct uart_omap_port *up)

{

	unsigned int status;
@@ -504,7 +583,7 @@ static unsigned int serial_omap_get_mctrl(struct uart_port *port) 
static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)

{

	struct uart_omap_port *up = to_uart_omap_port(port);

	unsigned char mcr = 0;

	unsigned char mcr = 0, old_mcr;



	dev_dbg(up->port.dev, "serial_omap_set_mctrl+%d\n", up->port.line);

	if (mctrl & TIOCM_RTS)
@@ -519,8 +598,10 @@ static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl) 
		mcr |= UART_MCR_LOOP;



	pm_runtime_get_sync(up->dev);

	up->mcr = serial_in(up, UART_MCR);

	up->mcr |= mcr;

	old_mcr = serial_in(up, UART_MCR);

	old_mcr &= ~(UART_MCR_LOOP | UART_MCR_OUT2 | UART_MCR_OUT1 |

		     UART_MCR_DTR | UART_MCR_RTS);

	up->mcr = old_mcr | mcr;

	serial_out(up, UART_MCR, up->mcr);

	pm_runtime_mark_last_busy(up->dev);

	pm_runtime_put_autosuspend(up->dev);
@@ -654,61 +735,6 @@ static void serial_omap_shutdown(struct uart_port *port) 
	free_irq(up->port.irq, up);

}



static inline void

serial_omap_configure_xonxoff

		(struct uart_omap_port *up, struct ktermios *termios)

{

	up->lcr = serial_in(up, UART_LCR);

	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

	up->efr = serial_in(up, UART_EFR);

	serial_out(up, UART_EFR, up->efr & ~UART_EFR_ECB);



	serial_out(up, UART_XON1, termios->c_cc[VSTART]);

	serial_out(up, UART_XOFF1, termios->c_cc[VSTOP]);



	/* clear SW control mode bits */

	up->efr &= OMAP_UART_SW_CLR;



	/*

	 * IXON Flag:

	 * Enable XON/XOFF flow control on output.

	 * Transmit XON1, XOFF1

	 */

	if (termios->c_iflag & IXON)

		up->efr |= OMAP_UART_SW_TX;



	/*

	 * IXOFF Flag:

	 * Enable XON/XOFF flow control on input.

	 * Receiver compares XON1, XOFF1.

	 */

	if (termios->c_iflag & IXOFF)

		up->efr |= OMAP_UART_SW_RX;



	serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);

	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);



	up->mcr = serial_in(up, UART_MCR);



	/*

	 * IXANY Flag:

	 * Enable any character to restart output.

	 * Operation resumes after receiving any

	 * character after recognition of the XOFF character

	 */

	if (termios->c_iflag & IXANY)

		up->mcr |= UART_MCR_XONANY;



	serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);

	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

	serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_TRIG);



	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);



	serial_out(up, UART_MCR, up->mcr & ~UART_MCR_TCRTLR);

	serial_out(up, UART_LCR, up->lcr);

}



static void serial_omap_uart_qos_work(struct work_struct *work)

{

	struct uart_omap_port *up = container_of(work, struct uart_omap_port,
@@ -726,7 +752,6 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios, 
{

	struct uart_omap_port *up = to_uart_omap_port(port);

	unsigned char cval = 0;

	unsigned char efr = 0;

	unsigned long flags = 0;

	unsigned int baud, quot;
@@ -836,11 +861,12 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios, 


	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);



	up->efr = serial_in(up, UART_EFR);

	up->efr = serial_in(up, UART_EFR) & ~UART_EFR_ECB;

	up->efr &= ~UART_EFR_SCD;

	serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);



	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);

	up->mcr = serial_in(up, UART_MCR);

	up->mcr = serial_in(up, UART_MCR) & ~UART_MCR_TCRTLR;

	serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);

	/* FIFO ENABLE, DMA MODE */
@@ -859,9 +885,12 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios, 


	serial_out(up, UART_OMAP_SCR, up->scr);



	serial_out(up, UART_EFR, up->efr);

	/* Reset UART_MCR_TCRTLR: this must be done with the EFR_ECB bit set */

	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);

	serial_out(up, UART_MCR, up->mcr);

	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

	serial_out(up, UART_EFR, up->efr);

	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);



	/* Protocol, Baud Rate, and Interrupt Settings */
@@ -871,8 +900,6 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios, 
		serial_out(up, UART_OMAP_MDR1, up->mdr1);



	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);



	up->efr = serial_in(up, UART_EFR);

	serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);



	serial_out(up, UART_LCR, 0);
@@ -899,29 +926,68 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios, 
	else

		serial_out(up, UART_OMAP_MDR1, up->mdr1);



	/* Hardware Flow Control Configuration */



	if (termios->c_cflag & CRTSCTS) {

		efr |= (UART_EFR_CTS | UART_EFR_RTS);

		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);

	/* Configure flow control */

	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);



		up->mcr = serial_in(up, UART_MCR);

		serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);

	/* XON1/XOFF1 accessible mode B, TCRTLR=0, ECB=0 */

	serial_out(up, UART_XON1, termios->c_cc[VSTART]);

	serial_out(up, UART_XOFF1, termios->c_cc[VSTOP]);



		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

		up->efr = serial_in(up, UART_EFR);

	/* Enable access to TCR/TLR */

	serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);

	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);

	serial_out(up, UART_MCR, up->mcr | UART_MCR_TCRTLR);



	serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_TRIG);

		serial_out(up, UART_EFR, efr); /* Enable AUTORTS and AUTOCTS */

		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);

		serial_out(up, UART_MCR, up->mcr | UART_MCR_RTS);

		serial_out(up, UART_LCR, cval);



	if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) {

		/* Enable AUTORTS and AUTOCTS */

		up->efr |= UART_EFR_CTS | UART_EFR_RTS;



		/* Ensure MCR RTS is asserted */

		up->mcr |= UART_MCR_RTS;

	} else {

		/* Disable AUTORTS and AUTOCTS */

		up->efr &= ~(UART_EFR_CTS | UART_EFR_RTS);

	}



	if (up->port.flags & UPF_SOFT_FLOW) {

		/* clear SW control mode bits */

		up->efr &= OMAP_UART_SW_CLR;



		/*

		 * IXON Flag:

		 * Enable XON/XOFF flow control on input.

		 * Receiver compares XON1, XOFF1.

		 */

		if (termios->c_iflag & IXON)

			up->efr |= OMAP_UART_SW_RX;



		/*

		 * IXOFF Flag:

		 * Enable XON/XOFF flow control on output.

		 * Transmit XON1, XOFF1

		 */

		if (termios->c_iflag & IXOFF)

			up->efr |= OMAP_UART_SW_TX;



		/*

		 * IXANY Flag:

		 * Enable any character to restart output.

		 * Operation resumes after receiving any

		 * character after recognition of the XOFF character

		 */

		if (termios->c_iflag & IXANY)

			up->mcr |= UART_MCR_XONANY;

		else

			up->mcr &= ~UART_MCR_XONANY;

	}

	serial_out(up, UART_MCR, up->mcr);

	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);

	serial_out(up, UART_EFR, up->efr);

	serial_out(up, UART_LCR, up->lcr);



	serial_omap_set_mctrl(&up->port, up->port.mctrl);

	/* Software Flow Control Configuration */

	serial_omap_configure_xonxoff(up, termios);



	spin_unlock_irqrestore(&up->port.lock, flags);

	pm_runtime_mark_last_busy(up->dev);
@@ -987,6 +1053,7 @@ static void serial_omap_config_port(struct uart_port *port, int flags) 
	dev_dbg(up->port.dev, "serial_omap_config_port+%d\n",

							up->port.line);

	up->port.type = PORT_OMAP;

	up->port.flags |= UPF_SOFT_FLOW | UPF_HARD_FLOW;

}



static int
@@ -1190,6 +1257,8 @@ static struct uart_ops serial_omap_pops = { 
	.get_mctrl	= serial_omap_get_mctrl,

	.stop_tx	= serial_omap_stop_tx,

	.start_tx	= serial_omap_start_tx,

	.throttle	= serial_omap_throttle,

	.unthrottle	= serial_omap_unthrottle,

	.stop_rx	= serial_omap_stop_rx,

	.enable_ms	= serial_omap_enable_ms,

	.break_ctl	= serial_omap_break_ctl,

drivers/tty/serial/serial_core.c

+57 −14
Original line number Diff line number Diff line
@@ -610,27 +610,50 @@ static void uart_send_xchar(struct tty_struct *tty, char ch) 
static void uart_throttle(struct tty_struct *tty)

{

	struct uart_state *state = tty->driver_data;

	struct uart_port *port = state->uart_port;

	uint32_t mask = 0;



	if (I_IXOFF(tty))

		mask |= UPF_SOFT_FLOW;

	if (tty->termios.c_cflag & CRTSCTS)

		mask |= UPF_HARD_FLOW;



	if (port->flags & mask) {

		port->ops->throttle(port);

		mask &= ~port->flags;

	}



	if (mask & UPF_SOFT_FLOW)

		uart_send_xchar(tty, STOP_CHAR(tty));



	if (tty->termios.c_cflag & CRTSCTS)

		uart_clear_mctrl(state->uart_port, TIOCM_RTS);

	if (mask & UPF_HARD_FLOW)

		uart_clear_mctrl(port, TIOCM_RTS);

}



static void uart_unthrottle(struct tty_struct *tty)

{

	struct uart_state *state = tty->driver_data;

	struct uart_port *port = state->uart_port;

	uint32_t mask = 0;



	if (I_IXOFF(tty)) {

	if (I_IXOFF(tty))

		mask |= UPF_SOFT_FLOW;

	if (tty->termios.c_cflag & CRTSCTS)

		mask |= UPF_HARD_FLOW;



	if (port->flags & mask) {

		port->ops->unthrottle(port);

		mask &= ~port->flags;

	}



	if (mask & UPF_SOFT_FLOW) {

		if (port->x_char)

			port->x_char = 0;

		else

			uart_send_xchar(tty, START_CHAR(tty));

	}



	if (tty->termios.c_cflag & CRTSCTS)

	if (mask & UPF_HARD_FLOW)

		uart_set_mctrl(port, TIOCM_RTS);

}
@@ -1214,9 +1237,22 @@ static void uart_set_termios(struct tty_struct *tty, 
						struct ktermios *old_termios)

{

	struct uart_state *state = tty->driver_data;

	struct uart_port *uport = state->uart_port;

	unsigned long flags;

	unsigned int cflag = tty->termios.c_cflag;

	unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;

	bool sw_changed = false;



	/*

	 * Drivers doing software flow control also need to know

	 * about changes to these input settings.

	 */

	if (uport->flags & UPF_SOFT_FLOW) {

		iflag_mask |= IXANY|IXON|IXOFF;

		sw_changed =

		   tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||

		   tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];

	}



	/*

	 * These are the bits that are used to setup various
@@ -1224,11 +1260,11 @@ static void uart_set_termios(struct tty_struct *tty, 
	 * bits in c_cflag; c_[io]speed will always be set

	 * appropriately by set_termios() in tty_ioctl.c

	 */

#define RELEVANT_IFLAG(iflag)	((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))

	if ((cflag ^ old_termios->c_cflag) == 0 &&

	    tty->termios.c_ospeed == old_termios->c_ospeed &&

	    tty->termios.c_ispeed == old_termios->c_ispeed &&

	    RELEVANT_IFLAG(tty->termios.c_iflag ^ old_termios->c_iflag) == 0) {

	    ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&

	    !sw_changed) {

		return;

	}
@@ -1236,31 +1272,38 @@ static void uart_set_termios(struct tty_struct *tty, 


	/* Handle transition to B0 status */

	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))

		uart_clear_mctrl(state->uart_port, TIOCM_RTS | TIOCM_DTR);

		uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);

	/* Handle transition away from B0 status */

	else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {

		unsigned int mask = TIOCM_DTR;

		if (!(cflag & CRTSCTS) ||

		    !test_bit(TTY_THROTTLED, &tty->flags))

			mask |= TIOCM_RTS;

		uart_set_mctrl(state->uart_port, mask);

		uart_set_mctrl(uport, mask);

	}



	/*

	 * If the port is doing h/w assisted flow control, do nothing.

	 * We assume that tty->hw_stopped has never been set.

	 */

	if (uport->flags & UPF_HARD_FLOW)

		return;



	/* Handle turning off CRTSCTS */

	if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {

		spin_lock_irqsave(&state->uart_port->lock, flags);

		spin_lock_irqsave(&uport->lock, flags);

		tty->hw_stopped = 0;

		__uart_start(tty);

		spin_unlock_irqrestore(&state->uart_port->lock, flags);

		spin_unlock_irqrestore(&uport->lock, flags);

	}

	/* Handle turning on CRTSCTS */

	else if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {

		spin_lock_irqsave(&state->uart_port->lock, flags);

		if (!(state->uart_port->ops->get_mctrl(state->uart_port) & TIOCM_CTS)) {

		spin_lock_irqsave(&uport->lock, flags);

		if (!(uport->ops->get_mctrl(uport) & TIOCM_CTS)) {

			tty->hw_stopped = 1;

			state->uart_port->ops->stop_tx(state->uart_port);

			uport->ops->stop_tx(uport);

		}

		spin_unlock_irqrestore(&state->uart_port->lock, flags);

		spin_unlock_irqrestore(&uport->lock, flags);

	}

}

include/linux/serial_core.h

+6 −0
Original line number Diff line number Diff line
@@ -46,6 +46,8 @@ struct uart_ops { 
	unsigned int	(*get_mctrl)(struct uart_port *);

	void		(*stop_tx)(struct uart_port *);

	void		(*start_tx)(struct uart_port *);

	void		(*throttle)(struct uart_port *);

	void		(*unthrottle)(struct uart_port *);

	void		(*send_xchar)(struct uart_port *, char ch);

	void		(*stop_rx)(struct uart_port *);

	void		(*enable_ms)(struct uart_port *);
@@ -163,6 +165,10 @@ struct uart_port { 
#define UPF_BUGGY_UART		((__force upf_t) (1 << 14))

#define UPF_NO_TXEN_TEST	((__force upf_t) (1 << 15))

#define UPF_MAGIC_MULTIPLIER	((__force upf_t) (1 << 16))

/* Port has hardware-assisted h/w flow control (iow, auto-RTS *not* auto-CTS) */

#define UPF_HARD_FLOW		((__force upf_t) (1 << 21))

/* Port has hardware-assisted s/w flow control */

#define UPF_SOFT_FLOW		((__force upf_t) (1 << 22))

#define UPF_CONS_FLOW		((__force upf_t) (1 << 23))

#define UPF_SHARE_IRQ		((__force upf_t) (1 << 24))

#define UPF_EXAR_EFR		((__force upf_t) (1 << 25))