Commit 8324a54f authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by Greg Kroah-Hartman
Browse files

serial: 8250: Add serial8250_handle_irq_locked() 



8250_port exports serial8250_handle_irq() to HW specific 8250 drivers.
It takes port's lock within but a HW specific 8250 driver may want to
take port's lock itself, do something, and then call the generic
handler in 8250_port but to do that, the caller has to release port's
lock for no good reason.

Introduce serial8250_handle_irq_locked() which a HW specific driver can
call while already holding port's lock.

As this is new export, put it straight into a namespace (where all 8250
exports should eventually be moved).

Tested-by: default avatarBandal, Shankar <shankar.bandal@intel.com>
Tested-by: default avatarMurthy, Shanth <shanth.murthy@intel.com>
Cc: stable <stable@kernel.org>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260203171049.4353-4-ilpo.jarvinen@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8002d6d6

drivers/tty/serial/8250/8250_port.c

+16 −8
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/irq.h>

#include <linux/console.h>

#include <linux/gpio/consumer.h>

#include <linux/lockdep.h>

#include <linux/sysrq.h>

#include <linux/delay.h>

#include <linux/platform_device.h>
@@ -1782,20 +1783,16 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) 
}



/*

 * This handles the interrupt from one port.

 * Context: port's lock must be held by the caller.

 */

int serial8250_handle_irq(struct uart_port *port, unsigned int iir)

void serial8250_handle_irq_locked(struct uart_port *port, unsigned int iir)

{

	struct uart_8250_port *up = up_to_u8250p(port);

	struct tty_port *tport = &port->state->port;

	bool skip_rx = false;

	unsigned long flags;

	u16 status;



	if (iir & UART_IIR_NO_INT)

		return 0;



	uart_port_lock_irqsave(port, &flags);

	lockdep_assert_held_once(&port->lock);



	status = serial_lsr_in(up);
@@ -1828,8 +1825,19 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) 
		else if (!up->dma->tx_running)

			__stop_tx(up);

	}

}

EXPORT_SYMBOL_NS_GPL(serial8250_handle_irq_locked, "SERIAL_8250");



	uart_unlock_and_check_sysrq_irqrestore(port, flags);

/*

 * This handles the interrupt from one port.

 */

int serial8250_handle_irq(struct uart_port *port, unsigned int iir)

{

	if (iir & UART_IIR_NO_INT)

		return 0;



	guard(uart_port_lock_irqsave)(port);

	serial8250_handle_irq_locked(port, iir);



	return 1;

}

include/linux/serial_8250.h

+1 −0
Original line number Diff line number Diff line
@@ -195,6 +195,7 @@ void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl); 
void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,

			       unsigned int quot);

int fsl8250_handle_irq(struct uart_port *port);

void serial8250_handle_irq_locked(struct uart_port *port, unsigned int iir);

int serial8250_handle_irq(struct uart_port *port, unsigned int iir);

u16 serial8250_rx_chars(struct uart_8250_port *up, u16 lsr);

void serial8250_read_char(struct uart_8250_port *up, u16 lsr);