Commit 31fe9904 authored by chao bi's avatar chao bi Committed by Greg Kroah-Hartman
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serial:ifx6x60:Prevent data transfer when IFX6x60 port is shutdown 



This patch is to implement following 2 places to avoid potential error when IFX6x60 port shutdown:
1) Clear Flag IFX_SPI_STATE_IO_AVAILABLE to disable data transfer when Modem port is shutdown;
2) Clear Flag IFX_SPI_STATE_IO_IN_PROGRESS and IFX_SPI_STATE_IO_READY when reopen port.
This is because last port shutdown may happen when SPI/DMA transfer is in progress, if the last
data transfer is not completed(for example due to modem reset), the Flag IFX_SPI_STATE_IO_IN_PROGRESS
will be set forever, so when IFX port is activated again, IFX_SPI_STATE_IO_IN_PROGRESS will prevent
transferring data forever. And if don't clear IFX_SPI_STATE_IO_READY, it may cause one more SPI frame
transferring in spit there is not data need to be transfer.

cc: liu chuansheng <chuansheng.liu@intel.com>
cc: Chen Jun <jun.d.chen@intel.com>
Signed-off-by: default avatarchanning <chao.bi@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2ac4ad2a

drivers/tty/serial/ifx6x60.c

+10 −1
Original line number Diff line number Diff line
@@ -569,12 +569,19 @@ static int ifx_port_activate(struct tty_port *port, struct tty_struct *tty) 
	/* clear any old data; can't do this in 'close' */

	kfifo_reset(&ifx_dev->tx_fifo);



	/* clear any flag which may be set in port shutdown procedure */

	clear_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags);

	clear_bit(IFX_SPI_STATE_IO_READY, &ifx_dev->flags);



	/* put port data into this tty */

	tty->driver_data = ifx_dev;



	/* allows flip string push from int context */

	tty->low_latency = 1;



	/* set flag to allows data transfer */

	set_bit(IFX_SPI_STATE_IO_AVAILABLE, &ifx_dev->flags);



	return 0;

}
@@ -590,6 +597,7 @@ static void ifx_port_shutdown(struct tty_port *port) 
	struct ifx_spi_device *ifx_dev =

		container_of(port, struct ifx_spi_device, tty_port);



	clear_bit(IFX_SPI_STATE_IO_AVAILABLE, &ifx_dev->flags);

	mrdy_set_low(ifx_dev);

	clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);

	tasklet_kill(&ifx_dev->io_work_tasklet);
@@ -745,7 +753,8 @@ static void ifx_spi_io(unsigned long data) 
	int retval;

	struct ifx_spi_device *ifx_dev = (struct ifx_spi_device *) data;



	if (!test_and_set_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags)) {

	if (!test_and_set_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags) &&

		test_bit(IFX_SPI_STATE_IO_AVAILABLE, &ifx_dev->flags)) {

		if (ifx_dev->gpio.unack_srdy_int_nb > 0)

			ifx_dev->gpio.unack_srdy_int_nb--;

drivers/tty/serial/ifx6x60.h

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#define IFX_SPI_STATE_IO_IN_PROGRESS	1

#define IFX_SPI_STATE_IO_READY		2

#define IFX_SPI_STATE_TIMER_PENDING	3

#define IFX_SPI_STATE_IO_AVAILABLE	4



/* flow control bitfields */

#define IFX_SPI_DCD			0

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