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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: channing <chao.bi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
chao bi 2012-10-31 16:54:07 +08:00 committed by Greg Kroah-Hartman
parent 2ac4ad2a14
commit 31fe990488
2 changed files with 11 additions and 1 deletions
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11
drivers/tty/serial/ifx6x60.c
View File

@ -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--;

1
drivers/tty/serial/ifx6x60.h
View File

@ -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