From 31fe99048859b13a87f476016e7bb5c2b5220c36 Mon Sep 17 00:00:00 2001 From: chao bi Date: Wed, 31 Oct 2012 16:54:07 +0800 Subject: [PATCH] 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 cc: Chen Jun Signed-off-by: channing Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/ifx6x60.c | 11 ++++++++++- drivers/tty/serial/ifx6x60.h | 1 + 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c index e595c832be20..fbda37415f01 100644 --- a/drivers/tty/serial/ifx6x60.c +++ b/drivers/tty/serial/ifx6x60.c @@ -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--; diff --git a/drivers/tty/serial/ifx6x60.h b/drivers/tty/serial/ifx6x60.h index d8869f5a4632..4fbddc297839 100644 --- a/drivers/tty/serial/ifx6x60.h +++ b/drivers/tty/serial/ifx6x60.h @@ -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