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serial: tegra: flush the RX fifo on frame error 

FIFO reset/flush code implemented now does not follow programming
guidelines. RTS line has to be turned off while flushing FIFOs to
avoid new transfers. Also check LSR bits UART_LSR_TEMT and UART_LSR_DR
to confirm FIFOs are flushed.

Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: Krishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-4-git-send-email-kyarlagadda@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shardar Shariff Md 2019-09-04 10:12:58 +05:30 committed by Greg Kroah-Hartman
parent 494f79bd23
commit b9c2470fb1
1 changed files with 14 additions and 0 deletions
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14
drivers/tty/serial/serial-tegra.c
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@ -266,6 +266,10 @@ static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup,
static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
{
unsigned long fcr = tup->fcr_shadow;
unsigned int lsr, tmout = 10000;
if (tup->rts_active)
set_rts(tup, false);
if (tup->cdata->allow_txfifo_reset_fifo_mode) {
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
@ -289,6 +293,16 @@ static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
* to propagate, otherwise data could be lost.
*/
tegra_uart_wait_cycle_time(tup, 32);
do {
lsr = tegra_uart_read(tup, UART_LSR);
if ((lsr | UART_LSR_TEMT) && !(lsr & UART_LSR_DR))
break;
udelay(1);
} while (--tmout);
if (tup->rts_active)
set_rts(tup, true);
}
static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)