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authorShardar Shariff Md <smohammed@nvidia.com>2019-09-04 10:12:58 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-09-05 10:00:03 +0200
commitb9c2470fb150a3cc82a3ee8072da88cb2a73e213 (patch)
tree6d3043b8f583e99a5d378a031c2c150f813a2f89 /drivers/tty/serial
parent494f79bd2365703e4093efa0ecf4b139d83aba97 (diff)
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>
Diffstat (limited to 'drivers/tty/serial')
-rw-r--r--drivers/tty/serial/serial-tegra.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index 29bf7b774f42..4cd6d5f84171 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -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)