serial: tegra: Add delay after enabling FIFO mode

For all tegra devices (up to t210), there is a hardware issue that
requires software to wait for 3 UART clock periods after enabling
the TX fifo, otherwise data could be lost.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jon Hunter 2015-05-05 15:17:53 +01:00 committed by Greg Kroah-Hartman
parent 245c0278ab
commit 11e71007a5

View file

@ -885,6 +885,16 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup)
tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B;
tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
/* Dummy read to ensure the write is posted */
tegra_uart_read(tup, UART_SCR);
/*
* For all tegra devices (up to t210), there is a hardware issue that
* requires software to wait for 3 UART clock periods after enabling
* the TX fifo, otherwise data could be lost.
*/
tegra_uart_wait_cycle_time(tup, 3);
/*
* Initialize the UART with default configuration
* (115200, N, 8, 1) so that the receive DMA buffer may be