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authorQipan Li <Qipan.Li@csr.com>2015-05-26 09:35:58 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-06-01 06:51:37 +0900
commit326707ed88028283cf04d86848a0436cb966b01e (patch)
treeec04b40bc8df095fb0009be9ce98e7a8ea6ecfb3 /drivers/tty
parentba02406e9bee5726a604a4c8628aac56cb076fef (diff)
downloadop-kernel-dev-326707ed88028283cf04d86848a0436cb966b01e.zip
op-kernel-dev-326707ed88028283cf04d86848a0436cb966b01e.tar.gz
serial: sirf: fix system hung on console log output
A corner case exists in the current driver. if an app opens the console device, and before writing to console device, and there are huge kernel ogs to print out, system will hang on sirfsoc_uart_console_putchar: while (rd_regl(port, ureg->sirfsoc_tx_fifo_status) & ufifo_st->ff_full(port->line)) cpu_relax(); as in sirfsoc_uart_startup(), the driver assigns tx_fifo_op to 0 will stop TX FIFO, this loop will be endless. Signed-off-by: Qipan Li <Qipan.Li@csr.com> Signed-off-by: Barry Song <Baohua.Song@csr.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/sirfsoc_uart.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c
index 8d75962..6b1c92c 100644
--- a/drivers/tty/serial/sirfsoc_uart.c
+++ b/drivers/tty/serial/sirfsoc_uart.c
@@ -272,6 +272,7 @@ static void sirfsoc_uart_start_tx(struct uart_port *port)
if (sirfport->uart_reg->uart_type == SIRF_USP_UART)
wr_regl(port, ureg->sirfsoc_tx_rx_en, rd_regl(port,
ureg->sirfsoc_tx_rx_en) | SIRFUART_TX_EN);
+ wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_STOP);
sirfsoc_uart_pio_tx_chars(sirfport, port->fifosize);
wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_START);
if (!sirfport->is_atlas7)
@@ -1117,7 +1118,6 @@ static int sirfsoc_uart_startup(struct uart_port *port)
SIRFSOC_USP_ENDIAN_CTRL_LSBF |
SIRFSOC_USP_EN);
wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_RESET);
- wr_regl(port, ureg->sirfsoc_tx_fifo_op, 0);
wr_regl(port, ureg->sirfsoc_rx_fifo_op, SIRFUART_FIFO_RESET);
wr_regl(port, ureg->sirfsoc_rx_fifo_op, 0);
wr_regl(port, ureg->sirfsoc_tx_fifo_ctrl, SIRFUART_FIFO_THD(port));
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