diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_dwlib.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_dwlib.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c index 6d6a78eead3e..1cf229cca592 100644 --- a/drivers/tty/serial/8250/8250_dwlib.c +++ b/drivers/tty/serial/8250/8250_dwlib.c @@ -80,7 +80,7 @@ static void dw8250_set_divisor(struct uart_port *p, unsigned int baud, void dw8250_setup_port(struct uart_port *p) { struct uart_8250_port *up = up_to_u8250p(p); - u32 reg; + u32 reg, old_dlf; /* * If the Component Version Register returns zero, we know that @@ -93,9 +93,11 @@ void dw8250_setup_port(struct uart_port *p) dev_dbg(p->dev, "Designware UART version %c.%c%c\n", (reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff); + /* Preserve value written by firmware or bootloader */ + old_dlf = dw8250_readl_ext(p, DW_UART_DLF); dw8250_writel_ext(p, DW_UART_DLF, ~0U); reg = dw8250_readl_ext(p, DW_UART_DLF); - dw8250_writel_ext(p, DW_UART_DLF, 0); + dw8250_writel_ext(p, DW_UART_DLF, old_dlf); if (reg) { struct dw8250_port_data *d = p->private_data; |