diff options
| author |   Scott Telford <stelford@cadence.com> | 2016-09-22 16:58:16 +0100 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-27 12:54:41 +0200 |
| commit | c41251b17563234371a9b376ed4914efa4bc079b (patch) | |
| tree | 7fa3e64e794043e6184232621af6a7272b46bacc /drivers | |
| parent | serial: xuartps: Removed unwanted checks while reading the error conditions (diff) | |
| download | linux-dev-c41251b17563234371a9b376ed4914efa4bc079b.tar.xz linux-dev-c41251b17563234371a9b376ed4914efa4bc079b.zip | |
serial: xuartps: Add some register initialisation to cdns_early_console_setup()
Add initialisation of control register and baud rate to
cdns_early_console_setup(), required when running kernel standalone
without a boot loader. Baud rate is only initialised when specified in
earlycon command-line option, otherwise it is assumed this has been
set by a boot loader. Updated Documentation/kernel-parameters.txt
accordingly.
Signed-off-by: Scott Telford <stelford@cadence.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/serial/xilinx_uartps.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 39f41bfd7c22..f37edaa5ac75 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -1165,9 +1165,34 @@ static void __init cdns_early_write(struct console *con, const char *s, static int __init cdns_early_console_setup(struct earlycon_device *device, const char *opt) { - if (!device->port.membase) + struct uart_port *port = &device->port; + + if (!port->membase) return -ENODEV; + /* initialise control register */ + writel(CDNS_UART_CR_TX_EN|CDNS_UART_CR_TXRST|CDNS_UART_CR_RXRST, + port->membase + CDNS_UART_CR); + + /* only set baud if specified on command line - otherwise + * assume it has been initialized by a boot loader. + */ + if (device->baud) { + u32 cd = 0, bdiv = 0; + u32 mr; + int div8; + + cdns_uart_calc_baud_divs(port->uartclk, device->baud, + &bdiv, &cd, &div8); + mr = CDNS_UART_MR_PARITY_NONE; + if (div8) + mr |= CDNS_UART_MR_CLKSEL; + + writel(mr, port->membase + CDNS_UART_MR); + writel(cd, port->membase + CDNS_UART_BAUDGEN); + writel(bdiv, port->membase + CDNS_UART_BAUDDIV); + } + device->con->write = cdns_early_write; return 0; |