[PATCH/RFC 8/8] serial: pxa: Add OF_EARLYCON support
From: Kevin Cernekee <cernekee@gmail.com>
Date: 2014-11-12 08:46:33
Also in:
linux-mips, linux-serial
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
Implement a bare bones earlycon; this assumes that the bootloader sets up the tty parameters. Matches all three compatible strings. Signed-off-by: Kevin Cernekee <cernekee@gmail.com> --- drivers/tty/serial/pxa.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+)
diff --git a/drivers/tty/serial/pxa.c b/drivers/tty/serial/pxa.c
index f6cc773..0764cf5 100644
--- a/drivers/tty/serial/pxa.c
+++ b/drivers/tty/serial/pxa.c@@ -761,6 +761,51 @@ static struct console serial_pxa_console = { .data = &serial_pxa_reg, }; +static struct uart_pxa_port serial_pxa_early_port; + +static void __init early_wait_for_xmitr(struct uart_pxa_port *up) +{ + /* it's unsafe to call udelay() in the "early" variant */ + while ((serial_in(up, UART_LSR) & BOTH_EMPTY) != BOTH_EMPTY) + ; +} + +static void __init serial_pxa_early_putchar(struct uart_port *port, int ch) +{ + struct uart_pxa_port *up = (struct uart_pxa_port *)port; + + early_wait_for_xmitr(up); + serial_out(up, UART_TX, ch); +} + +static void __init serial_pxa_early_write(struct console *con, const char *s, + unsigned n) +{ + uart_console_write(&serial_pxa_early_port.port, s, n, + serial_pxa_early_putchar); + early_wait_for_xmitr(&serial_pxa_early_port); +} + +static int __init serial_pxa_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + serial_pxa_early_port.port.membase = device->port.membase; + serial_pxa_early_port.port.big_endian = device->port.big_endian; + + device->con->write = serial_pxa_early_write; + return 0; +} + +OF_EARLYCON_DECLARE(pxa_uart, "mrvl,pxa-uart", + serial_pxa_early_console_setup); +OF_EARLYCON_DECLARE(mmp_uart, "mrvl,mmp-uart", + serial_pxa_early_console_setup); +OF_EARLYCON_DECLARE(bcm7401_upg_uart, "brcm,bcm7401-upg-uart", + serial_pxa_early_console_setup); + #define PXA_CONSOLE &serial_pxa_console #else #define PXA_CONSOLE NULL
--
2.1.1