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serial: omap: Add omapserial earlycon

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Add DT earlycon for omap_serial driver. This boot console is included
with CONFIG_SERIAL_EARLYCON=y, CONFIG_OF=y, CONFIG_SERIAL_OMAP=y, and
CONFIG_OF_EARLY_FLATTREE=y.

This boot console is enabled with the command line option "earlycon"
(without "=<name>...") when the DT 'stdout-path' property matches a
compatible uart.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lokesh Vutla 2017-01-19 15:29:38 +05:30 committed by Greg Kroah-Hartman
parent 7951ffc9ea
commit 28ec9570a2
1 changed files with 55 additions and 0 deletions
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55
drivers/tty/serial/omap-serial.c
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@ -1234,6 +1234,61 @@ static int serial_omap_poll_get_char(struct uart_port *port)
#ifdef CONFIG_SERIAL_OMAP_CONSOLE
#ifdef CONFIG_SERIAL_EARLYCON
static unsigned int __init omap_serial_early_in(struct uart_port *port,
int offset)
{
offset <<= port->regshift;
return readw(port->membase + offset);
}
static void __init omap_serial_early_out(struct uart_port *port, int offset,
int value)
{
offset <<= port->regshift;
writew(value, port->membase + offset);
}
static void __init omap_serial_early_putc(struct uart_port *port, int c)
{
unsigned int status;
for (;;) {
status = omap_serial_early_in(port, UART_LSR);
if ((status & BOTH_EMPTY) == BOTH_EMPTY)
break;
cpu_relax();
}
omap_serial_early_out(port, UART_TX, c);
}
static void __init early_omap_serial_write(struct console *console,
const char *s, unsigned int count)
{
struct earlycon_device *device = console->data;
struct uart_port *port = &device->port;
uart_console_write(port, s, count, omap_serial_early_putc);
}
static int __init early_omap_serial_setup(struct earlycon_device *device,
const char *options)
{
struct uart_port *port = &device->port;
if (!(device->port.membase || device->port.iobase))
return -ENODEV;
port->regshift = 2;
device->con->write = early_omap_serial_write;
return 0;
}
OF_EARLYCON_DECLARE(omapserial, "ti,omap2-uart", early_omap_serial_setup);
OF_EARLYCON_DECLARE(omapserial, "ti,omap3-uart", early_omap_serial_setup);
OF_EARLYCON_DECLARE(omapserial, "ti,omap4-uart", early_omap_serial_setup);
#endif /* CONFIG_SERIAL_EARLYCON */
static struct uart_omap_port *serial_omap_console_ports[OMAP_MAX_HSUART_PORTS];
static struct uart_driver serial_omap_reg;