diff options
| author | Rob Herring <robh@kernel.org> | 2014-04-18 17:19:57 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-04-24 16:32:27 -0700 |
| commit | 0d3c673e7881e691991b2a4745bd4f149603baa2 (patch) | |
| tree | 3eb552f130c5ac8654552791e6cb4faf8bc39c98 | |
| parent | d2fd6810a823bcde1ee232668f5689837aafa772 (diff) | |
tty/serial: pl011: add generic earlycon support
Add earlycon support for the pl011 serial port. This allows enabling
the pl011 for console when early_params are processed. This is based
on the arm64 earlyprintk support and is intended to replace it.
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | Documentation/kernel-parameters.txt | 7 | ||||
| -rw-r--r-- | drivers/tty/serial/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/tty/serial/amba-pl011.c | 30 |
3 files changed, 37 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 43842177b771..2609ead7ff55 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -883,6 +883,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. which are not unmapped. earlycon= [KNL] Output early console device and options. + uart[8250],io,<addr>[,options] uart[8250],mmio,<addr>[,options] uart[8250],mmio32,<addr>[,options] @@ -892,6 +893,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. (mmio) or 32-bit (mmio32). The options are the same as for ttyS, above. + pl011,<addr> + Start an early, polled-mode console on a pl011 serial + port at the specified address. The pl011 serial port + must already be setup and configured. Options are not + yet supported. + earlyprintk= [X86,SH,BLACKFIN,ARM] earlyprintk=vga earlyprintk=efi diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 9fb6028ad900..4290d05875b1 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -60,6 +60,7 @@ config SERIAL_AMBA_PL011_CONSOLE bool "Support for console on AMBA serial port" depends on SERIAL_AMBA_PL011=y select SERIAL_CORE_CONSOLE + select SERIAL_EARLYCON ---help--- Say Y here if you wish to use an AMBA PrimeCell UART as the system console (the system console is the device which receives all kernel diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index dacf0a09ab24..ee3d80346780 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -303,7 +303,7 @@ static void pl011_dma_probe_initcall(struct device *dev, struct uart_amba_port * /* Optionally make use of an RX channel as well */ chan = dma_request_slave_channel(dev, "rx"); - + if (!chan && plat->dma_rx_param) { chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param); @@ -2045,6 +2045,34 @@ static struct console amba_console = { }; #define AMBA_CONSOLE (&amba_console) + +static void pl011_putc(struct uart_port *port, int c) +{ + while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) + ; + writeb(c, port->membase + UART01x_DR); + while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY) + ; +} + +static void pl011_early_write(struct console *con, const char *s, unsigned n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, pl011_putc); +} + +static int __init pl011_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = pl011_early_write; + return 0; +} +EARLYCON_DECLARE(pl011, pl011_early_console_setup); + #else #define AMBA_CONSOLE NULL #endif |