Add "rda" earlycon driver for RDA8810PL UART. Signed-off-by: Andreas Färber <afaerber@xxxxxxx> --- Documentation/admin-guide/kernel-parameters.txt | 6 ++ drivers/tty/serial/Kconfig | 19 ++++ drivers/tty/serial/Makefile | 1 + drivers/tty/serial/rda-uart.c | 117 ++++++++++++++++++++++++ 4 files changed, 143 insertions(+) create mode 100644 drivers/tty/serial/rda-uart.c diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 0e2091c6fa6b..c97f8b64b3f1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -967,6 +967,12 @@ specified address. The serial port must already be setup and configured. Options are not yet supported. + rda,<addr> + Start an early, polled-mode console on a serial port + of an RDA Micro SoC, such as RDA8810PL, at the + specified address. The serial port must already be + setup and configured. Options are not yet supported. + smh Use ARM semihosting calls for early console. s3c2410,<addr> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 1f096e2bb398..25e106a62e06 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1707,6 +1707,25 @@ config SERIAL_OWL_CONSOLE Say 'Y' here if you wish to use Actions Semiconductor S500/S900 UART as the system console. Only earlycon is implemented currently. +config SERIAL_RDA + bool "RDA Micro serial port support" + depends on ARCH_RDA || COMPILE_TEST + select SERIAL_CORE + help + This driver is for RDA8810PL SoC's UART. + Say 'Y' here if you wish to use the on-board serial port. + Otherwise, say 'N'. + +config SERIAL_RDA_CONSOLE + bool "Console on RDA Micro serial port" + depends on SERIAL_RDA=y + select SERIAL_CORE_CONSOLE + select SERIAL_EARLYCON + default y + help + Say 'Y' here if you wish to use the RDA8810PL UART as the system + console. Only earlycon is implemented currently. + endmenu config SERIAL_MCTRL_GPIO diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile index fe88a75d9a59..87f5a6e1e2d4 100644 --- a/drivers/tty/serial/Makefile +++ b/drivers/tty/serial/Makefile @@ -93,6 +93,7 @@ obj-$(CONFIG_SERIAL_MVEBU_UART) += mvebu-uart.o obj-$(CONFIG_SERIAL_PIC32) += pic32_uart.o obj-$(CONFIG_SERIAL_MPS2_UART) += mps2-uart.o obj-$(CONFIG_SERIAL_OWL) += owl-uart.o +obj-$(CONFIG_SERIAL_RDA) += rda-uart.o # GPIOLIB helpers for modem control lines obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o diff --git a/drivers/tty/serial/rda-uart.c b/drivers/tty/serial/rda-uart.c new file mode 100644 index 000000000000..c3c9cf1df015 --- /dev/null +++ b/drivers/tty/serial/rda-uart.c @@ -0,0 +1,117 @@ +/* + * RDA8810PL serial console + * + * Copyright RDA Microelectronics Company Limited + * Copyright (c) 2017 Andreas Färber + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/console.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/serial.h> +#include <linux/serial_core.h> + +#define RDA_UART_CTRL 0x00 +#define RDA_UART_STATUS 0x04 +#define RDA_UART_RXTX_BUFFER 0x08 +#define RDA_UART_IRQ_MASK 0x0c + +#define RDA_UART_STATUS_TX_FIFO_SPACE_MASK (0x1f << 8) + +static inline void rda_uart_write(struct uart_port *port, u32 val, unsigned int off) +{ + writel(val, port->membase + off); +} + +static inline u32 rda_uart_read(struct uart_port *port, unsigned int off) +{ + return readl(port->membase + off); +} + +#ifdef CONFIG_SERIAL_RDA_CONSOLE + +static void rda_console_putchar(struct uart_port *port, int ch) +{ + if (!port->membase) + return; + + while (!(rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_STATUS_TX_FIFO_SPACE_MASK)) + cpu_relax(); + + rda_uart_write(port, ch, RDA_UART_RXTX_BUFFER); +} + +static void rda_uart_port_write(struct uart_port *port, const char *s, + u_int count) +{ + u32 old_irq_mask; + unsigned long flags; + int locked; + + local_irq_save(flags); + + if (port->sysrq) + locked = 0; + else if (oops_in_progress) + locked = spin_trylock(&port->lock); + else { + spin_lock(&port->lock); + locked = 1; + } + + old_irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK); + rda_uart_write(port, 0, RDA_UART_IRQ_MASK); + + uart_console_write(port, s, count, rda_console_putchar); + + /* wait until all contents have been sent out */ + while (!(rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_STATUS_TX_FIFO_SPACE_MASK)) + cpu_relax(); + + rda_uart_write(port, old_irq_mask, RDA_UART_IRQ_MASK); + + if (locked) + spin_unlock(&port->lock); + + local_irq_restore(flags); +} + +static void rda_uart_early_console_write(struct console *co, + const char *s, + u_int count) +{ + struct earlycon_device *dev = co->data; + + rda_uart_port_write(&dev->port, s, count); +} + +static int __init +rda_uart_early_console_setup(struct earlycon_device *device, const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = rda_uart_early_console_write; + + return 0; +} +OF_EARLYCON_DECLARE(rda, "rda,8810pl-uart", + rda_uart_early_console_setup); + +#endif /* CONFIG_SERIAL_RDA_CONSOLE */ -- 2.12.3 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
