Commit e36361d7 authored by Andreas Färber's avatar Andreas Färber Committed by Greg Kroah-Hartman
Browse files

tty: serial: Add Actions Semi Owl UART earlycon



This implements an earlycon for Actions Semi S500/S900 SoCs.

Based on LeMaker linux-actions tree.
Signed-off-by: default avatarAndreas Färber <afaerber@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 80b208ed
......@@ -945,6 +945,12 @@
must already be setup and configured. Options are not
yet supported.
owl,<addr>
Start an early, polled-mode console on a serial port
of an Actions Semi SoC, such as S500 or S900, 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>
......
......@@ -1688,6 +1688,25 @@ config SERIAL_MVEBU_CONSOLE
and warnings and which allows logins in single user mode)
Otherwise, say 'N'.
config SERIAL_OWL
bool "Actions Semi Owl serial port support"
depends on ARCH_ACTIONS || COMPILE_TEST
select SERIAL_CORE
help
This driver is for Actions Semiconductor S500/S900 SoC's UART.
Say 'Y' here if you wish to use the on-board serial port.
Otherwise, say 'N'.
config SERIAL_OWL_CONSOLE
bool "Console on Actions Semi Owl serial port"
depends on SERIAL_OWL=y
select SERIAL_CORE_CONSOLE
select SERIAL_EARLYCON
default y
help
Say 'Y' here if you wish to use Actions Semiconductor S500/S900 UART
as the system console. Only earlycon is implemented currently.
endmenu
config SERIAL_MCTRL_GPIO
......
......@@ -92,6 +92,7 @@ obj-$(CONFIG_SERIAL_STM32) += stm32-usart.o
obj-$(CONFIG_SERIAL_MVEBU_UART) += mvebu-uart.o
obj-$(CONFIG_SERIAL_PIC32) += pic32_uart.o
obj-$(CONFIG_SERIAL_MPS2_UART) += mps2-uart.o
obj-$(CONFIG_SERIAL_OWL) += owl-uart.o
# GPIOLIB helpers for modem control lines
obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
......
/*
* Actions Semi Owl family serial console
*
* Copyright 2013 Actions Semi Inc.
* Author: Actions Semi, Inc.
*
* Copyright (c) 2016-2017 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 OWL_UART_CTL 0x000
#define OWL_UART_TXDAT 0x008
#define OWL_UART_STAT 0x00c
#define OWL_UART_CTL_TRFS_TX BIT(14)
#define OWL_UART_CTL_EN BIT(15)
#define OWL_UART_CTL_RXIE BIT(18)
#define OWL_UART_CTL_TXIE BIT(19)
#define OWL_UART_STAT_RIP BIT(0)
#define OWL_UART_STAT_TIP BIT(1)
#define OWL_UART_STAT_TFFU BIT(6)
#define OWL_UART_STAT_TRFL_MASK (0x1f << 11)
#define OWL_UART_STAT_UTBB BIT(17)
static inline void owl_uart_write(struct uart_port *port, u32 val, unsigned int off)
{
writel(val, port->membase + off);
}
static inline u32 owl_uart_read(struct uart_port *port, unsigned int off)
{
return readl(port->membase + off);
}
#ifdef CONFIG_SERIAL_OWL_CONSOLE
static void owl_console_putchar(struct uart_port *port, int ch)
{
if (!port->membase)
return;
while (owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_TFFU)
cpu_relax();
owl_uart_write(port, ch, OWL_UART_TXDAT);
}
static void owl_uart_port_write(struct uart_port *port, const char *s,
u_int count)
{
u32 old_ctl, val;
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_ctl = owl_uart_read(port, OWL_UART_CTL);
val = old_ctl | OWL_UART_CTL_TRFS_TX;
/* disable IRQ */
val &= ~(OWL_UART_CTL_RXIE | OWL_UART_CTL_TXIE);
owl_uart_write(port, val, OWL_UART_CTL);
uart_console_write(port, s, count, owl_console_putchar);
/* wait until all contents have been sent out */
while (owl_uart_read(port, OWL_UART_STAT) & OWL_UART_STAT_TRFL_MASK)
cpu_relax();
/* clear IRQ pending */
val = owl_uart_read(port, OWL_UART_STAT);
val |= OWL_UART_STAT_TIP | OWL_UART_STAT_RIP;
owl_uart_write(port, val, OWL_UART_STAT);
owl_uart_write(port, old_ctl, OWL_UART_CTL);
if (locked)
spin_unlock(&port->lock);
local_irq_restore(flags);
}
static void owl_uart_early_console_write(struct console *co,
const char *s,
u_int count)
{
struct earlycon_device *dev = co->data;
owl_uart_port_write(&dev->port, s, count);
}
static int __init
owl_uart_early_console_setup(struct earlycon_device *device, const char *opt)
{
if (!device->port.membase)
return -ENODEV;
device->con->write = owl_uart_early_console_write;
return 0;
}
OF_EARLYCON_DECLARE(owl, "actions,owl-uart",
owl_uart_early_console_setup);
#endif /* CONFIG_SERIAL_OWL_CONSOLE */
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