mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-30 08:02:30 +00:00
136 lines
3.4 KiB
C
136 lines
3.4 KiB
C
|
/*
|
||
|
* 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 */
|