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/*
* based on drivers/tty/serial/mxc_uart_early.c
*
* Copyright (C) 2011 Freescale Semiconductor, Inc.
*
* 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*!
* @file drivers/serial/mvf_uart_early.c
*
* @brief Driver for the Freescale Semiconductor MVF serial ports based on
* drivers/char/8250_early.c,
* Copyright 2004 Hewlett-Packard Development Company,
* L.P.by Bjorn Helgaasby.
*
* Early serial console for MVF UARTS.
*
* This is for use before the serial driver has initialized, in
* particular, before the UARTs have been discovered and named.
* Instead of specifying the console device as, e.g., "ttymvf0",
* we locate the device directly by its MMIO or I/O port address.
*
* The user can specify the device directly, e.g.,
* console=mvfuart,0x43f90000,115200n8
* or platform code can call early_uart_console_init() to set
* the early UART device.
*
* After the normal serial driver starts, we try to locate the
* matching ttymvf device and start a console there.
*/
/*
* Include Files
*/
#include <linux/tty.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/console.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <mach/mvf_uart.h>
struct mvf_early_uart_device {
struct uart_port port;
char options[16]; /* e.g., 115200n8 */
unsigned int baud;
struct clk *clk;
};
static struct mvf_early_uart_device mvf_early_device __initdata;
#if 0
static inline int mvf_uart_enable(struct mvf_port *sport)
{
unsigned char c2;
c2 = readb(sport->port.membase + MVF_UART_C2);
c2 |= (UART_C2_TE | UART_C2_RE);
writeb(c2, sport->port.membase + MVF_UART_C2);
}
static inline int mvf_uart_disable(struct mvf_port *sport)
{
unsigned char c2;
c2 = readb(sport->port.membase + MVF_UART_C2);
c2 &= ~(UART_C2_TE | UART_C2_RE);
writeb(c2, sport->port.membase + MVF_UART_C2);
}
#endif
/*
* Write out a character once the UART is ready
*/
static void __init mvfuart_console_write_char(struct uart_port *port, int ch)
{
while (!(readb(port->membase + MVF_UART_S1) & UART_S1_TDRE));
writeb(ch,port->membase + MVF_UART_D);
}
/*!
* This function is called to write the console messages through the UART port.
*
* @param co the console structure
* @param s the log message to be written to the UART
* @param count length of the message
*/
void __init early_mvfuart_console_write(struct console *co, const char *s,
u_int count)
{
struct uart_port *port = &mvf_early_device.port;
unsigned int status, oldc1, oldc2, oldc3, c2;
/*
* First save the control registers and then disable the interrupts
*/
oldc1 = readb(port->membase + MVF_UART_C1);
oldc2 = readb(port->membase + MVF_UART_C2);
oldc3 = readb(port->membase + MVF_UART_C3);
c2 = oldc2 & ~(UART_C2_TE | UART_C2_RE
| UART_C2_RIE | UART_C2_RIE);
c2 |= (UART_C2_TE | UART_C2_RE);
writeb(c2, port->membase + MVF_UART_C2);
/* Transmit string */
uart_console_write(port, s, count, mvfuart_console_write_char);
/*
* Finally, wait for the transmitter to become empty
*/
do {
status = readb(port->membase + MVF_UART_S1);
} while (!(status & UART_S1_TDRE));
/*
* Restore the control registers
*/
writeb(oldc2, port->membase + MVF_UART_C2);
}
static unsigned int __init probe_baud(struct uart_port *port)
{
/* FIXME Return Default Baud Rate */
return 115200;
}
static int __init mvf_early_uart_setup(struct console *console, char *options)
{
struct mvf_early_uart_device *device = &mvf_early_device;
struct uart_port *port = &device->port;
int length;
if (device->port.membase || device->port.iobase)
return -ENODEV;
/* Enable Early MVF UART Clock */
clk_enable(device->clk);
port->uartclk = 50000000;
port->iotype = UPIO_MEM;
port->membase = ioremap(port->mapbase, SZ_4K);
if (options) {
device->baud = simple_strtoul(options, NULL, 0);
length = min(strlen(options), sizeof(device->options));
strncpy(device->options, options, length);
} else {
device->baud = probe_baud(port);
snprintf(device->options, sizeof(device->options), "%u",
device->baud);
}
printk(KERN_INFO
"MVF_Early serial console at MMIO 0x%x (options '%s')\n",
port->mapbase, device->options);
return 0;
}
static struct console mvf_early_uart_console __initdata = {
.name = "ttymvf",
.write = early_mvfuart_console_write,
.setup = mvf_early_uart_setup,
.flags = CON_PRINTBUFFER | CON_BOOT,
.index = -1,
};
int __init mvf_early_serial_console_init(unsigned long base, struct clk *clk)
{
mvf_early_device.clk = clk;
mvf_early_device.port.mapbase = base;
register_console(&mvf_early_uart_console);
return 0;
}
int __init mvf_early_uart_console_disable(void)
{
struct mvf_early_uart_device *device = &mvf_early_device;
struct uart_port *port = &device->port;
if (mvf_early_uart_console.index >= 0) {
iounmap(port->membase);
clk_disable(device->clk);
clk_put(device->clk);
}
return 0;
}
late_initcall(mvf_early_uart_console_disable);
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