path: root/drivers/tty/serial/m32r_sio.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *  m32r_sio.c
 *
 *  Driver for M32R serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *  Based on drivers/serial/8250.c.
 *
 *  Copyright (C) 2001  Russell King.
 *  Copyright (C) 2004  Hirokazu Takata <takata at linux-m32r.org>
 *
 * 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.
 */

/*
 * A note about mapbase / membase
 *
 *  mapbase is the physical address of the IO port.  Currently, we don't
 *  support this very well, and it may well be dropped from this driver
 *  in future.  As such, mapbase should be NULL.
 *
 *  membase is an 'ioremapped' cookie.  This is compatible with the old
 *  serial.c driver, and is currently the preferred form.
 */

#if defined(CONFIG_SERIAL_M32R_SIO_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/serial.h>
#include <linux/delay.h>

#include <asm/m32r.h>
#include <asm/io.h>
#include <asm/irq.h>

#define BAUD_RATE	115200

#include <linux/serial_core.h>
#include "m32r_sio_reg.h"

#define PASS_LIMIT	256

static const struct {
	unsigned int port;
	unsigned int irq;
} old_serial_port[] = {
#if defined(CONFIG_PLAT_USRV)
	/* PORT  IRQ            FLAGS */
	{ 0x3F8, PLD_IRQ_UART0 }, /* ttyS0 */
	{ 0x2F8, PLD_IRQ_UART1 }, /* ttyS1 */
#elif defined(CONFIG_SERIAL_M32R_PLDSIO)
	{ ((unsigned long)PLD_ESIO0CR), PLD_IRQ_SIO0_RCV }, /* ttyS0 */
#else
	{ M32R_SIO_OFFSET, M32R_IRQ_SIO0_R }, /* ttyS0 */
#endif
};

#define UART_NR	ARRAY_SIZE(old_serial_port)

struct uart_sio_port {
	struct uart_port	port;
	struct timer_list	timer;		/* "no irq" timer */
	struct list_head	list;		/* ports on this IRQ */
	unsigned char		ier;
};

struct irq_info {
	spinlock_t		lock;
	struct list_head	*head;
};

static struct irq_info irq_lists[NR_IRQS];

#ifdef CONFIG_SERIAL_M32R_PLDSIO

#define __sio_in(x) inw((unsigned long)(x))
#define __sio_out(v,x) outw((v),(unsigned long)(x))

static inline void sio_set_baud_rate(unsigned long baud)
{
	unsigned short sbaud;
	sbaud = (boot_cpu_data.bus_clock / (baud * 4))-1;
	__sio_out(sbaud, PLD_ESIO0BAUR);
}

static void sio_reset(void)
{
	unsigned short tmp;

	tmp = __sio_in(PLD_ESIO0RXB);
	tmp = __sio_in(PLD_ESIO0RXB);
	tmp = __sio_in(PLD_ESIO0CR);
	sio_set_baud_rate(BAUD_RATE);
	__sio_out(0x0300, PLD_ESIO0CR);
	__sio_out(0x0003, PLD_ESIO0CR);
}

static void sio_init(void)
{
	unsigned short tmp;

	tmp = __sio_in(PLD_ESIO0RXB);
	tmp = __sio_in(PLD_ESIO0RXB);
	tmp = __sio_in(PLD_ESIO0CR);
	__sio_out(0x0300, PLD_ESIO0CR);
	__sio_out(0x0003, PLD_ESIO0CR);
}

static void sio_error(int *status)
{
	printk("SIO0 error[%04x]\n", *status);
	do {
		sio_init();
	} while ((*status = __sio_in(PLD_ESIO0CR)) != 3);
}

#else /* not CONFIG_SERIAL_M32R_PLDSIO */

#define __sio_in(x) inl(x)
#define __sio_out(v,x) outl((v),(x))

static inline void sio_set_baud_rate(unsigned long baud)
{
	unsigned long i, j;

	i = boot_cpu_data.bus_clock / (baud * 16);
	j = (boot_cpu_data.bus_clock - (i * baud * 16)) / baud;
	i -= 1;
	j = (j + 1) >> 1;

	__sio_out(i, M32R_SIO0_BAUR_PORTL);
	__sio_out(j, M32R_SIO0_RBAUR_PORTL);
}

static void sio_reset(void)
{
	__sio_out(0x00000300, M32R_SIO0_CR_PORTL);	/* init status */
	__sio_out(0x00000800, M32R_SIO0_MOD1_PORTL);	/* 8bit        */
	__sio_out(0x00000080, M32R_SIO0_MOD0_PORTL);	/* 1stop non   */
	sio_set_baud_rate(BAUD_RATE);
	__sio_out(0x00000000, M32R_SIO0_TRCR_PORTL);
	__sio_out(0x00000003, M32R_SIO0_CR_PORTL);	/* RXCEN */
}

static void sio_init(void)
{
	unsigned int tmp;

	tmp = __sio_in(M32R_SIO0_RXB_PORTL);
	tmp = __sio_in(M32R_SIO0_RXB_PORTL);
	tmp = __sio_in(M32R_SIO0_STS_PORTL);
	__sio_out(0x00000003, M32R_SIO0_CR_PORTL);
}

static void sio_error(int *status)
{
	printk("SIO0 error[%04x]\n", *status);
	do {
		sio_init();
	} while ((*status = __sio_in(M32R_SIO0_CR_PORTL)) != 3);
}

#endif /* CONFIG_SERIAL_M32R_PLDSIO */

static unsigned int sio_in(struct uart_sio_port *up, int offset)
{
	return __sio_in(up->port.iobase + offset);
}

static void sio_out(struct uart_sio_port *up, int offset, int value)
{
	__sio_out(value, up->port.iobase + offset);
}

static unsigned int serial_in(struct uart_sio_port *up, int offset)
{
	if (!offset)
		return 0;

	return __sio_in(offset);
}

static void serial_out(struct uart_sio_port *up, int offset, int value)
{
	if (!offset)
		return;

	__sio_out(value, offset);
}

static void m32r_sio_stop_tx(struct uart_port *port)
{
	struct uart_sio_port *up =
		container_of(port, struct uart_sio_port, port);

	if (up->ier