u-boot/drivers/serial/serial_ks8695.c

/*
 * serial.c -- KS8695 serial driver
 *
 * (C) Copyright 2004, Greg Ungerer <greg.ungerer@opengear.com>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <asm/arch/platform.h>
#include <serial.h>
#include <linux/compiler.h>

#ifndef CONFIG_SERIAL1
#error "Bad: you didn't configure serial ..."
#endif

DECLARE_GLOBAL_DATA_PTR;

/*
 *	Define the UART hardware register access structure.
 */
struct ks8695uart {
	unsigned int	RX;		/* 0x00	- Receive data (r) */
	unsigned int	TX;		/* 0x04	- Transmit data (w) */
	unsigned int	FCR;		/* 0x08	- Fifo Control (r/w) */
	unsigned int	LCR;		/* 0x0c	- Line Control (r/w) */
	unsigned int	MCR;		/* 0x10	- Modem Control (r/w) */
	unsigned int	LSR;		/* 0x14	- Line Status (r/w) */
	unsigned int	MSR;		/* 0x18	- Modem Status (r/w) */
	unsigned int	BD;		/* 0x1c	- Baud Rate (r/w) */
	unsigned int	SR;		/* 0x20	- Status (r/w) */
};

#define	KS8695_UART_ADDR	((void *) (KS8695_IO_BASE + KS8695_UART_RX_BUFFER))
#define	KS8695_UART_CLK		25000000


/*
 * Under some circumstances we want to be "quiet" and not issue any
 * serial output - though we want u-boot to otherwise work and behave
 * the same. By default be noisy.
 */
int serial_console = 1;


static void ks8695_serial_setbrg(void)
{
	volatile struct ks8695uart *uartp = KS8695_UART_ADDR;

	/* Set to global baud rate and 8 data bits, no parity, 1 stop bit*/
	uartp->BD = KS8695_UART_CLK / gd->baudrate;
	uartp->LCR = KS8695_UART_LINEC_WLEN8;
}

static int ks8695_serial_init(void)
{
	serial_console = 1;
	serial_setbrg();
	return 0;
}

static void ks8695_serial_raw_putc(const char c)
{
	volatile struct ks8695uart *uartp = KS8695_UART_ADDR;
	int i;

	for (i = 0; (i < 0x100000); i++) {
		if (uartp->LSR & KS8695_UART_LINES_TXFE)
			break;
	}

	uartp->TX = c;
}

static void ks8695_serial_putc(const char c)
{
	if (serial_console) {
		ks8695_serial_raw_putc(c);
		if (c == '\n')
			ks8695_serial_raw_putc('\r');
	}
}

static int ks8695_serial_tstc(void)
{
	volatile struct ks8695uart *uartp = KS8695_UART_ADDR;
	if (serial_console)
		return ((uartp->LSR & KS8695_UART_LINES_RXFE) ? 1 : 0);
	return 0;
}

static int ks8695_serial_getc(void)
{
	volatile struct ks8695uart *uartp = KS8695_UART_ADDR;

	while ((uartp->LSR & KS8695_UART_LINES_RXFE) == 0)
		;
	return (uartp->RX);
}

static struct serial_device ks8695_serial_drv = {
	.name	= "ks8695_serial",
	.start	= ks8695_serial_init,
	.stop	= NULL,
	.setbrg	= ks8695_serial_setbrg,
	.putc	= ks8695_serial_putc,
	.puts	= default_serial_puts,
	.getc	= ks8695_serial_getc,
	.tstc	= ks8695_serial_tstc,
};

void ks8695_serial_initialize(void)
{
	serial_register(&ks8695_serial_drv);
}

__weak struct serial_device *default_serial_console(void)
{
	return &ks8695_serial_drv;
}