u-boot/drivers/serial/serial_pl01x.c

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/*
* (C) Copyright 2000
* Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
*
* (C) Copyright 2004
* ARM Ltd.
* Philippe Robin, <philippe.robin@arm.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
/* Simple U-Boot driver for the PrimeCell PL010/PL011 UARTs */
#include <common.h>
#include <watchdog.h>
#include <asm/io.h>
#include <serial.h>
#include <linux/compiler.h>
#include "serial_pl01x.h"
/*
* Integrator AP has two UARTs, we use the first one, at 38400-8-N-1
* Integrator CP has two UARTs, use the first one, at 38400-8-N-1
* Versatile PB has four UARTs.
*/
#define CONSOLE_PORT CONFIG_CONS_INDEX
static volatile unsigned char *const port[] = CONFIG_PL01x_PORTS;
#define NUM_PORTS (sizeof(port)/sizeof(port[0]))
static void pl01x_putc (int portnum, char c);
static int pl01x_getc (int portnum);
static int pl01x_tstc (int portnum);
unsigned int baudrate = CONFIG_BAUDRATE;
DECLARE_GLOBAL_DATA_PTR;
static struct pl01x_regs *pl01x_get_regs(int portnum)
{
return (struct pl01x_regs *) port[portnum];
}
#ifdef CONFIG_PL010_SERIAL
static int pl01x_serial_init(void)
{
struct pl01x_regs *regs = pl01x_get_regs(CONSOLE_PORT);
unsigned int divisor;
/* First, disable everything */
writel(0, &regs->pl010_cr);
/* Set baud rate */
switch (baudrate) {
case 9600:
divisor = UART_PL010_BAUD_9600;
break;
case 19200:
divisor = UART_PL010_BAUD_9600;
break;
case 38400:
divisor = UART_PL010_BAUD_38400;
break;
case 57600:
divisor = UART_PL010_BAUD_57600;
break;
case 115200:
divisor = UART_PL010_BAUD_115200;
break;
default:
divisor = UART_PL010_BAUD_38400;
}
writel((divisor & 0xf00) >> 8, &regs->pl010_lcrm);
writel(divisor & 0xff, &regs->pl010_lcrl);
/* Set the UART to be 8 bits, 1 stop bit, no parity, fifo enabled */
writel(UART_PL010_LCRH_WLEN_8 | UART_PL010_LCRH_FEN, &regs->pl010_lcrh);
/* Finally, enable the UART */
writel(UART_PL010_CR_UARTEN, &regs->pl010_cr);
return 0;
}
#endif /* CONFIG_PL010_SERIAL */
#ifdef CONFIG_PL011_SERIAL
static int pl01x_serial_init(void)
{
struct pl01x_regs *regs = pl01x_get_regs(CONSOLE_PORT);
unsigned int temp;
unsigned int divider;
unsigned int remainder;
unsigned int fraction;
unsigned int lcr;
#ifdef CONFIG_PL011_SERIAL_FLUSH_ON_INIT
/* Empty RX fifo if necessary */
if (readl(&regs->pl011_cr) & UART_PL011_CR_UARTEN) {
while (!(readl(&regs->fr) & UART_PL01x_FR_RXFE))
readl(&regs->dr);
}
#endif
/* First, disable everything */
writel(0, &regs->pl011_cr);
/*
* Set baud rate
*
* IBRD = UART_CLK / (16 * BAUD_RATE)
* FBRD = RND((64 * MOD(UART_CLK,(16 * BAUD_RATE))) / (16 * BAUD_RATE))
*/
temp = 16 * baudrate;
divider = CONFIG_PL011_CLOCK / temp;
remainder = CONFIG_PL011_CLOCK % temp;
temp = (8 * remainder) / baudrate;
fraction = (temp >> 1) + (temp & 1);
writel(divider, &regs->pl011_ibrd);
writel(fraction, &regs->pl011_fbrd);
/* Set the UART to be 8 bits, 1 stop bit, no parity, fifo enabled */
lcr = UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN;
writel(lcr, &regs->pl011_lcrh);
#ifdef CONFIG_PL011_SERIAL_RLCR
{
int i;
/*
* Program receive line control register after waiting
* 10 bus cycles. Delay be writing to readonly register
* 10 times
*/
for (i = 0; i < 10; i++)
writel(lcr, &regs->fr);
writel(lcr, &regs->pl011_rlcr);
/* lcrh needs to be set again for change to be effective */
writel(lcr, &regs->pl011_lcrh);
}
#endif
/* Finally, enable the UART */
writel(UART_PL011_CR_UARTEN | UART_PL011_CR_TXE | UART_PL011_CR_RXE |
UART_PL011_CR_RTS, &regs->pl011_cr);
return 0;
}
#endif /* CONFIG_PL011_SERIAL */
static void pl01x_serial_putc(const char c)
{
if (c == '\n')
pl01x_putc (CONSOLE_PORT, '\r');
pl01x_putc (CONSOLE_PORT, c);
}
static int pl01x_serial_getc(void)
{
return pl01x_getc (CONSOLE_PORT);
}
static int pl01x_serial_tstc(void)
{
return pl01x_tstc (CONSOLE_PORT);
}
static void pl01x_serial_setbrg(void)
{
struct pl01x_regs *regs = pl01x_get_regs(CONSOLE_PORT);
baudrate = gd->baudrate;
/*
* Flush FIFO and wait for non-busy before changing baudrate to avoid
* crap in console
*/
while (!(readl(&regs->fr) & UART_PL01x_FR_TXFE))
WATCHDOG_RESET();
while (readl(&regs->fr) & UART_PL01x_FR_BUSY)
WATCHDOG_RESET();
serial_init();
}
static void pl01x_putc (int portnum, char c)
{
struct pl01x_regs *regs = pl01x_get_regs(portnum);
/* Wait until there is space in the FIFO */
while (readl(&regs->fr) & UART_PL01x_FR_TXFF)
WATCHDOG_RESET();
/* Send the character */
writel(c, &regs->dr);
}
static int pl01x_getc (int portnum)
{
struct pl01x_regs *regs = pl01x_get_regs(portnum);
unsigned int data;
/* Wait until there is data in the FIFO */
while (readl(&regs->fr) & UART_PL01x_FR_RXFE)
WATCHDOG_RESET();
data = readl(&regs->dr);
/* Check for an error flag */
if (data & 0xFFFFFF00) {
/* Clear the error */
writel(0xFFFFFFFF, &regs->ecr);
return -1;
}
return (int) data;
}
static int pl01x_tstc (int portnum)
{
struct pl01x_regs *regs = pl01x_get_regs(portnum);
WATCHDOG_RESET();
return !(readl(&regs->fr) & UART_PL01x_FR_RXFE);
}
static struct serial_device pl01x_serial_drv = {
.name = "pl01x_serial",
.start = pl01x_serial_init,
.stop = NULL,
.setbrg = pl01x_serial_setbrg,
.putc = pl01x_serial_putc,
.puts = default_serial_puts,
.getc = pl01x_serial_getc,
.tstc = pl01x_serial_tstc,
};
void pl01x_serial_initialize(void)
{
serial_register(&pl01x_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &pl01x_serial_drv;
}