u-boot/drivers/serial/serial_pl01x.c
Eric Anholt cd0fa5bff8 serial: pl01x: Add support for devices with the rate pre-configured.
For Raspberry Pi, we had the input clock rate to the pl011 fixed in
the rpi.c file, but it may be changed by firmware due to user changes
to config.txt.  Since the firmware always sets up the uart (default
115200 output unless the user changes it), we can just skip our own
uart init to simplify the boot process and more reliably get serial
output.

Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Tom Rini <trini@konsulko.com>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
2016-03-22 12:16:12 -04:00

404 lines
8.6 KiB
C

/*
* (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 <dm.h>
#include <errno.h>
#include <watchdog.h>
#include <asm/io.h>
#include <serial.h>
#include <dm/platform_data/serial_pl01x.h>
#include <linux/compiler.h>
#include "serial_pl01x_internal.h"
#include <fdtdec.h>
DECLARE_GLOBAL_DATA_PTR;
#ifndef CONFIG_DM_SERIAL
static volatile unsigned char *const port[] = CONFIG_PL01x_PORTS;
static enum pl01x_type pl01x_type __attribute__ ((section(".data")));
static struct pl01x_regs *base_regs __attribute__ ((section(".data")));
#define NUM_PORTS (sizeof(port)/sizeof(port[0]))
#endif
static int pl01x_putc(struct pl01x_regs *regs, char c)
{
/* Wait until there is space in the FIFO */
if (readl(&regs->fr) & UART_PL01x_FR_TXFF)
return -EAGAIN;
/* Send the character */
writel(c, &regs->dr);
return 0;
}
static int pl01x_getc(struct pl01x_regs *regs)
{
unsigned int data;
/* Wait until there is data in the FIFO */
if (readl(&regs->fr) & UART_PL01x_FR_RXFE)
return -EAGAIN;
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(struct pl01x_regs *regs)
{
WATCHDOG_RESET();
return !(readl(&regs->fr) & UART_PL01x_FR_RXFE);
}
static int pl01x_generic_serial_init(struct pl01x_regs *regs,
enum pl01x_type type)
{
switch (type) {
case TYPE_PL010:
/* disable everything */
writel(0, &regs->pl010_cr);
break;
case TYPE_PL011:
/* disable everything */
writel(0, &regs->pl011_cr);
break;
default:
return -EINVAL;
}
return 0;
}
static int pl011_set_line_control(struct pl01x_regs *regs)
{
unsigned int lcr;
/*
* Internal update of baud rate register require line
* control register write
*/
lcr = UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN;
writel(lcr, &regs->pl011_lcrh);
return 0;
}
static int pl01x_generic_setbrg(struct pl01x_regs *regs, enum pl01x_type type,
int clock, int baudrate)
{
switch (type) {
case TYPE_PL010: {
unsigned int divisor;
/* disable everything */
writel(0, &regs->pl010_cr);
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 line control for the PL010 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);
break;
}
case TYPE_PL011: {
unsigned int temp;
unsigned int divider;
unsigned int remainder;
unsigned int fraction;
/*
* 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 = clock / temp;
remainder = clock % temp;
temp = (8 * remainder) / baudrate;
fraction = (temp >> 1) + (temp & 1);
writel(divider, &regs->pl011_ibrd);
writel(fraction, &regs->pl011_fbrd);
pl011_set_line_control(regs);
/* Finally, enable the UART */
writel(UART_PL011_CR_UARTEN | UART_PL011_CR_TXE |
UART_PL011_CR_RXE | UART_PL011_CR_RTS, &regs->pl011_cr);
break;
}
default:
return -EINVAL;
}
return 0;
}
#ifndef CONFIG_DM_SERIAL
static void pl01x_serial_init_baud(int baudrate)
{
int clock = 0;
#if defined(CONFIG_PL010_SERIAL)
pl01x_type = TYPE_PL010;
#elif defined(CONFIG_PL011_SERIAL)
pl01x_type = TYPE_PL011;
clock = CONFIG_PL011_CLOCK;
#endif
base_regs = (struct pl01x_regs *)port[CONFIG_CONS_INDEX];
pl01x_generic_serial_init(base_regs, pl01x_type);
pl01x_generic_setbrg(base_regs, pl01x_type, clock, baudrate);
}
/*
* 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.
*/
int pl01x_serial_init(void)
{
pl01x_serial_init_baud(CONFIG_BAUDRATE);
return 0;
}
static void pl01x_serial_putc(const char c)
{
if (c == '\n')
while (pl01x_putc(base_regs, '\r') == -EAGAIN);
while (pl01x_putc(base_regs, c) == -EAGAIN);
}
static int pl01x_serial_getc(void)
{
while (1) {
int ch = pl01x_getc(base_regs);
if (ch == -EAGAIN) {
WATCHDOG_RESET();
continue;
}
return ch;
}
}
static int pl01x_serial_tstc(void)
{
return pl01x_tstc(base_regs);
}
static void pl01x_serial_setbrg(void)
{
/*
* Flush FIFO and wait for non-busy before changing baudrate to avoid
* crap in console
*/
while (!(readl(&base_regs->fr) & UART_PL01x_FR_TXFE))
WATCHDOG_RESET();
while (readl(&base_regs->fr) & UART_PL01x_FR_BUSY)
WATCHDOG_RESET();
pl01x_serial_init_baud(gd->baudrate);
}
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;
}
#endif /* nCONFIG_DM_SERIAL */
#ifdef CONFIG_DM_SERIAL
struct pl01x_priv {
struct pl01x_regs *regs;
enum pl01x_type type;
};
static int pl01x_serial_setbrg(struct udevice *dev, int baudrate)
{
struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
struct pl01x_priv *priv = dev_get_priv(dev);
if (!plat->skip_init) {
pl01x_generic_setbrg(priv->regs, priv->type, plat->clock,
baudrate);
}
return 0;
}
static int pl01x_serial_probe(struct udevice *dev)
{
struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
struct pl01x_priv *priv = dev_get_priv(dev);
priv->regs = (struct pl01x_regs *)plat->base;
priv->type = plat->type;
if (!plat->skip_init)
return pl01x_generic_serial_init(priv->regs, priv->type);
else
return 0;
}
static int pl01x_serial_getc(struct udevice *dev)
{
struct pl01x_priv *priv = dev_get_priv(dev);
return pl01x_getc(priv->regs);
}
static int pl01x_serial_putc(struct udevice *dev, const char ch)
{
struct pl01x_priv *priv = dev_get_priv(dev);
return pl01x_putc(priv->regs, ch);
}
static int pl01x_serial_pending(struct udevice *dev, bool input)
{
struct pl01x_priv *priv = dev_get_priv(dev);
unsigned int fr = readl(&priv->regs->fr);
if (input)
return pl01x_tstc(priv->regs);
else
return fr & UART_PL01x_FR_TXFF ? 0 : 1;
}
static const struct dm_serial_ops pl01x_serial_ops = {
.putc = pl01x_serial_putc,
.pending = pl01x_serial_pending,
.getc = pl01x_serial_getc,
.setbrg = pl01x_serial_setbrg,
};
#if CONFIG_IS_ENABLED(OF_CONTROL)
static const struct udevice_id pl01x_serial_id[] ={
{.compatible = "arm,pl011", .data = TYPE_PL011},
{.compatible = "arm,pl010", .data = TYPE_PL010},
{}
};
static int pl01x_serial_ofdata_to_platdata(struct udevice *dev)
{
struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
fdt_addr_t addr;
addr = dev_get_addr(dev);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
plat->base = addr;
plat->clock = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "clock", 1);
plat->type = dev_get_driver_data(dev);
return 0;
}
#endif
U_BOOT_DRIVER(serial_pl01x) = {
.name = "serial_pl01x",
.id = UCLASS_SERIAL,
.of_match = of_match_ptr(pl01x_serial_id),
.ofdata_to_platdata = of_match_ptr(pl01x_serial_ofdata_to_platdata),
.platdata_auto_alloc_size = sizeof(struct pl01x_serial_platdata),
.probe = pl01x_serial_probe,
.ops = &pl01x_serial_ops,
.flags = DM_FLAG_PRE_RELOC,
.priv_auto_alloc_size = sizeof(struct pl01x_priv),
};
#endif
#if defined(CONFIG_DEBUG_UART_PL010) || defined(CONFIG_DEBUG_UART_PL011)
#include <debug_uart.h>
static void _debug_uart_init(void)
{
#ifndef CONFIG_DEBUG_UART_SKIP_INIT
struct pl01x_regs *regs = (struct pl01x_regs *)CONFIG_DEBUG_UART_BASE;
enum pl01x_type type = CONFIG_IS_ENABLED(DEBUG_UART_PL011) ?
TYPE_PL011 : TYPE_PL010;
pl01x_generic_serial_init(regs, type);
pl01x_generic_setbrg(regs, type,
CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
#endif
}
static inline void _debug_uart_putc(int ch)
{
struct pl01x_regs *regs = (struct pl01x_regs *)CONFIG_DEBUG_UART_BASE;
pl01x_putc(regs, ch);
}
DEBUG_UART_FUNCS
#endif