u-boot/drivers/serial/atmel_usart.c
Simon Glass 0f65f48b64 dm: at91: Add driver model support for the serial driver
Add driver model support while retaining the existing legacy code. This
allows the driver to support boards that have converted to driver model
as well as those that have not.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-11-21 08:09:58 +01:00

210 lines
4.6 KiB
C

/*
* Copyright (C) 2004-2006 Atmel Corporation
*
* Modified to support C structur SoC access by
* Andreas Bießmann <biessmann@corscience.de>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <watchdog.h>
#include <serial.h>
#include <linux/compiler.h>
#include <asm/io.h>
#ifdef CONFIG_DM_SERIAL
#include <asm/arch/atmel_serial.h>
#endif
#include <asm/arch/clk.h>
#include <asm/arch/hardware.h>
#include "atmel_usart.h"
DECLARE_GLOBAL_DATA_PTR;
static void atmel_serial_setbrg_internal(atmel_usart3_t *usart, int id,
int baudrate)
{
unsigned long divisor;
unsigned long usart_hz;
/*
* Master Clock
* Baud Rate = --------------
* 16 * CD
*/
usart_hz = get_usart_clk_rate(id);
divisor = (usart_hz / 16 + baudrate / 2) / baudrate;
writel(USART3_BF(CD, divisor), &usart->brgr);
}
static void atmel_serial_init_internal(atmel_usart3_t *usart)
{
/*
* Just in case: drain transmitter register
* 1000us is enough for baudrate >= 9600
*/
if (!(readl(&usart->csr) & USART3_BIT(TXEMPTY)))
__udelay(1000);
writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr);
}
static void atmel_serial_activate(atmel_usart3_t *usart)
{
writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL)
| USART3_BF(USCLKS, USART3_USCLKS_MCK)
| USART3_BF(CHRL, USART3_CHRL_8)
| USART3_BF(PAR, USART3_PAR_NONE)
| USART3_BF(NBSTOP, USART3_NBSTOP_1)),
&usart->mr);
writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr);
/* 100us is enough for the new settings to be settled */
__udelay(100);
}
#ifndef CONFIG_DM_SERIAL
static void atmel_serial_setbrg(void)
{
atmel_serial_setbrg_internal((atmel_usart3_t *)CONFIG_USART_BASE,
CONFIG_USART_ID, gd->baudrate);
}
static int atmel_serial_init(void)
{
atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE;
atmel_serial_init_internal(usart);
serial_setbrg();
atmel_serial_activate(usart);
return 0;
}
static void atmel_serial_putc(char c)
{
atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE;
if (c == '\n')
serial_putc('\r');
while (!(readl(&usart->csr) & USART3_BIT(TXRDY)));
writel(c, &usart->thr);
}
static int atmel_serial_getc(void)
{
atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE;
while (!(readl(&usart->csr) & USART3_BIT(RXRDY)))
WATCHDOG_RESET();
return readl(&usart->rhr);
}
static int atmel_serial_tstc(void)
{
atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE;
return (readl(&usart->csr) & USART3_BIT(RXRDY)) != 0;
}
static struct serial_device atmel_serial_drv = {
.name = "atmel_serial",
.start = atmel_serial_init,
.stop = NULL,
.setbrg = atmel_serial_setbrg,
.putc = atmel_serial_putc,
.puts = default_serial_puts,
.getc = atmel_serial_getc,
.tstc = atmel_serial_tstc,
};
void atmel_serial_initialize(void)
{
serial_register(&atmel_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &atmel_serial_drv;
}
#endif
#ifdef CONFIG_DM_SERIAL
struct atmel_serial_priv {
atmel_usart3_t *usart;
};
int atmel_serial_setbrg(struct udevice *dev, int baudrate)
{
struct atmel_serial_priv *priv = dev_get_priv(dev);
atmel_serial_setbrg_internal(priv->usart, 0 /* ignored */, baudrate);
atmel_serial_activate(priv->usart);
return 0;
}
static int atmel_serial_getc(struct udevice *dev)
{
struct atmel_serial_priv *priv = dev_get_priv(dev);
if (!(readl(&priv->usart->csr) & USART3_BIT(RXRDY)))
return -EAGAIN;
return readl(&priv->usart->rhr);
}
static int atmel_serial_putc(struct udevice *dev, const char ch)
{
struct atmel_serial_priv *priv = dev_get_priv(dev);
if (!(readl(&priv->usart->csr) & USART3_BIT(TXRDY)))
return -EAGAIN;
writel(ch, &priv->usart->thr);
return 0;
}
static int atmel_serial_pending(struct udevice *dev, bool input)
{
struct atmel_serial_priv *priv = dev_get_priv(dev);
uint32_t csr = readl(&priv->usart->csr);
if (input)
return csr & USART3_BIT(RXRDY) ? 1 : 0;
else
return csr & USART3_BIT(TXEMPTY) ? 0 : 1;
}
static const struct dm_serial_ops atmel_serial_ops = {
.putc = atmel_serial_putc,
.pending = atmel_serial_pending,
.getc = atmel_serial_getc,
.setbrg = atmel_serial_setbrg,
};
static int atmel_serial_probe(struct udevice *dev)
{
struct atmel_serial_platdata *plat = dev->platdata;
struct atmel_serial_priv *priv = dev_get_priv(dev);
priv->usart = (atmel_usart3_t *)plat->base_addr;
atmel_serial_init_internal(priv->usart);
return 0;
}
U_BOOT_DRIVER(serial_atmel) = {
.name = "serial_atmel",
.id = UCLASS_SERIAL,
.probe = atmel_serial_probe,
.ops = &atmel_serial_ops,
.flags = DM_FLAG_PRE_RELOC,
.priv_auto_alloc_size = sizeof(struct atmel_serial_priv),
};
#endif