u-boot/drivers/serial/lpc32xx_hsuart.c

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/*
* Copyright (C) 2011 Vladimir Zapolskiy <vz@mleia.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#include <common.h>
#include <asm/arch/cpu.h>
#include <asm/arch/clk.h>
#include <asm/arch/uart.h>
#include <asm/io.h>
#include <serial.h>
#include <linux/compiler.h>
DECLARE_GLOBAL_DATA_PTR;
static struct hsuart_regs *hsuart = (struct hsuart_regs *)HS_UART_BASE;
static void lpc32xx_serial_setbrg(void)
{
u32 div;
/* UART rate = PERIPH_CLK / ((HSU_RATE + 1) x 14) */
div = (get_serial_clock() / 14 + gd->baudrate / 2) / gd->baudrate - 1;
if (div > 255)
div = 255;
writel(div, &hsuart->rate);
}
static int lpc32xx_serial_getc(void)
{
while (!(readl(&hsuart->level) & HSUART_LEVEL_RX))
/* NOP */;
return readl(&hsuart->rx) & HSUART_RX_DATA;
}
static void lpc32xx_serial_putc(const char c)
{
writel(c, &hsuart->tx);
/* Wait for character to be sent */
while (readl(&hsuart->level) & HSUART_LEVEL_TX)
/* NOP */;
}
static int lpc32xx_serial_tstc(void)
{
if (readl(&hsuart->level) & HSUART_LEVEL_RX)
return 1;
return 0;
}
static int lpc32xx_serial_init(void)
{
lpc32xx_serial_setbrg();
/* Disable hardware RTS and CTS flow control, set up RX and TX FIFO */
writel(HSUART_CTRL_TMO_16 | HSUART_CTRL_HSU_OFFSET(20) |
HSUART_CTRL_HSU_RX_TRIG_32 | HSUART_CTRL_HSU_TX_TRIG_0,
&hsuart->ctrl);
return 0;
}
static struct serial_device lpc32xx_serial_drv = {
.name = "lpc32xx_serial",
.start = lpc32xx_serial_init,
.stop = NULL,
.setbrg = lpc32xx_serial_setbrg,
.putc = lpc32xx_serial_putc,
.puts = default_serial_puts,
.getc = lpc32xx_serial_getc,
.tstc = lpc32xx_serial_tstc,
};
void lpc32xx_serial_initialize(void)
{
serial_register(&lpc32xx_serial_drv);
}
__weak struct serial_device *default_serial_console(void)
{
return &lpc32xx_serial_drv;
}