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/*
* U-boot - serial.c Blackfin Serial Driver
*
* Copyright (c) 2005-2008 Analog Devices Inc.
*
* Copyright (c) 2003 Bas Vermeulen <bas@buyways.nl>,
* BuyWays B.V. (www.buyways.nl)
*
* Based heavily on:
* blkfinserial.c: Serial driver for BlackFin DSP internal USRTs.
* Copyright(c) 2003 Metrowerks <mwaddel@metrowerks.com>
* Copyright(c) 2001 Tony Z. Kou <tonyko@arcturusnetworks.com>
* Copyright(c) 2001-2002 Arcturus Networks Inc. <www.arcturusnetworks.com>
*
* Based on code from 68328 version serial driver imlpementation which was:
* Copyright (C) 1995 David S. Miller <davem@caip.rutgers.edu>
* Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>
* Copyright (C) 1998, 1999 D. Jeff Dionne <jeff@uclinux.org>
* Copyright (C) 1999 Vladimir Gurevich <vgurevic@cisco.com>
*
* (C) Copyright 2000-2004
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* Licensed under the GPL-2 or later.
*/
/* Anomaly notes:
* 05000086 - we don't support autobaud
* 05000099 - we only use DR bit, so losing others is not a problem
* 05000100 - we don't use the UART_IIR register
* 05000215 - we poll the uart (no dma/interrupts)
* 05000225 - no workaround possible, but this shouldnt cause errors ...
* 05000230 - we tweak the baud rate calculation slightly
* 05000231 - we always use 1 stop bit
* 05000309 - we always enable the uart before we modify it in anyway
* 05000350 - we always enable the uart regardless of boot mode
* 05000363 - we don't support break signals, so don't generate one
*/
#include <common.h>
#include <watchdog.h>
#include <asm/blackfin.h>
#include <asm/mach-common/bits/uart.h>
DECLARE_GLOBAL_DATA_PTR;
#ifdef CONFIG_UART_CONSOLE
#include "serial.h"
#ifdef CONFIG_DEBUG_SERIAL
static uint16_t cached_lsr[256];
static uint16_t cached_rbr[256];
static size_t cache_count;
/* The LSR is read-to-clear on some parts, so we have to make sure status
* bits aren't inadvertently lost when doing various tests. This also
* works around anomaly 05000099 at the same time by keeping a cumulative
* tally of all the status bits.
*/
static uint16_t uart_lsr_save;
static uint16_t uart_lsr_read(void)
{
uint16_t lsr = bfin_read16(&pUART->lsr);
uart_lsr_save |= (lsr & (OE|PE|FE|BI));
return lsr | uart_lsr_save;
}
/* Just do the clear for everyone since it can't hurt. */
static void uart_lsr_clear(void)
{
uart_lsr_save = 0;
bfin_write16(&pUART->lsr, bfin_read16(&pUART->lsr) | -1);
}
#else
/* When debugging is disabled, we only care about the DR bit, so if other
* bits get set/cleared, we don't really care since we don't read them
* anyways (and thus anomaly 05000099 is irrelevant).
*/
static uint16_t uart_lsr_read(void)
{
return bfin_read16(&pUART->lsr);
}
static void uart_lsr_clear(void)
{
bfin_write16(&pUART->lsr, bfin_read16(&pUART->lsr) | -1);
}
#endif
/* Symbol for our assembly to call. */
void serial_set_baud(uint32_t baud)
{
serial_early_set_baud(baud);
}
/* Symbol for common u-boot code to call.
* Setup the baudrate (brg: baudrate generator).
*/
void serial_setbrg(void)
{
serial_set_baud(gd->baudrate);
}
/* Symbol for our assembly to call. */
void serial_initialize(void)
{
serial_early_init();
}
/* Symbol for common u-boot code to call. */
int serial_init(void)
{
serial_initialize();
serial_setbrg();
uart_lsr_clear();
return 0;
}
void serial_putc(const char c)
{
/* send a \r for compatibility */
if (c == '\n')
serial_putc('\r');
WATCHDOG_RESET();
/* wait for the hardware fifo to clear up */
while (!(uart_lsr_read() & THRE))
continue;
/* queue the character for transmission */
bfin_write16(&pUART->thr, c);
SSYNC();
WATCHDOG_RESET();
}
int serial_tstc(void)
{
WATCHDOG_RESET();
return (uart_lsr_read() & DR) ? 1 : 0;
}
int serial_getc(void)
{
uint16_t uart_rbr_val;
/* wait for data ! */
while (!serial_tstc())
continue;
/* grab the new byte */
uart_rbr_val = bfin_read16(&pUART->rbr);
#ifdef CONFIG_DEBUG_SERIAL
/* grab & clear the LSR */
uint16_t uart_lsr_val = uart_lsr_read();
cached_lsr[cache_count] = uart_lsr_val;
cached_rbr[cache_count] = uart_rbr_val;
cache_count = (cache_count + 1) % ARRAY_SIZE(cached_lsr);
if (uart_lsr_val & (OE|PE|FE|BI)) {
uint16_t dll, dlh;
printf("\n[SERIAL ERROR]\n");
ACCESS_LATCH();
dll = bfin_read16(&pUART->dll);
dlh = bfin_read16(&pUART->dlh);
ACCESS_PORT_IER();
printf("\tDLL=0x%x DLH=0x%x\n", dll, dlh);
do {
--cache_count;
printf("\t%3i: RBR=0x%02x LSR=0x%02x\n", cache_count,
cached_rbr[cache_count], cached_lsr[cache_count]);
} while (cache_count > 0);
return -1;
}
#endif
uart_lsr_clear();
return uart_rbr_val;
}
void serial_puts(const char *s)
{
while (*s)
serial_putc(*s++);
}
#endif
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