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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 <post.h>
#include <watchdog.h>
#include <serial.h>
#include <linux/compiler.h>
#include <asm/blackfin.h>
#include <asm/serial.h>
DECLARE_GLOBAL_DATA_PTR;
#ifdef CONFIG_UART_CONSOLE
#ifdef CONFIG_DEBUG_SERIAL
static uart_lsr_t cached_lsr[256];
static uart_lsr_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 uart_lsr_t uart_lsr_save;
static uart_lsr_t uart_lsr_read(uint32_t uart_base)
{
uart_lsr_t lsr = _lsr_read(pUART);
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(uint32_t uart_base)
{
uart_lsr_save = 0;
_lsr_write(pUART, -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 inline uart_lsr_t uart_lsr_read(uint32_t uart_base)
{
return _lsr_read(pUART);
}
static void uart_lsr_clear(uint32_t uart_base)
{
_lsr_write(pUART, -1);
}
#endif
static void uart_putc(uint32_t uart_base, 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(uart_base) & THRE))
continue;
/* queue the character for transmission */
bfin_write(&pUART->thr, c);
SSYNC();
WATCHDOG_RESET();
}
static int uart_tstc(uint32_t uart_base)
{
WATCHDOG_RESET();
return (uart_lsr_read(uart_base) & DR) ? 1 : 0;
}
static int uart_getc(uint32_t uart_base)
{
uint16_t uart_rbr_val;
/* wait for data ! */
while (!uart_tstc(uart_base))
continue;
/* grab the new byte */
uart_rbr_val = bfin_read(&pUART->rbr);
#ifdef CONFIG_DEBUG_SERIAL
/* grab & clear the LSR */
uart_lsr_t uart_lsr_val = uart_lsr_read(uart_base);
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)) {
printf("\n[SERIAL ERROR]\n");
do {
--cache_count;
printf("\t%3zu: 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(uart_base);
return uart_rbr_val;
}
#if CONFIG_POST & CONFIG_SYS_POST_UART
# define LOOP(x) x
#else
# define LOOP(x)
#endif
#if BFIN_UART_HW_VER < 4
LOOP(
static void uart_loop(uint32_t uart_base, int state)
{
u16 mcr;
/* Drain the TX fifo first so bytes don't come back */
while (!(uart_lsr_read(uart_base) & TEMT))
continue;
mcr = bfin_read(&pUART->mcr);
if (state)
mcr |= LOOP_ENA | MRTS;
else
mcr &= ~(LOOP_ENA | MRTS);
bfin_write(&pUART->mcr, mcr);
}
)
#else
LOOP(
static void uart_loop(uint32_t uart_base, int state)
{
u32 control;
/* Drain the TX fifo first so bytes don't come back */
while (!(uart_lsr_read(uart_base) & TEMT))
continue;
control = bfin_read(&pUART->control);
if (state)
control |= LOOP_ENA | MRTS;
else
control &= ~(LOOP_ENA | MRTS);
bfin_write(&pUART->control, control);
}
)
#endif
static inline void __serial_set_baud(uint32_t uart_base, uint32_t baud)
{
#ifdef CONFIG_DEBUG_EARLY_SERIAL
serial_early_set_baud(uart_base, baud);
#else
uint16_t divisor = (get_uart_clk() + (baud * 8)) / (baud * 16)
- ANOMALY_05000230;
/* Program the divisor to get the baud rate we want */
serial_set_divisor(uart_base, divisor);
#endif
}
static void uart_puts(uint32_t uart_base, const char *s)
{
while (*s)
uart_putc(uart_base, *s++);
}
#define DECL_BFIN_UART(n) \
static int uart##n##_init(void) \
{ \
const unsigned short pins[] = { _P_UART(n, RX), _P_UART(n, TX), 0, }; \
peripheral_request_list(pins, "bfin-uart"); \
uart_init(MMR_UART(n)); \
__serial_set_baud(MMR_UART(n), gd->baudrate); \
uart_lsr_clear(MMR_UART(n)); \
return 0; \
} \
\
static int uart##n##_uninit(void) \
{ \
return serial_early_uninit(MMR_UART(n)); \
} \
\
static void uart##n##_setbrg(void) \
{ \
__serial_set_baud(MMR_UART(n), gd->baudrate); \
} \
\
static int uart##n##_getc(void) \
{ \
return uart_getc(MMR_UART(n)); \
} \
\
static int uart##n##_tstc(void) \
{ \
return uart_tstc(MMR_UART(n)); \
} \
\
static void uart##n##_putc(const char c) \
{ \
uart_putc(MMR_UART(n), c); \
} \
\
static void uart##n##_puts(const char *s) \
{ \
uart_puts(MMR_UART(n), s); \
} \
\
LOOP( \
static void uart##n##_loop(int state) \
{ \
uart_loop(MMR_UART(n), state); \
} \
) \
\
struct serial_device bfin_serial##n##_device = { \
.name = "bfin_uart"#n, \
.start = uart##n##_init, \
.stop = uart##n##_uninit, \
.setbrg = uart##n##_setbrg, \
.getc = uart##n##_getc, \
.tstc = uart##n##_tstc, \
.putc = uart##n##_putc, \
.puts = uart##n##_puts, \
LOOP(.loop = uart##n##_loop) \
};
#ifdef UART0_RBR
DECL_BFIN_UART(0)
#endif
#ifdef UART1_RBR
DECL_BFIN_UART(1)
#endif
#ifdef UART2_RBR
DECL_BFIN_UART(2)
#endif
#ifdef UART3_RBR
DECL_BFIN_UART(3)
#endif
__weak struct serial_device *default_serial_console(void)
{
#if CONFIG_UART_CONSOLE == 0
return &bfin_serial0_device;
#elif CONFIG_UART_CONSOLE == 1
return &bfin_serial1_device;
#elif CONFIG_UART_CONSOLE == 2
return &bfin_serial2_device;
#elif CONFIG_UART_CONSOLE == 3
return &bfin_serial3_device;
#endif
}
void bfin_serial_initialize(void)
{
#ifdef UART0_RBR
serial_register(&bfin_serial0_device);
#endif
#ifdef UART1_RBR
serial_register(&bfin_serial1_device);
#endif
#ifdef UART2_RBR
serial_register(&bfin_serial2_device);
#endif
#ifdef UART3_RBR
serial_register(&bfin_serial3_device);
#endif
}
#ifdef CONFIG_DEBUG_EARLY_SERIAL
inline void uart_early_putc(uint32_t uart_base, const char c)
{
/* send a \r for compatibility */
if (c == '\n')
uart_early_putc(uart_base, '\r');
/* wait for the hardware fifo to clear up */
while (!(_lsr_read(pUART) & THRE))
continue;
/* queue the character for transmission */
bfin_write(&pUART->thr, c);
SSYNC();
}
void uart_early_puts(const char *s)
{
while (*s)
uart_early_putc(UART_BASE, *s++);
}
/* Symbol for our assembly to call. */
void _serial_early_set_baud(uint32_t baud)
{
serial_early_set_baud(UART_BASE, baud);
}
/* Symbol for our assembly to call. */
void _serial_early_init(void)
{
serial_early_init(UART_BASE);
}
#endif
#elif defined(CONFIG_UART_MEM)
char serial_logbuf[CONFIG_UART_MEM];
char *serial_logbuf_head = serial_logbuf;
int serial_mem_init(void)
{
serial_logbuf_head = serial_logbuf;
return 0;
}
void serial_mem_setbrg(void)
{
}
int serial_mem_tstc(void)
{
return 0;
}
int serial_mem_getc(void)
{
return 0;
}
void serial_mem_putc(const char c)
{
*serial_logbuf_head = c;
if (++serial_logbuf_head == serial_logbuf + CONFIG_UART_MEM)
serial_logbuf_head = serial_logbuf;
}
void serial_mem_puts(const char *s)
{
while (*s)
serial_putc(*s++);
}
struct serial_device bfin_serial_mem_device = {
.name = "bfin_uart_mem",
.start = serial_mem_init,
.setbrg = serial_mem_setbrg,
.getc = serial_mem_getc,
.tstc = serial_mem_tstc,
.putc = serial_mem_putc,
.puts = serial_mem_puts,
};
__weak struct serial_device *default_serial_console(void)
{
return &bfin_serial_mem_device;
}
void bfin_serial_initialize(void)
{
serial_register(&bfin_serial_mem_device);
}
#endif /* CONFIG_UART_MEM */