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Diffstat (limited to 'arch/blackfin/cpu/serial.c')
| -rw-r--r-- | arch/blackfin/cpu/serial.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/arch/blackfin/cpu/serial.c b/arch/blackfin/cpu/serial.c new file mode 100644 index 000000000..901cb97a1 --- /dev/null +++ b/arch/blackfin/cpu/serial.c @@ -0,0 +1,193 @@ +/* + * 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> + +#ifdef CONFIG_UART_CONSOLE + +#include "serial.h" + +#ifdef CONFIG_DEBUG_SERIAL +uint16_t cached_lsr[256]; +uint16_t cached_rbr[256]; +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) +{ + DECLARE_GLOBAL_DATA_PTR; + 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(); +#ifdef CONFIG_DEBUG_SERIAL + cache_count = 0; + memset(cached_lsr, 0x00, sizeof(cached_lsr)); + memset(cached_rbr, 0x00, sizeof(cached_rbr)); +#endif + 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 |