2 * U-boot - serial.c Blackfin Serial Driver
4 * Copyright (c) 2005-2008 Analog Devices Inc.
6 * Copyright (c) 2003 Bas Vermeulen <bas@buyways.nl>,
7 * BuyWays B.V. (www.buyways.nl)
10 * blkfinserial.c: Serial driver for BlackFin DSP internal USRTs.
11 * Copyright(c) 2003 Metrowerks <mwaddel@metrowerks.com>
12 * Copyright(c) 2001 Tony Z. Kou <tonyko@arcturusnetworks.com>
13 * Copyright(c) 2001-2002 Arcturus Networks Inc. <www.arcturusnetworks.com>
15 * Based on code from 68328 version serial driver imlpementation which was:
16 * Copyright (C) 1995 David S. Miller <davem@caip.rutgers.edu>
17 * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>
18 * Copyright (C) 1998, 1999 D. Jeff Dionne <jeff@uclinux.org>
19 * Copyright (C) 1999 Vladimir Gurevich <vgurevic@cisco.com>
21 * (C) Copyright 2000-2004
22 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
24 * Licensed under the GPL-2 or later.
28 * 05000086 - we don't support autobaud
29 * 05000099 - we only use DR bit, so losing others is not a problem
30 * 05000100 - we don't use the UART_IIR register
31 * 05000215 - we poll the uart (no dma/interrupts)
32 * 05000225 - no workaround possible, but this shouldnt cause errors ...
33 * 05000230 - we tweak the baud rate calculation slightly
34 * 05000231 - we always use 1 stop bit
35 * 05000309 - we always enable the uart before we modify it in anyway
36 * 05000350 - we always enable the uart regardless of boot mode
37 * 05000363 - we don't support break signals, so don't generate one
42 #include <asm/blackfin.h>
43 #include <asm/mach-common/bits/uart.h>
45 #ifdef CONFIG_UART_CONSOLE
49 #ifdef CONFIG_DEBUG_SERIAL
50 uint16_t cached_lsr[256];
51 uint16_t cached_rbr[256];
54 /* The LSR is read-to-clear on some parts, so we have to make sure status
55 * bits aren't inadvertently lost when doing various tests. This also
56 * works around anomaly 05000099 at the same time by keeping a cumulative
57 * tally of all the status bits.
59 static uint16_t uart_lsr_save;
60 static uint16_t uart_lsr_read(void)
62 uint16_t lsr = bfin_read16(&pUART->lsr);
63 uart_lsr_save |= (lsr & (OE|PE|FE|BI));
64 return lsr | uart_lsr_save;
66 /* Just do the clear for everyone since it can't hurt. */
67 static void uart_lsr_clear(void)
70 bfin_write16(&pUART->lsr, bfin_read16(&pUART->lsr) | -1);
73 /* When debugging is disabled, we only care about the DR bit, so if other
74 * bits get set/cleared, we don't really care since we don't read them
75 * anyways (and thus anomaly 05000099 is irrelevant).
77 static uint16_t uart_lsr_read(void)
79 return bfin_read16(&pUART->lsr);
81 static void uart_lsr_clear(void)
83 bfin_write16(&pUART->lsr, bfin_read16(&pUART->lsr) | -1);
87 /* Symbol for our assembly to call. */
88 void serial_set_baud(uint32_t baud)
90 serial_early_set_baud(baud);
93 /* Symbol for common u-boot code to call.
94 * Setup the baudrate (brg: baudrate generator).
96 void serial_setbrg(void)
98 DECLARE_GLOBAL_DATA_PTR;
99 serial_set_baud(gd->baudrate);
102 /* Symbol for our assembly to call. */
103 void serial_initialize(void)
108 /* Symbol for common u-boot code to call. */
109 int serial_init(void)
114 #ifdef CONFIG_DEBUG_SERIAL
116 memset(cached_lsr, 0x00, sizeof(cached_lsr));
117 memset(cached_rbr, 0x00, sizeof(cached_rbr));
122 void serial_putc(const char c)
124 /* send a \r for compatibility */
130 /* wait for the hardware fifo to clear up */
131 while (!(uart_lsr_read() & THRE))
134 /* queue the character for transmission */
135 bfin_write16(&pUART->thr, c);
141 int serial_tstc(void)
144 return (uart_lsr_read() & DR) ? 1 : 0;
147 int serial_getc(void)
149 uint16_t uart_rbr_val;
151 /* wait for data ! */
152 while (!serial_tstc())
155 /* grab the new byte */
156 uart_rbr_val = bfin_read16(&pUART->rbr);
158 #ifdef CONFIG_DEBUG_SERIAL
159 /* grab & clear the LSR */
160 uint16_t uart_lsr_val = uart_lsr_read();
162 cached_lsr[cache_count] = uart_lsr_val;
163 cached_rbr[cache_count] = uart_rbr_val;
164 cache_count = (cache_count + 1) % ARRAY_SIZE(cached_lsr);
166 if (uart_lsr_val & (OE|PE|FE|BI)) {
168 printf("\n[SERIAL ERROR]\n");
170 dll = bfin_read16(&pUART->dll);
171 dlh = bfin_read16(&pUART->dlh);
173 printf("\tDLL=0x%x DLH=0x%x\n", dll, dlh);
176 printf("\t%3i: RBR=0x%02x LSR=0x%02x\n", cache_count,
177 cached_rbr[cache_count], cached_lsr[cache_count]);
178 } while (cache_count > 0);
187 void serial_puts(const char *s)