cpu/blackfin/serial.c

   1 /*
   2  * U-boot - serial.c Blackfin Serial Driver
   3  *
   4  * Copyright (c) 2005-2008 Analog Devices Inc.
   5  *
   6  * Copyright (c) 2003   Bas Vermeulen <bas@buyways.nl>,
   7  *                      BuyWays B.V. (www.buyways.nl)
   8  *
   9  * Based heavily on:
  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>
  14  *
  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>
  20  *
  21  * (C) Copyright 2000-2004
  22  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  23  *
  24  * Licensed under the GPL-2 or later.
  25  */
  26
  27 #include <common.h>
  28 #include <watchdog.h>
  29 #include <asm/blackfin.h>
  30 #include <asm/mach-common/bits/uart.h>
  31
  32 #if defined(UART_LSR) && (CONFIG_UART_CONSOLE != 0)
  33 # error CONFIG_UART_CONSOLE must be 0 on parts with only one UART
  34 #endif
  35
  36 #include "serial.h"
  37
  38 /* Symbol for our assembly to call. */
  39 void serial_set_baud(uint32_t baud)
  40 {
  41         serial_early_set_baud(baud);
  42 }
  43
  44 /* Symbol for common u-boot code to call.
  45  * Setup the baudrate (brg: baudrate generator).
  46  */
  47 void serial_setbrg(void)
  48 {
  49         DECLARE_GLOBAL_DATA_PTR;
  50         serial_set_baud(gd->baudrate);
  51 }
  52
  53 /* Symbol for our assembly to call. */
  54 void serial_initialize(void)
  55 {
  56         serial_early_init();
  57 }
  58
  59 /* Symbol for common u-boot code to call. */
  60 int serial_init(void)
  61 {
  62         serial_initialize();
  63         serial_setbrg();
  64         return 0;
  65 }
  66
  67 void serial_putc(const char c)
  68 {
  69         /* send a \r for compatibility */
  70         if (c == '\n')
  71                 serial_putc('\r');
  72
  73         WATCHDOG_RESET();
  74
  75         /* wait for the hardware fifo to clear up */
  76         while (!(*pUART_LSR & THRE))
  77                 continue;
  78
  79         /* queue the character for transmission */
  80         *pUART_THR = c;
  81         SSYNC();
  82
  83         WATCHDOG_RESET();
  84
  85         /* wait for the byte to be shifted over the line */
  86         while (!(*pUART_LSR & TEMT))
  87                 continue;
  88 }
  89
  90 int serial_tstc(void)
  91 {
  92         WATCHDOG_RESET();
  93         return (*pUART_LSR & DR) ? 1 : 0;
  94 }
  95
  96 int serial_getc(void)
  97 {
  98         uint16_t uart_lsr_val, uart_rbr_val;
  99
 100         /* wait for data ! */
 101         while (!serial_tstc())
 102                 continue;
 103
 104         /* clear the status and grab the new byte */
 105         uart_lsr_val = *pUART_LSR;
 106         uart_rbr_val = *pUART_RBR;
 107
 108         if (uart_lsr_val & (OE|PE|FE|BI)) {
 109                 /* Some parts are read-to-clear while others are
 110                  * write-to-clear.  Just do the write for everyone
 111                  * since it cant hurt (other than code size).
 112                  */
 113                 *pUART_LSR = (OE|PE|FE|BI);
 114                 return -1;
 115         }
 116
 117         return uart_rbr_val & 0xFF;
 118 }
 119
 120 void serial_puts(const char *s)
 121 {
 122         while (*s)
 123                 serial_putc(*s++);
 124 }