mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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71 lines
2.1 KiB
C
71 lines
2.1 KiB
C
/*
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*
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* BRIEF MODULE DESCRIPTION
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* Low level uart routines to directly access a 16550 uart.
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*
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* Copyright 2001 MontaVista Software Inc.
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* Author: MontaVista Software, Inc.
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* ppopov@mvista.com or source@mvista.com
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
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* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/types.h>
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#include <asm/mach-au1x00/au1000.h>
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#define SERIAL_BASE UART_BASE
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#define SER_CMD 0x7
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#define SER_DATA 0x1
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#define TX_BUSY 0x20
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#define TIMEOUT 0xffffff
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#define SLOW_DOWN
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static volatile unsigned long * const com1 = (unsigned long *)SERIAL_BASE;
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#ifdef SLOW_DOWN
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static inline void slow_down(void)
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{
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int k;
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for (k=0; k<10000; k++);
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}
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#else
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#define slow_down()
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#endif
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void
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prom_putchar(const unsigned char c)
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{
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unsigned char ch;
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int i = 0;
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do {
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ch = com1[SER_CMD];
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slow_down();
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i++;
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if (i>TIMEOUT) {
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break;
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}
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} while (0 == (ch & TX_BUSY));
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com1[SER_DATA] = c;
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}
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