1 /* 2 * Copyright (C) 2015 Freescale Semiconductor, Inc. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 11 * 2. Redistributions in binary form must reproduce the above copyright notice, 12 * this list of conditions and the following disclaimer in the documentation 13 * and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 19 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25 * POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <drivers/ns16550.h> 29 #include <io.h> 30 31 /* uart register defines */ 32 #define UART_RBR 0x0 33 #define UART_THR 0x0 34 #define UART_IER 0x1 35 #define UART_FCR 0x2 36 #define UART_LCR 0x3 37 #define UART_MCR 0x4 38 #define UART_LSR 0x5 39 #define UART_MSR 0x6 40 #define UART_SPR 0x7 41 42 /* uart status register bits */ 43 #define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */ 44 45 void ns16550_flush(vaddr_t base) 46 { 47 while ((read8(base + UART_LSR) & UART_LSR_THRE) == 0) 48 ; 49 } 50 51 void ns16550_putc(int ch, vaddr_t base) 52 { 53 ns16550_flush(base); 54 55 /* write out charset to Transmit-hold-register */ 56 write8(ch, base + UART_THR); 57 } 58