1 /* 2 * Copyright (c) 2011 The Chromium OS Authors. 3 * See file CREDITS for list of people who contributed to this 4 * project. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation; either version 2 of 9 * the License, or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 19 * MA 02111-1307 USA 20 */ 21 22 /* 23 * This provide a test serial port. It provides an emulated serial port where 24 * a test program and read out the serial output and inject serial input for 25 * U-Boot. 26 */ 27 28 #include <common.h> 29 #include <os.h> 30 #include <serial.h> 31 #include <linux/compiler.h> 32 33 /* 34 * 35 * serial_buf: A buffer that holds keyboard characters for the 36 * Sandbox U-boot. 37 * 38 * invariants: 39 * serial_buf_write == serial_buf_read -> empty buffer 40 * (serial_buf_write + 1) % 16 == serial_buf_read -> full buffer 41 */ 42 static char serial_buf[16]; 43 static unsigned int serial_buf_write; 44 static unsigned int serial_buf_read; 45 46 static int sandbox_serial_init(void) 47 { 48 os_tty_raw(0); 49 return 0; 50 } 51 52 static void sandbox_serial_setbrg(void) 53 { 54 } 55 56 static void sandbox_serial_putc(const char ch) 57 { 58 os_write(1, &ch, 1); 59 } 60 61 static void sandbox_serial_puts(const char *str) 62 { 63 os_write(1, str, strlen(str)); 64 } 65 66 static unsigned int increment_buffer_index(unsigned int index) 67 { 68 return (index + 1) % ARRAY_SIZE(serial_buf); 69 } 70 71 static int sandbox_serial_tstc(void) 72 { 73 const unsigned int next_index = 74 increment_buffer_index(serial_buf_write); 75 ssize_t count; 76 77 os_usleep(100); 78 if (next_index == serial_buf_read) 79 return 1; /* buffer full */ 80 81 count = os_read_no_block(0, &serial_buf[serial_buf_write], 1); 82 if (count == 1) 83 serial_buf_write = next_index; 84 return serial_buf_write != serial_buf_read; 85 } 86 87 static int sandbox_serial_getc(void) 88 { 89 int result; 90 91 while (!sandbox_serial_tstc()) 92 ; /* buffer empty */ 93 94 result = serial_buf[serial_buf_read]; 95 serial_buf_read = increment_buffer_index(serial_buf_read); 96 return result; 97 } 98 99 static struct serial_device sandbox_serial_drv = { 100 .name = "sandbox_serial", 101 .start = sandbox_serial_init, 102 .stop = NULL, 103 .setbrg = sandbox_serial_setbrg, 104 .putc = sandbox_serial_putc, 105 .puts = sandbox_serial_puts, 106 .getc = sandbox_serial_getc, 107 .tstc = sandbox_serial_tstc, 108 }; 109 110 void sandbox_serial_initialize(void) 111 { 112 serial_register(&sandbox_serial_drv); 113 } 114 115 __weak struct serial_device *default_serial_console(void) 116 { 117 return &sandbox_serial_drv; 118 } 119