1 /* 2 * Copyright (c) 2011 The Chromium OS Authors. 3 * 4 * SPDX-License-Identifier: GPL-2.0+ 5 */ 6 7 /* 8 * This provide a test serial port. It provides an emulated serial port where 9 * a test program and read out the serial output and inject serial input for 10 * U-Boot. 11 */ 12 13 #include <common.h> 14 #include <lcd.h> 15 #include <os.h> 16 #include <serial.h> 17 #include <linux/compiler.h> 18 #include <asm/state.h> 19 20 /* 21 * 22 * serial_buf: A buffer that holds keyboard characters for the 23 * Sandbox U-boot. 24 * 25 * invariants: 26 * serial_buf_write == serial_buf_read -> empty buffer 27 * (serial_buf_write + 1) % 16 == serial_buf_read -> full buffer 28 */ 29 static char serial_buf[16]; 30 static unsigned int serial_buf_write; 31 static unsigned int serial_buf_read; 32 33 static int sandbox_serial_init(void) 34 { 35 struct sandbox_state *state = state_get_current(); 36 37 if (state->term_raw != STATE_TERM_COOKED) 38 os_tty_raw(0, state->term_raw == STATE_TERM_RAW_WITH_SIGS); 39 return 0; 40 } 41 42 static void sandbox_serial_setbrg(void) 43 { 44 } 45 46 static void sandbox_serial_putc(const char ch) 47 { 48 os_write(1, &ch, 1); 49 } 50 51 static void sandbox_serial_puts(const char *str) 52 { 53 os_write(1, str, strlen(str)); 54 } 55 56 static unsigned int increment_buffer_index(unsigned int index) 57 { 58 return (index + 1) % ARRAY_SIZE(serial_buf); 59 } 60 61 static int sandbox_serial_tstc(void) 62 { 63 const unsigned int next_index = 64 increment_buffer_index(serial_buf_write); 65 ssize_t count; 66 67 os_usleep(100); 68 #ifdef CONFIG_LCD 69 lcd_sync(); 70 #endif 71 if (next_index == serial_buf_read) 72 return 1; /* buffer full */ 73 74 count = os_read_no_block(0, &serial_buf[serial_buf_write], 1); 75 if (count == 1) 76 serial_buf_write = next_index; 77 return serial_buf_write != serial_buf_read; 78 } 79 80 static int sandbox_serial_getc(void) 81 { 82 int result; 83 84 while (!sandbox_serial_tstc()) 85 ; /* buffer empty */ 86 87 result = serial_buf[serial_buf_read]; 88 serial_buf_read = increment_buffer_index(serial_buf_read); 89 return result; 90 } 91 92 static struct serial_device sandbox_serial_drv = { 93 .name = "sandbox_serial", 94 .start = sandbox_serial_init, 95 .stop = NULL, 96 .setbrg = sandbox_serial_setbrg, 97 .putc = sandbox_serial_putc, 98 .puts = sandbox_serial_puts, 99 .getc = sandbox_serial_getc, 100 .tstc = sandbox_serial_tstc, 101 }; 102 103 void sandbox_serial_initialize(void) 104 { 105 serial_register(&sandbox_serial_drv); 106 } 107 108 __weak struct serial_device *default_serial_console(void) 109 { 110 return &sandbox_serial_drv; 111 } 112