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 <dm.h> 15 #include <fdtdec.h> 16 #include <lcd.h> 17 #include <os.h> 18 #include <serial.h> 19 #include <linux/compiler.h> 20 #include <asm/state.h> 21 22 DECLARE_GLOBAL_DATA_PTR; 23 24 /* 25 * 26 * serial_buf: A buffer that holds keyboard characters for the 27 * Sandbox U-boot. 28 * 29 * invariants: 30 * serial_buf_write == serial_buf_read -> empty buffer 31 * (serial_buf_write + 1) % 16 == serial_buf_read -> full buffer 32 */ 33 static char serial_buf[16]; 34 static unsigned int serial_buf_write; 35 static unsigned int serial_buf_read; 36 37 static int sandbox_serial_probe(struct udevice *dev) 38 { 39 struct sandbox_state *state = state_get_current(); 40 41 if (state->term_raw != STATE_TERM_COOKED) 42 os_tty_raw(0, state->term_raw == STATE_TERM_RAW_WITH_SIGS); 43 44 return 0; 45 } 46 47 static int sandbox_serial_putc(struct udevice *dev, const char ch) 48 { 49 os_write(1, &ch, 1); 50 51 return 0; 52 } 53 54 static unsigned int increment_buffer_index(unsigned int index) 55 { 56 return (index + 1) % ARRAY_SIZE(serial_buf); 57 } 58 59 static int sandbox_serial_pending(struct udevice *dev, bool input) 60 { 61 const unsigned int next_index = 62 increment_buffer_index(serial_buf_write); 63 ssize_t count; 64 65 if (!input) 66 return 0; 67 68 os_usleep(100); 69 #ifdef CONFIG_LCD 70 lcd_sync(); 71 #endif 72 if (next_index == serial_buf_read) 73 return 1; /* buffer full */ 74 75 count = os_read_no_block(0, &serial_buf[serial_buf_write], 1); 76 if (count == 1) 77 serial_buf_write = next_index; 78 79 return serial_buf_write != serial_buf_read; 80 } 81 82 static int sandbox_serial_getc(struct udevice *dev) 83 { 84 int result; 85 86 if (!sandbox_serial_pending(dev, true)) 87 return -EAGAIN; /* buffer empty */ 88 89 result = serial_buf[serial_buf_read]; 90 serial_buf_read = increment_buffer_index(serial_buf_read); 91 return result; 92 } 93 94 static const struct dm_serial_ops sandbox_serial_ops = { 95 .putc = sandbox_serial_putc, 96 .pending = sandbox_serial_pending, 97 .getc = sandbox_serial_getc, 98 }; 99 100 static const struct udevice_id sandbox_serial_ids[] = { 101 { .compatible = "sandbox,serial" }, 102 { } 103 }; 104 105 U_BOOT_DRIVER(serial_sandbox) = { 106 .name = "serial_sandbox", 107 .id = UCLASS_SERIAL, 108 .of_match = sandbox_serial_ids, 109 .probe = sandbox_serial_probe, 110 .ops = &sandbox_serial_ops, 111 .flags = DM_FLAG_PRE_RELOC, 112 }; 113 114 U_BOOT_DEVICE(serial_sandbox_non_fdt) = { 115 .name = "serial_sandbox", 116 }; 117