1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (c) 2015 Google, Inc 4 * Written by Simon Glass <sjg@chromium.org> 5 */ 6 7 #include <common.h> 8 #include <debug_uart.h> 9 #include <dm.h> 10 #include <efi.h> 11 #include <efi_api.h> 12 #include <errno.h> 13 #include <fdtdec.h> 14 #include <linux/compiler.h> 15 #include <asm/io.h> 16 #include <serial.h> 17 18 /* Information about the efi console */ 19 struct serial_efi_priv { 20 struct efi_simple_text_input_protocol *con_in; 21 struct efi_simple_text_output_protocol *con_out; 22 struct efi_input_key key; 23 bool have_key; 24 }; 25 26 int serial_efi_setbrg(struct udevice *dev, int baudrate) 27 { 28 return 0; 29 } 30 31 static int serial_efi_get_key(struct serial_efi_priv *priv) 32 { 33 int ret; 34 35 if (priv->have_key) 36 return 0; 37 ret = priv->con_in->read_key_stroke(priv->con_in, &priv->key); 38 if (ret == EFI_NOT_READY) 39 return -EAGAIN; 40 else if (ret != EFI_SUCCESS) 41 return -EIO; 42 43 priv->have_key = true; 44 45 return 0; 46 } 47 48 static int serial_efi_getc(struct udevice *dev) 49 { 50 struct serial_efi_priv *priv = dev_get_priv(dev); 51 int ret, ch; 52 53 ret = serial_efi_get_key(priv); 54 if (ret) 55 return ret; 56 57 priv->have_key = false; 58 ch = priv->key.unicode_char; 59 60 /* 61 * Unicode char 8 (for backspace) is never returned. Instead we get a 62 * key scan code of 8. Handle this so that backspace works correctly 63 * in the U-Boot command line. 64 */ 65 if (!ch && priv->key.scan_code == 8) 66 ch = 8; 67 debug(" [%x %x %x] ", ch, priv->key.unicode_char, priv->key.scan_code); 68 69 return ch; 70 } 71 72 static int serial_efi_putc(struct udevice *dev, const char ch) 73 { 74 struct serial_efi_priv *priv = dev_get_priv(dev); 75 uint16_t ucode[2]; 76 int ret; 77 78 ucode[0] = ch; 79 ucode[1] = '\0'; 80 ret = priv->con_out->output_string(priv->con_out, ucode); 81 if (ret) 82 return -EIO; 83 84 return 0; 85 } 86 87 static int serial_efi_pending(struct udevice *dev, bool input) 88 { 89 struct serial_efi_priv *priv = dev_get_priv(dev); 90 int ret; 91 92 /* We assume that EFI will stall if its output buffer fills up */ 93 if (!input) 94 return 0; 95 96 ret = serial_efi_get_key(priv); 97 if (ret == -EAGAIN) 98 return 0; 99 else if (ret) 100 return ret; 101 102 return 1; 103 } 104 105 /* 106 * There is nothing to init here since the EFI console is already running by 107 * the time we enter U-Boot. 108 */ 109 static inline void _debug_uart_init(void) 110 { 111 } 112 113 static inline void _debug_uart_putc(int ch) 114 { 115 struct efi_system_table *sys_table = efi_get_sys_table(); 116 uint16_t ucode[2]; 117 118 ucode[0] = ch; 119 ucode[1] = '\0'; 120 sys_table->con_out->output_string(sys_table->con_out, ucode); 121 } 122 123 DEBUG_UART_FUNCS 124 125 static int serial_efi_probe(struct udevice *dev) 126 { 127 struct efi_system_table *table = efi_get_sys_table(); 128 struct serial_efi_priv *priv = dev_get_priv(dev); 129 130 priv->con_in = table->con_in; 131 priv->con_out = table->con_out; 132 133 return 0; 134 } 135 136 static const struct dm_serial_ops serial_efi_ops = { 137 .putc = serial_efi_putc, 138 .getc = serial_efi_getc, 139 .pending = serial_efi_pending, 140 .setbrg = serial_efi_setbrg, 141 }; 142 143 static const struct udevice_id serial_efi_ids[] = { 144 { .compatible = "efi,uart" }, 145 { } 146 }; 147 148 U_BOOT_DRIVER(serial_efi) = { 149 .name = "serial_efi", 150 .id = UCLASS_SERIAL, 151 .of_match = serial_efi_ids, 152 .priv_auto_alloc_size = sizeof(struct serial_efi_priv), 153 .probe = serial_efi_probe, 154 .ops = &serial_efi_ops, 155 }; 156