1 /* 2 * Copyright (c) 2015 Google, Inc 3 * Written by Simon Glass <sjg@chromium.org> 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 #include <common.h> 9 #include <debug_uart.h> 10 #include <dm.h> 11 #include <efi.h> 12 #include <efi_api.h> 13 #include <errno.h> 14 #include <fdtdec.h> 15 #include <linux/compiler.h> 16 #include <asm/io.h> 17 #include <serial.h> 18 19 /* Information about the efi console */ 20 struct serial_efi_priv { 21 struct efi_simple_input_interface *con_in; 22 struct efi_simple_text_output_protocol *con_out; 23 struct efi_input_key key; 24 bool have_key; 25 }; 26 27 int serial_efi_setbrg(struct udevice *dev, int baudrate) 28 { 29 return 0; 30 } 31 32 static int serial_efi_get_key(struct serial_efi_priv *priv) 33 { 34 int ret; 35 36 if (priv->have_key) 37 return 0; 38 ret = priv->con_in->read_key_stroke(priv->con_in, &priv->key); 39 if (ret == EFI_NOT_READY) 40 return -EAGAIN; 41 else if (ret != EFI_SUCCESS) 42 return -EIO; 43 44 priv->have_key = true; 45 46 return 0; 47 } 48 49 static int serial_efi_getc(struct udevice *dev) 50 { 51 struct serial_efi_priv *priv = dev_get_priv(dev); 52 int ret, ch; 53 54 ret = serial_efi_get_key(priv); 55 if (ret) 56 return ret; 57 58 priv->have_key = false; 59 ch = priv->key.unicode_char; 60 61 /* 62 * Unicode char 8 (for backspace) is never returned. Instead we get a 63 * key scan code of 8. Handle this so that backspace works correctly 64 * in the U-Boot command line. 65 */ 66 if (!ch && priv->key.scan_code == 8) 67 ch = 8; 68 debug(" [%x %x %x] ", ch, priv->key.unicode_char, priv->key.scan_code); 69 70 return ch; 71 } 72 73 static int serial_efi_putc(struct udevice *dev, const char ch) 74 { 75 struct serial_efi_priv *priv = dev_get_priv(dev); 76 uint16_t ucode[2]; 77 int ret; 78 79 ucode[0] = ch; 80 ucode[1] = '\0'; 81 ret = priv->con_out->output_string(priv->con_out, ucode); 82 if (ret) 83 return -EIO; 84 85 return 0; 86 } 87 88 static int serial_efi_pending(struct udevice *dev, bool input) 89 { 90 struct serial_efi_priv *priv = dev_get_priv(dev); 91 int ret; 92 93 /* We assume that EFI will stall if its output buffer fills up */ 94 if (!input) 95 return 0; 96 97 ret = serial_efi_get_key(priv); 98 if (ret == -EAGAIN) 99 return 0; 100 else if (ret) 101 return ret; 102 103 return 1; 104 } 105 106 /* 107 * There is nothing to init here since the EFI console is already running by 108 * the time we enter U-Boot. 109 */ 110 static inline void _debug_uart_init(void) 111 { 112 } 113 114 static inline void _debug_uart_putc(int ch) 115 { 116 struct efi_system_table *sys_table = efi_get_sys_table(); 117 uint16_t ucode[2]; 118 119 ucode[0] = ch; 120 ucode[1] = '\0'; 121 sys_table->con_out->output_string(sys_table->con_out, ucode); 122 } 123 124 DEBUG_UART_FUNCS 125 126 static int serial_efi_probe(struct udevice *dev) 127 { 128 struct efi_system_table *table = efi_get_sys_table(); 129 struct serial_efi_priv *priv = dev_get_priv(dev); 130 131 priv->con_in = table->con_in; 132 priv->con_out = table->con_out; 133 134 return 0; 135 } 136 137 static const struct dm_serial_ops serial_efi_ops = { 138 .putc = serial_efi_putc, 139 .getc = serial_efi_getc, 140 .pending = serial_efi_pending, 141 .setbrg = serial_efi_setbrg, 142 }; 143 144 static const struct udevice_id serial_efi_ids[] = { 145 { .compatible = "efi,uart" }, 146 { } 147 }; 148 149 U_BOOT_DRIVER(serial_efi) = { 150 .name = "serial_efi", 151 .id = UCLASS_SERIAL, 152 .of_match = serial_efi_ids, 153 .priv_auto_alloc_size = sizeof(struct serial_efi_priv), 154 .probe = serial_efi_probe, 155 .ops = &serial_efi_ops, 156 .flags = DM_FLAG_PRE_RELOC, 157 }; 158