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
serial_efi_setbrg(struct udevice * dev,int baudrate)26 int serial_efi_setbrg(struct udevice *dev, int baudrate)
27 {
28 return 0;
29 }
30
serial_efi_get_key(struct serial_efi_priv * priv)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
serial_efi_getc(struct udevice * dev)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
serial_efi_putc(struct udevice * dev,const char ch)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
serial_efi_pending(struct udevice * dev,bool input)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 */
_debug_uart_init(void)109 static inline void _debug_uart_init(void)
110 {
111 }
112
_debug_uart_putc(int ch)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
serial_efi_probe(struct udevice * dev)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