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 <log.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_text_input_protocol *con_in;
22 struct efi_simple_text_output_protocol *con_out;
23 struct efi_input_key key;
24 bool have_key;
25 };
26
serial_efi_setbrg(struct udevice * dev,int baudrate)27 int serial_efi_setbrg(struct udevice *dev, int baudrate)
28 {
29 return 0;
30 }
31
serial_efi_get_key(struct serial_efi_priv * priv)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
serial_efi_getc(struct udevice * dev)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
serial_efi_putc(struct udevice * dev,const char ch)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
serial_efi_pending(struct udevice * dev,bool input)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 */
_debug_uart_init(void)110 static inline void _debug_uart_init(void)
111 {
112 }
113
_debug_uart_putc(int ch)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
serial_efi_probe(struct udevice * dev)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 = sizeof(struct serial_efi_priv),
154 .probe = serial_efi_probe,
155 .ops = &serial_efi_ops,
156 };
157