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 <debug_uart.h>
8 #include <dm.h>
9 #include <efi.h>
10 #include <efi_api.h>
11 #include <errno.h>
12 #include <fdtdec.h>
13 #include <log.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 /* Convert a lower-case character to its ctrl-char equivalent */
27 #define CTL_CH(c) ((c) - 'a' + 1)
28
serial_efi_setbrg(struct udevice * dev,int baudrate)29 int serial_efi_setbrg(struct udevice *dev, int baudrate)
30 {
31 return 0;
32 }
33
serial_efi_get_key(struct serial_efi_priv * priv)34 static int serial_efi_get_key(struct serial_efi_priv *priv)
35 {
36 int ret;
37
38 if (priv->have_key)
39 return 0;
40 ret = priv->con_in->read_key_stroke(priv->con_in, &priv->key);
41 if (ret == EFI_NOT_READY)
42 return -EAGAIN;
43 else if (ret != EFI_SUCCESS)
44 return -EIO;
45
46 priv->have_key = true;
47
48 return 0;
49 }
50
serial_efi_getc(struct udevice * dev)51 static int serial_efi_getc(struct udevice *dev)
52 {
53 struct serial_efi_priv *priv = dev_get_priv(dev);
54 char conv_scan[10] = {0, 'p', 'n', 'f', 'b', 'a', 'e', 0, 8};
55 int ret, ch;
56
57 ret = serial_efi_get_key(priv);
58 if (ret)
59 return ret;
60
61 priv->have_key = false;
62 ch = priv->key.unicode_char;
63
64 /*
65 * Unicode char 8 (for backspace) is never returned. Instead we get a
66 * key scan code of 8. Handle this so that backspace works correctly
67 * in the U-Boot command line.
68 */
69 if (!ch && priv->key.scan_code < sizeof(conv_scan)) {
70 ch = conv_scan[priv->key.scan_code];
71 if (ch >= 'a')
72 ch -= 'a' - 1;
73 }
74 debug(" [%x %x %x] ", ch, priv->key.unicode_char, priv->key.scan_code);
75
76 return ch;
77 }
78
serial_efi_putc(struct udevice * dev,const char ch)79 static int serial_efi_putc(struct udevice *dev, const char ch)
80 {
81 struct serial_efi_priv *priv = dev_get_priv(dev);
82 uint16_t ucode[2];
83 int ret;
84
85 ucode[0] = ch;
86 ucode[1] = '\0';
87 ret = priv->con_out->output_string(priv->con_out, ucode);
88 if (ret)
89 return -EIO;
90
91 return 0;
92 }
93
serial_efi_pending(struct udevice * dev,bool input)94 static int serial_efi_pending(struct udevice *dev, bool input)
95 {
96 struct serial_efi_priv *priv = dev_get_priv(dev);
97 int ret;
98
99 /* We assume that EFI will stall if its output buffer fills up */
100 if (!input)
101 return 0;
102
103 ret = serial_efi_get_key(priv);
104 if (ret == -EAGAIN)
105 return 0;
106 else if (ret)
107 return ret;
108
109 return 1;
110 }
111
112 /*
113 * There is nothing to init here since the EFI console is already running by
114 * the time we enter U-Boot.
115 */
_debug_uart_init(void)116 static inline void _debug_uart_init(void)
117 {
118 }
119
_debug_uart_putc(int ch)120 static inline void _debug_uart_putc(int ch)
121 {
122 struct efi_system_table *sys_table = efi_get_sys_table();
123 uint16_t ucode[2];
124
125 ucode[0] = ch;
126 ucode[1] = '\0';
127 sys_table->con_out->output_string(sys_table->con_out, ucode);
128 }
129
130 DEBUG_UART_FUNCS
131
serial_efi_probe(struct udevice * dev)132 static int serial_efi_probe(struct udevice *dev)
133 {
134 struct efi_system_table *table = efi_get_sys_table();
135 struct serial_efi_priv *priv = dev_get_priv(dev);
136
137 priv->con_in = table->con_in;
138 priv->con_out = table->con_out;
139
140 return 0;
141 }
142
143 static const struct dm_serial_ops serial_efi_ops = {
144 .putc = serial_efi_putc,
145 .getc = serial_efi_getc,
146 .pending = serial_efi_pending,
147 .setbrg = serial_efi_setbrg,
148 };
149
150 static const struct udevice_id serial_efi_ids[] = {
151 { .compatible = "efi,uart" },
152 { }
153 };
154
155 U_BOOT_DRIVER(serial_efi) = {
156 .name = "serial_efi",
157 .id = UCLASS_SERIAL,
158 .of_match = serial_efi_ids,
159 .priv_auto = sizeof(struct serial_efi_priv),
160 .probe = serial_efi_probe,
161 .ops = &serial_efi_ops,
162 };
163