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
27 /* Convert a lower-case character to its ctrl-char equivalent */
28 #define CTL_CH(c) ((c) - 'a' + 1)
29
serial_efi_setbrg(struct udevice * dev,int baudrate)30 int serial_efi_setbrg(struct udevice *dev, int baudrate)
31 {
32 return 0;
33 }
34
serial_efi_get_key(struct serial_efi_priv * priv)35 static int serial_efi_get_key(struct serial_efi_priv *priv)
36 {
37 int ret;
38
39 if (priv->have_key)
40 return 0;
41 ret = priv->con_in->read_key_stroke(priv->con_in, &priv->key);
42 if (ret == EFI_NOT_READY)
43 return -EAGAIN;
44 else if (ret != EFI_SUCCESS)
45 return -EIO;
46
47 priv->have_key = true;
48
49 return 0;
50 }
51
serial_efi_getc(struct udevice * dev)52 static int serial_efi_getc(struct udevice *dev)
53 {
54 struct serial_efi_priv *priv = dev_get_priv(dev);
55 char conv_scan[10] = {0, 'p', 'n', 'f', 'b', 'a', 'e', 0, 8};
56 int ret, ch;
57
58 ret = serial_efi_get_key(priv);
59 if (ret)
60 return ret;
61
62 priv->have_key = false;
63 ch = priv->key.unicode_char;
64
65 /*
66 * Unicode char 8 (for backspace) is never returned. Instead we get a
67 * key scan code of 8. Handle this so that backspace works correctly
68 * in the U-Boot command line.
69 */
70 if (!ch && priv->key.scan_code < sizeof(conv_scan)) {
71 ch = conv_scan[priv->key.scan_code];
72 if (ch >= 'a')
73 ch -= 'a' - 1;
74 }
75 debug(" [%x %x %x] ", ch, priv->key.unicode_char, priv->key.scan_code);
76
77 return ch;
78 }
79
serial_efi_putc(struct udevice * dev,const char ch)80 static int serial_efi_putc(struct udevice *dev, const char ch)
81 {
82 struct serial_efi_priv *priv = dev_get_priv(dev);
83 uint16_t ucode[2];
84 int ret;
85
86 ucode[0] = ch;
87 ucode[1] = '\0';
88 ret = priv->con_out->output_string(priv->con_out, ucode);
89 if (ret)
90 return -EIO;
91
92 return 0;
93 }
94
serial_efi_pending(struct udevice * dev,bool input)95 static int serial_efi_pending(struct udevice *dev, bool input)
96 {
97 struct serial_efi_priv *priv = dev_get_priv(dev);
98 int ret;
99
100 /* We assume that EFI will stall if its output buffer fills up */
101 if (!input)
102 return 0;
103
104 ret = serial_efi_get_key(priv);
105 if (ret == -EAGAIN)
106 return 0;
107 else if (ret)
108 return ret;
109
110 return 1;
111 }
112
113 /*
114 * There is nothing to init here since the EFI console is already running by
115 * the time we enter U-Boot.
116 */
_debug_uart_init(void)117 static inline void _debug_uart_init(void)
118 {
119 }
120
_debug_uart_putc(int ch)121 static inline void _debug_uart_putc(int ch)
122 {
123 struct efi_system_table *sys_table = efi_get_sys_table();
124 uint16_t ucode[2];
125
126 ucode[0] = ch;
127 ucode[1] = '\0';
128 sys_table->con_out->output_string(sys_table->con_out, ucode);
129 }
130
131 DEBUG_UART_FUNCS
132
serial_efi_probe(struct udevice * dev)133 static int serial_efi_probe(struct udevice *dev)
134 {
135 struct efi_system_table *table = efi_get_sys_table();
136 struct serial_efi_priv *priv = dev_get_priv(dev);
137
138 priv->con_in = table->con_in;
139 priv->con_out = table->con_out;
140
141 return 0;
142 }
143
144 static const struct dm_serial_ops serial_efi_ops = {
145 .putc = serial_efi_putc,
146 .getc = serial_efi_getc,
147 .pending = serial_efi_pending,
148 .setbrg = serial_efi_setbrg,
149 };
150
151 static const struct udevice_id serial_efi_ids[] = {
152 { .compatible = "efi,uart" },
153 { }
154 };
155
156 U_BOOT_DRIVER(serial_efi) = {
157 .name = "serial_efi",
158 .id = UCLASS_SERIAL,
159 .of_match = serial_efi_ids,
160 .priv_auto = sizeof(struct serial_efi_priv),
161 .probe = serial_efi_probe,
162 .ops = &serial_efi_ops,
163 };
164