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 */
20struct 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
30int serial_efi_setbrg(struct udevice *dev, int baudrate)
31{
32	return 0;
33}
34
35static 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
52static 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
80static 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
95static 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 */
117static inline void _debug_uart_init(void)
118{
119}
120
121static 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
131DEBUG_UART_FUNCS
132
133static 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
144static 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
151static const struct udevice_id serial_efi_ids[] = {
152	{ .compatible = "efi,uart" },
153	{ }
154};
155
156U_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