xref: /aosp_15_r20/external/coreboot/payloads/libpayload/drivers/serial/8250.c (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
1 /*
2  *
3  * Copyright (C) 2008 Advanced Micro Devices, Inc.
4  * Copyright (C) 2008 Ulf Jordan <[email protected]>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <libpayload-config.h>
31 #include <libpayload.h>
32 
33 static struct cb_serial cb_serial;
34 
35 #define IOBASE cb_serial.baseaddr
36 #define MEMBASE (phys_to_virt(IOBASE))
37 
38 static int serial_hardware_is_present = 0;
39 static int serial_is_mem_mapped = 0;
40 
serial_read_reg(int offset)41 static uint8_t serial_read_reg(int offset)
42 {
43 	offset *= cb_serial.regwidth;
44 
45 #if CONFIG(LP_IO_ADDRESS_SPACE)
46 	if (!serial_is_mem_mapped)
47 		return inb(IOBASE + offset);
48 	else
49 #endif
50 		if (cb_serial.regwidth == 4)
51 			return readl(MEMBASE + offset) & 0xff;
52 		else
53 			return readb(MEMBASE + offset);
54 }
55 
serial_write_reg(uint8_t val,int offset)56 static void serial_write_reg(uint8_t val, int offset)
57 {
58 	offset *= cb_serial.regwidth;
59 
60 #if CONFIG(LP_IO_ADDRESS_SPACE)
61 	if (!serial_is_mem_mapped)
62 		outb(val, IOBASE + offset);
63 	else
64 #endif
65 		if (cb_serial.regwidth == 4)
66 			writel(val & 0xff, MEMBASE + offset);
67 		else
68 			writeb(val, MEMBASE + offset);
69 }
70 
71 #if CONFIG(LP_SERIAL_SET_SPEED)
serial_hardware_init(int speed,int word_bits,int parity,int stop_bits)72 static void serial_hardware_init(int speed, int word_bits,
73 				 int parity, int stop_bits)
74 {
75 #if !CONFIG(LP_PL011_SERIAL_CONSOLE)
76 	unsigned char reg;
77 
78 	/* Disable interrupts. */
79 	serial_write_reg(0, 0x01);
80 
81 	/* Assert RTS and DTR. */
82 	serial_write_reg(3, 0x04);
83 
84 	/* Set the divisor latch. */
85 	reg = serial_read_reg(0x03);
86 	serial_write_reg(reg | 0x80, 0x03);
87 
88 	/* Write the divisor. */
89 	uint16_t divisor = 115200 / speed;
90 	serial_write_reg(divisor & 0xFF, 0x00);
91 	serial_write_reg(divisor >> 8, 0x01);
92 
93 	/* Restore the previous value of the divisor.
94 	 * And set 8 bits per character */
95 	serial_write_reg((reg & ~0x80) | 3, 0x03);
96 #endif
97 }
98 #endif
99 
100 static struct console_input_driver consin = {
101 	.havekey = &serial_havechar,
102 	.getchar = &serial_getchar,
103 	.input_type = CONSOLE_INPUT_TYPE_UART,
104 };
105 
106 static struct console_output_driver consout = {
107 	.putchar = &serial_putchar
108 };
109 
serial_init(void)110 void serial_init(void)
111 {
112 	serial_is_mem_mapped = (cb_serial.type == CB_SERIAL_TYPE_MEMORY_MAPPED);
113 
114 	if (!serial_is_mem_mapped) {
115 #if CONFIG(LP_IO_ADDRESS_SPACE)
116 		if ((inb(IOBASE + 0x05) == 0xFF) &&
117 				(inb(IOBASE + 0x06) == 0xFF)) {
118 			printf("IO space mapped serial not present.");
119 			return;
120 		}
121 #else
122 		printf("IO space mapped serial not supported.");
123 		return;
124 #endif
125 	}
126 
127 #if CONFIG(LP_SERIAL_SET_SPEED)
128 	serial_hardware_init(CONFIG_LP_SERIAL_BAUD_RATE, 8, 0, 1);
129 #endif
130 	serial_hardware_is_present = 1;
131 }
132 
serial_console_init(void)133 void serial_console_init(void)
134 {
135 	if (!lib_sysinfo.cb_serial)
136 		return;
137 	cb_serial = *(struct cb_serial *)phys_to_virt(lib_sysinfo.cb_serial);
138 
139 	serial_init();
140 
141 	console_add_input_driver(&consin);
142 	console_add_output_driver(&consout);
143 }
144 
serial_putchar(unsigned int c)145 void serial_putchar(unsigned int c)
146 {
147 	if (!serial_hardware_is_present)
148 		return;
149 #if !CONFIG(LP_PL011_SERIAL_CONSOLE)
150 	while ((serial_read_reg(0x05) & 0x20) == 0) ;
151 #endif
152 	serial_write_reg(c, 0x00);
153 	if (c == '\n')
154 		serial_putchar('\r');
155 }
156 
serial_havechar(void)157 int serial_havechar(void)
158 {
159 	if (!serial_hardware_is_present)
160 		return 0;
161 	return serial_read_reg(0x05) & 0x01;
162 }
163 
serial_getchar(void)164 int serial_getchar(void)
165 {
166 	if (!serial_hardware_is_present)
167 		return -1;
168 	while (!serial_havechar()) ;
169 	return serial_read_reg(0x00);
170 }
171