summaryrefslogtreecommitdiff
path: root/src/soc/rockchip/rk3288/uart.c
blob: 98477344d32d7a45331c9f1a066599797a5a26a2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
/*
 * This file is part of the coreboot project.
 *
 * Copyright 2014 Rockchip Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <arch/io.h>
#include <boot/coreboot_tables.h>
#include <console/console.h>	/* for __console definition */
#include <console/uart.h>
#include <drivers/uart/uart8250reg.h>
#include <stdint.h>

/*
 * TODO: Use DRIVERS_UART_8250MEM driver instead.
 * There is an issue in the IO call functions where x86 and ARM
 * ordering is reversed. This 8250MEM driver uses the x86 convention.
 * This driver can be replaced once the IO calls are sorted.
 */

struct rk3288_uart {
	union {
		uint32_t thr; /* Transmit holding register. */
		uint32_t rbr; /* Receive buffer register. */
		uint32_t dll; /* Divisor latch lsb. */
	};
	union {
		uint32_t ier; /* Interrupt enable register. */
		uint32_t dlm; /* Divisor latch msb. */
	};
	union {
		uint32_t iir; /* Interrupt identification register. */
		uint32_t fcr; /* FIFO control register. */
	};
	uint32_t lcr; /* Line control register. */
	uint32_t mcr; /* Modem control register. */
	uint32_t lsr; /* Line status register. */
	uint32_t msr; /* Modem status register. */
	uint32_t scr;
	uint32_t reserved1[(0x30 - 0x20) / 4];
	uint32_t srbr[(0x70 - 0x30) / 4];
	uint32_t far;
	uint32_t tfr;
	uint32_t rfw;
	uint32_t usr;
	uint32_t tfl;
	uint32_t rfl;
	uint32_t srr;
	uint32_t srts;
	uint32_t sbcr;
	uint32_t sdmam;
	uint32_t sfe;
	uint32_t srt;
	uint32_t stet;
	uint32_t htx;
	uint32_t dmasa;
	uint32_t reserver2[(0xf4 - 0xac) / 4];
	uint32_t cpr;
	uint32_t ucv;
	uint32_t ctr;
} __attribute__ ((packed));


static struct rk3288_uart * const uart_ptr =
	(void *)CONFIG_CONSOLE_SERIAL_UART_ADDRESS;

static void rk3288_uart_tx_flush(void);
static int rk3288_uart_tst_byte(void);

static void rk3288_uart_init(void)
{
	/* FIXME: Use a hardcoded divisor for now.
	 * uint16_t divisor = (u16) uart_baudrate_divisor(default_baudrate(),
	 *	uart_platform_refclk(), 16)
	 */
	const unsigned divisor = 13;
	const uint8_t line_config = UART8250_LCR_WLS_8; // 8n1

	rk3288_uart_tx_flush();

	// Disable interrupts.
	write32(&uart_ptr->ier, 0);
	// Force DTR and RTS to high.
	write32(&uart_ptr->mcr, UART8250_MCR_DTR | UART8250_MCR_RTS);
	// Set line configuration, access divisor latches.
	write32(&uart_ptr->lcr, UART8250_LCR_DLAB | line_config);
	// Set the divisor.
	write32(&uart_ptr->dll, divisor & 0xff);
	write32(&uart_ptr->dlm, (divisor >> 8) & 0xff);
	// Hide the divisor latches.
	write32(&uart_ptr->lcr, line_config);
	// Enable FIFOs, and clear receive and transmit.
	write32(&uart_ptr->fcr, UART8250_FCR_FIFO_EN |
		UART8250_FCR_CLEAR_RCVR | UART8250_FCR_CLEAR_XMIT);
}

static void rk3288_uart_tx_byte(unsigned char data)
{
	while (!(read32(&uart_ptr->lsr) & UART8250_LSR_THRE));
	write32(&uart_ptr->thr, data);
}

static void rk3288_uart_tx_flush(void)
{
	while (!(read32(&uart_ptr->lsr) & UART8250_LSR_TEMT));
}

static unsigned char rk3288_uart_rx_byte(void)
{
	if (!rk3288_uart_tst_byte())
		return 0;
	return read32(&uart_ptr->rbr);
}

static int rk3288_uart_tst_byte(void)
{
	return (read32(&uart_ptr->lsr) & UART8250_LSR_DR) == UART8250_LSR_DR;
}



void uart_init(int idx)
{
	rk3288_uart_init();
}

unsigned char uart_rx_byte(int idx)
{
	return rk3288_uart_rx_byte();
}

void uart_tx_byte(int idx, unsigned char data)
{
	rk3288_uart_tx_byte(data);
}

void uart_tx_flush(int idx)
{
	rk3288_uart_tx_flush();
}

#ifndef __PRE_RAM__
void uart_fill_lb(void *data)
{
	struct lb_serial serial;
	serial.type = LB_SERIAL_TYPE_MEMORY_MAPPED;
	serial.baseaddr = CONFIG_CONSOLE_SERIAL_UART_ADDRESS;
	serial.baud = default_baudrate();
	serial.regwidth = 1;
	lb_add_serial(&serial, data);

	lb_add_console(LB_TAG_CONSOLE_SERIAL8250MEM, data);
}
#endif