1 // SPDX-License-Identifier: BSD-2-Clause
2 /*
3 * Copyright (C) 2015 Freescale Semiconductor, Inc.
4 * Copyright (c) 2017, 2020, Linaro Limited
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright notice,
14 * this list of conditions and the following disclaimer in the documentation
15 * and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18 * AND 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 COPYRIGHT HOLDER OR CONTRIBUTORS BE
21 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #include <drivers/ns16550.h>
31 #include <keep.h>
32 #include <util.h>
33
34 /* uart register defines */
35 #define UART_RBR 0x0
36 #define UART_THR 0x0
37 #define UART_IER 0x1
38 #define UART_FCR 0x2
39 #define UART_LCR 0x3
40 #define UART_MCR 0x4
41 #define UART_LSR 0x5
42 #define UART_MSR 0x6
43 #define UART_SPR 0x7
44
45 /* uart status register bits */
46 #define UART_LSR_DR 0x01 /* DATA Ready */
47 #define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
48
chip_to_base_and_data(struct serial_chip * chip,struct ns16550_data ** pd)49 static vaddr_t chip_to_base_and_data(struct serial_chip *chip,
50 struct ns16550_data **pd)
51 {
52 *pd = container_of(chip, struct ns16550_data, chip);
53
54 return io_pa_or_va(&(*pd)->base, NS16550_UART_REG_SIZE);
55 }
56
ns16550_flush(struct serial_chip * chip)57 static void ns16550_flush(struct serial_chip *chip)
58 {
59 struct ns16550_data *pd = NULL;
60 vaddr_t base = chip_to_base_and_data(chip, &pd);
61
62 while ((serial_in(base + (UART_LSR << pd->reg_shift), pd->io_width) &
63 UART_LSR_THRE) == 0)
64 ;
65 }
66
ns16550_putc(struct serial_chip * chip,int ch)67 static void ns16550_putc(struct serial_chip *chip, int ch)
68 {
69 struct ns16550_data *pd = NULL;
70 vaddr_t base = chip_to_base_and_data(chip, &pd);
71
72 ns16550_flush(chip);
73
74 /* write out charset to Transmit-hold-register */
75 serial_out(base + (UART_THR << pd->reg_shift), pd->io_width, ch);
76 }
77
ns16550_have_rx_data(struct serial_chip * chip)78 static bool ns16550_have_rx_data(struct serial_chip *chip)
79 {
80 struct ns16550_data *pd = NULL;
81 vaddr_t base = chip_to_base_and_data(chip, &pd);
82
83 return serial_in(base + (UART_LSR << pd->reg_shift), pd->io_width) &
84 UART_LSR_DR;
85 }
86
ns16550_getchar(struct serial_chip * chip)87 static int ns16550_getchar(struct serial_chip *chip)
88 {
89 struct ns16550_data *pd = NULL;
90 vaddr_t base = chip_to_base_and_data(chip, &pd);
91
92 while (!ns16550_have_rx_data(chip)) {
93 /* Data is not ready, waiting again */
94 ;
95 }
96
97 return serial_in(base + (UART_RBR << pd->reg_shift), pd->io_width) &
98 0xFF;
99 }
100
101 static const struct serial_ops ns16550_ops = {
102 .flush = ns16550_flush,
103 .putc = ns16550_putc,
104 .getchar = ns16550_getchar,
105 .have_rx_data = ns16550_have_rx_data,
106 };
107 DECLARE_KEEP_PAGER(ns16550_ops);
108
ns16550_init(struct ns16550_data * pd,paddr_t base,uint8_t io_width,uint8_t reg_shift)109 void ns16550_init(struct ns16550_data *pd, paddr_t base, uint8_t io_width,
110 uint8_t reg_shift)
111 {
112 pd->base.pa = base;
113 pd->io_width = io_width;
114 pd->reg_shift = reg_shift;
115 pd->chip.ops = &ns16550_ops;
116
117 /*
118 * Do nothing, uart driver shared with normal world,
119 * everything for uart driver initialization is done in bootloader.
120 */
121 }
122