1 // SPDX-License-Identifier: BSD-2-Clause
2 /*
3 * Copyright (c) 2016, Xilinx Inc.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the documentation
14 * and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28 #include <assert.h>
29 #include <drivers/cdns_uart.h>
30 #include <io.h>
31 #include <keep.h>
32 #include <mm/core_mmu.h>
33 #include <util.h>
34
35 #define CDNS_UART_CONTROL 0
36 #define CDNS_UART_MODE 4
37 #define CDNS_UART_IEN 8
38 #define CDNS_UART_IRQ_STATUS 0x14
39 #define CDNS_UART_CHANNEL_STATUS 0x2c
40 #define CDNS_UART_FIFO 0x30
41 #define CDNS_UART_SIZE 0x34
42
43 #define CDNS_UART_CONTROL_RXRES BIT(0)
44 #define CDNS_UART_CONTROL_TXRES BIT(1)
45 #define CDNS_UART_CONTROL_RXEN BIT(2)
46 #define CDNS_UART_CONTROL_TXEN BIT(4)
47
48 #define CDNS_UART_MODE_8BIT (0 << 1)
49 #define CDNS_UART_MODE_PARITY_NONE (0x4 << 3)
50 #define CDNS_UART_MODE_1STP (0 << 6)
51
52 #define CDNS_UART_CHANNEL_STATUS_TFUL BIT(4)
53 #define CDNS_UART_CHANNEL_STATUS_TEMPTY BIT(3)
54 #define CDNS_UART_CHANNEL_STATUS_REMPTY BIT(1)
55
56 #define CDNS_UART_IRQ_RXTRIG BIT(0)
57 #define CDNS_UART_IRQ_RXTOUT BIT(8)
58
chip_to_base(struct serial_chip * chip)59 static vaddr_t chip_to_base(struct serial_chip *chip)
60 {
61 struct cdns_uart_data *pd =
62 container_of(chip, struct cdns_uart_data, chip);
63
64 return io_pa_or_va(&pd->base, CDNS_UART_SIZE);
65 }
66
cdns_uart_flush(struct serial_chip * chip)67 static void cdns_uart_flush(struct serial_chip *chip)
68 {
69 vaddr_t base = chip_to_base(chip);
70
71 while (!(io_read32(base + CDNS_UART_CHANNEL_STATUS) &
72 CDNS_UART_CHANNEL_STATUS_TEMPTY))
73 ;
74 }
75
cdns_uart_have_rx_data(struct serial_chip * chip)76 static bool cdns_uart_have_rx_data(struct serial_chip *chip)
77 {
78 vaddr_t base = chip_to_base(chip);
79
80 return !(io_read32(base + CDNS_UART_CHANNEL_STATUS) &
81 CDNS_UART_CHANNEL_STATUS_REMPTY);
82 }
83
cdns_uart_getchar(struct serial_chip * chip)84 static int cdns_uart_getchar(struct serial_chip *chip)
85 {
86 vaddr_t base = chip_to_base(chip);
87
88 while (!cdns_uart_have_rx_data(chip))
89 ;
90 return io_read32(base + CDNS_UART_FIFO) & 0xff;
91 }
92
cdns_uart_putc(struct serial_chip * chip,int ch)93 static void cdns_uart_putc(struct serial_chip *chip, int ch)
94 {
95 vaddr_t base = chip_to_base(chip);
96
97 /* Wait until there is space in the FIFO */
98 while (io_read32(base + CDNS_UART_CHANNEL_STATUS) &
99 CDNS_UART_CHANNEL_STATUS_TFUL)
100 ;
101
102 /* Send the character */
103 io_write32(base + CDNS_UART_FIFO, ch);
104 }
105
106
107 static const struct serial_ops cdns_uart_ops = {
108 .flush = cdns_uart_flush,
109 .getchar = cdns_uart_getchar,
110 .have_rx_data = cdns_uart_have_rx_data,
111 .putc = cdns_uart_putc,
112 };
113 DECLARE_KEEP_PAGER(cdns_uart_ops);
114
115 /*
116 * we rely on the bootloader having set up the HW correctly, we just enable
117 * transmitter/receiver here, just in case.
118 */
cdns_uart_init(struct cdns_uart_data * pd,paddr_t base,uint32_t uart_clk,uint32_t baud_rate)119 void cdns_uart_init(struct cdns_uart_data *pd, paddr_t base, uint32_t uart_clk,
120 uint32_t baud_rate)
121 {
122 pd->base.pa = base;
123 pd->chip.ops = &cdns_uart_ops;
124
125 if (!uart_clk || !baud_rate)
126 return;
127
128 /* Enable UART and RX/TX */
129 io_write32(base + CDNS_UART_CONTROL,
130 CDNS_UART_CONTROL_RXEN | CDNS_UART_CONTROL_TXEN);
131
132 cdns_uart_flush(&pd->chip);
133 }
134