1 /*
2 * Copyright (c) 2015-2022, Xilinx Inc.
3 * Copyright (c) 2022-2025, Advanced Micro Devices, Inc. All rights reserved.
4 * Written by Michal Simek.
5 *
6 * SPDX-License-Identifier: BSD-3-Clause
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
10 *
11 * Redistributions of source code must retain the above copyright notice, this
12 * list of conditions and the following disclaimer.
13 *
14 * Redistributions in binary form must reproduce the above copyright notice,
15 * this list of conditions and the following disclaimer in the documentation
16 * and/or other materials provided with the distribution.
17 *
18 * Neither the name of ARM nor the names of its contributors may be used
19 * to endorse or promote products derived from this software without specific
20 * prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
23 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
26 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32 * POSSIBILITY OF SUCH DAMAGE.
33 */
34
35 #include <errno.h>
36 #include <stddef.h>
37 #include <arch_helpers.h>
38 #include <drivers/arm/dcc.h>
39 #include <drivers/console.h>
40 #include <drivers/delay_timer.h>
41 #include <lib/mmio.h>
42
43 /* DCC Status Bits */
44 #define DCC_STATUS_RX BIT(30)
45 #define DCC_STATUS_TX BIT(29)
46 #define TIMEOUT_COUNT_US U(0x10624)
47
48 struct dcc_console {
49 console_t console;
50 };
51
__dcc_getstatus(void)52 static inline u_register_t __dcc_getstatus(void)
53 {
54 return read_mdccsr_el0();
55 }
56
57 #if ENABLE_CONSOLE_GETC
__dcc_getchar(void)58 static inline char __dcc_getchar(void)
59 {
60 char c;
61
62 c = read_dbgdtrrx_el0();
63
64 return c;
65 }
66 #endif
67
__dcc_putchar(char c)68 static inline void __dcc_putchar(char c)
69 {
70 /*
71 * The typecast is to make absolutely certain that 'c' is
72 * zero-extended.
73 */
74 write_dbgdtrtx_el0((unsigned char)c);
75 }
76
dcc_status_timeout(uint32_t mask)77 static int32_t dcc_status_timeout(uint32_t mask)
78 {
79 const unsigned int timeout_count = TIMEOUT_COUNT_US;
80 uint64_t timeout;
81 u_register_t status;
82
83 timeout = timeout_init_us(timeout_count);
84
85 do {
86 status = (__dcc_getstatus() & mask);
87 if (timeout_elapsed(timeout)) {
88 return -ETIMEDOUT;
89 }
90 } while ((status != 0U));
91
92 return 0;
93 }
94
dcc_console_putc(int32_t ch,console_t * console)95 static int32_t dcc_console_putc(int32_t ch, console_t *console)
96 {
97 int32_t status;
98
99 (void)console;
100
101 status = dcc_status_timeout(DCC_STATUS_TX);
102 if (status != 0U) {
103 return status;
104 }
105 __dcc_putchar(ch);
106
107 return ch;
108 }
109
110 #if ENABLE_CONSOLE_GETC
dcc_console_getc(console_t * console)111 static int32_t dcc_console_getc(console_t *console)
112 {
113 int32_t status;
114
115 status = dcc_status_timeout(DCC_STATUS_RX);
116 if (status != 0U) {
117 return status;
118 }
119
120 return __dcc_getchar();
121 }
122 #endif
123
124 /**
125 * dcc_console_flush() - Function to force a write of all buffered data
126 * that hasn't been output.
127 * @console Console struct
128 *
129 */
dcc_console_flush(console_t * console)130 static void dcc_console_flush(console_t *console)
131 {
132 int32_t status;
133
134 (void)console;
135
136 status = dcc_status_timeout(DCC_STATUS_TX);
137 if (status != 0U) {
138 return;
139 }
140 }
141
142 static struct dcc_console dcc_console = {
143 .console = {
144 .flags = CONSOLE_FLAG_BOOT |
145 CONSOLE_FLAG_RUNTIME |
146 CONSOLE_FLAG_CRASH,
147 .putc = dcc_console_putc,
148 #if ENABLE_CONSOLE_GETC
149 .getc = dcc_console_getc,
150 #endif
151 .flush = dcc_console_flush,
152 },
153 };
154
console_dcc_register(console_t * console)155 int console_dcc_register(console_t *console)
156 {
157 memcpy(console, &dcc_console.console, sizeof(console_t));
158 return console_register(console);
159 }
160
console_dcc_unregister(console_t * console)161 void console_dcc_unregister(console_t *console)
162 {
163 dcc_console_flush(console);
164 (void)console_unregister(console);
165 }
166