1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2004-2007 ARM Limited.
4 * Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
5 * Copyright (C) 2015 - 2016 Xilinx, Inc, Michal Simek
6 *
7 * As a special exception, if other files instantiate templates or use macros
8 * or inline functions from this file, or you compile this file and link it
9 * with other works to produce a work based on this file, this file does not
10 * by itself cause the resulting work to be covered by the GNU General Public
11 * License. However the source code for this file must still be made available
12 * in accordance with section (3) of the GNU General Public License.
13
14 * This exception does not invalidate any other reasons why a work based on
15 * this file might be covered by the GNU General Public License.
16 */
17
18 #include <dm.h>
19 #include <serial.h>
20
21 #if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V7A) || defined(CONFIG_CPU_V7R)
22 /*
23 * ARMV6 & ARMV7
24 */
25 #define DCC_RBIT (1 << 30)
26 #define DCC_WBIT (1 << 29)
27
28 #define write_dcc(x) \
29 __asm__ volatile ("mcr p14, 0, %0, c0, c5, 0\n" : : "r" (x))
30
31 #define read_dcc(x) \
32 __asm__ volatile ("mrc p14, 0, %0, c0, c5, 0\n" : "=r" (x))
33
34 #define status_dcc(x) \
35 __asm__ volatile ("mrc p14, 0, %0, c0, c1, 0\n" : "=r" (x))
36
37 #elif defined(CONFIG_CPU_XSCALE)
38 /*
39 * XSCALE
40 */
41 #define DCC_RBIT (1 << 31)
42 #define DCC_WBIT (1 << 28)
43
44 #define write_dcc(x) \
45 __asm__ volatile ("mcr p14, 0, %0, c8, c0, 0\n" : : "r" (x))
46
47 #define read_dcc(x) \
48 __asm__ volatile ("mrc p14, 0, %0, c9, c0, 0\n" : "=r" (x))
49
50 #define status_dcc(x) \
51 __asm__ volatile ("mrc p14, 0, %0, c14, c0, 0\n" : "=r" (x))
52
53 #elif defined(CONFIG_ARM64)
54 /*
55 * ARMV8
56 */
57 #define DCC_RBIT (1 << 30)
58 #define DCC_WBIT (1 << 29)
59
60 #define write_dcc(x) \
61 __asm__ volatile ("msr dbgdtrtx_el0, %0\n" : : "r" (x))
62
63 #define read_dcc(x) \
64 __asm__ volatile ("mrs %0, dbgdtrrx_el0\n" : "=r" (x))
65
66 #define status_dcc(x) \
67 __asm__ volatile ("mrs %0, mdccsr_el0\n" : "=r" (x))
68
69 #else
70 #define DCC_RBIT (1 << 0)
71 #define DCC_WBIT (1 << 1)
72
73 #define write_dcc(x) \
74 __asm__ volatile ("mcr p14, 0, %0, c1, c0, 0\n" : : "r" (x))
75
76 #define read_dcc(x) \
77 __asm__ volatile ("mrc p14, 0, %0, c1, c0, 0\n" : "=r" (x))
78
79 #define status_dcc(x) \
80 __asm__ volatile ("mrc p14, 0, %0, c0, c0, 0\n" : "=r" (x))
81
82 #endif
83
84 #define can_read_dcc(x) do { \
85 status_dcc(x); \
86 x &= DCC_RBIT; \
87 } while (0);
88
89 #define can_write_dcc(x) do { \
90 status_dcc(x); \
91 x &= DCC_WBIT; \
92 x = (x == 0); \
93 } while (0);
94
95 #define TIMEOUT_COUNT 0x4000000
96
arm_dcc_getc(struct udevice * dev)97 static int arm_dcc_getc(struct udevice *dev)
98 {
99 int ch;
100 register unsigned int reg;
101
102 do {
103 can_read_dcc(reg);
104 } while (!reg);
105 read_dcc(ch);
106
107 return ch;
108 }
109
arm_dcc_putc(struct udevice * dev,char ch)110 static int arm_dcc_putc(struct udevice *dev, char ch)
111 {
112 register unsigned int reg;
113 unsigned int timeout_count = TIMEOUT_COUNT;
114
115 while (--timeout_count) {
116 can_write_dcc(reg);
117 if (reg)
118 break;
119 }
120 if (timeout_count == 0)
121 return -EAGAIN;
122 else
123 write_dcc(ch);
124
125 return 0;
126 }
127
arm_dcc_pending(struct udevice * dev,bool input)128 static int arm_dcc_pending(struct udevice *dev, bool input)
129 {
130 register unsigned int reg;
131
132 if (input) {
133 can_read_dcc(reg);
134 } else {
135 can_write_dcc(reg);
136 }
137
138 return reg;
139 }
140
141 static const struct dm_serial_ops arm_dcc_ops = {
142 .putc = arm_dcc_putc,
143 .pending = arm_dcc_pending,
144 .getc = arm_dcc_getc,
145 };
146
147 static const struct udevice_id arm_dcc_ids[] = {
148 { .compatible = "arm,dcc", },
149 { }
150 };
151
152 U_BOOT_DRIVER(serial_dcc) = {
153 .name = "arm_dcc",
154 .id = UCLASS_SERIAL,
155 .of_match = arm_dcc_ids,
156 .ops = &arm_dcc_ops,
157 };
158
159 #ifdef CONFIG_DEBUG_UART_ARM_DCC
160
161 #include <debug_uart.h>
162
_debug_uart_init(void)163 static inline void _debug_uart_init(void)
164 {
165 }
166
_debug_uart_putc(int ch)167 static inline void _debug_uart_putc(int ch)
168 {
169 arm_dcc_putc(NULL, ch);
170 }
171
172 DEBUG_UART_FUNCS
173 #endif
174