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 <common.h>
19 #include <dm.h>
20 #include <serial.h>
21
22 #if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V7A) || defined(CONFIG_CPU_V7R)
23 /*
24 * ARMV6 & ARMV7
25 */
26 #define DCC_RBIT (1 << 30)
27 #define DCC_WBIT (1 << 29)
28
29 #define write_dcc(x) \
30 __asm__ volatile ("mcr p14, 0, %0, c0, c5, 0\n" : : "r" (x))
31
32 #define read_dcc(x) \
33 __asm__ volatile ("mrc p14, 0, %0, c0, c5, 0\n" : "=r" (x))
34
35 #define status_dcc(x) \
36 __asm__ volatile ("mrc p14, 0, %0, c0, c1, 0\n" : "=r" (x))
37
38 #elif defined(CONFIG_CPU_XSCALE)
39 /*
40 * XSCALE
41 */
42 #define DCC_RBIT (1 << 31)
43 #define DCC_WBIT (1 << 28)
44
45 #define write_dcc(x) \
46 __asm__ volatile ("mcr p14, 0, %0, c8, c0, 0\n" : : "r" (x))
47
48 #define read_dcc(x) \
49 __asm__ volatile ("mrc p14, 0, %0, c9, c0, 0\n" : "=r" (x))
50
51 #define status_dcc(x) \
52 __asm__ volatile ("mrc p14, 0, %0, c14, c0, 0\n" : "=r" (x))
53
54 #elif defined(CONFIG_CPU_ARMV8)
55 /*
56 * ARMV8
57 */
58 #define DCC_RBIT (1 << 30)
59 #define DCC_WBIT (1 << 29)
60
61 #define write_dcc(x) \
62 __asm__ volatile ("msr dbgdtrtx_el0, %0\n" : : "r" (x))
63
64 #define read_dcc(x) \
65 __asm__ volatile ("mrs %0, dbgdtrrx_el0\n" : "=r" (x))
66
67 #define status_dcc(x) \
68 __asm__ volatile ("mrs %0, mdccsr_el0\n" : "=r" (x))
69
70 #else
71 #define DCC_RBIT (1 << 0)
72 #define DCC_WBIT (1 << 1)
73
74 #define write_dcc(x) \
75 __asm__ volatile ("mcr p14, 0, %0, c1, c0, 0\n" : : "r" (x))
76
77 #define read_dcc(x) \
78 __asm__ volatile ("mrc p14, 0, %0, c1, c0, 0\n" : "=r" (x))
79
80 #define status_dcc(x) \
81 __asm__ volatile ("mrc p14, 0, %0, c0, c0, 0\n" : "=r" (x))
82
83 #endif
84
85 #define can_read_dcc(x) do { \
86 status_dcc(x); \
87 x &= DCC_RBIT; \
88 } while (0);
89
90 #define can_write_dcc(x) do { \
91 status_dcc(x); \
92 x &= DCC_WBIT; \
93 x = (x == 0); \
94 } while (0);
95
96 #define TIMEOUT_COUNT 0x4000000
97
arm_dcc_getc(struct udevice * dev)98 static int arm_dcc_getc(struct udevice *dev)
99 {
100 int ch;
101 register unsigned int reg;
102
103 do {
104 can_read_dcc(reg);
105 } while (!reg);
106 read_dcc(ch);
107
108 return ch;
109 }
110
arm_dcc_putc(struct udevice * dev,char ch)111 static int arm_dcc_putc(struct udevice *dev, char ch)
112 {
113 register unsigned int reg;
114 unsigned int timeout_count = TIMEOUT_COUNT;
115
116 while (--timeout_count) {
117 can_write_dcc(reg);
118 if (reg)
119 break;
120 }
121 if (timeout_count == 0)
122 return -EAGAIN;
123 else
124 write_dcc(ch);
125
126 return 0;
127 }
128
arm_dcc_pending(struct udevice * dev,bool input)129 static int arm_dcc_pending(struct udevice *dev, bool input)
130 {
131 register unsigned int reg;
132
133 if (input) {
134 can_read_dcc(reg);
135 } else {
136 can_write_dcc(reg);
137 }
138
139 return reg;
140 }
141
142 static const struct dm_serial_ops arm_dcc_ops = {
143 .putc = arm_dcc_putc,
144 .pending = arm_dcc_pending,
145 .getc = arm_dcc_getc,
146 };
147
148 static const struct udevice_id arm_dcc_ids[] = {
149 { .compatible = "arm,dcc", },
150 { }
151 };
152
153 U_BOOT_DRIVER(serial_dcc) = {
154 .name = "arm_dcc",
155 .id = UCLASS_SERIAL,
156 .of_match = arm_dcc_ids,
157 .ops = &arm_dcc_ops,
158 };
159
160 #ifdef CONFIG_DEBUG_UART_ARM_DCC
161
162 #include <debug_uart.h>
163
_debug_uart_init(void)164 static inline void _debug_uart_init(void)
165 {
166 }
167
_debug_uart_putc(int ch)168 static inline void _debug_uart_putc(int ch)
169 {
170 arm_dcc_putc(NULL, ch);
171 }
172
173 DEBUG_UART_FUNCS
174 #endif
175