1 /*
2 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 */
9
10 #include <dm.h>
11 #include <serial.h>
12 #include <asm/global_data.h>
13
14 DECLARE_GLOBAL_DATA_PTR;
15
16 struct arc_serial_regs {
17 unsigned int id0;
18 unsigned int id1;
19 unsigned int id2;
20 unsigned int id3;
21 unsigned int data;
22 unsigned int status;
23 unsigned int baudl;
24 unsigned int baudh;
25 };
26
27 struct arc_serial_plat {
28 struct arc_serial_regs *reg;
29 unsigned int uartclk;
30 };
31
32 /* Bit definitions of STATUS register */
33 #define UART_RXEMPTY (1 << 5)
34 #define UART_OVERFLOW_ERR (1 << 1)
35 #define UART_TXEMPTY (1 << 7)
36
arc_serial_setbrg(struct udevice * dev,int baudrate)37 static int arc_serial_setbrg(struct udevice *dev, int baudrate)
38 {
39 struct arc_serial_plat *plat = dev_get_plat(dev);
40 struct arc_serial_regs *const regs = plat->reg;
41 int arc_console_baud = gd->cpu_clk / (baudrate * 4) - 1;
42
43 writeb(arc_console_baud & 0xff, ®s->baudl);
44 writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh);
45
46 return 0;
47 }
48
arc_serial_putc(struct udevice * dev,const char c)49 static int arc_serial_putc(struct udevice *dev, const char c)
50 {
51 struct arc_serial_plat *plat = dev_get_plat(dev);
52 struct arc_serial_regs *const regs = plat->reg;
53
54 if (!(readb(®s->status) & UART_TXEMPTY))
55 return -EAGAIN;
56
57 writeb(c, ®s->data);
58
59 return 0;
60 }
61
arc_serial_tstc(struct arc_serial_regs * const regs)62 static int arc_serial_tstc(struct arc_serial_regs *const regs)
63 {
64 return !(readb(®s->status) & UART_RXEMPTY);
65 }
66
arc_serial_pending(struct udevice * dev,bool input)67 static int arc_serial_pending(struct udevice *dev, bool input)
68 {
69 struct arc_serial_plat *plat = dev_get_plat(dev);
70 struct arc_serial_regs *const regs = plat->reg;
71 uint32_t status = readb(®s->status);
72
73 if (input)
74 return status & UART_RXEMPTY ? 0 : 1;
75 else
76 return status & UART_TXEMPTY ? 0 : 1;
77 }
78
arc_serial_getc(struct udevice * dev)79 static int arc_serial_getc(struct udevice *dev)
80 {
81 struct arc_serial_plat *plat = dev_get_plat(dev);
82 struct arc_serial_regs *const regs = plat->reg;
83
84 if (!arc_serial_tstc(regs))
85 return -EAGAIN;
86
87 /* Check for overflow errors */
88 if (readb(®s->status) & UART_OVERFLOW_ERR)
89 return 0;
90
91 return readb(®s->data) & 0xFF;
92 }
93
arc_serial_probe(struct udevice * dev)94 static int arc_serial_probe(struct udevice *dev)
95 {
96 return 0;
97 }
98
99 static const struct dm_serial_ops arc_serial_ops = {
100 .putc = arc_serial_putc,
101 .pending = arc_serial_pending,
102 .getc = arc_serial_getc,
103 .setbrg = arc_serial_setbrg,
104 };
105
106 static const struct udevice_id arc_serial_ids[] = {
107 { .compatible = "snps,arc-uart" },
108 { }
109 };
110
arc_serial_of_to_plat(struct udevice * dev)111 static int arc_serial_of_to_plat(struct udevice *dev)
112 {
113 struct arc_serial_plat *plat = dev_get_plat(dev);
114 DECLARE_GLOBAL_DATA_PTR;
115
116 plat->reg = dev_read_addr_ptr(dev);
117 plat->uartclk = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
118 "clock-frequency", 0);
119
120 return 0;
121 }
122
123 U_BOOT_DRIVER(serial_arc) = {
124 .name = "serial_arc",
125 .id = UCLASS_SERIAL,
126 .of_match = arc_serial_ids,
127 .of_to_plat = arc_serial_of_to_plat,
128 .plat_auto = sizeof(struct arc_serial_plat),
129 .probe = arc_serial_probe,
130 .ops = &arc_serial_ops,
131 };
132
133 #ifdef CONFIG_DEBUG_ARC_SERIAL
134 #include <debug_uart.h>
135
_debug_uart_init(void)136 static inline void _debug_uart_init(void)
137 {
138 struct arc_serial_regs *regs = (struct arc_serial_regs *)CONFIG_VAL(DEBUG_UART_BASE);
139 int arc_console_baud = CONFIG_DEBUG_UART_CLOCK / (CONFIG_BAUDRATE * 4) - 1;
140
141 writeb(arc_console_baud & 0xff, ®s->baudl);
142 writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh);
143 }
144
_debug_uart_putc(int c)145 static inline void _debug_uart_putc(int c)
146 {
147 struct arc_serial_regs *regs = (struct arc_serial_regs *)CONFIG_VAL(DEBUG_UART_BASE);
148
149 while (!(readb(®s->status) & UART_TXEMPTY))
150 ;
151
152 writeb(c, ®s->data);
153 }
154
155 DEBUG_UART_FUNCS
156
157 #endif
158