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 <common.h>
11 #include <dm.h>
12 #include <serial.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
28 struct arc_serial_platdata {
29 struct arc_serial_regs *reg;
30 unsigned int uartclk;
31 };
32
33 /* Bit definitions of STATUS register */
34 #define UART_RXEMPTY (1 << 5)
35 #define UART_OVERFLOW_ERR (1 << 1)
36 #define UART_TXEMPTY (1 << 7)
37
arc_serial_setbrg(struct udevice * dev,int baudrate)38 static int arc_serial_setbrg(struct udevice *dev, int baudrate)
39 {
40 struct arc_serial_platdata *plat = dev->platdata;
41 struct arc_serial_regs *const regs = plat->reg;
42 int arc_console_baud = gd->cpu_clk / (baudrate * 4) - 1;
43
44 writeb(arc_console_baud & 0xff, ®s->baudl);
45 writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh);
46
47 return 0;
48 }
49
arc_serial_putc(struct udevice * dev,const char c)50 static int arc_serial_putc(struct udevice *dev, const char c)
51 {
52 struct arc_serial_platdata *plat = dev->platdata;
53 struct arc_serial_regs *const regs = plat->reg;
54
55 while (!(readb(®s->status) & UART_TXEMPTY))
56 ;
57
58 writeb(c, ®s->data);
59
60 return 0;
61 }
62
arc_serial_tstc(struct arc_serial_regs * const regs)63 static int arc_serial_tstc(struct arc_serial_regs *const regs)
64 {
65 return !(readb(®s->status) & UART_RXEMPTY);
66 }
67
arc_serial_pending(struct udevice * dev,bool input)68 static int arc_serial_pending(struct udevice *dev, bool input)
69 {
70 struct arc_serial_platdata *plat = dev->platdata;
71 struct arc_serial_regs *const regs = plat->reg;
72 uint32_t status = readb(®s->status);
73
74 if (input)
75 return status & UART_RXEMPTY ? 0 : 1;
76 else
77 return status & UART_TXEMPTY ? 0 : 1;
78 }
79
arc_serial_getc(struct udevice * dev)80 static int arc_serial_getc(struct udevice *dev)
81 {
82 struct arc_serial_platdata *plat = dev->platdata;
83 struct arc_serial_regs *const regs = plat->reg;
84
85 while (!arc_serial_tstc(regs))
86 ;
87
88 /* Check for overflow errors */
89 if (readb(®s->status) & UART_OVERFLOW_ERR)
90 return 0;
91
92 return readb(®s->data) & 0xFF;
93 }
94
arc_serial_probe(struct udevice * dev)95 static int arc_serial_probe(struct udevice *dev)
96 {
97 return 0;
98 }
99
100 static const struct dm_serial_ops arc_serial_ops = {
101 .putc = arc_serial_putc,
102 .pending = arc_serial_pending,
103 .getc = arc_serial_getc,
104 .setbrg = arc_serial_setbrg,
105 };
106
107 static const struct udevice_id arc_serial_ids[] = {
108 { .compatible = "snps,arc-uart" },
109 { }
110 };
111
arc_serial_ofdata_to_platdata(struct udevice * dev)112 static int arc_serial_ofdata_to_platdata(struct udevice *dev)
113 {
114 struct arc_serial_platdata *plat = dev_get_platdata(dev);
115 DECLARE_GLOBAL_DATA_PTR;
116
117 plat->reg = (struct arc_serial_regs *)devfdt_get_addr(dev);
118 plat->uartclk = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
119 "clock-frequency", 0);
120
121 return 0;
122 }
123
124 U_BOOT_DRIVER(serial_arc) = {
125 .name = "serial_arc",
126 .id = UCLASS_SERIAL,
127 .of_match = arc_serial_ids,
128 .ofdata_to_platdata = arc_serial_ofdata_to_platdata,
129 .platdata_auto_alloc_size = sizeof(struct arc_serial_platdata),
130 .probe = arc_serial_probe,
131 .ops = &arc_serial_ops,
132 };
133
134 #ifdef CONFIG_DEBUG_ARC_SERIAL
135 #include <debug_uart.h>
136
_debug_uart_init(void)137 static inline void _debug_uart_init(void)
138 {
139 struct arc_serial_regs *regs = (struct arc_serial_regs *)CONFIG_DEBUG_UART_BASE;
140 int arc_console_baud = CONFIG_DEBUG_UART_CLOCK / (CONFIG_BAUDRATE * 4) - 1;
141
142 writeb(arc_console_baud & 0xff, ®s->baudl);
143 writeb((arc_console_baud & 0xff00) >> 8, ®s->baudh);
144 }
145
_debug_uart_putc(int c)146 static inline void _debug_uart_putc(int c)
147 {
148 struct arc_serial_regs *regs = (struct arc_serial_regs *)CONFIG_DEBUG_UART_BASE;
149
150 while (!(readb(®s->status) & UART_TXEMPTY))
151 ;
152
153 writeb(c, ®s->data);
154 }
155
156 DEBUG_UART_FUNCS
157
158 #endif
159