1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
4  * Scott McNutt <smcnutt@psyent.com>
5  */
6 
7 #include <common.h>
8 #include <dm.h>
9 #include <errno.h>
10 #include <serial.h>
11 #include <asm/io.h>
12 
13 /* data register */
14 #define ALTERA_JTAG_RVALID	BIT(15)	/* Read valid */
15 
16 /* control register */
17 #define ALTERA_JTAG_AC		BIT(10)	/* activity indicator */
18 #define ALTERA_JTAG_RRDY	BIT(12)	/* read available */
19 #define ALTERA_JTAG_WSPACE(d)	((d) >> 16)	/* Write space avail */
20 /* Write fifo size. FIXME: this should be extracted with sopc2dts */
21 #define ALTERA_JTAG_WRITE_DEPTH	64
22 
23 struct altera_jtaguart_regs {
24 	u32	data;			/* Data register */
25 	u32	control;		/* Control register */
26 };
27 
28 struct altera_jtaguart_platdata {
29 	struct altera_jtaguart_regs *regs;
30 };
31 
32 static int altera_jtaguart_setbrg(struct udevice *dev, int baudrate)
33 {
34 	return 0;
35 }
36 
37 static int altera_jtaguart_putc(struct udevice *dev, const char ch)
38 {
39 	struct altera_jtaguart_platdata *plat = dev->platdata;
40 	struct altera_jtaguart_regs *const regs = plat->regs;
41 	u32 st = readl(&regs->control);
42 
43 #ifdef CONFIG_ALTERA_JTAG_UART_BYPASS
44 	if (!(st & ALTERA_JTAG_AC)) /* no connection yet */
45 		return -ENETUNREACH;
46 #endif
47 
48 	if (ALTERA_JTAG_WSPACE(st) == 0)
49 		return -EAGAIN;
50 
51 	writel(ch, &regs->data);
52 
53 	return 0;
54 }
55 
56 static int altera_jtaguart_pending(struct udevice *dev, bool input)
57 {
58 	struct altera_jtaguart_platdata *plat = dev->platdata;
59 	struct altera_jtaguart_regs *const regs = plat->regs;
60 	u32 st = readl(&regs->control);
61 
62 	if (input)
63 		return st & ALTERA_JTAG_RRDY ? 1 : 0;
64 	else
65 		return !(ALTERA_JTAG_WSPACE(st) == ALTERA_JTAG_WRITE_DEPTH);
66 }
67 
68 static int altera_jtaguart_getc(struct udevice *dev)
69 {
70 	struct altera_jtaguart_platdata *plat = dev->platdata;
71 	struct altera_jtaguart_regs *const regs = plat->regs;
72 	u32 val;
73 
74 	val = readl(&regs->data);
75 
76 	if (!(val & ALTERA_JTAG_RVALID))
77 		return -EAGAIN;
78 
79 	return val & 0xff;
80 }
81 
82 static int altera_jtaguart_probe(struct udevice *dev)
83 {
84 #ifdef CONFIG_ALTERA_JTAG_UART_BYPASS
85 	struct altera_jtaguart_platdata *plat = dev->platdata;
86 	struct altera_jtaguart_regs *const regs = plat->regs;
87 
88 	writel(ALTERA_JTAG_AC, &regs->control); /* clear AC flag */
89 #endif
90 	return 0;
91 }
92 
93 static int altera_jtaguart_ofdata_to_platdata(struct udevice *dev)
94 {
95 	struct altera_jtaguart_platdata *plat = dev_get_platdata(dev);
96 
97 	plat->regs = map_physmem(devfdt_get_addr(dev),
98 				 sizeof(struct altera_jtaguart_regs),
99 				 MAP_NOCACHE);
100 
101 	return 0;
102 }
103 
104 static const struct dm_serial_ops altera_jtaguart_ops = {
105 	.putc = altera_jtaguart_putc,
106 	.pending = altera_jtaguart_pending,
107 	.getc = altera_jtaguart_getc,
108 	.setbrg = altera_jtaguart_setbrg,
109 };
110 
111 static const struct udevice_id altera_jtaguart_ids[] = {
112 	{ .compatible = "altr,juart-1.0" },
113 	{}
114 };
115 
116 U_BOOT_DRIVER(altera_jtaguart) = {
117 	.name	= "altera_jtaguart",
118 	.id	= UCLASS_SERIAL,
119 	.of_match = altera_jtaguart_ids,
120 	.ofdata_to_platdata = altera_jtaguart_ofdata_to_platdata,
121 	.platdata_auto_alloc_size = sizeof(struct altera_jtaguart_platdata),
122 	.probe = altera_jtaguart_probe,
123 	.ops	= &altera_jtaguart_ops,
124 };
125 
126 #ifdef CONFIG_DEBUG_UART_ALTERA_JTAGUART
127 
128 #include <debug_uart.h>
129 
130 static inline void _debug_uart_init(void)
131 {
132 }
133 
134 static inline void _debug_uart_putc(int ch)
135 {
136 	struct altera_jtaguart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
137 
138 	while (1) {
139 		u32 st = readl(&regs->control);
140 
141 		if (ALTERA_JTAG_WSPACE(st))
142 			break;
143 	}
144 
145 	writel(ch, &regs->data);
146 }
147 
148 DEBUG_UART_FUNCS
149 
150 #endif
151