xref: /openbmc/u-boot/drivers/serial/altera_uart.c (revision 1d6edcbf)
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 DECLARE_GLOBAL_DATA_PTR;
14 
15 /* status register */
16 #define ALTERA_UART_TMT		BIT(5)	/* tx empty */
17 #define ALTERA_UART_TRDY	BIT(6)	/* tx ready */
18 #define ALTERA_UART_RRDY	BIT(7)	/* rx ready */
19 
20 struct altera_uart_regs {
21 	u32	rxdata;		/* Rx data reg */
22 	u32	txdata;		/* Tx data reg */
23 	u32	status;		/* Status reg */
24 	u32	control;	/* Control reg */
25 	u32	divisor;	/* Baud rate divisor reg */
26 	u32	endofpacket;	/* End-of-packet reg */
27 };
28 
29 struct altera_uart_platdata {
30 	struct altera_uart_regs *regs;
31 	unsigned int uartclk;
32 };
33 
altera_uart_setbrg(struct udevice * dev,int baudrate)34 static int altera_uart_setbrg(struct udevice *dev, int baudrate)
35 {
36 	struct altera_uart_platdata *plat = dev->platdata;
37 	struct altera_uart_regs *const regs = plat->regs;
38 	u32 div;
39 
40 	div = (plat->uartclk / baudrate) - 1;
41 	writel(div, &regs->divisor);
42 
43 	return 0;
44 }
45 
altera_uart_putc(struct udevice * dev,const char ch)46 static int altera_uart_putc(struct udevice *dev, const char ch)
47 {
48 	struct altera_uart_platdata *plat = dev->platdata;
49 	struct altera_uart_regs *const regs = plat->regs;
50 
51 	if (!(readl(&regs->status) & ALTERA_UART_TRDY))
52 		return -EAGAIN;
53 
54 	writel(ch, &regs->txdata);
55 
56 	return 0;
57 }
58 
altera_uart_pending(struct udevice * dev,bool input)59 static int altera_uart_pending(struct udevice *dev, bool input)
60 {
61 	struct altera_uart_platdata *plat = dev->platdata;
62 	struct altera_uart_regs *const regs = plat->regs;
63 	u32 st = readl(&regs->status);
64 
65 	if (input)
66 		return st & ALTERA_UART_RRDY ? 1 : 0;
67 	else
68 		return !(st & ALTERA_UART_TMT);
69 }
70 
altera_uart_getc(struct udevice * dev)71 static int altera_uart_getc(struct udevice *dev)
72 {
73 	struct altera_uart_platdata *plat = dev->platdata;
74 	struct altera_uart_regs *const regs = plat->regs;
75 
76 	if (!(readl(&regs->status) & ALTERA_UART_RRDY))
77 		return -EAGAIN;
78 
79 	return readl(&regs->rxdata) & 0xff;
80 }
81 
altera_uart_probe(struct udevice * dev)82 static int altera_uart_probe(struct udevice *dev)
83 {
84 	return 0;
85 }
86 
altera_uart_ofdata_to_platdata(struct udevice * dev)87 static int altera_uart_ofdata_to_platdata(struct udevice *dev)
88 {
89 	struct altera_uart_platdata *plat = dev_get_platdata(dev);
90 
91 	plat->regs = map_physmem(devfdt_get_addr(dev),
92 				 sizeof(struct altera_uart_regs),
93 				 MAP_NOCACHE);
94 	plat->uartclk = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
95 		"clock-frequency", 0);
96 
97 	return 0;
98 }
99 
100 static const struct dm_serial_ops altera_uart_ops = {
101 	.putc = altera_uart_putc,
102 	.pending = altera_uart_pending,
103 	.getc = altera_uart_getc,
104 	.setbrg = altera_uart_setbrg,
105 };
106 
107 static const struct udevice_id altera_uart_ids[] = {
108 	{ .compatible = "altr,uart-1.0" },
109 	{}
110 };
111 
112 U_BOOT_DRIVER(altera_uart) = {
113 	.name	= "altera_uart",
114 	.id	= UCLASS_SERIAL,
115 	.of_match = altera_uart_ids,
116 	.ofdata_to_platdata = altera_uart_ofdata_to_platdata,
117 	.platdata_auto_alloc_size = sizeof(struct altera_uart_platdata),
118 	.probe = altera_uart_probe,
119 	.ops	= &altera_uart_ops,
120 };
121 
122 #ifdef CONFIG_DEBUG_UART_ALTERA_UART
123 
124 #include <debug_uart.h>
125 
_debug_uart_init(void)126 static inline void _debug_uart_init(void)
127 {
128 	struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
129 	u32 div;
130 
131 	div = (CONFIG_DEBUG_UART_CLOCK / CONFIG_BAUDRATE) - 1;
132 	writel(div, &regs->divisor);
133 }
134 
_debug_uart_putc(int ch)135 static inline void _debug_uart_putc(int ch)
136 {
137 	struct altera_uart_regs *regs = (void *)CONFIG_DEBUG_UART_BASE;
138 
139 	while (1) {
140 		u32 st = readl(&regs->status);
141 
142 		if (st & ALTERA_UART_TRDY)
143 			break;
144 	}
145 
146 	writel(ch, &regs->txdata);
147 }
148 
149 DEBUG_UART_FUNCS
150 
151 #endif
152