aboutsummaryrefslogtreecommitdiff
path: root/drivers/serial/serial_zynq.c
blob: 38322367b42981da0b9e3b36cea54c3009f85763 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
/*
 * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <watchdog.h>
#include <asm/io.h>
#include <linux/compiler.h>
#include <serial.h>

#define ZYNQ_UART_SR_TXFULL	0x00000010 /* TX FIFO full */
#define ZYNQ_UART_SR_RXEMPTY	0x00000002 /* RX FIFO empty */

#define ZYNQ_UART_CR_TX_EN	0x00000010 /* TX enabled */
#define ZYNQ_UART_CR_RX_EN	0x00000004 /* RX enabled */
#define ZYNQ_UART_CR_TXRST	0x00000002 /* TX logic reset */
#define ZYNQ_UART_CR_RXRST	0x00000001 /* RX logic reset */

#define ZYNQ_UART_MR_PARITY_NONE	0x00000020  /* No parity mode */

/* Some clock/baud constants */
#define ZYNQ_UART_BDIV	15 /* Default/reset BDIV value */
#define ZYNQ_UART_BASECLK	3125000L /* master / (bdiv + 1) */

struct uart_zynq {
	u32 control; /* Control Register [8:0] */
	u32 mode; /* Mode Register [10:0] */
	u32 reserved1[4];
	u32 baud_rate_gen; /* Baud Rate Generator [15:0] */
	u32 reserved2[4];
	u32 channel_sts; /* Channel Status [11:0] */
	u32 tx_rx_fifo; /* FIFO [15:0] or [7:0] */
	u32 baud_rate_divider; /* Baud Rate Divider [7:0] */
};

static struct uart_zynq *uart_zynq_ports[2] = {
#ifdef CONFIG_ZYNQ_SERIAL_BASEADDR0
	[0] = (struct uart_zynq *)CONFIG_ZYNQ_SERIAL_BASEADDR0,
#endif
#ifdef CONFIG_ZYNQ_SERIAL_BASEADDR1
	[1] = (struct uart_zynq *)CONFIG_ZYNQ_SERIAL_BASEADDR1,
#endif
};

struct uart_zynq_params {
	u32 baudrate;
	u32 clock;
};

static struct uart_zynq_params uart_zynq_ports_param[2] = {
#if defined(CONFIG_ZYNQ_SERIAL_BAUDRATE0) && defined(CONFIG_ZYNQ_SERIAL_CLOCK0)
	[0].baudrate = CONFIG_ZYNQ_SERIAL_BAUDRATE0,
	[0].clock = CONFIG_ZYNQ_SERIAL_CLOCK0,
#endif
#if defined(CONFIG_ZYNQ_SERIAL_BAUDRATE1) && defined(CONFIG_ZYNQ_SERIAL_CLOCK1)
	[1].baudrate = CONFIG_ZYNQ_SERIAL_BAUDRATE1,
	[1].clock = CONFIG_ZYNQ_SERIAL_CLOCK1,
#endif
};

/* Set up the baud rate in gd struct */
static void uart_zynq_serial_setbrg(const int port)
{
	/* Calculation results. */
	unsigned int calc_bauderror, bdiv, bgen;
	unsigned long calc_baud = 0;
	unsigned long baud = uart_zynq_ports_param[port].baudrate;
	unsigned long clock = uart_zynq_ports_param[port].clock;
	struct uart_zynq *regs = uart_zynq_ports[port];

	/*                master clock
	 * Baud rate = ------------------
	 *              bgen * (bdiv + 1)
	 *
	 * Find acceptable values for baud generation.
	 */
	for (bdiv = 4; bdiv < 255; bdiv++) {
		bgen = clock / (baud * (bdiv + 1));
		if (bgen < 2 || bgen > 65535)
			continue;

		calc_baud = clock / (bgen * (bdiv + 1));

		/*
		 * Use first calculated baudrate with
		 * an acceptable (<3%) error
		 */
		if (baud > calc_baud)
			calc_bauderror = baud - calc_baud;
		else
			calc_bauderror = calc_baud - baud;
		if (((calc_bauderror * 100) / baud) < 3)
			break;
	}

	writel(bdiv, &regs->baud_rate_divider);
	writel(bgen, &regs->baud_rate_gen);
}

/* Initialize the UART, with...some settings. */
static int uart_zynq_serial_init(const int port)
{
	struct uart_zynq *regs = uart_zynq_ports[port];

	if (!regs)
		return -1;

	/* RX/TX enabled & reset */
	writel(ZYNQ_UART_CR_TX_EN | ZYNQ_UART_CR_RX_EN | ZYNQ_UART_CR_TXRST | \
					ZYNQ_UART_CR_RXRST, &regs->control);
	writel(ZYNQ_UART_MR_PARITY_NONE, &regs->mode); /* 8 bit, no parity */
	uart_zynq_serial_setbrg(port);

	return 0;
}

static void uart_zynq_serial_putc(const char c, const int port)
{
	struct uart_zynq *regs = uart_zynq_ports[port];

	while ((readl(&regs->channel_sts) & ZYNQ_UART_SR_TXFULL) != 0)
		WATCHDOG_RESET();

	if (c == '\n') {
		writel('\r', &regs->tx_rx_fifo);
		while ((readl(&regs->channel_sts) & ZYNQ_UART_SR_TXFULL) != 0)
			WATCHDOG_RESET();
	}
	writel(c, &regs->tx_rx_fifo);
}

static void uart_zynq_serial_puts(const char *s, const int port)
{
	while (*s)
		uart_zynq_serial_putc(*s++, port);
}

static int uart_zynq_serial_tstc(const int port)
{
	struct uart_zynq *regs = uart_zynq_ports[port];

	return (readl(&regs->channel_sts) & ZYNQ_UART_SR_RXEMPTY) == 0;
}

static int uart_zynq_serial_getc(const int port)
{
	struct uart_zynq *regs = uart_zynq_ports[port];

	while (!uart_zynq_serial_tstc(port))
		WATCHDOG_RESET();
	return readl(&regs->tx_rx_fifo);
}

#if !defined(CONFIG_SERIAL_MULTI)
int serial_init(void)
{
	return uart_zynq_serial_init(0);
}

void serial_setbrg(void)
{
	uart_zynq_serial_setbrg(0);
}

void serial_putc(const char c)
{
	uart_zynq_serial_putc(c, 0);
}

void serial_puts(const char *s)
{
	uart_zynq_serial_puts(s, 0);
}

int serial_getc(void)
{
	return uart_zynq_serial_getc(0);
}

int serial_tstc(void)
{
	return uart_zynq_serial_tstc(0);
}
#else
/* Multi serial device functions */
#define DECLARE_PSSERIAL_FUNCTIONS(port) \
	int uart_zynq##port##_init(void) \
				{ return uart_zynq_serial_init(port); } \
	void uart_zynq##port##_setbrg(void) \
				{ return uart_zynq_serial_setbrg(port); } \
	int uart_zynq##port##_getc(void) \
				{ return uart_zynq_serial_getc(port); } \
	int uart_zynq##port##_tstc(void) \
				{ return uart_zynq_serial_tstc(port); } \
	void uart_zynq##port##_putc(const char c) \
				{ uart_zynq_serial_putc(c, port); } \
	void uart_zynq##port##_puts(const char *s) \
				{ uart_zynq_serial_puts(s, port); }

/* Serial device descriptor */
#define INIT_PSSERIAL_STRUCTURE(port, __name) {	\
	  .name   = __name,			\
	  .init   = uart_zynq##port##_init,	\
	  .uninit = NULL,			\
	  .setbrg = uart_zynq##port##_setbrg,	\
	  .getc   = uart_zynq##port##_getc,	\
	  .tstc   = uart_zynq##port##_tstc,	\
	  .putc   = uart_zynq##port##_putc,	\
	  .puts   = uart_zynq##port##_puts,	\
}

DECLARE_PSSERIAL_FUNCTIONS(0);
struct serial_device uart_zynq_serial0_device =
	INIT_PSSERIAL_STRUCTURE(0, "ttyPS0");
DECLARE_PSSERIAL_FUNCTIONS(1);
struct serial_device uart_zynq_serial1_device =
	INIT_PSSERIAL_STRUCTURE(1, "ttyPS1");

__weak struct serial_device *default_serial_console(void)
{
	if (uart_zynq_ports[0])
		return &uart_zynq_serial0_device;
	if (uart_zynq_ports[1])
		return &uart_zynq_serial1_device;

	return NULL;
}
#endif