1/*
2 * The platform specific code for virtex devices since a boot loader is not
3 * always used.
4 *
5 * (C) Copyright 2008 Xilinx, Inc.
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published
9 * by the Free Software Foundation.
10 */
11
12#include "ops.h"
13#include "io.h"
14#include "stdio.h"
15
16#define UART_DLL		0	/* Out: Divisor Latch Low */
17#define UART_DLM		1	/* Out: Divisor Latch High */
18#define UART_FCR		2	/* Out: FIFO Control Register */
19#define UART_FCR_CLEAR_RCVR 	0x02 	/* Clear the RCVR FIFO */
20#define UART_FCR_CLEAR_XMIT	0x04 	/* Clear the XMIT FIFO */
21#define UART_LCR		3	/* Out: Line Control Register */
22#define UART_MCR		4	/* Out: Modem Control Register */
23#define UART_MCR_RTS		0x02 	/* RTS complement */
24#define UART_MCR_DTR		0x01 	/* DTR complement */
25#define UART_LCR_DLAB		0x80 	/* Divisor latch access bit */
26#define UART_LCR_WLEN8		0x03 	/* Wordlength: 8 bits */
27
28static int virtex_ns16550_console_init(void *devp)
29{
30	unsigned char *reg_base;
31	u32 reg_shift, reg_offset, clk, spd;
32	u16 divisor;
33	int n;
34
35	if (dt_get_virtual_reg(devp, (void **)&reg_base, 1) < 1)
36		return -1;
37
38	n = getprop(devp, "reg-offset", &reg_offset, sizeof(reg_offset));
39	if (n == sizeof(reg_offset))
40		reg_base += reg_offset;
41
42	n = getprop(devp, "reg-shift", &reg_shift, sizeof(reg_shift));
43	if (n != sizeof(reg_shift))
44		reg_shift = 0;
45
46	n = getprop(devp, "current-speed", (void *)&spd, sizeof(spd));
47	if (n != sizeof(spd))
48		spd = 9600;
49
50	/* should there be a default clock rate?*/
51	n = getprop(devp, "clock-frequency", (void *)&clk, sizeof(clk));
52	if (n != sizeof(clk))
53		return -1;
54
55	divisor = clk / (16 * spd);
56
57	/* Access baud rate */
58	out_8(reg_base + (UART_LCR << reg_shift), UART_LCR_DLAB);
59
60	/* Baud rate based on input clock */
61	out_8(reg_base + (UART_DLL << reg_shift), divisor & 0xFF);
62	out_8(reg_base + (UART_DLM << reg_shift), divisor >> 8);
63
64	/* 8 data, 1 stop, no parity */
65	out_8(reg_base + (UART_LCR << reg_shift), UART_LCR_WLEN8);
66
67	/* RTS/DTR */
68	out_8(reg_base + (UART_MCR << reg_shift), UART_MCR_RTS | UART_MCR_DTR);
69
70	/* Clear transmitter and receiver */
71	out_8(reg_base + (UART_FCR << reg_shift),
72				UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
73	return 0;
74}
75
76/* For virtex, the kernel may be loaded without using a bootloader and if so
77   some UARTs need more setup than is provided in the normal console init
78*/
79int platform_specific_init(void)
80{
81	void *devp;
82	char devtype[MAX_PROP_LEN];
83	char path[MAX_PATH_LEN];
84
85	devp = finddevice("/chosen");
86	if (devp == NULL)
87		return -1;
88
89	if (getprop(devp, "linux,stdout-path", path, MAX_PATH_LEN) > 0) {
90		devp = finddevice(path);
91		if (devp == NULL)
92			return -1;
93
94		if ((getprop(devp, "device_type", devtype, sizeof(devtype)) > 0)
95				&& !strcmp(devtype, "serial")
96				&& (dt_is_compatible(devp, "ns16550")))
97				virtex_ns16550_console_init(devp);
98	}
99	return 0;
100}
101