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}