u-boot/arch/x86/cpu/sc520/sc520_ssi.c

/*
 * (C) Copyright 2002
 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
 *
 * 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 <asm/io.h>
#include <asm/arch/ssi.h>
#include <asm/arch/sc520.h>

int ssi_set_interface(int freq, int lsb_first, int inv_clock, int inv_phase)
{
	u8 temp = 0;

	if (freq >= 8192)
		temp |= CTL_CLK_SEL_4;
	else if (freq >= 4096)
		temp |= CTL_CLK_SEL_8;
	else if (freq >= 2048)
		temp |= CTL_CLK_SEL_16;
	else if (freq >= 1024)
		temp |= CTL_CLK_SEL_32;
	else if (freq >= 512)
		temp |= CTL_CLK_SEL_64;
	else if (freq >= 256)
		temp |= CTL_CLK_SEL_128;
	else if (freq >= 128)
		temp |= CTL_CLK_SEL_256;
	else
		temp |= CTL_CLK_SEL_512;

	if (!lsb_first)
		temp |= MSBF_ENB;

	if (inv_clock)
		temp |= CLK_INV_ENB;

	if (inv_phase)
		temp |= PHS_INV_ENB;

	writeb(temp, &sc520_mmcr->ssictl);

	return 0;
}

u8 ssi_txrx_byte(u8 data)
{
	writeb(data, &sc520_mmcr->ssixmit);
	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY)
		;
	writeb(SSICMD_CMD_SEL_XMITRCV, &sc520_mmcr->ssicmd);
	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY)
		;

	return readb(&sc520_mmcr->ssircv);
}

void ssi_tx_byte(u8 data)
{
	writeb(data, &sc520_mmcr->ssixmit);
	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY)
		;
	writeb(SSICMD_CMD_SEL_XMIT, &sc520_mmcr->ssicmd);
}

u8 ssi_rx_byte(void)
{
	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY)
		;
	writeb(SSICMD_CMD_SEL_RCV, &sc520_mmcr->ssicmd);
	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY)
		;

	return readb(&sc520_mmcr->ssircv);
}