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/*
* Copyright (C) 2005-2006 Atmel Corporation
*
* 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/sdram.h>
#include <asm/arch/clk.h>
#include <asm/arch/hardware.h>
#include "hsdramc1.h"
unsigned long sdram_init(void *sdram_base, const struct sdram_config *config)
{
unsigned long sdram_size;
uint32_t cfgreg;
unsigned int i;
cfgreg = (HSDRAMC1_BF(NC, config->col_bits - 8)
| HSDRAMC1_BF(NR, config->row_bits - 11)
| HSDRAMC1_BF(NB, config->bank_bits - 1)
| HSDRAMC1_BF(CAS, config->cas)
| HSDRAMC1_BF(TWR, config->twr)
| HSDRAMC1_BF(TRC, config->trc)
| HSDRAMC1_BF(TRP, config->trp)
| HSDRAMC1_BF(TRCD, config->trcd)
| HSDRAMC1_BF(TRAS, config->tras)
| HSDRAMC1_BF(TXSR, config->txsr));
if (config->data_bits == SDRAM_DATA_16BIT)
cfgreg |= HSDRAMC1_BIT(DBW);
hsdramc1_writel(CR, cfgreg);
/* Send a NOP to turn on the clock (necessary on some chips) */
hsdramc1_writel(MR, HSDRAMC1_MODE_NOP);
hsdramc1_readl(MR);
writel(0, sdram_base);
/*
* Initialization sequence for SDRAM, from the data sheet:
*
* 1. A minimum pause of 200 us is provided to precede any
* signal toggle.
*/
udelay(200);
/*
* 2. A Precharge All command is issued to the SDRAM
*/
hsdramc1_writel(MR, HSDRAMC1_MODE_BANKS_PRECHARGE);
hsdramc1_readl(MR);
writel(0, sdram_base);
/*
* 3. Eight auto-refresh (CBR) cycles are provided
*/
hsdramc1_writel(MR, HSDRAMC1_MODE_AUTO_REFRESH);
hsdramc1_readl(MR);
for (i = 0; i < 8; i++)
writel(0, sdram_base);
/*
* 4. A mode register set (MRS) cycle is issued to program
* SDRAM parameters, in particular CAS latency and burst
* length.
*
* The address will be chosen by the SDRAMC automatically; we
* just have to make sure BA[1:0] are set to 0.
*/
hsdramc1_writel(MR, HSDRAMC1_MODE_LOAD_MODE);
hsdramc1_readl(MR);
writel(0, sdram_base);
/*
* 5. The application must go into Normal Mode, setting Mode
* to 0 in the Mode Register and performing a write access
* at any location in the SDRAM.
*/
hsdramc1_writel(MR, HSDRAMC1_MODE_NORMAL);
hsdramc1_readl(MR);
writel(0, sdram_base);
/*
* 6. Write refresh rate into SDRAMC refresh timer count
* register (refresh rate = timing between refresh cycles).
*/
hsdramc1_writel(TR, config->refresh_period);
if (config->data_bits == SDRAM_DATA_16BIT)
sdram_size = 1 << (config->row_bits + config->col_bits
+ config->bank_bits + 1);
else
sdram_size = 1 << (config->row_bits + config->col_bits
+ config->bank_bits + 2);
return sdram_size;
}
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