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d38da53794
The existing code assumes the SDRAM row refresh period should always be 15.6 us. This is not always true, and indeed on the ATNGW100, the refresh rate should really be 7.81 us. Add a refresh_period member to struct sdram_info and initialize it properly for both ATSTK1000 and ATNGW100. Out-of-tree boards will panic() until the refresh_period member is updated properly. Big thanks to Gerhard Berghofer for pointing out this issue. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
144 lines
3.8 KiB
C
144 lines
3.8 KiB
C
/*
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* Copyright (C) 2005-2006 Atmel Corporation
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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#ifdef CFG_HSDRAMC
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#include <asm/io.h>
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#include <asm/sdram.h>
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#include <asm/arch/clk.h>
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#include <asm/arch/memory-map.h>
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#include "hsdramc1.h"
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unsigned long sdram_init(const struct sdram_info *info)
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{
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unsigned long *sdram = (unsigned long *)uncached(info->phys_addr);
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unsigned long sdram_size;
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unsigned long tmp;
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unsigned long bus_hz;
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unsigned int i;
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if (!info->refresh_period)
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panic("ERROR: SDRAM refresh period == 0. "
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"Please update the board code\n");
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tmp = (HSDRAMC1_BF(NC, info->col_bits - 8)
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| HSDRAMC1_BF(NR, info->row_bits - 11)
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| HSDRAMC1_BF(NB, info->bank_bits - 1)
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| HSDRAMC1_BF(CAS, info->cas)
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| HSDRAMC1_BF(TWR, info->twr)
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| HSDRAMC1_BF(TRC, info->trc)
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| HSDRAMC1_BF(TRP, info->trp)
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| HSDRAMC1_BF(TRCD, info->trcd)
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| HSDRAMC1_BF(TRAS, info->tras)
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| HSDRAMC1_BF(TXSR, info->txsr));
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#ifdef CFG_SDRAM_16BIT
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tmp |= HSDRAMC1_BIT(DBW);
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sdram_size = 1 << (info->row_bits + info->col_bits
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+ info->bank_bits + 1);
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#else
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sdram_size = 1 << (info->row_bits + info->col_bits
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+ info->bank_bits + 2);
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#endif
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hsdramc1_writel(CR, tmp);
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/*
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* Initialization sequence for SDRAM, from the data sheet:
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*
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* 1. A minimum pause of 200 us is provided to precede any
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* signal toggle.
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*/
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udelay(200);
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/*
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* 2. A Precharge All command is issued to the SDRAM
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*/
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hsdramc1_writel(MR, HSDRAMC1_MODE_BANKS_PRECHARGE);
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hsdramc1_readl(MR);
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writel(0, sdram);
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/*
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* 3. Eight auto-refresh (CBR) cycles are provided
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*/
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hsdramc1_writel(MR, HSDRAMC1_MODE_AUTO_REFRESH);
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hsdramc1_readl(MR);
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for (i = 0; i < 8; i++)
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writel(0, sdram);
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/*
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* 4. A mode register set (MRS) cycle is issued to program
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* SDRAM parameters, in particular CAS latency and burst
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* length.
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*
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* CAS from info struct, burst length 1, serial burst type
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*/
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hsdramc1_writel(MR, HSDRAMC1_MODE_LOAD_MODE);
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hsdramc1_readl(MR);
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writel(0, sdram + (info->cas << 4));
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/*
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* 5. A Normal Mode command is provided, 3 clocks after tMRD
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* is met.
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*
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* From the timing diagram, it looks like tMRD is 3
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* cycles...try a dummy read from the peripheral bus.
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*/
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hsdramc1_readl(MR);
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hsdramc1_writel(MR, HSDRAMC1_MODE_NORMAL);
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hsdramc1_readl(MR);
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writel(0, sdram);
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/*
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* 6. Write refresh rate into SDRAMC refresh timer count
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* register (refresh rate = timing between refresh cycles).
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*
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* 15.6 us is a typical value for a burst of length one
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*/
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bus_hz = get_sdram_clk_rate();
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hsdramc1_writel(TR, info->refresh_period);
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printf("SDRAM: %u MB at address 0x%08lx\n",
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sdram_size >> 20, info->phys_addr);
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printf("Testing SDRAM...");
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for (i = 0; i < sdram_size / 4; i++)
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sdram[i] = i;
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for (i = 0; i < sdram_size / 4; i++) {
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tmp = sdram[i];
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if (tmp != i) {
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printf("FAILED at address 0x%08lx\n",
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info->phys_addr + i * 4);
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printf("SDRAM: read 0x%lx, expected 0x%lx\n", tmp, i);
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return 0;
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}
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}
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puts("OK\n");
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return sdram_size;
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}
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#endif /* CFG_HSDRAMC */
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