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https://github.com/AsahiLinux/u-boot
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78 lines
2.5 KiB
C
78 lines
2.5 KiB
C
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/*
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* LPC32xx dram init
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*
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* (C) Copyright 2014 DENX Software Engineering GmbH
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* Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
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*
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* This is called by SPL to gain access to the SDR DRAM.
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*
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* This code runs from SRAM.
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*
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* Actual CONFIG_LPC32XX_SDRAM_* parameters must be provided
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* by the board configuration file.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <netdev.h>
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#include <asm/arch/cpu.h>
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#include <asm/arch/clk.h>
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#include <asm/arch/wdt.h>
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#include <asm/arch/emc.h>
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#include <asm/io.h>
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static struct clk_pm_regs *clk = (struct clk_pm_regs *)CLK_PM_BASE;
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static struct emc_regs *emc = (struct emc_regs *)EMC_BASE;
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void ddr_init(struct emc_dram_settings *dram)
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{
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uint32_t ck;
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/* Enable EMC interface and choose little endian mode */
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writel(1, &emc->ctrl);
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writel(0, &emc->config);
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/* Select maximum EMC Dynamic Memory Refresh Time */
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writel(0x7FF, &emc->refresh);
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/* Determine CLK */
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ck = get_sdram_clk_rate();
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/* Configure SDRAM */
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writel(dram->cmddelay, &clk->sdramclk_ctrl);
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writel(dram->config0, &emc->config0);
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writel(dram->rascas0, &emc->rascas0);
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writel(dram->rdconfig, &emc->read_config);
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/* Set timings */
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writel((ck / dram->trp) & 0x0000000F, &emc->t_rp);
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writel((ck / dram->tras) & 0x0000000F, &emc->t_ras);
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writel((ck / dram->tsrex) & 0x0000007F, &emc->t_srex);
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writel((ck / dram->twr) & 0x0000000F, &emc->t_wr);
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writel((ck / dram->trc) & 0x0000001F, &emc->t_rc);
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writel((ck / dram->trfc) & 0x0000001F, &emc->t_rfc);
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writel((ck / dram->txsr) & 0x000000FF, &emc->t_xsr);
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writel(dram->trrd, &emc->t_rrd);
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writel(dram->tmrd, &emc->t_mrd);
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writel(dram->tcdlr, &emc->t_cdlr);
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/* Dynamic refresh */
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writel((((ck / dram->refresh) >> 4) & 0x7FF), &emc->refresh);
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udelay(10);
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/* Force all clocks, enable inverted ck, issue NOP command */
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writel(0x00000193, &emc->control);
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udelay(100);
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/* Keep all clocks enabled, issue a PRECHARGE ALL command */
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writel(0x00000113, &emc->control);
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/* Fast dynamic refresh for at least a few SDRAM ck cycles */
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writel((((128) >> 4) & 0x7FF), &emc->refresh);
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udelay(10);
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/* set correct dynamic refresh timing */
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writel((((ck / dram->refresh) >> 4) & 0x7FF), &emc->refresh);
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udelay(10);
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/* set normal mode to CAS=3 */
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writel(0x00000093, &emc->control);
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readl(EMC_DYCS0_BASE | dram->mode);
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/* set extended mode to all zeroes */
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writel(0x00000093, &emc->control);
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readl(EMC_DYCS0_BASE | dram->emode);
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/* stop forcing clocks, keep inverted clock, issue normal mode */
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writel(0x00000010, &emc->control);
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}
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