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Diffstat (limited to 'arch/arm/cpu/arm926ejs/lpc32xx/dram.c')
-rw-r--r--arch/arm/cpu/arm926ejs/lpc32xx/dram.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/arch/arm/cpu/arm926ejs/lpc32xx/dram.c b/arch/arm/cpu/arm926ejs/lpc32xx/dram.c
new file mode 100644
index 0000000000..1eea8e2bbf
--- /dev/null
+++ b/arch/arm/cpu/arm926ejs/lpc32xx/dram.c
@@ -0,0 +1,77 @@
+/*
+ * LPC32xx dram init
+ *
+ * (C) Copyright 2014 DENX Software Engineering GmbH
+ * Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
+ *
+ * This is called by SPL to gain access to the SDR DRAM.
+ *
+ * This code runs from SRAM.
+ *
+ * Actual CONFIG_LPC32XX_SDRAM_* parameters must be provided
+ * by the board configuration file.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <netdev.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/clk.h>
+#include <asm/arch/wdt.h>
+#include <asm/arch/emc.h>
+#include <asm/io.h>
+
+static struct clk_pm_regs *clk = (struct clk_pm_regs *)CLK_PM_BASE;
+static struct emc_regs *emc = (struct emc_regs *)EMC_BASE;
+
+void ddr_init(struct emc_dram_settings *dram)
+{
+ uint32_t ck;
+
+ /* Enable EMC interface and choose little endian mode */
+ writel(1, &emc->ctrl);
+ writel(0, &emc->config);
+ /* Select maximum EMC Dynamic Memory Refresh Time */
+ writel(0x7FF, &emc->refresh);
+ /* Determine CLK */
+ ck = get_sdram_clk_rate();
+ /* Configure SDRAM */
+ writel(dram->cmddelay, &clk->sdramclk_ctrl);
+ writel(dram->config0, &emc->config0);
+ writel(dram->rascas0, &emc->rascas0);
+ writel(dram->rdconfig, &emc->read_config);
+ /* Set timings */
+ writel((ck / dram->trp) & 0x0000000F, &emc->t_rp);
+ writel((ck / dram->tras) & 0x0000000F, &emc->t_ras);
+ writel((ck / dram->tsrex) & 0x0000007F, &emc->t_srex);
+ writel((ck / dram->twr) & 0x0000000F, &emc->t_wr);
+ writel((ck / dram->trc) & 0x0000001F, &emc->t_rc);
+ writel((ck / dram->trfc) & 0x0000001F, &emc->t_rfc);
+ writel((ck / dram->txsr) & 0x000000FF, &emc->t_xsr);
+ writel(dram->trrd, &emc->t_rrd);
+ writel(dram->tmrd, &emc->t_mrd);
+ writel(dram->tcdlr, &emc->t_cdlr);
+ /* Dynamic refresh */
+ writel((((ck / dram->refresh) >> 4) & 0x7FF), &emc->refresh);
+ udelay(10);
+ /* Force all clocks, enable inverted ck, issue NOP command */
+ writel(0x00000193, &emc->control);
+ udelay(100);
+ /* Keep all clocks enabled, issue a PRECHARGE ALL command */
+ writel(0x00000113, &emc->control);
+ /* Fast dynamic refresh for at least a few SDRAM ck cycles */
+ writel((((128) >> 4) & 0x7FF), &emc->refresh);
+ udelay(10);
+ /* set correct dynamic refresh timing */
+ writel((((ck / dram->refresh) >> 4) & 0x7FF), &emc->refresh);
+ udelay(10);
+ /* set normal mode to CAS=3 */
+ writel(0x00000093, &emc->control);
+ readl(EMC_DYCS0_BASE | dram->mode);
+ /* set extended mode to all zeroes */
+ writel(0x00000093, &emc->control);
+ readl(EMC_DYCS0_BASE | dram->emode);
+ /* stop forcing clocks, keep inverted clock, issue normal mode */
+ writel(0x00000010, &emc->control);
+}