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-rw-r--r--u-boot/arch/avr32/cpu/hsdramc.c117
1 files changed, 117 insertions, 0 deletions
diff --git a/u-boot/arch/avr32/cpu/hsdramc.c b/u-boot/arch/avr32/cpu/hsdramc.c
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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/memory-map.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;
+}