arm: atmel: add ddr2 initialization function
The MPDDRC supports different type of SDRAM
This patch add ddr2 initialization function
Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/arch/arm/cpu/at91-common/mpddrc.c b/arch/arm/cpu/at91-common/mpddrc.c
new file mode 100644
index 0000000..8136396
--- /dev/null
+++ b/arch/arm/cpu/at91-common/mpddrc.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2013 Atmel Corporation
+ * Bo Shen <voice.shen@atmel.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/atmel_mpddrc.h>
+
+static inline void atmel_mpddr_op(int mode, u32 ram_address)
+{
+ struct atmel_mpddr *mpddr = (struct atmel_mpddr *)ATMEL_BASE_MPDDRC;
+
+ writel(mode, &mpddr->mr);
+ writel(0, ram_address);
+}
+
+int ddr2_init(const unsigned int ram_address,
+ const struct atmel_mpddr *mpddr_value)
+{
+ struct atmel_mpddr *mpddr = (struct atmel_mpddr *)ATMEL_BASE_MPDDRC;
+ u32 ba_off, cr;
+
+ /* Compute bank offset according to NC in configuration register */
+ ba_off = (mpddr_value->cr & ATMEL_MPDDRC_CR_NC_MASK) + 9;
+ if (!(mpddr_value->cr & ATMEL_MPDDRC_CR_DECOD_INTERLEAVED))
+ ba_off += ((mpddr->cr & ATMEL_MPDDRC_CR_NR_MASK) >> 2) + 11;
+
+ ba_off += (mpddr_value->md & ATMEL_MPDDRC_MD_DBW_MASK) ? 1 : 2;
+
+ /* Program the memory device type into the memory device register */
+ writel(mpddr_value->md, &mpddr->md);
+
+ /* Program the configuration register */
+ writel(mpddr_value->cr, &mpddr->cr);
+
+ /* Program the timing register */
+ writel(mpddr_value->tpr0, &mpddr->tpr0);
+ writel(mpddr_value->tpr1, &mpddr->tpr1);
+ writel(mpddr_value->tpr2, &mpddr->tpr2);
+
+ /* Issue a NOP command */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_NOP_CMD, ram_address);
+
+ /* A 200 us is provided to precede any signal toggle */
+ udelay(200);
+
+ /* Issue a NOP command */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_NOP_CMD, ram_address);
+
+ /* Issue an all banks precharge command */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_PRCGALL_CMD, ram_address);
+
+ /* Issue an extended mode register set(EMRS2) to choose operation */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_EXT_LMR_CMD,
+ ram_address + (0x2 << ba_off));
+
+ /* Issue an extended mode register set(EMRS3) to set EMSR to 0 */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_EXT_LMR_CMD,
+ ram_address + (0x3 << ba_off));
+
+ /*
+ * Issue an extended mode register set(EMRS1) to enable DLL and
+ * program D.I.C (output driver impedance control)
+ */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_EXT_LMR_CMD,
+ ram_address + (0x1 << ba_off));
+
+ /* Enable DLL reset */
+ cr = readl(&mpddr->cr);
+ writel(cr | ATMEL_MPDDRC_CR_DLL_RESET_ENABLED, &mpddr->cr);
+
+ /* A mode register set(MRS) cycle is issued to reset DLL */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_LMR_CMD, ram_address);
+
+ /* Issue an all banks precharge command */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_PRCGALL_CMD, ram_address);
+
+ /* Two auto-refresh (CBR) cycles are provided */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_RFSH_CMD, ram_address);
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_RFSH_CMD, ram_address);
+
+ /* Disable DLL reset */
+ cr = readl(&mpddr->cr);
+ writel(cr & (~ATMEL_MPDDRC_CR_DLL_RESET_ENABLED), &mpddr->cr);
+
+ /* A mode register set (MRS) cycle is issued to disable DLL reset */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_LMR_CMD, ram_address);
+
+ /* Set OCD calibration in default state */
+ cr = readl(&mpddr->cr);
+ writel(cr | ATMEL_MPDDRC_CR_OCD_DEFAULT, &mpddr->cr);
+
+ /*
+ * An extended mode register set (EMRS1) cycle is issued
+ * to OCD default value
+ */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_EXT_LMR_CMD,
+ ram_address + (0x1 << ba_off));
+
+ /* OCD calibration mode exit */
+ cr = readl(&mpddr->cr);
+ writel(cr & (~ATMEL_MPDDRC_CR_OCD_DEFAULT), &mpddr->cr);
+
+ /*
+ * An extended mode register set (EMRS1) cycle is issued
+ * to enable OCD exit
+ */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_EXT_LMR_CMD,
+ ram_address + (0x1 << ba_off));
+
+ /* A nornal mode command is provided */
+ atmel_mpddr_op(ATMEL_MPDDRC_MR_MODE_NORMAL_CMD, ram_address);
+
+ /* Perform a write access to any DDR2-SDRAM address */
+ writel(0, ram_address);
+
+ /* Write the refresh rate */
+ writel(mpddr_value->rtr, &mpddr->rtr);
+
+ return 0;
+}