diff options
Diffstat (limited to 'arch/arm/cpu/at91-common/mpddrc.c')
| -rw-r--r-- | arch/arm/cpu/at91-common/mpddrc.c | 124 |
1 files changed, 124 insertions, 0 deletions
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; +} |