nuttx/boards/arm/samv7/samv71-xult/src/sam_sdram.c

/****************************************************************************
 * boards/arm/samv7/samv71-xult/src/sam_sdram.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <debug.h>

#include <nuttx/arch.h>
#include <arch/board/board.h>

#include "arm_internal.h"
#include "sam_periphclks.h"
#include "hardware/sam_memorymap.h"
#include "hardware/sam_pinmap.h"
#include "hardware/sam_pmc.h"
#include "hardware/sam_matrix.h"
#include "hardware/sam_sdramc.h"

#include "samv71-xult.h"

#ifdef CONFIG_SAMV7_SDRAMC

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

#define SDRAM_BA0 (1 << 20)
#define SDRAM_BA1 (1 << 21)

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: sam_sdram_config
 *
 * Description:
 *   Configures the on-board SDRAM.  SAMV71 Xplained Ultra features one
 *   external IS42S16100E-7BLI, 512Kx16x2, 10ns, SDRAM. SDRAM0 is connected
 *   to chip select NCS1.
 *
 *  Input Parameters:
 *     None
 *
 *  Assumptions:
 *    This test runs early in initialization before I- and D-caches are
 *    enabled.
 *
 *    NOTE: Since the delay loop is calibrate with caches in enabled, the
 *    calls to up_udelay() are wrong ty orders of magnitude.
 *
 ****************************************************************************/

void sam_sdram_config(void)
{
  volatile uint8_t *psdram = (uint8_t *)SAM_SDRAMCS_BASE;
  uint32_t regval;
  int i;

  /* Configure SDRAM pins */

  sam_configgpio(GPIO_SMC_D0);
  sam_configgpio(GPIO_SMC_D1);
  sam_configgpio(GPIO_SMC_D2);
  sam_configgpio(GPIO_SMC_D3);
  sam_configgpio(GPIO_SMC_D4);
  sam_configgpio(GPIO_SMC_D5);
  sam_configgpio(GPIO_SMC_D6);
  sam_configgpio(GPIO_SMC_D7);
  sam_configgpio(GPIO_SMC_D8);
  sam_configgpio(GPIO_SMC_D9);
  sam_configgpio(GPIO_SMC_D10);
  sam_configgpio(GPIO_SMC_D11);
  sam_configgpio(GPIO_SMC_D12);
  sam_configgpio(GPIO_SMC_D13);
  sam_configgpio(GPIO_SMC_D14);
  sam_configgpio(GPIO_SMC_D15);

  /*   SAMV71          SDRAM
   *   --------------- -----------
   *   PC20 A2         A0
   *   PC21 A3         A1
   *   PC22 A4         A2
   *   PC23 A5         A3
   *   PC24 A6         A4
   *   PC25 A7         A5
   *   PC26 A8         A6
   *   PC27 A9         A7
   *   PC28 A10        A8
   *   PC29 A11        A9
   *   PD13 SDA10      A10
   *   PA20 BA0        A11
   *   PD17 CAS        nCAS
   *   PD14 SDCKE      CKE
   *   PD23 SDCK       CLK
   *   PC15 SDCS       nCS
   *   PC18 A0/NBS0    LDQM
   *   PD16 RAS        nRAS
   *   PD15 NWR1/NBS1  UDQM
   *   PD29 SDWE       nWE
   */

  sam_configgpio(GPIO_SMC_A2);        /* PC20 A2        -> A0 */
  sam_configgpio(GPIO_SMC_A3);        /* PC21 A3        -> A1 */
  sam_configgpio(GPIO_SMC_A4);        /* PC22 A4        -> A2 */
  sam_configgpio(GPIO_SMC_A5);        /* PC23 A5        -> A3 */
  sam_configgpio(GPIO_SMC_A6);        /* PC24 A6        -> A4 */
  sam_configgpio(GPIO_SMC_A7);        /* PC25 A7        -> A5 */
  sam_configgpio(GPIO_SMC_A8);        /* PC26 A8        -> A6 */
  sam_configgpio(GPIO_SMC_A9);        /* PC27 A9        -> A7 */
  sam_configgpio(GPIO_SMC_A10);       /* PC28 A10       -> A8 */
  sam_configgpio(GPIO_SMC_A11);       /* PC29 A11       -> A9 */
  sam_configgpio(GPIO_SDRAMC_A10_2);  /* PD13 SDA10     -> A10 */
  sam_configgpio(GPIO_SDRAMC_BA0);    /* PA20 BA0       -> A11 */

  sam_configgpio(GPIO_SDRAMC_CKE);    /* PD14 SDCKE     -> CKE */
  sam_configgpio(GPIO_SDRAMC_CK);     /* PD23 SDCK      -> CLK */
  sam_configgpio(GPIO_SDRAMC_CS_1);   /* PC15 SDCS      -> nCS */
  sam_configgpio(GPIO_SDRAMC_RAS);    /* PD16 RAS       -> nRAS */
  sam_configgpio(GPIO_SDRAMC_CAS);    /* PD17 CAS       -> nCAS */
  sam_configgpio(GPIO_SDRAMC_WE);     /* PD29 SDWE      -> nWE */
  sam_configgpio(GPIO_SMC_NBS0);      /* PC18 A0/NBS0   -> LDQM */
  sam_configgpio(GPIO_SMC_NBS1);      /* PD15 NWR1/NBS1 -> UDQM */

  /* Enable the SDRAMC peripheral */

  sam_sdramc_enableclk();

  regval  = getreg32(SAM_MATRIX_CCFG_SMCNFCS);
  regval |= MATRIX_CCFG_SMCNFCS_SDRAMEN;
  putreg32(regval, SAM_MATRIX_CCFG_SMCNFCS);

  /* 1. SDRAM features must be set in the configuration register:
   *    asynchronous timings (TRC, TRAS, etc.), number of columns, rows, CAS
   *    latency, and the data bus width.
   *
   *    SDRAMC_CR_NC_COL8          8 column bits
   *    SDRAMC_CR_NR_ROW11         1 row bits
   *    SDRAMC_CR_NB_BANK2         2 banks
   *    SDRAMC_CR_CAS_LATENCY3     3 cycle CAS latency
   *    SDRAMC_CR_DBW             16 bit
   *    SDRAMC_CR_TWR(4)           4 cycle write recovery delay
   *    SDRAMC_CR_TRCTRFC(11)     63 ns min
   *    SDRAMC_CR_TRP(5)          21 ns min Command period (PRE to ACT)
   *    SDRAMC_CR_TRCD(5)         21 ns min Active Command to read/Write
   *                                        Command delay time
   *    SDRAMC_CR_TRAS(8)         42 ns min Command period (ACT to PRE)
   *    SDRAMC_CR_TXSR(13)        70 ns min Exit self-refresh to active time
   */

  regval = SDRAMC_CR_NC_COL8       |  /* 8 column bits */
           SDRAMC_CR_NR_ROW11      |  /* 11 row bits */
           SDRAMC_CR_NB_BANK2      |  /* 2 banks */
           SDRAMC_CR_CAS_LATENCY3  |  /* 3 cycle CAS latency */
           SDRAMC_CR_DBW           |  /* 16 bit */
           SDRAMC_CR_TWR(4)        |  /* 4 cycle write recovery delay */
           SDRAMC_CR_TRCTRFC(11)   |  /* 63 ns min */
           SDRAMC_CR_TRP(5)        |  /* 21 ns min Command period (PRE to ACT) */
           SDRAMC_CR_TRCD(5)       |  /* 21 ns min Active Command to read/Write Command delay time */
           SDRAMC_CR_TRAS(8)       |  /* 42 ns min Command period (ACT to PRE) */
           SDRAMC_CR_TXSR(13);        /* 70 ns min Exit self-refresh to active time */

  putreg32(regval, SAM_SDRAMC_CR);

  /* 2. For mobile SDRAM, temperature-compensated self refresh (TCSR), drive
   *    strength (DS) and partial array self refresh (PASR) must be set in
   *    the Low Power Register.
   */

  putreg32(0, SAM_SDRAMC_LPR);

  /* 3. The SDRAM memory type must be set in the Memory Device Register. */

  putreg32(SDRAMC_MDR_SDRAM, SAM_SDRAMC_MDR);

  /* 4. A minimum pause of 200 usec is provided to precede any signal
   * toggle.
   */

  up_udelay(200);

  /* 5. A NOP command is issued to the SDRAM devices. The application must
   *    set Mode to 1 in the Mode Register and perform a write access to any
   *    SDRAM address.
   */

  putreg32(SDRAMC_MR_MODE_NOP, SAM_SDRAMC_MR);
  *psdram = 0;
  up_udelay(200);

  /* 6. An All Banks Precharge command is issued to the SDRAM devices. The
   *    application must set Mode to 2 in the Mode Register and perform a
   *    write access to any SDRAM address.
   */

  putreg32(SDRAMC_MR_MODE_PRECHARGE, SAM_SDRAMC_MR);
  *psdram = 0;
  up_udelay(200);

  /* 7. Eight auto-refresh (CBR) cycles are provided. The application must
   *    set the Mode to 4 in the Mode Register and perform a write access to
   *    any SDRAM location eight times.
   */

  for (i = 0 ; i < 8; i++)
    {
      putreg32(SDRAMC_MR_MODE_AUTOREFRESH, SAM_SDRAMC_MR);
      *psdram = 0;
    }

  up_udelay(200);

  /* 8. A Mode Register set (MRS) cycle is issued to program the parameters
   *    of the SDRAM devices, in particular CAS latency and burst length.
   *    The application must set Mode to 3 in the Mode Register and perform
   *    a write access to the SDRAM. The write address must be chosen so
   *    that BA[1:0] are set to 0. For example, with a 16-bit 128 MB SDRAM
   *    (12 rows, 9 columns, 4 banks) bank address, the SDRAM write access
   *    should be done at the address 0x70000000.
   */

  putreg32(SDRAMC_MR_MODE_LOADMODE, SAM_SDRAMC_MR);
  *psdram = 0;
  up_udelay(200);

  /* 9. For mobile SDRAM initialization, an Extended Mode Register set
   *    (EMRS) cycle is issued to program the SDRAM parameters (TCSR, PASR,
   *     DS). The application must set Mode to 5 in the Mode Register and
   *     perform a write access to the SDRAM. The write address must be
   *     chosen so that BA[1] or BA[0] are set to 1.
   *
   *     For example, with a 16-bit 128 MB SDRAM, (12 rows, 9 columns, 4
   *     banks) bank address the SDRAM write access should be done at the
   *     address 0x70800000 or 0x70400000.
   */

  /* putreg32(SDRAMC_MR_MODE_EXTLOADMODE, SDRAMC_MR_MODE_EXT_LOAD_MODEREG);
   * *((uint8_t *)(psdram + SDRAM_BA0)) = 0;
   */

  /* 10. 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.
   */

  putreg32(SDRAMC_MR_MODE_NORMAL, SAM_SDRAMC_MR);
  *psdram = 0;
  up_udelay(200);

  /* 11. Write the refresh rate into the count field in the SDRAMC Refresh
   *     Timer register. (Refresh rate = delay between refresh cycles). The
   *     SDRAM device requires a refresh every 15.625 usec or 7.81 usec. With
   *     a 100 MHz frequency, the Refresh Timer Counter Register must be set
   *     with the value 1562(15.625 usec x 100 MHz) or 781(7.81 usec x 100
   *     MHz).
   *
   * For IS42S16100E, 2048 refresh cycle every 32ms, every 15.625 usec
   */

  regval = (32 * (BOARD_MCK_FREQUENCY / 1000)) / 2048 ;
  putreg32(regval, SAM_SDRAMC_TR);

  regval  = getreg32(SAM_SDRAMC_CFR1);
  regval |= SDRAMC_CFR1_UNAL;
  putreg32(regval, SAM_SDRAMC_CFR1);

  /* After initialization, the SDRAM devices are fully functional. */
}

#endif /* CONFIG_SAMV7_SDRAMC */