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Adding second NAND Flash IC to AM3703 in Linux

James Hillman
Expert 1436 points
Other Parts Discussed in Thread: AM3703

Hi There,

I am new to Sitara Processors and a basic Linux user. I am interested in adding a second NAND Flash IC to an AM3703. The first IC, is a dual package RAM/NAND package and I am using a system on module.

Does anyone have any advice on how to make Linux aware of the second IC?

For starters, I wondered what needs to be done in uboot and in the kernel. I am using a Linux kernel version 3.0 - no device tree.

I do not need an OS on the second IC - the IC will just contain data which the Linux system will need to read (no error correction either).

Many thanks,

James

  • 0
    TI__Guru**** 393215 points
    Hi,

    Since you are saying that you are using a SOM, the first important question is whether this module has the GPMC interface exposed?
  • 0 in reply to Biser Gatchev-XID
    Expert 1436 points
    Hi Biser,
    Thanks for your interest in my problem/learning.
    Yes it does.
    It has DOtoD7 (the nand flash IC I want to use is 8bit parallel bus).
    It has several of the Chip Enable lines.
    It has ALE, CLE, WE, RE, R/B. (I'm using nand flash naming, rather than the AM3703 names).
    It also has WAIT3 and WAIT0.
  • 0 in reply to James Hillman
    TI__Guru**** 393215 points
    Sounds OK. I will hand this over to the software team.
  • 0 in reply to Biser Gatchev-XID
    Expert 1436 points

    Biser Gatchev-XID said:
    Sounds OK. I will hand this over to the software team.

    Thanks that would be great.

    I just want the ability to read raw bytes from another NAND flash memory IC. The first one, is used, by the OS filesystem.

    Thanks,

  • 0 in reply to James Hillman
    TI__Guru**** 393215 points
    They will reply directly here shortly.
  • 0 in reply to James Hillman
    TI__Guru**** 161600 points

    Hi James,

    You will need to mux the GPMC pins & init the nand IC in the board file. That should do it.

    The closest kernel to yours, which TI offers is from SDK6 (kernel 3.2). I am attaching the board_am335xevm.c file: 8863.board-am335xevm.c

    Search for nand to see how pinmux & IC init are done and modify your sources accordingly. You may need to change gpmc CS to match your hardware. Basically you need to adopt pinmux_config nand_pin_mux [], mtd_partition am335x_nand_partitions[] (if needed for booting), gpmc_timings am335x_nand_timings, evm_nand_init(int evm_id, int profile) and add the corresponding {evm_nand_init, DEV_ON_DGHTR_BRD, (PROFILE_ALL & ~PROFILE_2 & ~PROFILE_3)} line in evm_dev_cfg gen_purp_evm_dev_cfg[] structure.  

    Similarly for u-boot initialization you need to add the pinmux settigns:   

    static struct module_pin_mux nand_pin_mux[] = {
    {OFFSET(gpmc_ad0), (MODE(0) | PULLUP_EN | RXACTIVE)}, /* NAND AD0 */
    {OFFSET(gpmc_ad1), (MODE(0) | PULLUP_EN | RXACTIVE)}, /* NAND AD1 */
    {OFFSET(gpmc_ad2), (MODE(0) | PULLUP_EN | RXACTIVE)}, /* NAND AD2 */
    {OFFSET(gpmc_ad3), (MODE(0) | PULLUP_EN | RXACTIVE)}, /* NAND AD3 */
    {OFFSET(gpmc_ad4), (MODE(0) | PULLUP_EN | RXACTIVE)}, /* NAND AD4 */
    {OFFSET(gpmc_ad5), (MODE(0) | PULLUP_EN | RXACTIVE)}, /* NAND AD5 */
    {OFFSET(gpmc_ad6), (MODE(0) | PULLUP_EN | RXACTIVE)}, /* NAND AD6 */
    {OFFSET(gpmc_ad7), (MODE(0) | PULLUP_EN | RXACTIVE)}, /* NAND AD7 */
    {OFFSET(gpmc_wait0), (MODE(0) | RXACTIVE | PULLUP_EN)}, /* NAND WAIT */
    {OFFSET(gpmc_wpn), (MODE(7) | PULLUP_EN | RXACTIVE)}, /* NAND_WPN */
    {OFFSET(gpmc_csn0), (MODE(0) | PULLUDEN)}, /* NAND_CS0 */                                                //Change the CS to match your hardware
    {OFFSET(gpmc_advn_ale), (MODE(0) | PULLUDEN)}, /* NAND_ADV_ALE */
    {OFFSET(gpmc_oen_ren), (MODE(0) | PULLUDEN)}, /* NAND_OE */
    {OFFSET(gpmc_wen), (MODE(0) | PULLUDEN)}, /* NAND_WEN */
    {OFFSET(gpmc_be0n_cle), (MODE(0) | PULLUDEN)}, /* NAND_BE_CLE */
    {-1},
    };

    And call the configure_module_pin_mux(nand_pin_mux); in board/ti/<board_name>/mux.c file. 

    Best Regards, 
    Yordan