Flash device can't find in kernel and redboot - Embedded

This is a discussion on Flash device can't find in kernel and redboot - Embedded ; hi all: when i selected configuration entries in MTD subsystem in the process of kernel compiling, in the "RAM/ROM/Flash chip driver" subentry, if only I select "Support for absent chips in bus mapping" subsubentry, I just get result such as ...

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Thread: Flash device can't find in kernel and redboot

  1. Flash device can't find in kernel and redboot

    hi all:
    when i selected configuration entries in MTD subsystem in the process
    of kernel compiling, in the "RAM/ROM/Flash chip driver" subentry, if
    only I select "Support for absent chips in bus mapping" subsubentry, I
    just get result such as follows:
    --------------------------------------------------
    sh-2.04# cat /proc/mtd
    dev: size erasesize name
    mtd0: 01000000 00001000 "Physically mapped flash"
    --------------------------------------------------
    This make me think about the flash devices had recongnized.
    however:
    ---------------------------------------------------
    sh-2.04# cat /dev/mtd0
    cat: /dev/mtd0: No such device
    ---------------------------------------------------
    It indicates that kernel has no such device. I read help of "Support
    for absent chips in bus mapping" in details:
    -----------------------------------------------------------
    CONFIG_MTD_ABSENT:
    This option enables support for a dummy probing driver used to
    allocated placeholder MTD devices on systems that have socketed
    or removable media. Use of this driver as a fallback chip probe
    preserves the expected registration order of MTD device nodes on
    the system regardless of media presence. Device nodes created
    with this driver will return -ENODEV upon access.
    -----------------------------------------------------------
    This means regardless flash devices exist, they will always be
    registered and get own device nodes, but if you want to have access to
    them, which will prompt: no such device.

    my flash is spansion s29GL064M, the two flashes both linked to CS1#, I
    have compiled kernel many times and try many configuration entry in MTD
    subsystem, but all of those always told me "Found no Physically mapped
    flash device at location zero" except when I use the above
    configuration --- but that's useless.
    ----------------------------------------------------
    My typical configuration in MTD subsystem is follows:

    Memory Techonology Device(MTD) support
    MTD partiotioning support
    Redboot partitions table parsing
    Direct char device access to MTD devices
    Caching block device access to MTD devices
    RAM/ROM/Flash chip drivers->Detect flash chips by Common Flash
    Interface(CFI) probe
    RAM/ROM/Flash chip drivers->Detect non-CFI AMD/JEDEC-compatiable flash
    chips
    RAM/ROM/Flash chip drivers->Support for AMD/Fujitsu flash chips
    Mapping drivers for chip access->CFI flash device mapping driver

    OR

    all of entries in "RAM/ROM/Flash chip drivers" was selected.

    but the result was always:
    physmap flash device 1000000 at 4000000
    genprobe_new_chip called with unsupported buswidth 2
    JEDEC: Found no Physically mapped flash device at location zero
    priv->size is zero
    genprobe_new_chip called with unsupported buswidth 2
    CFI: Found no Physically mapped flash device at location zero
    Physically mapped flash: Probing for AMD compatible flash...
    Physically mapped flash: Found no AMD compatible device at location
    zero

    -----------------------------------------------------------------
    In both cases I can't find my flash devices. What's wrong with them or
    kernel?
    Hope you can throw light on this.


  2. Re: Flash device can't find in kernel and redboot

    I also want to know which driver can drive spansion flash properly?? Do
    it exist?
    Kevin wrote:
    > hi all:
    > when i selected configuration entries in MTD subsystem in the process
    > of kernel compiling, in the "RAM/ROM/Flash chip driver" subentry, if
    > only I select "Support for absent chips in bus mapping" subsubentry, I
    > just get result such as follows:
    > --------------------------------------------------
    > sh-2.04# cat /proc/mtd
    > dev: size erasesize name
    > mtd0: 01000000 00001000 "Physically mapped flash"
    > --------------------------------------------------
    > This make me think about the flash devices had recongnized.
    > however:
    > ---------------------------------------------------
    > sh-2.04# cat /dev/mtd0
    > cat: /dev/mtd0: No such device
    > ---------------------------------------------------
    > It indicates that kernel has no such device. I read help of "Support
    > for absent chips in bus mapping" in details:
    > -----------------------------------------------------------
    > CONFIG_MTD_ABSENT:
    > This option enables support for a dummy probing driver used to
    > allocated placeholder MTD devices on systems that have socketed
    > or removable media. Use of this driver as a fallback chip probe
    > preserves the expected registration order of MTD device nodes on
    > the system regardless of media presence. Device nodes created
    > with this driver will return -ENODEV upon access.
    > -----------------------------------------------------------
    > This means regardless flash devices exist, they will always be
    > registered and get own device nodes, but if you want to have access to
    > them, which will prompt: no such device.
    >
    > my flash is spansion s29GL064M, the two flashes both linked to CS1#, I
    > have compiled kernel many times and try many configuration entry in MTD
    > subsystem, but all of those always told me "Found no Physically mapped
    > flash device at location zero" except when I use the above
    > configuration --- but that's useless.
    > ----------------------------------------------------
    > My typical configuration in MTD subsystem is follows:
    >
    > Memory Techonology Device(MTD) support
    > MTD partiotioning support
    > Redboot partitions table parsing
    > Direct char device access to MTD devices
    > Caching block device access to MTD devices
    > RAM/ROM/Flash chip drivers->Detect flash chips by Common Flash
    > Interface(CFI) probe
    > RAM/ROM/Flash chip drivers->Detect non-CFI AMD/JEDEC-compatiable flash
    > chips
    > RAM/ROM/Flash chip drivers->Support for AMD/Fujitsu flash chips
    > Mapping drivers for chip access->CFI flash device mapping driver
    >
    > OR
    >
    > all of entries in "RAM/ROM/Flash chip drivers" was selected.
    >
    > but the result was always:
    > physmap flash device 1000000 at 4000000
    > genprobe_new_chip called with unsupported buswidth 2
    > JEDEC: Found no Physically mapped flash device at location zero
    > priv->size is zero
    > genprobe_new_chip called with unsupported buswidth 2
    > CFI: Found no Physically mapped flash device at location zero
    > Physically mapped flash: Probing for AMD compatible flash...
    > Physically mapped flash: Found no AMD compatible device at location
    > zero
    >
    > -----------------------------------------------------------------
    > In both cases I can't find my flash devices. What's wrong with them or
    > kernel?
    > Hope you can throw light on this.



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