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building a kernel module/device driver for zedboard/zynq

Former Member

I have a PL design to which I need to write my own char device driver to control. I did the driver development on my linux VM and have a standard kernel module makefile

obj-m += mydriver.o
mydriver-objs := my_driver.o

all:    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
clean:
        make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

however when I go to build it on my zedboard linux install (Linaro) i get this error:

make: *** /lib/modules/3.18.0-xilinx-06444-g06af32c/build: No such file or directory.  Stop.
make: *** [all] Error 2

how may I go about building my driver on zynq?

  • 0

    Hi BluePAZ,

    Are you compiling your driver statically into the kernel image?

    When I add a new PL driver to the kernel, I typically put it in a new drivers/pl/ folder under the kernel source.

    Then I make edits to drivers/Kconfig to add the Kconfig from my PL driver:

    source "drivers/pl/Kconfig"

    Then I make edits to drivers/Makefile to add the PL driver directory to the build traversal list:

    obj-$(CONFIG_PL)tt+= pl/

    Then I edit the PL driver Kconfig in /drivers/pl/Kconfig to add the configuration information needed for my PL driver:

    menuconfig PL
    tbool "Programmable Logic Support"
    tdepends on HAS_IOMEM && OF
    thelp
    ttAvnet Programmable Logic Support

    if PL

    config PL_DEBUG
    tbool "Enable Debug Message"

    config LEDBRIGHTNESS
    ttristate "LED Brightness Controller"
    thelp
    ttThe Avnet LED Brightness Controller

    endif # PL

    Edit the /drivers/pl/Makefile to add the appropriate source files to your kernel build.

    obj-$(CONFIG_LEDBRIGHTNESS) += led-brightness.o

    Finally you will need to edit your kernel config file to add your new driver configuration to the list and specify whether it is to be built statically or built as a dynamic kernel module.

    Once you are done setting up the source tree, you should be able to build by using the following command:

    make ARCH=arm

    Using the updated configuration and Kconfigs, the kernel should end up building only your new driver (plus and added dependencies) into the kernel image or kernel module depending on how your driver was configured.

    Regards,

    -Kevin

  • 0

    Hello Kevin,


    menuconfig PL
    bool "Programmable Logic Support"
    depends on HAS_IOMEM && OF
    help
    Avnet Programmable Logic Support

    if PL

    config PL_DEBUG
    bool "Enable Debug Message"

    config LEDBRIGHTNESS
    tristate "LED Brightness Controller"
    help
    The Avnet LED Brightness Controller

    endif # PL




    Is above step common for all drivers or its special for your driver?
    where do you find kernel config file? and what changes you made in it?
    after you get kernel image including static module, how do you test it on zynq board?

    Please Guide.

    Ganesh.