deploying USB gadget into rootfs on the t1040rdb

[jaket]

I'm using the Freescale QorIQ SDK 1.7.  I've modified my kernel config 'make menuconfig' to include the USB gadget drivers as a module and to include either Gadget zero or the serial gadget as a module.

I've also compiled the net2280 peripheral device directly into the kernel and it is loading and binding to the PCI device just fine.

After I run `bitbake`, the newly built rootfs doesn't include the newly built gadget modules yet I can see the `.ko` files have been built:

$ find -name g_zero.ko
 ./tmp/work/t1040rdb-fsl-linux/linux-qoriq/3.12-r0/git/drivers/usb/gadget/g_zero.ko
 ./tmp/work/t1040rdb-fsl-linux/linux-qoriq/3.12-r0/image/lib/modules/3.12.19-rt30-QorIQ-SDK-V1.7+g6619b8b/kernel/drivers/usb/gadget/g_zero.ko

but when I look in the image I get nothing.

$ tar -tzvf tmp/deploy/images/t1040rdb/fsl-image-core-t1040rdb.tar.gz | grep g_zero

One thing I found in searching is that it was suggested that `.config` needs to be copied into `meta-fsl-arm/recipies-kernel/linux/`. Unfortunately I'm using `meta-fsl-ppc` and it seems to use a completely different scheme for the kernel config.

First, there is a variable defined in `meta-fsl-ppc/conf/machine/machine.conf` that looks like this:

KERNEL_DEFCONFIG ?= "${S}/arch/powerpc/configs/corenet32_fmanv3_smp_defconfig"

My thinking was that maybe I need to overwrite that file. However, I'm confused as to where `${S}` is *actually* pointing.

$ bitbake -e | grep KERNEL_DEFCONFIG
KERNEL_DEFCONFIG="/home/jaket/QorIQ-SDK-V1.7-20141218-yocto/build_t1040rdb_release/tmp/work/ppce5500-fsl-linux/defaultpkgname/1.0-r0/defaultpkgname-1.0/arch/powerpc/configs/corenet32_fmanv3_smp_defconfig"

Which matches nothing in my tree:

$ find -name corenet32_fmanv3_smp_defconfig
./tmp/sysroots/t1040rdb/usr/src/kernel/arch/powerpc/configs/corenet32_fmanv3_smp_defconfig
./tmp/work/t1040rdb-fsl-linux/linux-qoriq/3.12-r0/sysroot-destdir/usr/src/kernel/arch/powerpc/configs/corenet32_fmanv3_smp_defconfig
./tmp/work/t1040rdb-fsl-linux/linux-qoriq/3.12-r0/package/usr/src/kernel/arch/powerpc/configs/corenet32_fmanv3_smp_defconfig
./tmp/work/t1040rdb-fsl-linux/linux-qoriq/3.12-r0/git/arch/powerpc/configs/corenet32_fmanv3_smp_defconfig
./tmp/work/t1040rdb-fsl-linux/linux-qoriq/3.12-r0/image/usr/src/kernel/arch/powerpc/configs/corenet32_fmanv3_smp_defconfig
./tmp/work/t1040rdb-fsl-linux/linux-qoriq/3.12-r0/packages-split/kernel-dev/usr/src/kernel/arch/powerpc/configs/corenet32_fmanv3_smp_defconfig

So I guess my question is: when a loadable module is configured in the kernel, is it expected that the module will magically find its way onto the rootfs or is there more to it than that?

[yipingwang · Accepted solution]

Hello Jacob Tummond,

In SDK 1.7, Kernel modules could be built into rootfs automatically, the file tmp/deploy/images/t1040rdb/fsl-image-core-t1040rdb.tar.gz is a symbolic link, please extract the real file and check whether the module is in it.

I summarize build Kernel modules procedure as the following, please have a reference.

1. bitbake virtual/kernel -c cleansstate

2. bitbake virtual/kernel -c patch

3. bitbake virtual/kernel -c configure

4. Go the source folder tmp/work/t1040rdb-fsl-linux/linux-qoriq/3.12-r0/git/, and configure Kernel

make ARCH=powerpc menuconfig

Configure Gadget zero and the serial gadget as modules.

5. Go back to build folder and run "bitbake fsl-image-core", Kernel also gets rebuilt.

6. Go to image deploy folder tmp/deploy/images/t1040rdb/, and find the real file which fsl-image-core-t1040rdb.tar.gz links to, run

$ tar -tzvf tmp/deploy/images/t1040rdb/fsl-image-core-t1040rdb-<time>.tar.gz | grep g_zero

Have a great day,
Yiping

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