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Driver Development Procedure
Added by david kasper over 13 years ago
I need to create a loadable Linux module that runs on the ARM9 of the MityDSP-L138 and accesses the FPGA. Preferrably the build would be performed "out-of-tree" such that an environment variable references the angstrom kernel tree. I have successfully performed this method for another distribution (see example makefile below) however I get errors with the Angstrom distribution (see below). Does anybody have an example that I can modify or a tutorial on how this can be accomplished?
Thank you,
David Kasper
>>>>>>>>>BUILD ERRORS
[student@localhost modules]$ make -f make_gpio
========= building dir ==> gpio
CC [M] //home/student/build/sup_sw/linux/angstrom/arm9/modules/gpio/gpio.o
//home/student/build/sup_sw/linux/angstrom/arm9/modules/gpio/gpio.c:1: error: code model âkernelâ not supported in the 32 bit mode
//home/student/build/sup_sw/linux/angstrom/arm9/modules/gpio/gpio.c:1: sorry, unimplemented: 64-bit mode not compiled in
make[2]: *** [//home/student/build/sup_sw/linux/angstrom/arm9/modules/gpio/gpio.o] Error 1
make[1]: *** [_module_//home/student/build/sup_sw/linux/angstrom/arm9/modules/gpio] Error 2
make[1]: *** No rule to make target `zip'. Stop.
make: *** [build] Error 2
[student@localhost modules]$
#
# Sample out of tree build Makefile
# for the TARGET system
#
PWD = $(shell pwd)
ROOTDIR ?= $(KERNEL_ROOT)/..
KSRC = $(ROOTDIR)/$(LINUXDIR)
ARCH ?= arm
CROSS_COMPILE ?=arm-angstrom-linux-gnueabi-
MAKEARCH_KERNEL ?= $(MAKE) ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE)
#ifdef M
obj-m += gpio.o
#else
all:
CFLAGS="" CPPFLAGS="" LDFLAGS="" \
$(MAKEARCH_KERNEL) -C $(ROOTDIR)/$(LINUXDIR) M=$(PWD) modules
$(MAKEARCH_KERNEL) -C $(ROOTDIR)/$(LINUXDIR) M=$(PWD) \
INSTALL_MOD_PATH=$(ROOTDIR)/romfs DEPMOD=true modules_install
romfs:
clean:
$(MAKEARCH_KERNEL) -C $(ROOTDIR)/$(LINUXDIR) M=$(PWD) clean
#endif
Replies (3)
RE: Driver Development Procedure - Added by Michael Williamson over 13 years ago
Hi David,
There's no magic with the kernel sources we're using. Your makefile looks OK to me.
This is just a guess, but the error messages suggest that perhaps your trying to use the wrong toolchain (64 bit on a 32 bit host). Are you using the VM provided, or a native linux install (what distro/version, e.g., what's "uname -a" give you)? Are you using a 32 bit or 64 bit version of linux on your host machine? What version of the toolchain do you have installed?
-Mike
RE: Driver Development Procedure - Added by david kasper over 13 years ago
Mike,
Thanks for your fast reply. I have installed the 32-bit GCC running on Fedora 9. Also I have successfully compiled and tested hello world, an application and shared libraries. Uname generates the following response:
[student@localhost modules]$ uname -a
Linux localhost.localdomain 2.6.25-14.fc9.i686 #1 SMP Thu May 1 06:28:41 EDT 2008 i686 i686 i386 GNU/Linux
FYI I invoked the previous makefile from a top-level makefile listed below. Note the kernel tree was referenced at the ~linux-davinci level as follows:
[student@localhost modules]$ $KERNEL_ROOT
-bash: /home/student/work/arm9/linux-davinci: is a directory
Let me know if you have any suggestions or a simple example to try.
Thanks,
David Kasper
#############################################################################
# uClinux Module Makefile
#
# INVOCATION: make -f make_gpio [build] [clean] [host]
#
# INPUTS: build - rebuild .ko's and compress result
# clean - remove module .o and .ko files
# host - copy module to TFTP_DIR
# KERNEL_ROOT - path to compiler kernel folder
#
#############################################################################
############################################################################
# Environment Variables Section
############################################################################
# Check if required variables are set
ifeq "$(KERNEL_ROOT)" ""
$(error ERROR: KERNEL_ROOT environment variable not set.)
endif
############################################################################
# Module Names Section
############################################################################
MODULENAMES=gpio \
############################################################################
# Make Options Section
#
# ignore-errors - ignore errors in all rules
# no-print-directory - suppress directory messages during recursive make
############################################################################
BUILD_MOPTS=--no-print-directory -C $(KERNEL_ROOT) SUBDIRS=/$(PWD)/$$i modules
MOPTS=--ignore-errors --no-print-directory
############################################################################
# Default Target
#
# all - build libraries
############################################################################
all: build
############################################################################
# Build Modules
############################################################################
build::
@for i in $(MODULENAMES); do \
(echo "========= building dir ==> "$$i; cd $$i; $(MAKE) $(BUILD_MOPTS); \
$(MAKE) $(MOPTS) zip) || exit $?; \
done
############################################################################
# Clean Modules
############################################################################
clean::
@for i in $(MODULENAMES); do \
(echo "======== cleaning dir ==> "$$i; cd $$i; $(MAKE) $(MOPTS) clean) \
|| exit $?; \
done
############################################################################
# Host Modules
############################################################################
host::
@for i in $(MODULENAMES); do \
(echo "======== Hosting module ==> "$$i; cd $$i; $(MAKE) $(MOPTS) host) \
|| exit $?; \
done
RE: Driver Development Procedure - Added by david kasper over 13 years ago
Mike,
For some reason the source gets messed-up when pasting into the reply box. Therefore, I have attached the make files. Note prior to compiling I export the location of the Linux tree as follows:
export KERNEL_ROOT=/home/student/work/arm9/linux-davinci
It will be more efficient to build out of tree during testing.
- Dave
