Merge pull request #14 from aiguo159/esd_inst

instruction to compile and install out-of-tree ESD kernel module

Author: quning18

linux/ESDCAN-README.md

@@ -2,30 +2,27 @@
 
 In the first release of Apollo software, ESD PCIe CAN is used for CAN communications with the vehicle -- please refer to *Apollo 1.0 Hardware and System Installation Guide* for more information. You MUST obtain ESD CAN driver (kernel module) software from ESD Electronics, and compile it with Apollo Linux kernel to run Apollo software stack.
 
-### How To Add ESD CAN Support
+### How To Add ESD CAN Support to Apollo Kernel
 
 1. After/when you purchase CAN card from ESD Electronics, please contact [email protected] to obtain their supporting software package (search for can-pcie/402 to find it on their download website). We have tested version 3.10.3. You may need to make some changes if you use a different version.
-2. After unpacking the software package, please copy all files under src/ directory to drivers/esdcan/, except for Makefile.
+2. After unpacking the software package, please copy all files under src/ directory to drivers/esdcan/ (after having applied path linux/patches/esdcan.path), except for Makefile.
 3. Do the following to prepare for build:
 ```bash
 cd drivers/esdcan/;rm Makefile Kconfig;ln -s Makefile.esd Makefile;ln -s Kconfig.esd Kconfig;cd ../..
 ```
 4. If you have run build.sh to customize your build, you may need to do it again. You can now run "./build.sh [target]" to build the kernel.
 
-### Build ESD Kernel Driver with Pre-Built Apollo Kernel
+### Build & Install Out-of-Tree ESD Kernel Driver
 
-The ESD CAN driver is not included in the pre-built kernel image release; you can build it after you install the pre-built image, follow the steps below.
-1. Download ESD CAN Linux software package from ESD as instructed above.
-2. Unpack the package, cd into the package directory; then do the following:
+The ESD CAN driver is not included in the pre-built Apollo kernel image release; you can build it after you install the pre-built image, follow the steps below. This also works for other pre-built Linux kernels.
+1. Install kernel headers for your version of Linux kernel, if not done already. Pre-built Apollo kernel comes with kernel headers.
+2. Download ESD CAN Linux software package from ESD as instructed above.
+3. Unpack the package, cd into the package directory; then do the following:
 ```bash
-cd src/; mv Makefile Makefile.orig
+cd src/; make -C /lib/modules/`uname -r`/build M=`pwd`
+sudo make -C /lib/modules/`uname -r`/build M=`pwd` modules_install
 ```
-3. Download Apollo's modified ESD kernel module makefile (path: linux/drivers/esdcan/Makefile.esd), and save Makefile.esd into the src/ directory.
-4. Do the following to build the kernel module:
-```bash
-ln -s Makefile.esd Makefile;make
-```
-5. The compiled ESD driver is esdcan-pcie402.ko.
+4. The newly compiled ESD driver is esdcan-pcie402.ko, and is installed into /lib/modules/`uname -r`/extra/.
 
 ### Legal Disclaimer
-The kernel image that you build contains the ESD CAN driver module compiled from source code provided by ESD Electronics (hereby referred as ESD) if ESD CAN driver code is added as instructed above. In the process of obtaining the software, you should have entered a licensing agreement with ESD which shall have granted you (as an individual or a business entity) the right to use the said software provided by ESD; however, you may (and likely you do) need explicit re-distribution permission from ESD to publish the kernel image for any other third party to consume. Such licensing agreement is solely between you and ESD, and is not covered by the license terms of the Apollo project (see file LICENSE under Apollo top directory).
+The kernel image that you build contains the ESD CAN driver module compiled from source code provided by ESD Electronics (hereby referred as ESD) if ESD CAN driver code is added as instructed above. In the process of obtaining the software, you should have entered a licensing agreement with ESD which shall have granted you (as an individual or a business entity) the right to use the said software provided by ESD; however, you may or may not need explicit re-distribution permission from ESD to publish the kernel image for any other third party to consume. Such licensing agreement is solely between you and ESD, and is not covered by the license terms of the Apollo project (see file LICENSE under Apollo top directory).