update README.md

Signed-off-by: Jim Ma <majinjing3@gmail.com>

README.md

@@ -1,4 +1,4 @@
-# Intel igc driver for Synology
+# Intel igc driver for Synology Kernel 4.4.180
 
 > Backport from Linux Kernel v5.12, commit: 9f4ad9e425a1d3b6a34617b8ea226d56a119a717
 
@@ -6,13 +6,47 @@
 
 ### 1. Setup develop environment
 
+#### Prepare Environment
+
+Refer: https://help.synology.com/developer-guide/getting_started/prepare_environment.html
+
+Assume `platform=geminilake`, `version=7.1`, working directory is `/synology-toolkit`
+
+Now the build env is `/synology-toolkit/build_env/ds.geminilake-7.1`
+
+#### Enter chrooot
+
 ```
 sudo chroot /synology-toolkit/build_env/ds.geminilake-7.1
 ```
 
-### 3. Build module
+#### Clone source code
+
+```
+cd /usr/src/
+git clone https://github.com/jim3ma/synology-igc.git
+```
+
+### 2. Build module
 
 ```shell
 cd /usr/src/synology-igc/
 make -C /usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.1/build M=$PWD modules
 ```
+
+### 3. Load module
+
+Copy `igc.ko` to target machine
+
+#### Find i225/i226 pci device
+
+```
+03:00.0 Ethernet controller: Intel Corporation Ethernet Controller I225-V (rev 03)
+```
+
+```
+insmod igc.ko debug=1
+echo igc > /sys/bus/pci/devices/0000:03:00.0/driver_override
+echo 0000:03:00.0 > /sys/bus/pci/drivers_probe
+ip link set up eth1 # in my machine, the nic name is eth1
+```