update doc based upon new machine structure

README.md

@@ -103,24 +103,29 @@ docker run --rm -p 8080:8080 -v $(pwd):/workspace rtlplayground-dev \
   tools/output/httpd_sim /workspace/html
 ```
 
-Edit `machine.h` or `config.txt` on your host, then re-run `make` — the
+Edit `config.txt` on your host, then re-run `make` — the
 source directory is mounted into the container, so changes take effect
-immediately. To build for a different machine, pass `MACHINE=...`.
+immediately. To build for a different machine, pass `MACHINE=<name>`, which
+selects `machine/<name>.c` (see [Adding a new device](doc/adding-a-device.md)).
 
 </details>
 
 ## (1) Compiling for direct chip flashing AND upgrading an existing RTLPlayground running device
 
-Edit machine.h with an editor like vi or nano. Select the correct machine the firmware should build for.
+Pass the machine that matches your device, for example:
+```
+make MACHINE=DEFAULT_8C_1SFP
+```
+The name selects the board definition `machine/<name>.c`; `make` without a
+`MACHINE` value stops with an error listing what is expected. If your board is
+not in the list yet, see [Adding a new device](doc/adding-a-device.md).
 
 > [!TIP]
 > You can write configuration parameters in config.txt (see below) in order your switch to get
 > straight at the first boot, a correct IP configuration.
 
-Now, building the firmware image should work:
-```
-make 
-```
+Now, building the firmware image should work.
+
 Note, that the image generated ends in .bin, not .img, in order to make IMSProg happy.
 
 image location is stored in `RTLPlayground/output/rtlplayground_version_machine.bin`
@@ -353,6 +358,7 @@ Enjoy playing!
 ## (11) Other documents
 
 The following documents give further documentation on specific features of the RTL837x SoCs:
+- [Adding a new device](doc/adding-a-device.md)
 - [RTL8372/3 Feature support](doc/hardware.md)
 - [CPU Port](doc/CpuPort.md)
 - [L2 learning](doc/l2.md) 

doc/devices/2M-PCB23-V3_2.md

@@ -17,8 +17,8 @@ The original web interface reports this board as hardware version V3.2
 The component placement matches [2M-PCB23-V3.1](2M-PCB23-V3_1.md): same
 positions for the flash (U8), the T7/T8/T9/T10 headers, the SFP cage and its
 LED, and the unpopulated U7/U9 footprints. Build with
-`MACHINE=KP_9000_9XHML_X_V3_2`, which uses the V3.1 machine definition and
-only differs in the reported name.
+`make MACHINE=KP_9000_9XHML_X_V3_2`, whose board file is a symlink to the V3.1
+definition and only differs in the reported name.
 
 ## Tested
 

doc/devices/2M-PCB43-V1.1.md

@@ -15,7 +15,7 @@ and sold by Mokerlink.
 The device is fully supported:
 - All 4 2.5GBASE-T RJ45 ports work at 10/100/1000/2500 Mbps
 - The SFP+ port supports 1G, 2.5G and 10G modules 
-- LEDs work with the same indiciations as the OEM firmware (use KP_9000_6XHML_X2_V1_1 in machine.h if building yourself or the corresponding pre-compiled binary)
+- LEDs work with the same indiciations as the OEM firmware (build with `make MACHINE=KP_9000_6XHML_X2_V1_1` if building yourself, or use the corresponding pre-compiled binary)
 - untested due to missing Hardware: SFP+ ports equipped with 1G or 2.5G SFPs.
 
 ### Hardware overview

doc/devices/SWTGW215AS.md

@@ -9,7 +9,7 @@
 
 ## RTLPlayground target
 
-Use machine target `MACHINE_LIANGUO_ZX_SWTGW215AS` for this device.
+Build for this device with `make MACHINE=LIANGUO_ZX_SWTGW215AS`, which selects the `machine/LIANGUO_ZX_SWTGW215AS.c` board definition.
 
 Physical hardware verification: 5x RJ45 ports + 1x SFP port. 
 Port 5 RJ45 is interfaced through a RTL8221B IC.