Merge branch 'multiple' into 'master'

Update docs for quantization usage

See merge request !1232

docs/user_guide/quantization_usage.rst

@@ -13,6 +13,11 @@ Refer to `Tensorflow quantization-aware training <https://github.com/tensorflow/
 After pre-training model using float point, estimate output range of each activation layer using sample inputs.
 
 
+.. note::
+
+  `quantize_weights` and `quantize_nodes` should not be specified when using `TransformGraph` tool if using MACE quantization.
+
+
 Quantization-aware training
 ----------------------------
 It is recommended that developers fine tune the fixed-point model, as experiments show that by this way accuracy could be improved, especially for lightweight
@@ -69,6 +74,41 @@ MACE provides tools to do statistics with following steps:
   `quantize` to `1` and `quantize_range_file` to the overall_range file path in yaml config).
 
 
-.. note::
+Supported devices
+-----------------
+MACE supports running quantized models on ARM CPU and other acceleration devices, e.g., Qualcomm Hexagon DSP, MediaTek APU.
+ARM CPU is ubiquitous, which can speed up most of edge devices. However, AI specialized devices may run much faster
+than ARM CPU, and in the meantime consume much lower power. Headers and libraries of these devices can be found in `third_party`
+directory.
 
-	`quantize_weights` and `quantize_nodes` should not be specified when using `TransformGraph` tool if using MACE quantization.
+* **To run models on Hexagon DSP, users should**
+
+  1. Make sure SOCs of the phone is manufactured by Qualcomm and has HVX supported.
+
+  2. Make sure the phone disables secure boot (once enabled, cannot be reversed, so you probably can only get that type
+     phones from manufacturers). This can be checked by executing the following command.
+
+   .. code-block:: sh
+
+       adb shell getprop ro.boot.secureboot
+
+   The return value should be 0.
+
+  3. Root the phone.
+
+  4. Sign the phone by using testsig provided by Qualcomm. (Download Qualcomm Hexagon SDK first, plugin the phone to PC,
+     run scripts/testsig.py)
+
+  5. Push `third_party/nnlib/v6x/libhexagon_nn_skel.so` to `/system/vendor/lib/rfsa/adsp/`. You can check
+     `docs/feature_matrix.html` in Hexagon SDK to make sure which version to use.
+
+Then, there you go, you can run Mace on Hexagon DSP. This indeed seems like a whole lot of work to do. Well, the good news
+is that starting in the SM8150 family(some devices with old firmware may still not work), signature-free dynamic
+module offload is enabled on cDSP. So, steps 2-4 can be skipped. This can be achieved by calling `SetHexagonToUnsignedPD()`
+before creating MACE engine.
+
+* **To run models on MediaTek APU, users should**
+
+  1. Make sure SOCs of the phone is manufactured by MediaTek and has APU supported.
+
+  2. Push `third_party/apu/mtxxxx/libapu-platform.so` to `/vendor/lib64/`.