hexagon: add support for linux on snapdragon (ggml-org#21707)

* hexagon: add support for debian on ex2

* hexagon: add -fvectotize to c/c++ cmake flags

* hexagon: remove trailing white space

* update onboarding steps

* hexagon: update linux setup documentation

* hexagon: update intallation scripts

* Hexagon: update docs

* hexagon: update onboarding scripts

---------

Co-authored-by: Zack Li <zackli@qti.qualcomm.com>

Author: tboinovski1

cmake/arm64-linux-clang.cmake

@@ -0,0 +1,17 @@
+set( CMAKE_SYSTEM_NAME Linux )
+set( CMAKE_SYSTEM_PROCESSOR arm64 )
+
+set( target aarch64-linux-gnu )
+
+set( CMAKE_C_COMPILER    clang )
+set( CMAKE_CXX_COMPILER  clang++ )
+
+set( CMAKE_C_COMPILER_TARGET   ${target} )
+set( CMAKE_CXX_COMPILER_TARGET ${target} )
+
+set( arch_c_flags "-march=armv8.7-a -fvectorize -ffp-model=fast -fno-finite-math-only" )
+set( warn_c_flags "-Wno-format -Wno-unused-variable -Wno-unused-function -Wno-gnu-zero-variadic-macro-arguments" )
+
+set( CMAKE_C_FLAGS_INIT   "${arch_c_flags} ${warn_c_flags}" )
+set( CMAKE_CXX_FLAGS_INIT "${arch_c_flags} ${warn_c_flags}" )
+

docs/backend/snapdragon/CMakeUserPresets.json

@@ -52,10 +52,39 @@
         }
     },
 
+    {
+        "name": "arm64-linux-snapdragon",
+        "hidden": true,
+        "architecture": { "value": "arm64",       "strategy": "external" },
+        "toolset":      { "value": "host=x86_64", "strategy": "external" },
+        "cacheVariables": {
+            "CMAKE_TOOLCHAIN_FILE": "cmake/arm64-linux-clang.cmake",
+            "CMAKE_C_FLAGS":   "-march=armv8 -fno-finite-math-only -flto -D_GNU_SOURCE",
+            "CMAKE_CXX_FLAGS": "-march=armv8 -fno-finite-math-only -flto -D_GNU_SOURCE",
+            "CMAKE_C_FLAGS_RELEASE":          "-O3 -DNDEBUG",
+            "CMAKE_CXX_FLAGS_RELEASE":        "-O3 -DNDEBUG",
+            "CMAKE_C_FLAGS_RELWITHDEBINFO":   "-O3 -DNDEBUG -g",
+            "CMAKE_CXX_FLAGS_RELWITHDEBINFO": "-O3 -DNDEBUG -g",
+            "CMAKE_PREFIX_PATH":  "$env{OPENCL_SDK_ROOT}",
+            "HEXAGON_SDK_ROOT":   "$env{HEXAGON_SDK_ROOT}",
+            "HEXAGON_TOOLS_ROOT": "$env{HEXAGON_TOOLS_ROOT}",
+            "PREBUILT_LIB_DIR": "linux_aarch64",
+            "GGML_OPENMP":      "OFF",
+            "GGML_LLAMAFILE":   "OFF",
+            "GGML_OPENCL":      "OFF",
+            "GGML_HEXAGON":     "ON",
+            "GGML_HEXAGON_FP32_QUANTIZE_GROUP_SIZE": "128",
+            "LLAMA_OPENSSL":    "OFF"
+        }
+    },
+
     { "name": "arm64-android-snapdragon-debug"  , "inherits": [ "base", "arm64-android-snapdragon", "debug" ] },
     { "name": "arm64-android-snapdragon-release", "inherits": [ "base", "arm64-android-snapdragon", "release" ] },
 
     { "name": "arm64-windows-snapdragon-debug"  , "inherits": [ "base", "arm64-windows-snapdragon", "debug" ] },
-    { "name": "arm64-windows-snapdragon-release", "inherits": [ "base", "arm64-windows-snapdragon", "release" ] }
+    { "name": "arm64-windows-snapdragon-release", "inherits": [ "base", "arm64-windows-snapdragon", "release" ] },
+
+    { "name": "arm64-linux-snapdragon-debug"  , "inherits": [ "base", "arm64-linux-snapdragon", "debug" ] },
+    { "name": "arm64-linux-snapdragon-release", "inherits": [ "base", "arm64-linux-snapdragon", "release" ] }
   ]
 }

docs/backend/snapdragon/linux.md

@@ -0,0 +1,58 @@
+# Snapdragon-based Linux devices
+
+## Docker Setup
+
+The easiest way to build llama.cpp for a Snapdragon-based Linux device is using the toolchain Docker image (see [github.com/snapdragon-toolchain](https://github.com/snapdragon-toolchain)).
+This image includes OpenCL SDK, Hexagon SDK, CMake, and the ARM64 Linux cross-compilation toolchain.
+
+Cross-compilation is supported on **Linux X86** hosts. The resulting binaries are deployed to and run on the target **Qualcomm Snapdragon ARM64 Linux** device.
+
+```
+~/src/llama.cpp$ docker run -it -u $(id -u):$(id -g) --volume $(pwd):/workspace --platform linux/amd64 ghcr.io/snapdragon-toolchain/arm64-linux:v0.1
+[d]/> cd /workspace
+```
+
+Note: The rest of the **Linux** build process assumes that you're running inside the toolchain container.
+
+
+## How to Build
+
+Let's build llama.cpp with CPU, OpenCL, and Hexagon backends via CMake presets:
+
+```
+[d]/workspace> cp docs/backend/snapdragon/CMakeUserPresets.json .
+
+[d]/workspace> cmake --preset arm64-linux-snapdragon-release -B build-snapdragon
+
+[d]/workspace> cmake --build build-snapdragon -j $(nproc)
+```
+
+To generate an installable "package" simply use cmake --install, then zip it:
+
+```
+[d]/workspace> cmake --install build-snapdragon --prefix pkg-snapdragon
+[d]/workspace> zip -r pkg-snapdragon.zip pkg-snapdragon
+```
+
+## How to Install
+
+For this step, you will deploy the built binaries and libraries to the target Linux device. Transfer `pkg-snapdragon.zip` to the target device, then unzip it and set up the environment variables:
+
+```
+$ unzip pkg-snapdragon.zip
+$ cd pkg-snapdragon
+$ export LD_LIBRARY_PATH=./lib
+$ export ADSP_LIBRARY_PATH=./lib
+```
+
+At this point, you should also download some models onto the device:
+
+```
+$ wget https://huggingface.co/bartowski/Llama-3.2-3B-Instruct-GGUF/resolve/main/Llama-3.2-3B-Instruct-Q4_0.gguf
+```
+
+## How to Run
+Next, since we have setup the environment variables, we can run the llama-cli with the Hexagon backends:
+```
+$ ./bin/llama-cli -m Llama-3.2-3B-Instruct-Q4_0.gguf --device HTP0 -ngl 99 -p "what is the most popular cookie in the world?"
+```