hexagon: overhaul of buffer and DMA handling to support 64bit mappings + improvements (#29197)

* hex-dma64: enable support extended buffer mappings and 64bit dma

hex-dma64: expand binary ops to support more DMA scenarios

hex-dma64: add binary-ops.h

hex-dma64: add --hex-dma64 to run.py and fix minor issues

hex-dma64: update SSM_CONV to use dma with proper support for 64bit

hex-ops: remove obsolete gate for % 128 in binary ops

hex-l2: dont check weight tensors against dirty ranges

hex-dma64: most binary ops now support dma

hex-dma: use dma_addr_t instead of plain uint64_t to avoid overhead on older targets

hex-dma: update all dma users to use dma_data (instead of pointers)

hex-dma64: simplify lazy buffer mapping and clonning

hex-fusion: factor out try_fuse_common that checks for dma64 buffers

hex-bufs: minor cleanup for mmaping logic

hex-bufs: simplify buffer clonning

hex-ssm-conv: tighten gating checks and check vtcm size in kparams

hex-binary: fix incorred mod/wrap in scalar ops

hex-binary: make sure to call precompute kparams in support checks

hex-dma64: update addr handling in mm,concat,binary

hex-dma64: fixing up leftover of dma_addr_t conversion

hex-binary: redo the kernel selection again and fix regressions in MOEs

hex-binary: specialize per-type/per-op

hex-binary: vtcm-layout and per-src dma-queue

hex-dma64: update dma_push to transparently handle 64bit/extended

* hex-cpy: fix improper rebase with the fixes for cont. tensors

* hex-dma-cpy: update CPY to use safe dma rows/size limits

* hex-mmap: bump number of mmaps to 64 to allow avoid eviction in larger models

* hex-dma: add support for the secondary ring as a fallback for too-large transactions

* hex-rope: fix freq_factors access with 64bit dma

* hex-dma: audit all ops for proper use/gards for 64bit addresses

* hex-dma64: uninline glu-compute funcs to avoid register pressure due to 64bit addr math

* hex-dma64: refactor binary ops to separate dma loops

* hex-devel: add inspect script to help with dbg and analysis

* hex-dma: refactor dma-pipelines in unary-ops

* hex-dma: rewrite softmax to use dma

* hex-dma: rewrite GDN dma loops and improve HVX register usage

* hex-gdn: fuse GDN+CPY

* hex-mm: factor out HVX solver

* hex-mm: remove hvx-flat kernels, the chunked version now handles vtcm limits much better

* hex-buffs: reject huge buffer allocations that we cannot memory map

* hex-inspect: add logic to look for float promo calls

* hex-mm: reduce HVX register spills in HVX prompt kernels

* hex-bufs: do not double count buffers from tensors in the same op

* hex-roll: fix merge conflict

* hex-dma: reroute all matmul ddr kernels to new chunked dma/vtcm kernels

* hex-dev: update developer docs to include inspection for register spils and float promos

* hex-ops: forgot to add new headers

* hex-softmax: fix gpt-oss dims

* hex-dma64: cleanup dma_addr_t casts

* hex-dma64: add support for dma/vtcm for flash-atten with sinks

* hex-mm-add: fix MUL_MAT+ADD fusion with bias.weights in extended bufs

* hex-add-id: add support for dma for src1 (exp. table)

* hex-dma: imrpove v73 fallback paths

* hex-bufs: do not drop extended mappings during va defrag

* hex-scripts: fix flake8 warnings

* hex-docs: fix editor-config warnings

* hex-inspect: fix warnings from ty

docs/backend/snapdragon/README.md

@@ -327,6 +327,9 @@ on 4 physical NPUs, or `--devices 'HTP0[0-1:0],HTP1[0-1:1]'` on 2 physical NPUs
 - `GGML_HEXAGON_HOSTBUF=1` (default: 0, disabled)
   Enables allocating host buffers for debugging. By default, host buffers are disabled.
 
+- `GGML_HEXAGON_DMA64=0` (default: enabled on v81+)
+  Disables 64-bit DMA for model weights. Set to `1` to enable it explicitly on a supported architecture.
+
 - `GGML_HEXAGON_VERBOSE=1`
   Enables verbose logging of Ops from the backend. Example output:
 

docs/backend/snapdragon/developer.md

@@ -146,6 +146,28 @@ Writing high-performance operators for Hexagon requires following specific guide
   python3 scripts/snapdragon/ggml-hexagon-align-macros.py --fix ggml/src/ggml-hexagon/htp/
   ```
 
+### Binary Inspection and Spill Analysis
+
+Use [`scripts/snapdragon/ggml-hexagon-inspect.py`](../../../scripts/snapdragon/ggml-hexagon-inspect.py) to audit Hexagon binaries for register
+spills, unexpected float promotions, or disassembly:
+
+- Always verify that compute kernels have zero in-loop vector spills (`--spills --strict`) and no float promotions (`--promotions`).
+- Avoid excessive loop unrolling (`#pragma unroll`), which increases register pressure and causes spills.
+
+```bash
+# Check for vector and scalar register spills
+python3 scripts/snapdragon/ggml-hexagon-inspect.py --spills --strict --func "^compute_"
+
+# Check for float promotions
+python3 scripts/snapdragon/ggml-hexagon-inspect.py --promotions --func "^compute_"
+
+# Disassemble with annotated loops and spill markers
+python3 scripts/snapdragon/ggml-hexagon-inspect.py --disasm compute_same_shape_div_f32
+
+# Resolve crash addresses to function symbols and lines
+python3 scripts/snapdragon/ggml-hexagon-inspect.py --addr2line 0x51a30 0x5ba54
+```
+
 ## Multi-Device Partitioning (mdev)
 
 Multi-device (mdev) mode enables row-level tensor parallel execution across multiple physical NPU cores or virtual NPU