hexagon : fix DMA transfers with strides > 24 bits (#31442)

* hexagon : fix DMA transfers with strides > 24 bits

On v75+ the 2D DMA descriptor stores row_size and strides in 24 bits.
dma_queue_push sent oversized strides to fallback_2d, which only splits
nrows, so strides of 16 MB or more were truncated - wrong addresses.
Fix will fall back to one transfer per row in that case.

Also added two CONT tests with source strides over 16 MB.

* hex-dma: refactor the fallback paths to remove duplication

---------

Co-authored-by: Max Krasnyansky <maxk@qti.qualcomm.com>

ggml/src/ggml-hexagon/htp/dma-queue.c

@@ -141,43 +141,9 @@ bool dma_queue_push_fallback_2d(dma_queue * q, dma_data ddata, size_t dst_stride
     dma_ring_flush(r1);
     r0->tail = r1->tail;
 
-    return dma_ring_push_single_2d(r0, ddata, 0, 0, 0, /*nrows=*/ 0);
-}
-
-bool dma_queue_push_fallback_contig(dma_queue * q, dma_data ddata, size_t total) {
-    dma_ring * r0 = q->ring0;
-    dma_ring * r1 = q->ring1;
-
-    if (((r0->push_idx + 1) & r0->idx_mask) == r0->pop_idx) {
-        return false;
-    }
-
-    r1->tail = r0->tail;
-
-    size_t rem_bytes   = total;
-    dma_addr_t cur_dst = ddata.dst;
-    dma_addr_t cur_src = ddata.src;
-
-    while (rem_bytes > 0) {
-        const uint32_t cur_bytes = MIN(rem_bytes, DMA_SAFE_CHUNK_SIZE);
-        dma_data cur_data = dma_make_data(cur_dst, cur_src);
-        if (!dma_ring_push_single_contig(r1, cur_data, cur_bytes)) {
-            dma_ring_flush(r1);
-            dma_ring_push_single_contig(r1, cur_data, cur_bytes);
-        }
-        cur_dst   += cur_bytes;
-        cur_src   += cur_bytes;
-        rem_bytes -= cur_bytes;
-    }
-
-    dma_ring_flush(r1);
-    r0->tail = r1->tail;
-
     return dma_ring_push_single_1d(r0, ddata, /*size=*/ 0);
 }
 
-#if __HVX_ARCH__ < 75
-
 bool dma_queue_push_fallback_1d(dma_queue * q, dma_data ddata, size_t dst_stride, size_t src_stride, size_t row_size, size_t nrows) {
     dma_ring * r0 = q->ring0;
     dma_ring * r1 = q->ring1;
@@ -188,19 +154,28 @@ bool dma_queue_push_fallback_1d(dma_queue * q, dma_data ddata, size_t dst_stride
 
     r1->tail = r0->tail;
 
-    size_t rem_rows    = nrows;
-    dma_addr_t cur_dst = ddata.dst;
-    dma_addr_t cur_src = ddata.src;
+    dma_addr_t row_dst = ddata.dst;
+    dma_addr_t row_src = ddata.src;
 
-    while (rem_rows > 0) {
-        dma_data cur_data = dma_make_data(cur_dst, cur_src);
-        if (!dma_ring_push_single_1d(r1, cur_data, row_size)) {
-            dma_ring_flush(r1);
-            dma_ring_push_single_1d(r1, cur_data, row_size);
+    for (size_t i = 0; i < nrows; i++) {
+        size_t     rem_bytes = row_size;
+        dma_addr_t cur_dst   = row_dst;
+        dma_addr_t cur_src   = row_src;
+
+        while (rem_bytes > 0) {
+            const uint32_t cur_bytes = MIN(rem_bytes, DMA_SAFE_CHUNK_SIZE);
+            dma_data cur_data = dma_make_data(cur_dst, cur_src);
+            if (!dma_ring_push_single_contig(r1, cur_data, cur_bytes)) {
+                dma_ring_flush(r1);
+                dma_ring_push_single_contig(r1, cur_data, cur_bytes);
+            }
+            cur_dst   += cur_bytes;
+            cur_src   += cur_bytes;
+            rem_bytes -= cur_bytes;
         }
-        cur_dst  += dst_stride;
-        cur_src  += src_stride;
-        rem_rows -= 1;
+
+        row_dst += dst_stride;
+        row_src += src_stride;
     }
 
     dma_ring_flush(r1);
@@ -208,5 +183,3 @@ bool dma_queue_push_fallback_1d(dma_queue * q, dma_data ddata, size_t dst_stride
 
     return dma_ring_push_single_1d(r0, ddata, /*size=*/ 0);
 }
-
-#endif

ggml/src/ggml-hexagon/htp/dma-queue.h

@@ -148,10 +148,7 @@ dma_queue_t dma_queue_alias_init(void * ptr, dma_queue_t main_q);
 void        dma_queue_alias_free(dma_queue_t q);
 
 bool        dma_queue_push_fallback_2d(dma_queue * q, dma_data ddata, size_t dst_stride, size_t src_stride, size_t row_size, size_t nrows);
-bool        dma_queue_push_fallback_contig(dma_queue * q, dma_data ddata, size_t total);
-#if __HVX_ARCH__ < 75
 bool        dma_queue_push_fallback_1d(dma_queue * q, dma_data ddata, size_t dst_stride, size_t src_stride, size_t row_size, size_t nrows);
-#endif
 
 // TODO: technically we don't need these and could use Q6_dmstart/wait/etc instead
 // but those do not seem to always compiler properly.
@@ -400,7 +397,7 @@ static inline bool dma_queue_push(dma_queue * q, dma_data ddata, size_t dst_stri
         if (__builtin_expect(total <= DMA_MAX_SIZE_24B, 1)) {
             return dma_ring_push_single_contig(q->ring0, ddata, total);
         }
-        return dma_queue_push_fallback_contig(q, ddata, total);
+        return dma_queue_push_fallback_1d(q, ddata, 0, 0, total, 1);
     }
 
     // 2. Hot path: Standard strided 2D (10-20% of calls)
@@ -410,14 +407,10 @@ static inline bool dma_queue_push(dma_queue * q, dma_data ddata, size_t dst_stri
     }
 
     // 3. Cold path: Descriptor chunking fallbacks (< 0.1%)
-#if __HVX_ARCH__ < 75
-    if (row_size <= DMA_MAX_SIZE_16B && (src_stride | dst_stride) <= DMA_MAX_STRIDE_16B) {
+    if ((row_size | src_stride | dst_stride) <= DMA_MAX_2D_ROW_SIZE) {
         return dma_queue_push_fallback_2d(q, ddata, dst_stride, src_stride, row_size, nrows);
     }
     return dma_queue_push_fallback_1d(q, ddata, dst_stride, src_stride, row_size, nrows);
-#else
-    return dma_queue_push_fallback_2d(q, ddata, dst_stride, src_stride, row_size, nrows);
-#endif
 }
 
 static inline void dma_sync_read(dma_queue * dma_q, void * dst, dma_addr_t src, size_t bytes) {

tests/test-backend-ops.cpp

@@ -10831,6 +10831,10 @@ static std::vector<std::unique_ptr<test_case>> make_test_cases_eval() {
         }
     }
 
+    // source strides over 16 MB (24-bit DMA descriptor limit)
+    test_cases.emplace_back(new test_cont(GGML_TYPE_F32, {512, 8193, 2, 1}, false, {2, 1, 0, 3}));
+    test_cases.emplace_back(new test_cont(GGML_TYPE_F32, {256, 16385, 2, 1}, false, {0, 2, 1, 3}));
+
     auto add_test_bin_bcast = [&](ggml_type type, std::array<int64_t, 4> ne, std::array<int, 4> nr, bool perm1 = false, bool src_overlap = false) {
         for (auto op : {ggml_add, ggml_sub, ggml_mul, ggml_div}) {
             test_cases.emplace_back(new test_bin_bcast(op, type, ne, nr, 1, perm1, src_overlap));