ggml-hexagon: add PAD op HVX kernel (#23078)

* ggml-hexagon: add PAD op HVX kernel

Implements GGML_OP_PAD on the Hexagon HTP backend using HVX vectorized
kernels. Supports zero-padding and circular padding across all 4 tensor
dimensions.

* hex-ggml: remove duplicate op cases (merge conflict)

* hex-pad: fix editorconfig checks and macro alignment

---------

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

Author: pdhinaka

ggml/src/ggml-hexagon/ggml-hexagon.cpp

@@ -2744,6 +2744,18 @@ static bool ggml_hexagon_supported_ssm_conv(const struct ggml_hexagon_session *
     return true;
 }
 
+static bool ggml_hexagon_supported_pad(const struct ggml_hexagon_session * sess, const struct ggml_tensor * op) {
+    const struct ggml_tensor * src0 = op->src[0];
+    const struct ggml_tensor * dst  = op;
+
+    if (src0->type != GGML_TYPE_F32 || dst->type != GGML_TYPE_F32) {
+        return false;
+    }
+
+    GGML_UNUSED(sess);
+    return true;
+}
+
 static bool ggml_hexagon_supported_cumsum(const struct ggml_hexagon_session * sess, const struct ggml_tensor * op) {
     const struct ggml_tensor * src0 = op->src[0];
     const struct ggml_tensor * dst  = op;
@@ -2857,6 +2869,8 @@ static htp_op_code op_remap_to_htp(const ggml_tensor * t) {
         case GGML_OP_FILL:            return HTP_OP_FILL;
         case GGML_OP_DIAG:            return HTP_OP_DIAG;
         case GGML_OP_SOLVE_TRI:       return HTP_OP_SOLVE_TRI;
+        case GGML_OP_PAD:             return HTP_OP_PAD;
+
         case GGML_OP_UNARY:
             switch (ggml_get_unary_op(t)) {
                 case GGML_UNARY_OP_SILU:     return HTP_OP_UNARY_SILU;
@@ -3416,6 +3430,10 @@ static bool ggml_backend_hexagon_device_supports_op(ggml_backend_dev_t dev, cons
             supp = ggml_hexagon_supported_solve_tri(sess, op);
             break;
 
+        case GGML_OP_PAD:
+            supp = ggml_hexagon_supported_pad(sess, op);
+            break;
+
         default:
             break;
     }

ggml/src/ggml-hexagon/htp/CMakeLists.txt

@@ -38,6 +38,7 @@ add_library(${HTP_LIB} SHARED
     diag-ops.c
     solve-tri-ops.c
     gated-delta-net-ops.c
+    pad-ops.c
 )
 
 target_compile_definitions(${HTP_LIB} PRIVATE

ggml/src/ggml-hexagon/htp/htp-ctx.h

@@ -107,5 +107,6 @@ int op_fill(struct htp_ops_context * octx);
 int op_diag(struct htp_ops_context * octx);
 int op_solve_tri(struct htp_ops_context * octx);
 int op_gated_delta_net(struct htp_ops_context * octx);
+int op_pad(struct htp_ops_context * octx);
 
 #endif /* HTP_CTX_H */

ggml/src/ggml-hexagon/htp/htp-ops.h

@@ -86,6 +86,7 @@ enum htp_op_code {
     HTP_OP_SOLVE_TRI,
     HTP_OP_L2_NORM,
     HTP_OP_GATED_DELTA_NET,
+    HTP_OP_PAD,
 
     HTP_OP_INVALID
 };

ggml/src/ggml-hexagon/htp/main.c

@@ -595,6 +595,9 @@ static int execute_op(struct htp_ops_context * octx) {
         case HTP_OP_SOLVE_TRI:
             return op_solve_tri(octx);
 
+        case HTP_OP_PAD:
+            return op_pad(octx);
+
         case HTP_OP_GATED_DELTA_NET:
             return op_gated_delta_net(octx);