[Model][3/N] Refactor sfa into mla and remove deepseek_v3_2.py (#3769)

This is the follow-up PR to PR #3189, which continues to refactor sfa
into mla and finally remove deepseek_v3_2.py. This is the last PR of
deepseek modeling refactoring. After this, all deepseek-related model
codes are removed from vllm_ascend.

FurtherMore, after this PR deepseek v3.2 can run chunk-prefill with
correct accuracy.

- vLLM version: v0.11.0rc3
- vLLM main:
vllm-project/vllm@83f478b

---------

Signed-off-by: whx-sjtu <[email protected]>

Author: whx-sjtu

vllm_ascend/attention/mla_v1.py

@@ -52,6 +52,8 @@
 if TYPE_CHECKING:
     from vllm.v1.core.sched.output import SchedulerOutput
 
+MAX_O_PROJ_PREFETCH_SIZE = 16 * 1024 * 1024
+
 
 class AscendMLABackend(AttentionBackend):
 
@@ -808,16 +810,17 @@ def get_and_maybe_dequant_weights(layer: LinearBase):
         # self.W_UV.data = torch_npu.npu_format_cast(self.W_UV.data, 29)
         # self.W_UK_T.data = torch_npu.npu_format_cast(self.W_UK_T.data, 29)
 
-        # Currently mlapo only supports W8A8 quantization in MLA scenario
-        # TODO(whx): modify this limitation when mlapo supports floating point
-        if self.fused_qkv_a_proj is None or not isinstance(
-                getattr(self.fused_qkv_a_proj.quant_method, 'quant_method',
-                        None), AscendW8A8LinearMethod):
-            self.enable_mlapo = False
-            logger.warning_once(
-                "Currently mlapo only supports W8A8 quantization in MLA scenario."
-                "Some layers in your model are not quantized with W8A8,"
-                "thus mlapo is disabled for these layers.")
+        if self.enable_mlapo:
+            # Currently mlapo only supports W8A8 quantization in MLA scenario
+            # TODO(whx): modify this limitation when mlapo supports floating point
+            if self.fused_qkv_a_proj is None or not isinstance(
+                    getattr(self.fused_qkv_a_proj.quant_method, 'quant_method',
+                            None), AscendW8A8LinearMethod):
+                self.enable_mlapo = False
+                logger.warning_once(
+                    "Currently mlapo only supports W8A8 quantization in MLA scenario."
+                    "Some layers in your model are not quantized with W8A8,"
+                    "thus mlapo is disabled for these layers.")
         if self.enable_mlapo:
             self._process_weights_for_fused_mlapo(act_dtype)
 
@@ -1282,12 +1285,13 @@ def _mla_decode_preprocess(self, hidden_states, kv_cache, attn_metadata):
     def _mla_preprocess(self, layer_name, hidden_states, kv_cache,
                         attn_metadata, need_gather_q_kv):
         # MLA Preprocess:
-        # 1. Perform q_a_proj and q_a_layernorm to obtain q_c
-        # 2. Perform kv_a_proj_with_mqa to obtain kv_no_split
-        # 3. If need_gather_q_kv, perform all_gather.
-        # 4. Preprocess decode tokens, write kv cache and get:
+        # 1. Perform fused_qkv_a_proj and q_a_layernorm to obtain q_c and kv_no_split
+        # or
+        #    Perform kv_a_proj_with_mqa to obtain kv_no_split
+        # 2. If need_gather_q_kv, perform all_gather.
+        # 3. Preprocess decode tokens, write kv cache and get:
         # decode_ql_nope, decode_q_pe, decode_k_pe, decode_k_nope
-        # 5. Preprocess prefill tokens, write kv cache and get:
+        # 4. Preprocess prefill tokens, write kv cache and get:
         # prefill_q_nope, prefill_q_pe, prefill_k_nope, prefill_k_pe, prefill_value
         has_decode = attn_metadata.num_decodes > 0
         has_prefill = attn_metadata.num_prefills > 0