[Hardware][Ascend] Integrate MindIE dense and sparse quantized attention for Wan2.2 T2V (#7561)

Signed-off-by: zqxu <xuzhenqiang3@huawei.com>
Co-authored-by: zqxu <xuzhenqiang3@huawei.com>

docs/user_guide/diffusion/attention_backends/rainfusion.md

@@ -78,3 +78,35 @@ Protected video tails require a compatible MindIE-SD release.
 For common configuration and selector behavior, see the
 [attention backend overview](../attention_backends.md) and the
 [backend selection design](../../../design/feature/attention_backend_selection.md).
+
+## Wan2.2 T2V quantization on Ascend
+
+`RAINFUSION_ATTN` accepts `diffusion_kv_cache_dtype: fp8` or `mxfp4` for
+Wan2.2 T2V A14B.
+MindIE-SD must expose `sparse_attention` with `rf_v3` and an explicit `precision`
+argument. Omni passes the selected precision directly to this API; the installed
+native operators must support that precision. Unsupported inputs or an
+incompatible Python API raise an actionable error; Omni does not change BSA
+precision automatically. Update `diffusion_kv_cache_dtype` to a precision
+supported by the installed MindIE-SD, or unset it. Native execution errors also
+propagate without retry.
+BSA FP8 and MXFP4 retain MindIE-SD's default rotation policy.
+
+`diffusion_kv_cache_skip_layers`/`diffusion_kv_cache_skip_steps` explicitly
+select floating-point BSA and keep attention sparse. The existing `block_sparse`
+warmup/layer exclusions and short-sequence threshold instead select Dense
+attention, using the configured Dense precision. Leave `block_sparse.precision`
+at its default when using `diffusion_kv_cache_dtype` as the shared Dense/BSA
+precision setting.
+
+Configure BSA quantization in the model's existing deployment YAML with
+`backend: RAINFUSION_ATTN` and stage-level `diffusion_kv_cache_dtype: fp8` or
+`mxfp4`. The precision and skip selectors are siblings of
+`diffusion_attention_config`; they are not per-role `quant` fields.
+For 40 denoising steps, `diffusion_kv_cache_skip_steps: "0,1,38,39"` and
+`diffusion_kv_cache_skip_layers: "0,39"` are recommended starting points. These
+fixed step indices do not automatically follow a changed step count. Selected
+forwards remain floating-point BSA; unsupported BSA precision is an error rather
+than an automatic fallback. See
+[quantized attention](../../quantization/quantized_kvcache.md#wan22-t2v-quantized-attention-on-ascend)
+for the shared configuration structure and index semantics.