diff --git a/doc/mpp_design.txt b/doc/design/1.mpp_design.txt
similarity index 100%
rename from doc/mpp_design.txt
rename to doc/design/1.mpp_design.txt
diff --git a/doc/kernel_driver.txt b/doc/design/2.kernel_driver.txt
similarity index 100%
rename from doc/kernel_driver.txt
rename to doc/design/2.kernel_driver.txt
diff --git a/doc/mpp_buffer.txt b/doc/design/3.mpp_buffer.txt
similarity index 100%
rename from doc/mpp_buffer.txt
rename to doc/design/3.mpp_buffer.txt
diff --git a/doc/mpp_task.txt b/doc/design/4.mpp_task.txt
similarity index 100%
rename from doc/mpp_task.txt
rename to doc/design/4.mpp_task.txt