diff --git a/CHANGELOG.md b/CHANGELOG.md
index 46d7d71..8f3dbfb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [unreleased]
 
+### Added
+
+- Added register map validator and flattened map generator.
+
 ### Changed
 
 - Changed block, register type definitions to support multiple backends. See [the merge request at mpsoc software](https://gitlab.cern.ch/wotsubo/mpsoc-software/-/merge_requests/9) for more information.
diff --git a/Cargo.lock b/Cargo.lock
index 550b77e..fa8e6aa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -260,6 +260,27 @@ dependencies = [
  "typenum",
 ]
 
+[[package]]
+name = "csv"
+version = "1.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "acdc4883a9c96732e4733212c01447ebd805833b7275a73ca3ee080fd77afdaf"
+dependencies = [
+ "csv-core",
+ "itoa",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "csv-core"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d02f3b0da4c6504f86e9cd789d8dbafab48c2321be74e9987593de5a894d93d"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "darling"
 version = "0.20.10"
@@ -358,6 +379,7 @@ dependencies = [
  "anyhow",
  "chrono",
  "clap",
+ "csv",
  "env_logger",
  "heck",
  "hex",
diff --git a/Cargo.toml b/Cargo.toml
index 2a17f3a..eac1783 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,6 +20,7 @@ path = "src/lib.rs"
 anyhow = { version = "1.0", optional = true }
 chrono = "0.4"
 clap = { version = "4.5", features = ["derive"] }
+csv = { version = "1.3.1", optional = true }
 env_logger = { version = "0.11", optional = true }
 heck = "0.5"
 hex = "0.4"
@@ -38,3 +39,4 @@ vergen-gitcl = { version = "1.0", features = ["build", "cargo", "rustc", "si"] }
 
 [features]
 bin = ["anyhow", "env_logger"]
+flatmap = ["csv"]
diff --git a/src/integrated.rs b/src/integrated.rs
index a342730..121e506 100644
--- a/src/integrated.rs
+++ b/src/integrated.rs
@@ -1,11 +1,12 @@
 use std::path;
 
+use itertools::Itertools;
 use thiserror::Error;
 
 use crate::{
     converter, generator,
     io::{get_xml_gitinfo, XmlGitInfoError},
-    types,
+    types, validator,
 };
 
 #[derive(Debug, Error)]
@@ -18,8 +19,13 @@ pub enum Error {
     XmlParseError(#[from] roxmltree::Error),
     #[error("dom conversion error: {0}")]
     DomConversionError(#[from] converter::DomConversionError),
+    #[error("invalid register map:\n{}", ._0.iter().map(|e| e.to_string()).join("\n"))]
+    RegmapValidationError(Vec<validator::ValidationError>),
     #[error("code generation error: {0}")]
     CodeGenError(#[from] generator::CodeGenError),
+    #[cfg(feature = "flatmap")]
+    #[error("csv write error: {0}")]
+    CsvWriteError(#[from] csv::Error),
 }
 
 /// Generate register interface code from xml in `xml` and write them under directory `out`.
@@ -42,6 +48,31 @@ pub fn generate(xml: &path::Path, out: &path::Path) -> Result<(), Error> {
     let register_map = types::Module::from_xml_dom(doc.root_element(), xml_git_info)?;
     log::debug!("converted {register_map:?}");
 
+    let (maps, errors) = register_map.validate();
+    if !errors.is_empty() {
+        return Err(Error::RegmapValidationError(errors));
+    }
+    // TODO: this is a temporarily implementation
+    println!("address,path,name,multiple_id,modf,description");
+    for (addr, reg) in maps.iter().enumerate() {
+        match reg {
+            Some(reg) => {
+                let path = reg.0.join("/");
+                let multiple_id = reg.2.map_or("".to_string(), |x| x.to_string());
+                println!(
+                    "0x{:04x},{},{},{},{},{},",
+                    addr,
+                    path,
+                    reg.1.name,
+                    multiple_id,
+                    reg.1.modf,
+                    reg.1.desc.as_ref().map_or_else(|| "", |s| s),
+                )
+            }
+            None => println!("0x{:04x},,,,", addr),
+        }
+    }
+
     let files = register_map.generate_code()?;
     if log::log_enabled!(log::Level::Debug) {
         for (path, code) in &files {
@@ -56,3 +87,76 @@ pub fn generate(xml: &path::Path, out: &path::Path) -> Result<(), Error> {
 
     Ok(())
 }
+
+#[cfg(feature = "flatmap")]
+pub fn generate_flatmap(xml: &path::Path, out: Option<&path::Path>) -> Result<(), Error> {
+    use std::{
+        fs::File,
+        io::{self, BufWriter, Write},
+    };
+
+    log::debug!("generate called: xml:{:?}, out: {:?}", xml, out);
+
+    let xml_git_info = get_xml_gitinfo(xml)?;
+    log::debug!("xml git info {xml_git_info:?}");
+
+    let xmlfile = std::fs::read_to_string(xml)?;
+    let doc = roxmltree::Document::parse_with_options(
+        &xmlfile,
+        roxmltree::ParsingOptions {
+            allow_dtd: true,
+            nodes_limit: u32::MAX,
+        },
+    )?;
+    log::debug!("xml parsed {doc:?}");
+
+    let register_map = types::Module::from_xml_dom(doc.root_element(), xml_git_info)?;
+    log::debug!("converted {register_map:?}");
+
+    let (maps, errors) = register_map.validate();
+    if !errors.is_empty() {
+        return Err(Error::RegmapValidationError(errors));
+    }
+    let f: Box<dyn Write> = match out {
+        Some(f) => {
+            let file = File::options().write(true).truncate(true).open(f)?;
+            Box::new(BufWriter::new(file))
+        }
+        None => Box::new(io::stdout()),
+    };
+    let mut wtr = csv::Writer::from_writer(f);
+
+    wtr.write_record([
+        "address",
+        "path",
+        "name",
+        "multiple_id",
+        "modf",
+        "description",
+    ])?;
+    for (addr, reg) in maps.iter().enumerate() {
+        match reg {
+            Some(reg) => {
+                let path = reg.0.join("/");
+                let multiple_id = reg.2.map_or("".to_string(), |x| x.to_string());
+                wtr.write_record([
+                    format!("0x{:04x}", addr),
+                    path,
+                    reg.1.name.clone(),
+                    multiple_id,
+                    reg.1.modf.to_string(),
+                    reg.1.desc.as_ref().unwrap_or(&"".to_string()).to_string(),
+                ])?;
+            }
+            None => wtr.write_record([
+                format!("0x{:04x}", addr),
+                "".to_string(),
+                "".to_string(),
+                "".to_string(),
+                "".to_string(),
+                "".to_string(),
+            ])?,
+        }
+    }
+    Ok(())
+}
diff --git a/src/lib.rs b/src/lib.rs
index e76a395..483816a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -31,6 +31,7 @@ pub mod meta;
 mod parser;
 mod type_traits;
 pub mod types;
+pub mod validator;
 
 pub use integrated::generate;
 pub use io::write_to_files;
diff --git a/src/main.rs b/src/main.rs
index 3dc85ac..e37c513 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,7 +1,7 @@
 use std::path;
 
 use anyhow::Result;
-use clap::Parser;
+use clap::{Parser, Subcommand};
 
 /// Generate register interface from register map xml.
 #[derive(Parser, Debug)]
@@ -9,8 +9,21 @@ use clap::Parser;
 struct Args {
     /// Input XML register map.
     xml: path::PathBuf,
-    /// Output directory.
-    out: path::PathBuf,
+    #[command(subcommand)]
+    command: Commands,
+}
+
+#[derive(Debug, Subcommand)]
+enum Commands {
+    Generate {
+        /// Output directory.
+        out: path::PathBuf,
+    },
+    #[cfg(feature = "flatmap")]
+    Flatmap {
+        /// Flattened csv out path.
+        flatmap: Option<path::PathBuf>,
+    },
 }
 
 fn main() -> Result<()> {
@@ -19,7 +32,17 @@ fn main() -> Result<()> {
     let args = Args::parse();
     log::debug!("args: {:?}", args);
 
-    endcap_sl_software_ri_generator::generate(&args.xml, &args.out)?;
+    match args.command {
+        Commands::Generate { out } => endcap_sl_software_ri_generator::generate(&args.xml, &out)?,
+        #[cfg(feature = "flatmap")]
+        Commands::Flatmap { flatmap } => {
+            let outpath: Option<&path::Path> = match flatmap {
+                Some(ref p) => Some(p.as_path()),
+                None => None,
+            };
+            endcap_sl_software_ri_generator::integrated::generate_flatmap(&args.xml, outpath)?
+        }
+    }
 
     Ok(())
 }
diff --git a/src/type_traits.rs b/src/type_traits.rs
index d68da02..09f638d 100644
--- a/src/type_traits.rs
+++ b/src/type_traits.rs
@@ -1,6 +1,8 @@
 //! Util traits to get info from types in [`crate::types`].
 
-use crate::types::{Block, ModuleBlockElements, Register};
+use std::fmt::Display;
+
+use crate::types::{Block, ModuleBlockElements, Register, RwSpecifier};
 
 pub(crate) trait GetName {
     fn get_name(&self) -> String;
@@ -28,3 +30,14 @@ impl GetName for Register {
         self.name.clone()
     }
 }
+
+impl Display for RwSpecifier {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let s = match self {
+            RwSpecifier::R => "r",
+            RwSpecifier::W => "w",
+            RwSpecifier::RW => "rw",
+        };
+        write!(f, "{}", s)
+    }
+}
diff --git a/src/validator.rs b/src/validator.rs
new file mode 100644
index 0000000..479bcb5
--- /dev/null
+++ b/src/validator.rs
@@ -0,0 +1,251 @@
+//! Validate the address assignment and generate a flattened register map.
+
+use thiserror::Error;
+
+use crate::types::{Block, Module, ModuleBlockElements, Register};
+
+type FlattenedRegisterMap<'a> = Vec<Option<(Vec<&'a str>, &'a Register, Option<u32>)>>;
+
+impl Module {
+    /// Validate the address assignment, generating a flatten register map.
+    pub fn validate(&self) -> (FlattenedRegisterMap, Vec<ValidationError>) {
+        let mut mapping = Vec::new();
+        mapping.resize(self.size.try_into().unwrap(), None);
+        let errors = Vec::new();
+        self.fill(mapping, errors, (0x0, Vec::new()))
+    }
+}
+
+#[derive(Debug, Error)]
+pub enum ValidationError {
+    #[error("address duplicated at 0x{address:08x}: \"{existing_name}\", \"{new_name}\"")]
+    AddressDuplicated {
+        address: u32,
+        existing_name: String,
+        new_name: String,
+    },
+    #[error("unsupported structure: {msg}")]
+    UnsupportedStructure { msg: &'static str },
+}
+
+trait Validate {
+    fn fill<'a>(
+        &'a self,
+        mapping: FlattenedRegisterMap<'a>,
+        errors: Vec<ValidationError>,
+        base: (u32, Vec<&'a str>),
+    ) -> (FlattenedRegisterMap<'a>, Vec<ValidationError>);
+}
+
+impl Validate for Module {
+    fn fill<'a>(
+        &'a self,
+        mut mapping: FlattenedRegisterMap<'a>,
+        mut errors: Vec<ValidationError>,
+        base: (u32, Vec<&'a str>),
+    ) -> (FlattenedRegisterMap<'a>, Vec<ValidationError>) {
+        for child in &self.elements_other {
+            (mapping, errors) = child.fill(mapping, errors, base.clone());
+        }
+        (mapping, errors)
+    }
+}
+
+impl Validate for ModuleBlockElements {
+    fn fill<'a>(
+        &'a self,
+        mapping: FlattenedRegisterMap<'a>,
+        errors: Vec<ValidationError>,
+        base: (u32, Vec<&'a str>),
+    ) -> (FlattenedRegisterMap<'a>, Vec<ValidationError>) {
+        match self {
+            ModuleBlockElements::Block(block) => block.fill(mapping, errors, base),
+            ModuleBlockElements::Register(register) => register.fill(mapping, errors, base),
+            ModuleBlockElements::Memory(_memory) => todo!(),
+            ModuleBlockElements::Fifo(_fifo) => todo!(),
+        }
+    }
+}
+
+impl Validate for Block {
+    fn fill<'a>(
+        &'a self,
+        mut mapping: FlattenedRegisterMap<'a>,
+        mut errors: Vec<ValidationError>,
+        base: (u32, Vec<&'a str>),
+    ) -> (FlattenedRegisterMap<'a>, Vec<ValidationError>) {
+        if self.multiple.is_some() {
+            errors.push(ValidationError::UnsupportedStructure {
+                msg: "multiple in block",
+            });
+        }
+
+        let addr = base.0 + self.addr;
+        let mut path = base.1;
+        path.push(&self.name);
+        for child in &self.elements {
+            (mapping, errors) = child.fill(mapping, errors, (addr, path.clone()));
+        }
+        (mapping, errors)
+    }
+}
+
+impl Validate for Register {
+    fn fill<'a>(
+        &'a self,
+        mut mapping: FlattenedRegisterMap<'a>,
+        mut errors: Vec<ValidationError>,
+        base: (u32, Vec<&'a str>),
+    ) -> (FlattenedRegisterMap<'a>, Vec<ValidationError>) {
+        let addr = base.0 + self.addr;
+        let path = base.1;
+        let (len, offset) = match &self.multiple {
+            Some(multiple) => (multiple.multiple, multiple.offset),
+            None => (1, 1),
+        };
+        for id in 0..len {
+            let addr = addr + id * offset;
+            let regmap: &mut Option<_> = mapping
+                .get_mut::<usize>(addr.try_into().unwrap())
+                .expect("index of mapping out of range");
+            if let Some(old) = regmap {
+                let existing_name = {
+                    let mut path = old.0.clone();
+                    path.push(&old.1.name);
+                    path.join("/")
+                };
+                let new_name = {
+                    let mut path = path.clone();
+                    path.push(&self.name);
+                    path.join("/")
+                };
+                errors.push(ValidationError::AddressDuplicated {
+                    address: addr,
+                    existing_name,
+                    new_name,
+                });
+            } else {
+                let multiple_id = if len == 1 { None } else { Some(id) };
+                *regmap = Some((path.clone(), self, multiple_id))
+            }
+        }
+
+        (mapping, errors)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use itertools::Itertools;
+
+    use crate::types::{
+        Module, ModuleBlockElements, MultipleParams, Register, RwSpecifier, XmlGitInfo,
+    };
+
+    #[test]
+    fn duplicate() {
+        let reg1 = Register {
+            name: "test1".to_string(),
+            addr: 0,
+            r#type: crate::types::DataType::D32,
+            mask: None,
+            modf: RwSpecifier::R,
+            multiple: None,
+            default: None,
+            desc: None,
+            elements: vec![],
+        };
+        let reg2 = Register {
+            name: "test1".to_string(),
+            addr: 0,
+            r#type: crate::types::DataType::D32,
+            mask: None,
+            modf: RwSpecifier::R,
+            multiple: None,
+            default: None,
+            desc: None,
+            elements: vec![],
+        };
+        let module = Module {
+            name: "module".to_string(),
+            addr: 0,
+            size: 0x10,
+            amod: None,
+            r#type: None,
+            desc: None,
+            elements_bitstring: vec![],
+            elements_other: vec![
+                ModuleBlockElements::Register(reg1),
+                ModuleBlockElements::Register(reg2),
+            ],
+            xmlhash: [0; 32],
+            git_info: XmlGitInfo {
+                describe: "".to_string(),
+                commit_timestamp: "".to_string(),
+                sha: "".to_string(),
+            },
+        };
+
+        let (maps, errors) = module.validate();
+        eprintln!("{:#?}", maps);
+        eprintln!(
+            "{:#?}",
+            maps.iter().filter(|e| e.is_some()).collect_vec().len()
+        );
+        assert_eq!(maps.len(), 0x10);
+        assert!(!errors.is_empty());
+        assert_eq!(maps.iter().filter(|e| e.is_some()).collect_vec().len(), 0x1);
+    }
+
+    #[test]
+    fn duplicate_with_multiple() {
+        let reg1 = Register {
+            name: "test1".to_string(),
+            addr: 0,
+            r#type: crate::types::DataType::D32,
+            mask: None,
+            modf: RwSpecifier::R,
+            multiple: Some(MultipleParams {
+                multiple: 16,
+                offset: 1,
+            }),
+            default: None,
+            desc: None,
+            elements: vec![],
+        };
+        let reg2 = Register {
+            name: "test1".to_string(),
+            addr: 15,
+            r#type: crate::types::DataType::D32,
+            mask: None,
+            modf: RwSpecifier::R,
+            multiple: None,
+            default: None,
+            desc: None,
+            elements: vec![],
+        };
+        let module = Module {
+            name: "module".to_string(),
+            addr: 0,
+            size: 0x1000,
+            amod: None,
+            r#type: None,
+            desc: None,
+            elements_bitstring: vec![],
+            elements_other: vec![
+                ModuleBlockElements::Register(reg1),
+                ModuleBlockElements::Register(reg2),
+            ],
+            xmlhash: [0; 32],
+            git_info: XmlGitInfo {
+                describe: "".to_string(),
+                commit_timestamp: "".to_string(),
+                sha: "".to_string(),
+            },
+        };
+
+        let (maps, errors) = module.validate();
+        assert_eq!(maps.len(), 0x1000);
+        assert_eq!(errors.len(), 1);
+    }
+}