docs(BM): add structured baremetal documentation and align build/run flow with PAL

docs/baremetal/README.md

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+# Baremetal README
+**Please Note**: The code in the "baremetal" directory provides reference PAL implementations meant to be adapted to real platforms; only the RD-family FVPs are regression-tested on the supplied reference models, and all new platforms must validate their own PAL changes on the relevant hardware or model before relying on them.
+The directory baremetal consists of the reference code of the PAL API's specific to a platform.
+Description of each directory are as follows:
+
+## Directory Structure
+  - `base`: The implementation for all modules are present in this directory.\
+    - `include`: Consists of the include files\
+    - `src`: Source files for all modules which do not require user modification.\
+      Eg: Info tables parsing, PCIe enumeration code, etc.
+
+  - `target`: Contains Platform specific code. The details in this folder need to be modified w.r.t the platform\
+&emsp; &emsp; - `<platformname>`: Info tables parsing, PCIe enumeration code, etc\
+&emsp; &emsp; &emsp; - `include`: Consists of the include files for the platform specific information\
+&emsp; &emsp; &emsp; - `src`: Source files for all modules which require user modification.
+
+## Build Steps
+
+### Pre-requisite
+
+>Note: If you want to build ACS for the reference model(s) provided as part of ACS (for example, RDN2), you can directly follow the build steps below.
+If you want to build ACS for your own platform, you must first complete the PAL porting for your platform (refer to the Baremetal [PAL Porting Overview](porting-pal/overview.md)) and  fill platform-specific knobs using: [Platform override guides](porting-pal/platform-override-guides/README.md). Once the PAL porting is complete, execute the build steps below.
+
+> Note: <acs>.bin stands for either bsa.bin or sbsa.bin or pc_bsa.bin. Any platform specific changes can be done by using `TARGET_BAREMETAL` macro definition. The baremetal reference code is located in [baremetal](../../pal/baremetal/).
+
+Run the command
+- `cd sysarch-acs`
+- `python tools/scripts/generate.py <platformname>`
+
+> Eg: `python tools/scripts/generate.py RDN2`
+> This command will create a folder RDN2 under the `pal/target` folder path and the files `pal_bsa.c` and `pal_sbsa.c` files within the `RDN2/src` folder.
+
+1. To compile BSA, perform the following steps\
+&emsp; 1.1 `cd sysarch-acs`\
+&emsp; 1.2 `export CROSS_COMPILE=<path_to_the_toolchain>/bin/aarch64-none-elf-`\
+&emsp; 1.3 `cmake --preset bsa -DTARGET="Target platform"`\
+&emsp; 1.4 `cmake --build --preset bsa`
+
+2. To compile SBSA, perform the following steps\
+&emsp; 2.1 `cd sysarch-acs`\
+&emsp; 2.2 `export CROSS_COMPILE=<path_to_the_toolchain>/bin/aarch64-none-elf-`\
+&emsp; 2.3 `cmake --preset sbsa -DTARGET="Target platform"`\
+&emsp; 2.4 `cmake --build --preset sbsa`
+
+3. To compile PC_BSA, perform the following steps\
+&emsp; 3.1 `cd sysarch-acs`\
+&emsp; 3.2 `export CROSS_COMPILE=<path_to_the_toolchain>/bin/aarch64-none-elf-`\
+&emsp; 3.3 `cmake --preset pc_bsa -DTARGET="Target platform"`\
+&emsp; 3.4 `cmake --build --preset pc_bsa`
+
+</br>
+
+> **Note:**
+> You can check available presets using `cmake --list-presets`
+> If you do not provide `-DTARGET`, defaults to `RDN2`.
+> If you like to use make command do `cmake --preset acs_all; cd build; make bsa` (for all baremetal acs `make acs_all`)
+> Recommended: CMake v3.21 (min version to support --preset), GCC v12.2
+
+</br>
+
+```
+CMake Command Line Options:
+ `-DARM_ARCH_MAJOR` = Arch major version. Default value is 9.
+ `-DARM_ARCH_MINOR` = Arch minor version. Default value is 0.
+ `-DCROSS_COMPILE`  = Cross compiler path
+ `-DTARGET`         = Target platform. Should be same as folder under baremetal/target/
+ `-DACS`            = To compile <bsa/sbsa/pc_bsa> ACS
+```
+
+</br>
+
+> On a successful build, *.bin, *.elf, *.img and debug binaries are generated at `build/<acs>_build/output` directory. The output library files will be generated at `build/<acs>_build/tools/cmake` directory.
+
+## Running ACS with Bootwrapper on RDN2
+
+**1. In RDN2 software stack make following change:**
+
+  In `<rdn2_path>/build-scripts/build-target-bins.sh` - replace `uefi.bin` with `acs_latest.bin`
+
+```bash
+  if [ "${!tfa_tbbr_enabled}" == "1" ]; then
+      $TOP_DIR/$TF_A_PATH/tools/cert_create/cert_create  \
+      ${cert_tool_param} \
+-     ${bl33_param_id} ${OUTDIR}/${!uefi_out}/uefi.bin
++     ${bl33_param_id} ${OUTDIR}/${!uefi_out}/acs_latest.bin
+  fi
+
+  ${fip_tool} update \
+  ${fip_param} \
+- ${bl33_param_id} ${OUTDIR}/${!uefi_out}/uefi.bin \
++ ${bl33_param_id} ${OUTDIR}/${!uefi_out}/acs_latest.bin \
+  ${PLATDIR}/${!target_name}/fip-uefi.bin
+
+```
+
+**2. Repackage the FIP image with this new binary**
+- `cp <sysarch-acs>/build/<acs>_build/output/<acs>.bin <rdn2_path>/output/rdn2/components/css-common/acs_latest.bin`
+- `cd <rdn2_path>`
+- `./build-scripts/rdinfra/build-test-acs.sh -p rdn2 package`
+- `export MODEL=<path_to_FVP_RDN2_model>`
+- `cd <rdn2>/model-scripts/rdinfra/platforms/rdn2`
+- `./run_model.sh`
+
+
+For more details on how to port the reference code to a specific platform and for further customisation please refer to the [User Guide](porting-pal/overview.md)
+
+-----------------
+
+*Copyright (c) 2026, Arm Limited and Contributors. All rights reserved.*

docs/baremetal/porting-pal/checklists/new-pal-readiness-checklist.md

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+# Release readiness checklist (Baremetal)
+
+Use this checklist before you upstream/check-in a new platform port.
+
+## Documentation
+- [ ] `docs/baremetal/README.md` links are valid
+- [ ] Platform-specific bring-up notes are captured somewhere discoverable
+- [ ] Override guides used are referenced/linked
+
+## Build reproducibility
+- [ ] Clean build works from scratch (documented steps)
+- [ ] Toolchain requirements documented
+- [ ] Platform selection mechanism documented
+
+## Functional coverage
+- [ ] Smoke run passes (define what smoke is for your suite set)
+- [ ] No hard faults / aborts in normal run
+- [ ] Logs contain platform ID and build ID for traceability
+
+## Platform override correctness
+- [ ] Counts match number of populated entries for each block
+- [ ] Memory map has no overlaps
+- [ ] ECAM and MMIO windows validated
+- [ ] IORT ID mappings validated (unit test or sanity dump)
+
+## Artifact hygiene
+- [ ] Example logs attached to PR (or referenced)
+- [ ] Known limitations documented (what doesn’t work yet)

docs/baremetal/porting-pal/checklists/porting-checklist.md

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+# Porting checklist (Baremetal)
+
+Use this checklist while bringing up a new platform.
+
+## Boot & console
+- [ ] Can boot a minimal payload
+- [ ] UART console prints reliably
+- [ ] UART config matches actual IP and base
+- [ ] UART region is marked DEVICE in memory map
+
+## Memory map
+- [ ] DRAM regions are correct and marked NORMAL
+- [ ] MMIO windows are marked DEVICE
+- [ ] Reserved carveouts marked RESERVED
+- [ ] Holes/unbacked regions marked NOT_POPULATED (if required)
+
+## Timers & watchdog
+- [ ] Per-CPU timer GSIVs correct (PPIs)
+- [ ] Timer flags (mode/polarity/always-on) correct
+- [ ] CNTFRQ correct
+- [ ] Platform timer frames correct (if used)
+- [ ] Watchdog bases + GSIVs correct (if used)
+
+## PCIe (if used)
+- [ ] ECAM base + bus ranges correct
+- [ ] Enumeration limits correct
+- [ ] PCIe MMIO resource windows don’t overlap
+- [ ] Static device list (if used) matches enumeration
+
+## IORT / SMMU (if used)
+- [ ] SMMU base addresses correct
+- [ ] ITS count/grouping consistent with firmware
+- [ ] RID→StreamID mappings correct
+- [ ] StreamID→DeviceID mappings correct
+- [ ] No overlapping StreamID windows
+
+## Optional blocks (as required by suites)
+- [ ] Cache/topology overrides
+- [ ] HMAT bandwidth hints
+- [ ] PMU nodes
+- [ ] RAS / RAS2 blocks
+
+## Repro artifacts
+- [ ] Save binary + git SHA
+- [ ] Save override header
+- [ ] Save UART log