From 4ed5fc91fd9d8c8fc0d5f300f4ef132a11e7cb68 Mon Sep 17 00:00:00 2001
From: Adam Jesionowski <jesionowski@google.com>
Date: Fri, 10 Dec 2021 10:23:23 -0800
Subject: [PATCH] Use CSR initialization for clearing ITCM.

Clears the ITCM in one go before loading an ELF file using the
hardware initialization CSRs.
DTCM is not cleared as it's temporarily larger than the CSRs can fit.

Tested manually.

Change-Id: Ie4620508404cebc8724771eb579c873fcc0cf0ee
GitOrigin-RevId: ef5de7003c22a1871ab0f74a23fce34593b73fe1
---
 .../kata-ml-coordinator/src/run.rs            |  8 +++---
 .../kata-ml-interface/src/lib.rs              |  1 -
 .../MlCoordinator/kata-vec-core/src/lib.rs    | 25 ++++++++++++++++---
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/apps/system/components/MlCoordinator/kata-ml-coordinator/src/run.rs b/apps/system/components/MlCoordinator/kata-ml-coordinator/src/run.rs
index d2b9a9f..f8fa660 100644
--- a/apps/system/components/MlCoordinator/kata-ml-coordinator/src/run.rs
+++ b/apps/system/components/MlCoordinator/kata-ml-coordinator/src/run.rs
@@ -5,9 +5,9 @@ extern crate kata_panic;
 
 use core::slice;
 use kata_logger::KataLogger;
-use kata_vec_core::MlCore;
 use kata_ml_interface::MlCoordinatorInterface;
 use kata_ml_interface::MlCoreInterface;
+use kata_vec_core::MlCore;
 use log::{error, info, trace};
 
 pub struct MLCoordinator {
@@ -65,7 +65,9 @@ impl MLCoordinator {
 
 impl MlCoordinatorInterface for MLCoordinator {
     fn execute(&mut self) {
-        if self.is_running { return; }
+        if self.is_running {
+            return;
+        }
 
         if !self.is_loaded {
             let res = self
@@ -81,7 +83,7 @@ impl MlCoordinatorInterface for MLCoordinator {
 
         if self.is_loaded {
             self.is_running = true;
-            self.ml_core.run();      // Unhalt, start at default PC.
+            self.ml_core.run(); // Unhalt, start at default PC.
         }
     }
 
diff --git a/apps/system/components/MlCoordinator/kata-ml-interface/src/lib.rs b/apps/system/components/MlCoordinator/kata-ml-interface/src/lib.rs
index bf1e47e..cc7ab25 100644
--- a/apps/system/components/MlCoordinator/kata-ml-interface/src/lib.rs
+++ b/apps/system/components/MlCoordinator/kata-ml-interface/src/lib.rs
@@ -7,7 +7,6 @@ pub trait MlCoordinatorInterface {
 
 pub trait MlCoreInterface {
     fn enable_interrupts(&mut self, enabled: bool);
-    fn clear_tcm(&mut self, start: *const u32, len: usize);
     fn run(&mut self);
     fn load_elf(&mut self, elf_slice: &[u8]) -> Result<(), &'static str>;
     fn get_return_code() -> u32;
diff --git a/apps/system/components/MlCoordinator/kata-vec-core/src/lib.rs b/apps/system/components/MlCoordinator/kata-vec-core/src/lib.rs
index 679a744..e6df114 100644
--- a/apps/system/components/MlCoordinator/kata-vec-core/src/lib.rs
+++ b/apps/system/components/MlCoordinator/kata-vec-core/src/lib.rs
@@ -31,6 +31,24 @@ fn get_dtcm_slice() -> &'static mut [u32] {
 
 pub struct MlCore {}
 
+fn clear_section(start: u32, end: u32, is_itcm: bool) {
+    let init_start = vc_top::InitStart::new()
+        .with_address(start)
+        .with_imem_dmem_sel(is_itcm);
+    vc_top::set_init_start(init_start);
+
+    let init_end = vc_top::InitEnd::new().with_address(end).with_valid(true);
+    vc_top::set_init_end(init_end);
+
+    while !vc_top::get_init_status().init_done() {}
+}
+
+fn clear_tcm() {
+    clear_section(0, ITCM_SIZE as u32, true);
+    // TODO(jesionowski): Enable when DTCM_SIZE fits into INIT_END.
+    // clear_section(0, DTCM_SIZE as u32, false);
+}
+
 impl MlCoreInterface for MlCore {
     fn enable_interrupts(&mut self, enable: bool) {
         let intr_enable = vc_top::IntrEnable::new()
@@ -41,9 +59,6 @@ impl MlCoreInterface for MlCore {
         vc_top::set_intr_enable(intr_enable);
     }
 
-    // TODO(jesionowski): Implement using hardware clear CSRs.
-    fn clear_tcm(&mut self, _start: *const u32, _len: usize) {}
-
     fn run(&mut self) {
         let ctrl = vc_top::Ctrl::new()
             .with_freeze(false)
@@ -58,6 +73,8 @@ impl MlCoreInterface for MlCore {
 
         let elf = ElfFile::new(elf_slice)?;
 
+        clear_tcm();
+
         for seg in elf.program_iter() {
             if seg.get_type()? == Type::Load {
                 let fsize = seg.file_size() as usize;
@@ -83,7 +100,7 @@ impl MlCoreInterface for MlCore {
                     if let SegmentData::Undefined(bytes) = seg.get_data(&elf)? {
                         dtcm_slice[..fsize].copy_from_slice(&bytes);
                     }
-                    // TODO(jesionowski): Use clear_tcm instead.
+                    // TODO(jesionowski): Remove when clear_tcm is fully implemented.
                     // Clear NOBITS sections.
                     dtcm_slice[fsize..msize].fill(0x00);
                 } else {