Use SoC interface to talk to Caliptra

`caliptra-sw`'s emulator has an "external" SoC interface that can be used to communicate with it via the standard SoC interface. This writes a simple adapter layer so that the MCU emulator can mount that external interface as a peripheral on our root bus. I also added some code to the ROM that reads the flow status from the SoC interface as a basic check that the functionality is working. When running the MCU with a Caliptra ROM and runtime FW, it outputs: ``` Caliptra flow status 40000000 ``` When no Caliptra ROM or firmware are provided, the status is 0, so we can skip straight to Tock in that case (for now).
chipsalliance · Jan 3, 2025 · 04045f4 · 04045f4
1 parent ebb25ae
commit 04045f4
Show file tree

Hide file tree

Showing 24 changed files with 485 additions and 330 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -134,6 +134,7 @@ caliptra-api-types = { git = "https://github.com/chipsalliance/caliptra-sw.git",
 caliptra-emu-bus = { git = "https://github.com/chipsalliance/caliptra-sw.git", rev = "2f6de531e321b7bb24b17b1bd02b43d2854aef3a" }
 caliptra-emu-cpu = { git = "https://github.com/chipsalliance/caliptra-sw.git", rev = "2f6de531e321b7bb24b17b1bd02b43d2854aef3a" }
 caliptra-emu-periph = { git = "https://github.com/chipsalliance/caliptra-sw.git", rev = "2f6de531e321b7bb24b17b1bd02b43d2854aef3a" }
+caliptra-emu-types = { git = "https://github.com/chipsalliance/caliptra-sw.git", rev = "2f6de531e321b7bb24b17b1bd02b43d2854aef3a" }
 caliptra-hw-model = { git = "https://github.com/chipsalliance/caliptra-sw.git", rev = "2f6de531e321b7bb24b17b1bd02b43d2854aef3a" }
 caliptra-registers = { git = "https://github.com/chipsalliance/caliptra-sw.git", rev = "2f6de531e321b7bb24b17b1bd02b43d2854aef3a" }
 

diff --git a/emulator/app/src/main.rs b/emulator/app/src/main.rs
@@ -24,11 +24,12 @@ use caliptra_emu_cpu::{Cpu as CaliptraMainCpu, StepAction as CaliptraMainStepAct
 use caliptra_emu_periph::CaliptraRootBus as CaliptraMainRootBus;
 use clap::{ArgAction, Parser};
 use crossterm::event::{Event, KeyCode, KeyEvent};
-use emulator_bus::{Clock, Timer};
+use emulator_bus::{Bus, BusConverter, Clock, Timer};
 use emulator_caliptra::{start_caliptra, StartCaliptraArgs};
 use emulator_cpu::{Cpu, Pic, RvInstr, StepAction};
 use emulator_periph::{CaliptraRootBus, CaliptraRootBusArgs, DummyFlashCtrl, I3c, I3cController};
 use emulator_registers_generated::root_bus::AutoRootBus;
+use emulator_registers_generated::soc::SocPeripheral;
 use emulator_types::ROM_SIZE;
 use gdb::gdb_state;
 use gdb::gdb_target::GdbTarget;
@@ -268,7 +269,7 @@ fn run(cli: Emulator, capture_uart_output: bool) -> io::Result<Vec<u8>> {
         exit(-1);
     }
 
-    let caliptra_cpu = if cli.caliptra {
+    let (caliptra_cpu, soc_to_caliptra) = if cli.caliptra {
         if cli.gdb_port.is_some() {
             println!("Caliptra CPU cannot be started with GDB enabled");
             exit(-1);
@@ -281,16 +282,15 @@ fn run(cli: Emulator, capture_uart_output: bool) -> io::Result<Vec<u8>> {
             println!("Caliptra ROM File is required if Caliptra is enabled");
             exit(-1);
         }
-        Some(
-            start_caliptra(&StartCaliptraArgs {
-                rom: cli.caliptra_rom.unwrap(),
-                firmware: cli.caliptra_firmware,
-                ..Default::default()
-            })
-            .expect("Failed to start Caliptra CPU"),
-        )
+        let (caliptra_cpu, soc_to_caliptra) = start_caliptra(&StartCaliptraArgs {
+            rom: cli.caliptra_rom.unwrap(),
+            firmware: cli.caliptra_firmware,
+            ..Default::default()
+        })
+        .expect("Failed to start Caliptra CPU");
+        (Some(caliptra_cpu), Some(soc_to_caliptra))
     } else {
-        None
+        (None, None)
     };
 
     let rom_buffer = read_binary(args_rom, 0)?;
@@ -397,15 +397,24 @@ fn run(cli: Emulator, capture_uart_output: bool) -> io::Result<Vec<u8>> {
     )
     .unwrap();
 
+    let mut delegates: Vec<Box<dyn Bus>> = vec![Box::new(root_bus)];
+    let soc_periph = if let Some(soc_to_caliptra) = soc_to_caliptra {
+        delegates.push(Box::new(BusConverter::new(Box::new(soc_to_caliptra))));
+        None
+    } else {
+        // pass an empty SoC interface that returns 0 for everything
+        Some(Box::new(FakeSoc {}) as Box<dyn SocPeripheral>)
+    };
+
     let mut auto_root_bus = AutoRootBus::new(
-        Some(Box::new(root_bus)),
+        delegates,
         Some(Box::new(i3c)),
         Some(Box::new(flash_controller)),
         None,
         None,
         None,
         None,
-        None,
+        soc_periph,
         None,
     );
 
@@ -442,3 +451,7 @@ fn run(cli: Emulator, capture_uart_output: bool) -> io::Result<Vec<u8>> {
 
     Ok(uart_output.map(|o| o.borrow().clone()).unwrap_or_default())
 }
+
+struct FakeSoc {}
+
+impl SocPeripheral for FakeSoc {}
diff --git a/emulator/bus/Cargo.toml b/emulator/bus/Cargo.toml
@@ -8,5 +8,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+caliptra-emu-bus.workspace = true
+caliptra-emu-types.workspace = true
 emulator-types.workspace = true
 tock-registers.workspace = true
diff --git a/emulator/bus/src/bus.rs b/emulator/bus/src/bus.rs
@@ -35,6 +35,18 @@ pub enum BusError {
     StoreAccessFault,
 }
 
+impl From<caliptra_emu_bus::BusError> for BusError {
+    fn from(value: caliptra_emu_bus::BusError) -> Self {
+        match value {
+            caliptra_emu_bus::BusError::InstrAccessFault => BusError::InstrAccessFault,
+            caliptra_emu_bus::BusError::LoadAddrMisaligned => BusError::LoadAddrMisaligned,
+            caliptra_emu_bus::BusError::LoadAccessFault => BusError::LoadAccessFault,
+            caliptra_emu_bus::BusError::StoreAddrMisaligned => BusError::StoreAddrMisaligned,
+            caliptra_emu_bus::BusError::StoreAccessFault => BusError::StoreAccessFault,
+        }
+    }
+}
+
 /// Represents an abstract memory bus. Used to read and write from RAM and
 /// peripheral addresses.
 pub trait Bus {
@@ -78,3 +90,42 @@ pub trait Bus {
         // By default, do nothing
     }
 }
+
+pub struct BusConverter {
+    caliptra_bus: Box<dyn caliptra_emu_bus::Bus>,
+}
+
+impl BusConverter {
+    pub fn new(caliptra_bus: Box<dyn caliptra_emu_bus::Bus>) -> Self {
+        Self { caliptra_bus }
+    }
+}
+
+impl Bus for BusConverter {
+    fn read(&mut self, size: RvSize, addr: RvAddr) -> Result<RvData, BusError> {
+        self.caliptra_bus
+            .read((size as usize).into(), addr as caliptra_emu_types::RvAddr)
+            .map_err(|x| x.into())
+    }
+
+    fn write(&mut self, size: RvSize, addr: RvAddr, val: RvData) -> Result<(), BusError> {
+        self.caliptra_bus
+            .write(
+                (size as usize).into(),
+                addr as caliptra_emu_types::RvAddr,
+                val,
+            )
+            .map_err(|x| x.into())
+    }
+    fn poll(&mut self) {
+        self.caliptra_bus.poll();
+    }
+
+    fn warm_reset(&mut self) {
+        self.caliptra_bus.warm_reset();
+    }
+
+    fn update_reset(&mut self) {
+        self.caliptra_bus.update_reset();
+    }
+}
diff --git a/emulator/bus/src/lib.rs b/emulator/bus/src/lib.rs
@@ -21,7 +21,7 @@ mod register_array;
 mod rom;
 pub mod testing;
 
-pub use crate::bus::{Bus, BusError, Trap};
+pub use crate::bus::{Bus, BusConverter, BusError, Trap};
 pub use crate::clock::{ActionHandle, Clock, Timer, TimerAction};
 pub use crate::dynamic_bus::DynamicBus;
 pub use crate::ram::Ram;

diff --git a/emulator/caliptra/src/caliptra.rs b/emulator/caliptra/src/caliptra.rs
@@ -18,7 +18,7 @@ use caliptra_emu_cpu::Cpu;
 use caliptra_emu_periph::soc_reg::DebugManufService;
 use caliptra_emu_periph::{
     CaliptraRootBus, CaliptraRootBusArgs, DownloadIdevidCsrCb, MailboxInternal, ReadyForFwCb,
-    TbServicesCb, UploadUpdateFwCb,
+    SocToCaliptraBus, TbServicesCb, UploadUpdateFwCb,
 };
 use caliptra_hw_model::BusMmio;
 use std::fs::File;
@@ -64,7 +64,9 @@ pub struct StartCaliptraArgs {
 }
 
 /// Creates and returns an initialized a Caliptra emulator CPU.
-pub fn start_caliptra(args: &StartCaliptraArgs) -> io::Result<Cpu<CaliptraRootBus>> {
+pub fn start_caliptra(
+    args: &StartCaliptraArgs,
+) -> io::Result<(Cpu<CaliptraRootBus>, SocToCaliptraBus)> {
     let args_rom = &args.rom;
     let args_current_fw = &args.firmware;
     let args_update_fw = &args.update_firmware;
@@ -295,7 +297,8 @@ pub fn start_caliptra(args: &StartCaliptraArgs) -> io::Result<Cpu<CaliptraRootBu
             .write(|_| (wdt_timeout >> 32) as u32);
     }
 
-    Ok(Cpu::new(root_bus, clock))
+    let ext_soc_ifc = root_bus.soc_to_caliptra_bus();
+    Ok((Cpu::new(root_bus, clock), ext_soc_ifc))
 }
 
 fn change_dword_endianess(data: &mut [u8]) {

diff --git a/emulator/periph/src/flash_ctrl.rs b/emulator/periph/src/flash_ctrl.rs
@@ -547,7 +547,7 @@ mod test {
         }
 
         AutoRootBus::new(
-            None,
+            vec![],
             None,
             Some(flash_controller),
             None,

diff --git a/emulator/periph/src/i3c.rs b/emulator/periph/src/i3c.rs
@@ -410,7 +410,7 @@ mod tests {
             .tcri_send(DynamicI3cAddress::new(8).unwrap(), cmd)
             .unwrap();
 
-        let mut bus = AutoRootBus::new(None, Some(i3c), None, None, None, None, None, None, None);
+        let mut bus = AutoRootBus::new(vec![], Some(i3c), None, None, None, None, None, None, None);
         for _ in 0..10000 {
             clock.increment_and_process_timer_actions(1, &mut bus);
         }

diff --git a/registers/generated-emulator/src/entropy_src.rs b/registers/generated-emulator/src/entropy_src.rs
@@ -5,6 +5,7 @@
 #[allow(unused_imports)]
 use tock_registers::interfaces::{Readable, Writeable};
 pub trait EntropySrcPeripheral {
+    fn set_dma_ram(&mut self, _ram: std::rc::Rc<std::cell::RefCell<emulator_bus::Ram>>) {}
     fn poll(&mut self) {}
     fn warm_reset(&mut self) {}
     fn update_reset(&mut self) {}

diff --git a/registers/generated-emulator/src/otp.rs b/registers/generated-emulator/src/otp.rs
@@ -5,6 +5,7 @@
 #[allow(unused_imports)]
 use tock_registers::interfaces::{Readable, Writeable};
 pub trait OtpPeripheral {
+    fn set_dma_ram(&mut self, _ram: std::rc::Rc<std::cell::RefCell<emulator_bus::Ram>>) {}
     fn poll(&mut self) {}
     fn warm_reset(&mut self) {}
     fn update_reset(&mut self) {}

diff --git a/registers/generated-emulator/src/root_bus.rs b/registers/generated-emulator/src/root_bus.rs
@@ -3,7 +3,7 @@
 // generated by registers_generator with caliptra-ss repo at a621fff9df7015821eda6f7f73265fef74a01375
 //
 pub struct AutoRootBus {
-    delegate: Option<Box<dyn emulator_bus::Bus>>,
+    delegates: Vec<Box<dyn emulator_bus::Bus>>,
     pub i3c_periph: Option<crate::i3c::I3cBus>,
     pub flash_periph: Option<crate::flash::FlashBus>,
     pub entropy_src_periph: Option<crate::entropy_src::EntropySrcBus>,
@@ -16,7 +16,7 @@ pub struct AutoRootBus {
 impl AutoRootBus {
     #[allow(clippy::too_many_arguments)]
     pub fn new(
-        delegate: Option<Box<dyn emulator_bus::Bus>>,
+        delegates: Vec<Box<dyn emulator_bus::Bus>>,
         i3c_periph: Option<Box<dyn crate::i3c::I3cPeripheral>>,
         flash_periph: Option<Box<dyn crate::flash::FlashPeripheral>>,
         entropy_src_periph: Option<Box<dyn crate::entropy_src::EntropySrcPeripheral>>,
@@ -27,7 +27,7 @@ impl AutoRootBus {
         el2_pic_periph: Option<Box<dyn crate::el2_pic::El2PicPeripheral>>,
     ) -> Self {
         Self {
-            delegate,
+            delegates,
             i3c_periph: i3c_periph.map(|p| crate::i3c::I3cBus { periph: p }),
             flash_periph: flash_periph.map(|p| crate::flash::FlashBus { periph: p }),
             entropy_src_periph: entropy_src_periph
@@ -106,14 +106,16 @@ impl emulator_bus::Bus for AutoRootBus {
             }
             _ => Err(emulator_bus::BusError::LoadAccessFault),
         };
-        if let Some(delegate) = self.delegate.as_mut() {
-            match result {
-                Err(emulator_bus::BusError::LoadAccessFault) => delegate.read(size, addr),
-                _ => result,
+        if !matches!(result, Err(emulator_bus::BusError::LoadAccessFault)) {
+            return result;
+        }
+        for delegate in self.delegates.iter_mut() {
+            let result = delegate.read(size, addr);
+            if !matches!(result, Err(emulator_bus::BusError::LoadAccessFault)) {
+                return result;
             }
-        } else {
-            result
         }
+        result
     }
     fn write(
         &mut self,
@@ -180,14 +182,16 @@ impl emulator_bus::Bus for AutoRootBus {
             }
             _ => Err(emulator_bus::BusError::StoreAccessFault),
         };
-        if let Some(delegate) = self.delegate.as_mut() {
-            match result {
-                Err(emulator_bus::BusError::StoreAccessFault) => delegate.write(size, addr, val),
-                _ => result,
+        if !matches!(result, Err(emulator_bus::BusError::StoreAccessFault)) {
+            return result;
+        }
+        for delegate in self.delegates.iter_mut() {
+            let result = delegate.write(size, addr, val);
+            if !matches!(result, Err(emulator_bus::BusError::StoreAccessFault)) {
+                return result;
             }
-        } else {
-            result
         }
+        result
     }
     fn poll(&mut self) {
         if let Some(periph) = self.i3c_periph.as_mut() {
@@ -214,7 +218,7 @@ impl emulator_bus::Bus for AutoRootBus {
         if let Some(periph) = self.el2_pic_periph.as_mut() {
             periph.poll();
         }
-        if let Some(delegate) = self.delegate.as_mut() {
+        for delegate in self.delegates.iter_mut() {
             delegate.poll();
         }
     }
@@ -243,7 +247,7 @@ impl emulator_bus::Bus for AutoRootBus {
         if let Some(periph) = self.el2_pic_periph.as_mut() {
             periph.warm_reset();
         }
-        if let Some(delegate) = self.delegate.as_mut() {
+        for delegate in self.delegates.iter_mut() {
             delegate.warm_reset();
         }
     }
@@ -272,7 +276,7 @@ impl emulator_bus::Bus for AutoRootBus {
         if let Some(periph) = self.el2_pic_periph.as_mut() {
             periph.update_reset();
         }
-        if let Some(delegate) = self.delegate.as_mut() {
+        for delegate in self.delegates.iter_mut() {
             delegate.update_reset();
         }
     }
-Original file line number
+Diff line change
@@ Expand Up / @@ -547,7 +547,7 @@ mod test { @@
             }
             AutoRootBus::new(
-                None,
+                vec![],
                 None,
                 Some(flash_controller),
                 None,
@@ Expand Down @@