Merge #1911

1911: New Platform: Msp432 r=bradjc a=lebakassemmerl

### New Platform Support for the MSP-EXP432P401R Eval-Board

This pull-request adds support for MSP432P401R chip from Texas Instruments.
The implementation is currently very, very basic, only the GPIO-module is properly implemented in order to create a panic-handler which blinks an LED and to be able to test a simple user-space application. 

If this PR will be accepted, the next step would be to implement the UART and timer modules for supporting debug-output and delays in userspace.

## Adding a Platform to Tock Repository

- [x] The hardware must be widely available. Generally that means the hardware platform can be purchased online.
- The port of Tock to the platform must include at least:
   - [x] Console support so that debug!() and printf() work.
   - [x] Timer support.
   - [x] GPIO support with interrupt functionality.
- [x] The contributor must be willing to maintain the platform, at least initially, and help test the platform for future releases.


Co-authored-by: hotschi <hotschi@gmx.at>

.vscode/launch.json

@@ -15,6 +15,19 @@
                 "monitor speed auto",
                 "b reset_handler"
             ]
+        },
+        {
+            "name": "MSP432 Cortex Debug",
+            "type": "cortex-debug",
+            "servertype": "openocd",
+            "request": "launch",
+            "executable": "${workspaceRoot}/target/thumbv7em-none-eabi/debug/msp-exp432p401r.elf",
+            "cwd": "${workspaceRoot}",
+            "svdFile": "${workspaceRoot}/boards/msp_exp432p401r/msp432.svd",
+            "runToMain": true,
+            "configFiles": [
+                "${workspaceRoot}/boards/msp_exp432p401r/openocd.cfg",
+            ]
         }
     ]
 }

Cargo.toml

@@ -10,6 +10,7 @@ members = [
     "boards/hail",
     "boards/hifive1",
     "boards/imix",
+    "boards/msp_exp432p401r",
     "boards/nordic/nrf52840dk",
     "boards/nordic/nrf52840_dongle",
     "boards/nordic/nrf52dk",
@@ -26,6 +27,7 @@ members = [
     "chips/e310x",
     "chips/earlgrey",
     "chips/lowrisc",
+    "chips/msp432",
     "chips/nrf52",
     "chips/nrf52832",
     "chips/nrf52840",

boards/msp_exp432p401r/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "msp-exp432p401r"
+version = "0.1.0"
+authors = ["Tock Project Developers <tock-dev@googlegroups.com>"]
+build = "build.rs"
+edition = "2018"
+
+[dependencies]
+components = { path = "../components" }
+cortexm4 = { path = "../../arch/cortex-m4" }
+capsules = { path = "../../capsules" }
+kernel = { path = "../../kernel" }
+msp432 = { path = "../../chips/msp432" }

boards/msp_exp432p401r/Makefile

@@ -0,0 +1,23 @@
+# Makefile for building the tock kernel for the MSP-EXP432P401 launchpad
+#
+TARGET=thumbv7em-none-eabi
+PLATFORM=msp-exp432p401r
+
+include ../Makefile.common
+
+OPENOCD=openocd
+OPENOCD_OPTIONS=-f openocd.cfg
+APP_START_ADDR=0x20000
+APP?=
+
+.PHONY: flash-debug
+flash-debug: $(TOCK_ROOT_DIRECTORY)target/$(TARGET)/debug/$(PLATFORM).elf
+	$(OPENOCD) $(OPENOCD_OPTIONS) -c "init; reset halt; flash write_image erase $<; verify_image $<; reset; shutdown"
+
+.PHONY: flash
+flash: $(TOCK_ROOT_DIRECTORY)target/$(TARGET)/release/$(PLATFORM).elf
+	$(OPENOCD) $(OPENOCD_OPTIONS) -c "init; reset halt; flash write_image erase $<; verify_image $<; reset; shutdown"
+
+.PHONY: flash-app
+flash-app:
+	$(OPENOCD) $(OPENOCD_OPTIONS) -c "init; reset halt; flash write_image erase $(APP) $(APP_START_ADDR) bin; verify_image_checksum $(APP) $(APP_START_ADDR) bin; reset; shutdown"

boards/msp_exp432p401r/README.md

@@ -0,0 +1,33 @@
+MSP432 Evaluation kit MSP432P401R MCU
+=====================================
+
+For more details [visit the Evaluation kit website](https://www.ti.com/tool/MSP-EXP432P401R).
+
+## Flashing the kernel
+
+The kernel can be programmed using OpenOCD. `cd` into `boards/msp_exp432p401r`
+directory and run:
+
+```bash
+$ make flash
+
+(or)
+
+$ make flash-debug
+```
+
+**Note:** Make sure to use the latest git-openOCD-version as there is currently no support for the
+XDS110 debug-probe in the pre-built binaries!
+
+## Flashing an app
+
+Apps are also flashed via openOCD. Make sure, your app is was compiled and converted into the TBF
+(Tock Binary Format) format. Then `cd` into the `boards/msp_exp432p401r`directory and run:
+
+```bash
+$ make flash-app APP=<path_to_tbf_file>
+
+(e.g.)
+
+$ make flash-app APP=../../../libtock-c/examples/c_hello/build/cortex-m4/cortex-m4.tbf
+```

boards/msp_exp432p401r/build.rs

@@ -0,0 +1,5 @@
+fn main() {
+    println!("cargo:rerun-if-changed=layout.ld");
+    println!("cargo:rerun-if-changed=chip_layout.ld");
+    println!("cargo:rerun-if-changed=../kernel_layout.ld");
+}

boards/msp_exp432p401r/chip_layout.ld

@@ -0,0 +1,9 @@
+/* Memory Space Definitions, 256K flash, 64K ram */
+MEMORY
+{
+  rom (rx)  : ORIGIN = 0x00000000, LENGTH = 128K
+  prog (rx) : ORIGIN = 0x00020000, LENGTH = 128K
+  ram (rwx) : ORIGIN = 0x20000000, LENGTH = 64K
+}
+
+MPU_MIN_ALIGN = 4K;

boards/msp_exp432p401r/layout.ld

@@ -0,0 +1,2 @@
+INCLUDE ./chip_layout.ld
+INCLUDE ../kernel_layout.ld

boards/msp_exp432p401r/openocd.cfg

@@ -0,0 +1,6 @@
+adapter driver xds110
+adapter speed 2500
+source [find board/ti_msp432_launchpad.cfg]
+
+init;
+reset halt;

boards/msp_exp432p401r/src/io.rs

@@ -0,0 +1,57 @@
+use crate::CHIP;
+use crate::PROCESSES;
+
+use core::fmt::Write;
+use core::panic::PanicInfo;
+use kernel::debug;
+use kernel::debug::IoWrite;
+use kernel::hil::led;
+use msp432::gpio::PinNr;
+
+/// Uart is used by kernel::debug to panic message to the serial port.
+pub struct Uart {
+    initialized: bool,
+}
+
+/// Global static for debug writer
+pub static mut UART: Uart = Uart { initialized: false };
+
+impl Uart {
+    /// Indicate that UART has already been initialized.
+    pub fn set_initialized(&mut self) {
+        self.initialized = true;
+    }
+}
+
+impl Write for Uart {
+    fn write_str(&mut self, s: &str) -> ::core::fmt::Result {
+        self.write(s.as_bytes());
+        Ok(())
+    }
+}
+
+impl IoWrite for Uart {
+    fn write(&mut self, buf: &[u8]) {
+        unsafe {
+            msp432::uart::UART0.transmit_sync(buf);
+        }
+    }
+}
+
+/// Panic handler
+#[no_mangle]
+#[panic_handler]
+pub unsafe extern "C" fn panic_fmt(info: &PanicInfo) -> ! {
+    const LED1_PIN: PinNr = PinNr::P01_0;
+    let led = &mut led::LedHigh::new(&mut msp432::gpio::PINS[LED1_PIN as usize]);
+    let writer = &mut UART;
+
+    debug::panic(
+        &mut [led],
+        writer,
+        info,
+        &cortexm4::support::nop,
+        &PROCESSES,
+        &CHIP,
+    )
+}