Merge pull request #153 from ferrous-systems/fixup-arm-demos

Fixup arm demos

example-code/qemu-aarch64v8a/criticalup.toml

@@ -0,0 +1,5 @@
+manifest-version = 1
+
+[products.ferrocene]
+release = "nightly-2024-04-24"
+packages = ["rustc-${rustc-host}", "rust-std-${rustc-host}", "cargo-${rustc-host}", "rustfmt-${rustc-host}", "rust-src", "rust-std-aarch64-unknown-none",]

example-code/qemu-aarch64v8a/linker.ld

@@ -15,7 +15,7 @@ SECTIONS {
     /DISCARD/ : {
         *(.note .note*)
     }
-    . = ALIGN(8);
-    . += 0x10000; /* 64kB of stack memory */
+    . = ALIGN(16);
+    . += 0x100000; /* 1024kB of stack memory */
     stack_top = .;
 }

example-code/qemu-aarch64v8a/src/main.rs

@@ -2,7 +2,7 @@
 //!
 //! Written by Jonathan Pallant at Ferrous Systems
 //!
-//! Copyright (c) Ferrous Systems, 2023
+//! Copyright (c) Ferrous Systems, 2024
 //!
 //! To
 
@@ -11,39 +11,7 @@
 
 use core::fmt::Write;
 
-/// Represents an emulated QEMU UART.
-struct Uart {
-    base: *mut u32,
-}
-
-impl Uart {
-    /// Create a handle to the first UART
-    pub fn uart0() -> Uart {
-        const UART0_ADDR: usize = 0x0000_0000_0900_0000;
-        Uart {
-            base: UART0_ADDR as *mut u32,
-        }
-    }
-
-    /// Write one byte to the QEMU virtual UART.
-    ///
-    /// We don't have to check for FIFO space as the emulated FIFO never runs
-    /// out of space.
-    pub fn putchar(&mut self, byte: u8) {
-        unsafe {
-            self.base.write_volatile(u32::from(byte));
-        }
-    }
-}
-
-impl core::fmt::Write for Uart {
-    fn write_str(&mut self, s: &str) -> core::fmt::Result {
-        for b in s.bytes() {
-            self.putchar(b);
-        }
-        Ok(())
-    }
-}
+mod virt_uart;
 
 /// The entry-point to the Rust application.
 ///
@@ -60,14 +28,14 @@ pub extern "C" fn kmain() {
 ///
 /// Called by [`kmain`].
 fn main() -> Result<(), core::fmt::Error> {
-    let mut c = Uart::uart0();
-    writeln!(c, "Hello, this is Rust!")?;
+    let mut uart0 = unsafe { virt_uart::Uart::new_uart0() };
+    writeln!(uart0, "Hello, this is Rust!")?;
     for x in 1..=10 {
         for y in 1..=10 {
-            let z = x * y;
-            write!(c, "{z:4}")?;
+            let z = f64::from(x) * f64::from(y);
+            write!(uart0, "{z:>8.2} ")?;
         }
-        writeln!(c)?;
+        writeln!(uart0)?;
     }
     panic!("I am a panic");
 }
@@ -79,7 +47,7 @@ fn main() -> Result<(), core::fmt::Error> {
 #[panic_handler]
 fn panic(info: &core::panic::PanicInfo) -> ! {
     const SYS_REPORTEXC: u64 = 0x18;
-    let mut c = Uart::uart0();
+    let mut c = unsafe { virt_uart::Uart::new_uart0() };
     let _ = writeln!(c, "PANIC: {:?}", info);
     loop {
         // Exit, using semihosting

example-code/qemu-aarch64v8a/src/virt_uart.rs

@@ -0,0 +1,75 @@
+//! A driver the Arm PL011 Uart
+//!
+//! Written by Jonathan Pallant at Ferrous Systems
+//!
+//! Copyright (c) Ferrous Systems, 2024
+
+/// A driver for a virtual PL011 Uart
+///
+/// It skips almost all the important initialisation, but it works on QEMU.
+pub struct Uart<const ADDR: usize>();
+
+impl Uart<0x0900_0000> {
+    /// Create a new UART object for UART0
+    ///
+    /// # Safety
+    ///
+    /// Only construct one object per UART at any given time.
+    pub unsafe fn new_uart0() -> Self {
+        let mut u = Uart();
+        u.set_control(Self::CONTROL_UARTEN | Self::CONTROL_TXE);
+        u
+    }
+}
+
+impl<const ADDR: usize> Uart<ADDR> {
+    const FLAG_TXFF: u32 = 1 << 5;
+    const CONTROL_UARTEN: u32 = 1 << 0;
+    const CONTROL_TXE: u32 = 1 << 8;
+
+    const DATA_OFFSET: usize = 0x000 >> 2;
+    const FLAG_OFFSET: usize = 0x018 >> 2;
+    const CONTROL_OFFSET: usize = 0x030 >> 2;
+
+    /// Write a byte (blocking if there's no space)
+    pub fn write(&mut self, byte: u8) {
+        // Check the TX FIFO Full bit
+        while (self.get_flags() & Self::FLAG_TXFF) != 0 {}
+        self.write_data(byte);
+    }
+
+    /// Write to the data register
+    fn write_data(&mut self, value: u8) {
+        unsafe {
+            let ptr = (ADDR as *mut u32).add(Self::DATA_OFFSET);
+            ptr.write_volatile(value as u32);
+        }
+    }
+
+    /// Read from the Flag Register
+    fn get_flags(&mut self) -> u32 {
+        unsafe {
+            let ptr = (ADDR as *const u32).add(Self::FLAG_OFFSET);
+            ptr.read_volatile()
+        }
+    }
+
+    /// Write to the control register
+    fn set_control(&mut self, value: u32) {
+        unsafe {
+            let ptr = (ADDR as *mut u32).add(Self::CONTROL_OFFSET);
+            ptr.write_volatile(value);
+        }
+    }
+}
+
+impl<const N: usize> core::fmt::Write for Uart<N> {
+    fn write_str(&mut self, s: &str) -> core::fmt::Result {
+        for b in s.bytes() {
+            self.write(b);
+        }
+        Ok(())
+    }
+}
+
+// End of file

example-code/qemu-armv8r/.cargo/config.toml

@@ -2,7 +2,8 @@
 rustflags = [
     "-Clink-arg=-Tlinker.ld",
 ]
-runner = "/Users/jonathan/Documents/open-source/qemu/build/qemu-system-arm -machine mps3-an536 -cpu cortex-r52 -semihosting -nographic -kernel"
+# Note, this requires QEMU 9 or higher
+runner = "qemu-system-arm -machine mps3-an536 -cpu cortex-r52 -semihosting -nographic -kernel"
 
 [build]
 target = ["armv8r-none-eabihf"]

example-code/qemu-armv8r/criticalup.toml

@@ -0,0 +1,5 @@
+manifest-version = 1
+
+[products.ferrocene]
+release = "nightly-2024-04-24"
+packages = ["rustc-${rustc-host}", "rust-std-${rustc-host}", "cargo-${rustc-host}", "rustfmt-${rustc-host}", "rust-src", "rust-std-armv8r-none-eabihf",]

example-code/qemu-armv8r/linker.ld

@@ -16,7 +16,7 @@ SECTIONS {
     /DISCARD/ : {
         *(.note .note*)
     }
-    . = ALIGN(8);
-    . += 0x10000; /* 64kB of stack memory */
+    . = ALIGN(16);
+    . += 0x100000; /* 1024kB of stack memory */
     stack_top = .;
 }

example-code/qemu-armv8r/qemu.sh

@@ -2,4 +2,4 @@
 
 TARGET_DIR=target/production
 BINARY=${TARGET_DIR}/basic-rust
-/Users/jonathan/Documents/open-source/qemu/build/qemu-system-arm -machine mps3-an536 -cpu cortex-r52 -semihosting -nographic -kernel ${BINARY}
+qemu-system-arm -machine mps3-an536 -cpu cortex-r52 -semihosting -nographic -kernel ${BINARY}

example-code/qemu-armv8r/src/cmsdk_uart.rs

@@ -0,0 +1,86 @@
+//! A driver the Arm CMSDK Uart
+//!
+//! Written by Jonathan Pallant at Ferrous Systems
+//!
+//! Copyright (c) Ferrous Systems, 2024
+
+/// A driver for CMSDK Uart
+pub struct Uart<const ADDR: usize>();
+
+impl Uart<0xe7c0_0000> {
+    /// Create a new UART object for UART0
+    ///
+    /// # Safety
+    ///
+    /// Only construct one object per UART at any given time.
+    pub unsafe fn new_uart0() -> Self {
+        Uart()
+    }
+}
+
+impl<const ADDR: usize> Uart<ADDR> {
+    const STATUS_TX_FULL: u32 = 1 << 0;
+    const CONTROL_TX_EN: u32 = 1 << 0;
+
+    const DATA_OFFSET: usize = 0x000 >> 2;
+    const STATUS_OFFSET: usize = 0x004 >> 2;
+    const CONTROL_OFFSET: usize = 0x008 >> 2;
+    const BAUD_OFFSET: usize = 0x010 >> 2;
+
+    /// Turn on TX and RX
+    pub fn enable(&mut self, baudrate: u32, system_clock: u32) {
+        let divider = system_clock / baudrate;
+        self.set_bauddiv(divider);
+        self.set_control(Self::CONTROL_TX_EN);
+    }
+
+    /// Write a byte (blocking if there's no space)
+    pub fn write(&mut self, byte: u8) {
+        // Check the Buffer Full bit
+        while (self.get_status() & Self::STATUS_TX_FULL) != 0 {}
+        self.set_data(byte as u32);
+    }
+
+    /// Write the data register
+    fn set_data(&mut self, data: u32) {
+        unsafe {
+            let ptr = (ADDR as *mut u32).add(Self::DATA_OFFSET);
+            ptr.write_volatile(data)
+        }
+    }
+
+    /// Read the status register
+    fn get_status(&self) -> u32 {
+        unsafe {
+            let ptr = (ADDR as *mut u32).add(Self::STATUS_OFFSET);
+            ptr.read_volatile()
+        }
+    }
+
+    /// Set the control register
+    fn set_control(&mut self, data: u32) {
+        unsafe {
+            let ptr = (ADDR as *mut u32).add(Self::CONTROL_OFFSET);
+            ptr.write_volatile(data)
+        }
+    }
+
+    /// Set the baud rate divider register
+    fn set_bauddiv(&mut self, data: u32) {
+        unsafe {
+            let ptr = (ADDR as *mut u32).add(Self::BAUD_OFFSET);
+            ptr.write_volatile(data)
+        }
+    }
+}
+
+impl<const N: usize> core::fmt::Write for Uart<N> {
+    fn write_str(&mut self, s: &str) -> core::fmt::Result {
+        for b in s.bytes() {
+            self.write(b);
+        }
+        Ok(())
+    }
+}
+
+// End of file

example-code/qemu-armv8r/src/main.rs

@@ -1,75 +1,21 @@
-//! An example program for QEMU's Aarch64 Virtual Machine
+//! An example program for QEMU's Armv8-R Virtual Machine
 //!
 //! Written by Jonathan Pallant at Ferrous Systems
 //!
-//! Copyright (c) Ferrous Systems, 2023
-//!
-//! To
+//! Copyright (c) Ferrous Systems, 2024
 
 #![no_std]
 #![no_main]
 
 use core::fmt::Write;
 
+mod cmsdk_uart;
+
 /// The clock speed of the peripheral subsystem on an SSE-300 SoC an on MPS3 board.
 ///
 /// Probably right for an MPS3-
 const PERIPHERAL_CLOCK: u32 = 25_000_000;
 
-/// A driver for CMSDK Uart
-struct Uart<const ADDR: usize>();
-
-impl<const ADDR: usize> Uart<ADDR> {
-    const STATUS_TX_FULL: u32 = 1 << 0;
-
-    /// Turn on TX and RX
-    fn enable(&mut self, baudrate: u32, system_clock: u32) {
-        let divider = system_clock / baudrate;
-        self.set_bauddiv(divider);
-        self.set_control(0b0000_0011);
-    }
-
-    /// Write a byte (blocking if there's no space)
-    fn write(&mut self, byte: u8) {
-        // Check the Buffer Full bit
-        while (self.get_status() & Self::STATUS_TX_FULL) != 0 {}
-        self.set_data(byte as u32);
-    }
-
-    /// Write the data register
-    fn set_data(&mut self, data: u32) {
-        let ptr = ADDR as *mut u32;
-        unsafe { ptr.write_volatile(data) }
-    }
-
-    /// Read the status register
-    fn get_status(&self) -> u32 {
-        let ptr = (ADDR + 4) as *mut u32;
-        unsafe { ptr.read_volatile() }
-    }
-
-    /// Set the control register
-    fn set_control(&mut self, data: u32) {
-        let ptr = (ADDR + 8) as *mut u32;
-        unsafe { ptr.write_volatile(data) }
-    }
-
-    /// Set the baud rate divider register
-    fn set_bauddiv(&mut self, data: u32) {
-        let ptr = (ADDR + 16) as *mut u32;
-        unsafe { ptr.write_volatile(data) }
-    }
-}
-
-impl<const N: usize> core::fmt::Write for Uart<N> {
-    fn write_str(&mut self, s: &str) -> core::fmt::Result {
-        for b in s.bytes() {
-            self.write(b);
-        }
-        Ok(())
-    }
-}
-
 /// The entry-point to the Rust application.
 ///
 /// It is called by the start-up code in [`boot.S`](./boot.S) and thus exported
@@ -85,13 +31,13 @@ pub extern "C" fn kmain() {
 ///
 /// Called by [`kmain`].
 fn main() -> Result<(), core::fmt::Error> {
-    let mut uart0: Uart<0xe7c00000> = Uart();
+    let mut uart0 = unsafe { cmsdk_uart::Uart::new_uart0() };
     uart0.enable(115200, PERIPHERAL_CLOCK);
     writeln!(uart0, "Hello, this is Rust!")?;
     for x in 1..=10 {
         for y in 1..=10 {
             let z = f64::from(x) * f64::from(y);
-            write!(uart0, "{z:4.1} ")?;
+            write!(uart0, "{z:>8.2} ")?;
         }
         writeln!(uart0)?;
     }
@@ -106,7 +52,7 @@ fn main() -> Result<(), core::fmt::Error> {
 fn panic(info: &core::panic::PanicInfo) -> ! {
     const SYS_REPORTEXC: u32 = 0x18;
     // We assume it is already enabled
-    let mut uart0: Uart<0xe7c00000> = Uart();
+    let mut uart0 = unsafe { cmsdk_uart::Uart::new_uart0() };
     let _ = writeln!(uart0, "PANIC: {:?}", info);
     loop {
         // Exit, using semihosting