earlgrey: Add a uart loopback test

target/earlgrey/tests/uart/BUILD.bazel

@@ -0,0 +1,169 @@
+# Licensed under the Apache-2.0 license
+# SPDX-License-Identifier: Apache-2.0
+
+load("@pigweed//pw_kernel/tooling:app_package.bzl", "app_package")
+load("@pigweed//pw_kernel/tooling:system_image.bzl", "system_image")
+load("@pigweed//pw_kernel/tooling:target_codegen.bzl", "target_codegen")
+load("@pigweed//pw_kernel/tooling:target_linker_script.bzl", "target_linker_script")
+load("@pigweed//pw_kernel/tooling/panic_detector:rust_binary_no_panics_test.bzl", "rust_binary_no_panics_test")
+load("@rules_rust//rust:defs.bzl", "rust_binary")
+load("//target/earlgrey:defs.bzl", "TARGET_COMPATIBLE_WITH")
+load("//target/earlgrey/signing/keys:defs.bzl", "FPGA_ECDSA_KEY", "SILICON_ECDSA_KEY")
+load("//target/earlgrey/tooling:opentitan_runner.bzl", "opentitan_test")
+
+rust_binary(
+    name = "test_uart",
+    srcs = [
+        "test_uart.rs",
+    ],
+    edition = "2024",
+    tags = ["kernel"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":app_test_uart",
+        "//target/earlgrey/registers",
+        "@pigweed//pw_kernel/userspace",
+        "@pigweed//pw_log/rust:pw_log",
+        "@pigweed//pw_status/rust:pw_status",
+    ],
+)
+
+app_package(
+    name = "app_test_uart",
+    app_name = "test_uart",
+    edition = "2024",
+    system_config = "@pigweed//pw_kernel/target:system_config_file",
+    tags = ["kernel"],
+)
+
+rust_binary(
+    name = "test_uart_listener",
+    srcs = [
+        "test_uart_listener.rs",
+    ],
+    edition = "2024",
+    tags = ["kernel"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":app_test_uart_listener",
+        "//target/earlgrey/registers",
+        "@pigweed//pw_kernel/lib/pw_assert",
+        "@pigweed//pw_kernel/syscall:syscall_user",
+        "@pigweed//pw_kernel/userspace",
+        "@pigweed//pw_log/rust:pw_log",
+        "@pigweed//pw_status/rust:pw_status",
+    ],
+)
+
+app_package(
+    name = "app_test_uart_listener",
+    app_name = "test_uart_listener",
+    edition = "2024",
+    system_config = "@pigweed//pw_kernel/target:system_config_file",
+    tags = ["kernel"],
+)
+
+system_image(
+    name = "uart",
+    apps = [
+        ":test_uart",
+        ":test_uart_listener",
+    ],
+    kernel = ":target",
+    platform = "//target/earlgrey",
+    system_config = ":system_config",
+    tags = ["kernel"],
+)
+
+target_linker_script(
+    name = "linker_script",
+    system_config = ":system_config",
+    tags = ["kernel"],
+    template = "//target/earlgrey:linker_script_template",
+)
+
+rust_binary_no_panics_test(
+    name = "no_panics_test",
+    binary = ":uart",
+    tags = [
+        # TODO(cfrantz): Fix this test.
+        "disabled",
+        "kernel",
+    ],
+)
+
+filegroup(
+    name = "system_config",
+    srcs = ["system.json5"],
+)
+
+target_codegen(
+    name = "codegen",
+    arch = "@pigweed//pw_kernel/arch/riscv:arch_riscv",
+    system_config = ":system_config",
+)
+
+rust_binary(
+    name = "target",
+    srcs = [
+        "target.rs",
+    ],
+    edition = "2024",
+    tags = ["kernel"],
+    target_compatible_with = TARGET_COMPATIBLE_WITH,
+    deps = [
+        ":codegen",
+        ":linker_script",
+        "//target/earlgrey:entry",
+        "@pigweed//pw_kernel/arch/riscv:arch_riscv",
+        "@pigweed//pw_kernel/kernel",
+        "@pigweed//pw_kernel/subsys/console:console_backend",
+        "@pigweed//pw_kernel/target:target_common",
+        "@pigweed//pw_kernel/userspace",
+        "@pigweed//pw_log/rust:pw_log",
+    ],
+)
+
+opentitan_test(
+    name = "uart_verilator_test",
+    timeout = "eternal",
+    interface = "verilator",
+    tags = [
+        "nightly_test",
+        "verilator",
+    ],
+    target = ":uart",
+)
+
+opentitan_test(
+    name = "uart_hyper310_test",
+    ecdsa_key = FPGA_ECDSA_KEY,
+    interface = "hyper310",
+    tags = [
+        "hardware",
+        "hyper310",
+    ],
+    target = ":uart",
+)
+
+opentitan_test(
+    name = "uart_hyper340_test",
+    ecdsa_key = FPGA_ECDSA_KEY,
+    interface = "hyper340",
+    tags = [
+        "hardware",
+        "hyper340",
+    ],
+    target = ":uart",
+)
+
+opentitan_test(
+    name = "uart_silicon_test",
+    ecdsa_key = SILICON_ECDSA_KEY,
+    interface = "teacup",
+    tags = [
+        "earlgrey_silicon",
+        "hardware",
+    ],
+    target = ":uart",
+)

target/earlgrey/tests/uart/system.json5

@@ -0,0 +1,91 @@
+// Licensed under the Apache-2.0 license
+// SPDX-License-Identifier: Apache-2.0
+{
+  arch: {
+    type: "riscv",
+  },
+  kernel: {
+    flash_start_address: 0xA0010000,
+    flash_size_bytes: 65536,
+    ram_start_address: 0x10000000,
+    ram_size_bytes: 32768,
+    interrupt_table: {
+      table: {}
+    },
+  },
+  apps: [
+    {
+      name: "test_uart",
+      flash_size_bytes: 16384,
+      ram_size_bytes: 4096,
+      process: {
+        name: "test_uart process",
+        objects: [
+          {
+            name: "ipc",
+            type: "channel_handler",
+          },
+        ],
+        memory_mappings: [
+          {
+            name: "uart1",
+            type: "device",
+            start_address: 0x40010000,
+            size_bytes: 0x40,
+          }
+        ],
+        threads: [
+          {
+            name: "uart thread",
+            stack_size_bytes: 2048,
+          },
+        ],
+      },
+    },
+    {
+      name: "test_uart_listener",
+      flash_size_bytes: 16384,
+      ram_size_bytes: 4096,
+      process: {
+        name: "test_uart_listener process",
+        objects: [
+          {
+            name: "uart_interrupts",
+            type: "interrupt",
+            irqs: [
+              { name: "uart1_tx_watermark", number: 10 },
+              { name: "uart1_rx_watermark", number: 11 },
+              { name: "uart1_tx_done", number: 12 },
+              { name: "uart1_rx_overflow", number: 13 },
+              { name: "uart1_rx_frame_err", number: 14 },
+              { name: "uart1_rx_break_err", number: 15 },
+              { name: "uart1_rx_timeout", number: 16 },
+              { name: "uart1_rx_parity_err", number: 17 },
+              { name: "uart1_tx_empty", number: 18 },
+            ],
+          },
+          {
+            name: "ipc",
+            type: "channel_initiator",
+            handler_app: "test_uart",
+            handler_object_name: "ipc",
+          },
+        ],
+        memory_mappings: [
+          {
+            name: "uart1",
+            type: "device",
+            start_address: 0x40010000,
+            size_bytes: 0x40,
+          }
+        ],
+        threads: [
+          {
+            name: "uart thread",
+            stack_size_bytes: 2048,
+          },
+        ],
+      },
+    },
+  ],
+}

target/earlgrey/tests/uart/target.rs

@@ -0,0 +1,29 @@
+// Licensed under the Apache-2.0 license
+// SPDX-License-Identifier: Apache-2.0
+
+#![no_std]
+#![no_main]
+use target_common::{declare_target, TargetInterface};
+use {console_backend as _, entry as _};
+
+pub struct Target {}
+
+impl TargetInterface for Target {
+    const NAME: &'static str = "Earlgrey Userspace UART";
+
+    fn main() -> ! {
+        codegen::start();
+        loop {}
+    }
+
+    fn shutdown(code: u32) -> ! {
+        pw_log::info!("Shutting down with code {}", code as u32);
+        match code {
+            0 => pw_log::info!("PASS"),
+            _ => pw_log::info!("FAIL: {}", code as u32),
+        };
+        loop {}
+    }
+}
+
+declare_target!(Target);

target/earlgrey/tests/uart/test_uart.rs

@@ -0,0 +1,82 @@
+// Licensed under the Apache-2.0 license
+// SPDX-License-Identifier: Apache-2.0
+
+#![no_std]
+#![no_main]
+use app_test_uart::handle;
+use pw_status::{Error, Result, StatusCode};
+use userspace::syscall::Signals;
+use userspace::time::Instant;
+use userspace::{entry, syscall};
+
+use registers::uart::*;
+
+fn read_expected_value(expected_value: u8) -> Result<()> {
+    // the UART listener responds on IPC with the value written to the UART.
+    let wait_return = syscall::object_wait(handle::IPC, Signals::READABLE, Instant::MAX)?;
+
+    if !wait_return.pending_signals.contains(Signals::READABLE) || wait_return.user_data != 0 {
+        return Err(Error::Internal);
+    }
+
+    let mut buffer = [0u8; 1];
+    let len = syscall::channel_read(handle::IPC, 0, &mut buffer)?;
+    if len != 1 {
+        return Err(Error::OutOfRange);
+    };
+
+    if buffer[0] != expected_value {
+        pw_log::error!(
+            "UART read() wrong value {} (expected {})",
+            buffer[0] as u8,
+            expected_value as u8
+        );
+        return Err(Error::Internal);
+    }
+
+    let response_buffer = [0u8; 0];
+    syscall::channel_respond(handle::IPC, &response_buffer)?;
+
+    Ok(())
+}
+
+fn test_uart_interrupts() -> Result<()> {
+    let mut uart1 = unsafe { Uart1::new() };
+    let regs = uart1.regs_mut();
+
+    regs.ctrl()
+        .modify(|ctrl| ctrl.tx(true).rx(true).slpbk(true).nco(0xffff));
+
+    while !regs.status().read().rxempty() {
+        let _ = regs.rdata();
+    }
+
+    for txval in 65..91 {
+        regs.wdata().write(|w| w.wdata(txval as u32));
+        read_expected_value(txval)?;
+    }
+
+    Ok(())
+}
+
+#[entry]
+fn entry() -> ! {
+    pw_log::info!("🔄 RUNNING");
+    let ret = test_uart_interrupts();
+
+    // Log that an error occurred so that the app that caused the shutdown is logged.
+    if ret.is_err() {
+        pw_log::error!("❌ FAILED: {}", ret.status_code() as u32);
+    } else {
+        pw_log::info!("✅ PASSED");
+    }
+
+    // Since this is written as a test, shut down with the return status from `main()`.
+    let _ = syscall::debug_shutdown(ret);
+    loop {}
+}
+
+#[panic_handler]
+fn panic(_info: &core::panic::PanicInfo) -> ! {
+    loop {}
+}