Add native Rust unit tests that link GpioRegisters directly and exercise the CRL/CRH decode and IDR update algorithm in-process, without booting a machine or pulling in the softmmu memory subsystem.
Signed-off-by: Jack Wang <[email protected]> --- rust/hw/gpio/tests/tests.rs | 191 ++++++++++++++++++++++++++++++++++++ 1 file changed, 191 insertions(+) create mode 100644 rust/hw/gpio/tests/tests.rs diff --git a/rust/hw/gpio/tests/tests.rs b/rust/hw/gpio/tests/tests.rs new file mode 100644 index 0000000000..ca4d5ed4d6 --- /dev/null +++ b/rust/hw/gpio/tests/tests.rs @@ -0,0 +1,191 @@ +// Native Rust unit tests for the STM32F1xx GPIO register logic. +// +// Copyright 2026, Jack Wang +// Author(s): Jack Wang <[email protected]> +// SPDX-License-Identifier: GPL-2.0-or-later +// +// Unlike tests/qtest/stm32f103_gpio-test.c (which drives the device over a +// socket from an external qemu-system-arm process), these tests link the +// device crate directly and exercise `GpioRegisters` in-process. This gives +// fast, native Rust coverage of the CRL/CRH decode + IDR algorithm without +// booting a machine or pulling in the softmmu memory subsystem. +// +// `GpioRegisters` deliberately has no QOM object, no MemoryRegion and no +// InterruptSource, so it can be constructed with `GpioRegisters::new()` and +// called directly. Only the BQL mock (bql::start_test) is required, because +// the register cells are `BqlCell`s. +// +// SPDX-License-Identifier: GPL-2.0-or-later + +use stm32f1xx_gpio::gpio::{ + GpioRegisters, PinUpdate, REG_BRR, REG_BSRR, REG_CRH, REG_CRL, REG_IDR, REG_ODR, RESET_CRH, + RESET_CRL, +}; + +/// Take the mock BQL so `BqlCell` accesses are permitted. Integration tests +/// run with `--test-threads=1`, so this is safe to call from every test. +fn regs() -> GpioRegisters { + bql::start_test(); + GpioRegisters::new() +} + +// 4-bit MODE[1:0]+CNF[1:0] pin configurations (RM0008). +const CFG_INPUT_FLOATING: u32 = 0x4; // MODE=00 CNF=01 (reset default) +const CFG_INPUT_PULL: u32 = 0x8; // MODE=00 CNF=10, ODR selects up/down +const CFG_OUTPUT_PP: u32 = 0x1; // MODE=01 CNF=00, general push-pull + +/// Set the 4-bit config nibble for `pin` in CRL/CRH via an MMIO write. +fn set_config(r: &GpioRegisters, pin: usize, cfg: u32) { + let reg = if pin < 8 { REG_CRL } else { REG_CRH }; + let shift = ((pin % 8) * 4) as u32; + let old = r.read(reg); + r.write(reg, (old & !(0xF << shift)) | (cfg << shift)); +} + +fn set_odr_bit(r: &GpioRegisters, pin: usize, value: u32) { + let old = r.read(REG_ODR); + r.write(REG_ODR, (old & !(1 << pin)) | (value << pin)); +} + +/// True if pin `pin` is set in a [`PinUpdate`] and its reported level is +/// `level`. +fn pin_changed_to(upd: PinUpdate, pin: usize, level: bool) -> bool { + (upd.mask & (1 << pin)) != 0 && (((upd.levels >> pin) & 1) != 0) == level +} + +#[test] +/// A freshly created register block holds the RM0008 reset values. +fn test_reset_values() { + let r = regs(); + assert_eq!(r.read(REG_CRL), RESET_CRL); + assert_eq!(r.read(REG_CRH), RESET_CRH); + assert_eq!(r.read(REG_IDR), 0); + assert_eq!(r.read(REG_ODR), 0); +} + +#[test] +/// `reset` restores the reset state after the registers are dirtied. +fn test_reset_restores() { + let r = regs(); + r.write(REG_CRL, 0xDEAD_BEEF); + r.write(REG_ODR, 0x0000_FFFF); + assert_ne!(r.read(REG_CRL), RESET_CRL); + + r.reset(); + + assert_eq!(r.read(REG_CRL), RESET_CRL); + assert_eq!(r.read(REG_CRH), RESET_CRH); + assert_eq!(r.read(REG_IDR), 0); + assert_eq!(r.read(REG_ODR), 0); +} + +#[test] +/// Push-pull output: IDR follows ODR; ODR written while input is latched, +/// and the out-pin change is reported. +fn test_output_mode() { + let r = regs(); + let pin = 5; + + // Set ODR while still a floating input: IDR unaffected, no out change. + let idle = set_odr_and_report(&r, pin, 1); + assert_eq!(r.read(REG_IDR), 0); + assert_eq!(idle.mask & (1 << pin), 0); + + // Switch to push-pull output: pin now follows ODR (high), and flips. + let old = r.read(REG_CRL); + let to_output = r.write( + REG_CRL, + (old & !(0xF << (pin * 4))) | (CFG_OUTPUT_PP << (pin * 4)), + ); + assert_eq!(r.read(REG_IDR), 1 << pin); + assert!(pin_changed_to(to_output, pin, true)); + + // Clear ODR bit: pin goes low, and flips back. + let to_low = set_odr_and_report(&r, pin, 0); + assert_eq!(r.read(REG_IDR), 0); + assert!(pin_changed_to(to_low, pin, false)); +} + +/// Helper: write one ODR bit and return the resulting [`PinUpdate`]. +fn set_odr_and_report(r: &GpioRegisters, pin: usize, value: u32) -> PinUpdate { + let old = r.read(REG_ODR); + r.write(REG_ODR, (old & !(1 << pin)) | (value << pin)) +} + +#[test] +/// Floating input: an external drive is reflected in IDR and reported. +fn test_input_mode() { + let r = regs(); + let pin = 6usize; + + set_config(&r, pin, CFG_INPUT_FLOATING); + + let drive_high = r.gpio_set(pin, 1); + assert_eq!(r.read(REG_IDR), 1 << pin); + assert!(pin_changed_to(drive_high, pin, true)); + + let drive_low = r.gpio_set(pin, 0); + assert_eq!(r.read(REG_IDR), 0); + assert!(pin_changed_to(drive_low, pin, false)); +} + +#[test] +/// Input pull mode: ODR selects pull-up (IDR=1) vs pull-down (IDR=0), +/// with no external driver connected. +fn test_pull_up_down() { + let r = regs(); + let pin = 0; + + set_odr_bit(&r, pin, 1); + set_config(&r, pin, CFG_INPUT_PULL); + assert_eq!(r.read(REG_IDR), 1 << pin); + + set_odr_bit(&r, pin, 0); + assert_eq!(r.read(REG_IDR), 0); +} + +#[test] +/// BSRR sets/resets ODR bits (set has priority); BRR resets ODR bits. +fn test_bsrr_brr() { + let r = regs(); + let pin = 1; + + r.write(REG_BSRR, 1 << pin); + assert_eq!(r.read(REG_ODR), 1 << pin); + + r.write(REG_BSRR, 1 << (pin + 16)); + assert_eq!(r.read(REG_ODR), 0); + + r.write(REG_BSRR, 1 << pin); + r.write(REG_BRR, 1 << pin); + assert_eq!(r.read(REG_ODR), 0); + + // Set has priority over reset within one BSRR write. + r.write(REG_BSRR, (1 << pin) | (1 << (pin + 16))); + assert_eq!(r.read(REG_ODR), 1 << pin); +} + +#[test] +/// A pin driven externally, then reconfigured as push-pull output, is +/// disconnected: IDR follows ODR, not the stale external level. +fn test_push_pull_disconnect() { + let r = regs(); + let pin = 7usize; + + // Drive high externally as input. + set_config(&r, pin, CFG_INPUT_FLOATING); + r.gpio_set(pin, 1); + assert_eq!(r.read(REG_IDR), 1 << pin); + assert_eq!(r.disconnected_pins() & (1 << pin), 0); // now connected + + // Reconfigure as push-pull output with ODR=0: pin must drop to 0, + // and the external driver must be disconnected. + set_odr_bit(&r, pin, 0); + set_config(&r, pin, CFG_OUTPUT_PP); + assert_eq!(r.read(REG_IDR), 0); + assert_ne!(r.disconnected_pins() & (1 << pin), 0); // disconnected again + + // Further external drives are ignored while output push-pull. + r.gpio_set(pin, 1); + assert_eq!(r.read(REG_IDR), 0); +} -- 2.53.0
