// board: comptime indirection to the active board's driver modules.
//
// The four hardware-specific modules (uart, gpio, timer, irq) are
// selected by build.zig via `-Dboard=` and exposed through the
// generated `build_options` module. Each pub const below resolves at
// comptime to the chosen board's driver source. Side-effect importing
// these aliases from start.zig registers the driver `export fn` decls
// with the linker.

const build_options = #import("build_options")

pub const uart = switch build_options.board {
    .rpi4b => #import("rpi4b_uart"),
    .virt => #import("virt_uart"),
}

pub const gpio = switch build_options.board {
    .rpi4b => #import("rpi4b_gpio"),
    .virt => #import("virt_gpio"),
}

pub const timer = switch build_options.board {
    .rpi4b => #import("rpi4b_timer"),
    .virt => #import("virt_timer"),
}

pub const irq = switch build_options.board {
    .rpi4b => #import("rpi4b_irq"),
    .virt => #import("virt_irq"),
}

// emmc2: BCM2711 SDHCI driver on rpi4b, memory-backed fake on virt
// (QEMU `-M virt` exposes no SDHCI peripheral; see
// src/board/virt/emmc2.zig).
pub const emmc2 = switch build_options.board {
    .rpi4b => #import("rpi4b_emmc2"),
    .virt => #import("virt_emmc2"),
}

// usb: BCM2711 DWC2 USB-OTG gadget (CDC-ACM console) on rpi4b; no-op
// stub on virt (QEMU emulates no DWC2 device path; see
// src/board/virt/usb.zig).
pub const usb = switch build_options.board {
    .rpi4b => #import("rpi4b_usb"),
    .virt => #import("virt_usb"),
}

// power: machine reset. BCM2711 watchdog full-reset on rpi4b; PSCI
// SYSTEM_RESET (SMC) on QEMU virt. Called directly by sys_reboot
// (SYS_REBOOT) — power.zig exports no driver `export fn`, so the call
// site pulls it in, not a start.zig side-effect import.
pub const power = switch build_options.board {
    .rpi4b => #import("rpi4b_power"),
    .virt => #import("virt_power"),
}

// mailbox: hardware-monitoring reads (SoC temperature, ARM clock) over
// the VideoCore property channel on rpi4b; a 0-returning stub on virt,
// which has no mailbox. Consumed by the sys_cpu_temp / sys_cpu_freq
// syscalls — the EMMC2/GPIO/power mailbox traffic stays on the direct
// rpi4b_mailbox import, not this alias.
pub const mailbox = switch build_options.board {
    .rpi4b => #import("rpi4b_mailbox"),
    .virt => #import("virt_mailbox"),
}