// SPDX-License-Identifier: GPL-2.0

use core::marker::PhantomData;

use kernel::device;
use kernel::prelude::*;
use kernel::time::Delta;

use crate::driver::Bar0;
use crate::falcon::{
    Falcon, FalconBromParams, FalconEngine, FalconModSelAlgo, PeregrineCoreSelect,
};
use crate::regs;
use crate::util;

use super::FalconHal;

fn select_core_ga102<E: FalconEngine>(bar: &Bar0) -> Result {
    let bcr_ctrl = regs::NV_PRISCV_RISCV_BCR_CTRL::read(bar, E::BASE);
    if bcr_ctrl.core_select() != PeregrineCoreSelect::Falcon {
        regs::NV_PRISCV_RISCV_BCR_CTRL::default()
            .set_core_select(PeregrineCoreSelect::Falcon)
            .write(bar, E::BASE);

        // TIMEOUT: falcon core should take less than 10ms to report being enabled.
        util::wait_on(Delta::from_millis(10), || {
            let r = regs::NV_PRISCV_RISCV_BCR_CTRL::read(bar, E::BASE);
            if r.valid() {
                Some(())
            } else {
                None
            }
        })?;
    }

    Ok(())
}

fn signature_reg_fuse_version_ga102(
    dev: &device::Device,
    bar: &Bar0,
    engine_id_mask: u16,
    ucode_id: u8,
) -> Result<u32> {
    // TODO[REGA]: The ucode fuse versions are contained in the
    // FUSE_OPT_FPF_<ENGINE>_UCODE<X>_VERSION registers, which are an array. Our register
    // definition macros do not allow us to manage them properly, so we need to hardcode their
    // addresses for now. Clean this up once we support register arrays.

    // Each engine has 16 ucode version registers numbered from 1 to 16.
    if ucode_id == 0 || ucode_id > 16 {
        dev_err!(dev, "invalid ucode id {:#x}", ucode_id);
        return Err(EINVAL);
    }

    // Base address of the FUSE registers array corresponding to the engine.
    let reg_fuse_base = if engine_id_mask & 0x0001 != 0 {
        regs::NV_FUSE_OPT_FPF_SEC2_UCODE1_VERSION::OFFSET
    } else if engine_id_mask & 0x0004 != 0 {
        regs::NV_FUSE_OPT_FPF_NVDEC_UCODE1_VERSION::OFFSET
    } else if engine_id_mask & 0x0400 != 0 {
        regs::NV_FUSE_OPT_FPF_GSP_UCODE1_VERSION::OFFSET
    } else {
        dev_err!(dev, "unexpected engine_id_mask {:#x}", engine_id_mask);
        return Err(EINVAL);
    };

    // Read `reg_fuse_base[ucode_id - 1]`.
    let reg_fuse_version =
        bar.read32(reg_fuse_base + ((ucode_id - 1) as usize * core::mem::size_of::<u32>()));

    // TODO[NUMM]: replace with `last_set_bit` once it lands.
    Ok(u32::BITS - reg_fuse_version.leading_zeros())
}

fn program_brom_ga102<E: FalconEngine>(bar: &Bar0, params: &FalconBromParams) -> Result {
    regs::NV_PFALCON2_FALCON_BROM_PARAADDR::default()
        .set_value(params.pkc_data_offset)
        .write(bar, E::BASE);
    regs::NV_PFALCON2_FALCON_BROM_ENGIDMASK::default()
        .set_value(u32::from(params.engine_id_mask))
        .write(bar, E::BASE);
    regs::NV_PFALCON2_FALCON_BROM_CURR_UCODE_ID::default()
        .set_ucode_id(params.ucode_id)
        .write(bar, E::BASE);
    regs::NV_PFALCON2_FALCON_MOD_SEL::default()
        .set_algo(FalconModSelAlgo::Rsa3k)
        .write(bar, E::BASE);

    Ok(())
}

pub(super) struct Ga102<E: FalconEngine>(PhantomData<E>);

impl<E: FalconEngine> Ga102<E> {
    pub(super) fn new() -> Self {
        Self(PhantomData)
    }
}

impl<E: FalconEngine> FalconHal<E> for Ga102<E> {
    fn select_core(&self, _falcon: &Falcon<E>, bar: &Bar0) -> Result {
        select_core_ga102::<E>(bar)
    }

    fn signature_reg_fuse_version(
        &self,
        falcon: &Falcon<E>,
        bar: &Bar0,
        engine_id_mask: u16,
        ucode_id: u8,
    ) -> Result<u32> {
        signature_reg_fuse_version_ga102(&falcon.dev, bar, engine_id_mask, ucode_id)
    }

    fn program_brom(&self, _falcon: &Falcon<E>, bar: &Bar0, params: &FalconBromParams) -> Result {
        program_brom_ga102::<E>(bar, params)
    }
}