Re: [PATCH v4 29/33] gpu: nova-core: Hopper/Blackwell: add GSP lockdown release polling

[John Hubbard]

On 2/17/26 12:20 PM, Danilo Krummrich wrote:
> On Tue Feb 10, 2026 at 3:45 AM CET, John Hubbard wrote:
>> +    /// Check if GSP lockdown has been released after FSP Chain of Trust
>> +    fn gsp_lockdown_released(
>> +        dev: &device::Device,
>> +        gsp_falcon: &Falcon<Gsp>,
>> +        bar: &Bar0,
>> +        fmc_boot_params_addr: u64,
>> +        mbox0: &mut u32,
>> +    ) -> bool {
>> +        // Read GSP falcon mailbox0
>> +        *mbox0 = gsp_falcon.read_mailbox0(bar);
>> +
>> +        // Check 1: If mbox0 has 0xbadf4100 pattern, GSP is still locked down
>> +        if *mbox0 != 0 && (*mbox0 & 0xffffff00) == 0xbadf4100 {
>> +            return false;
>> +        }
> 
> Hm...we could create a tiny type wrapper around this value, and do the check
> with a method, such as Mbox::is_locked_down(&self).

OK, done in v5.

> 
>> +        // Check 2: If mbox0 has a value, check if it's an error
>> +        if *mbox0 != 0 {
>> +            let mbox1 = gsp_falcon.read_mailbox1(bar);
>> +
>> +            let combined_addr = (u64::from(mbox1) << 32) | u64::from(*mbox0);
> 
> This could also be part of the type.

Yes.

> 
>> +            if combined_addr != fmc_boot_params_addr {
>> +                // Address doesn't match - GSP wrote an error code
>> +                // Return TRUE (lockdown released) with error
>> +                dev_dbg!(
>> +                    dev,
>> +                    "GSP lockdown error: mbox0={:#x}, combined_addr={:#x}, expected={:#x}\n",
>> +                    *mbox0,
>> +                    combined_addr,
>> +                    fmc_boot_params_addr
>> +                );
>> +                return true;
>> +            }
>> +        }
>> +
>> +        // Check 3: Verify HWCFG2 RISCV_BR_PRIV_LOCKDOWN bit is clear
>> +        let hwcfg2 = regs::NV_PFALCON_FALCON_HWCFG2::read(bar, &crate::falcon::gsp::Gsp::ID);
>> +        !hwcfg2.riscv_br_priv_lockdown()
>> +    }

thanks,
-- 
John Hubbard