Commit 6ea52b6d authored by Deborah Brouwer's avatar Deborah Brouwer Committed by Alice Ryhl
Browse files

drm/tyr: use read_poll_timeout 



The L2 power-on sequence and soft reset in Tyr previously relied on fixed
sleeps followed by a single register check, since polling helpers were not
available in Rust at the time.

Now that read_poll_timeout() is available, poll the relevant registers
until the hardware reports readiness or a timeout is reached.

This avoids unnecessary delays on start-up.

Signed-off-by: default avatarDeborah Brouwer <deborah.brouwer@collabora.com>
Reviewed-by: default avatarAlice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260119202645.362457-1-deborah.brouwer@collabora.com


Signed-off-by: default avatarAlice Ryhl <aliceryhl@google.com>
parent 793e8f7d

drivers/gpu/drm/tyr/driver.rs

+8 −14
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
use kernel::devres::Devres;

use kernel::drm;

use kernel::drm::ioctl;

use kernel::io::poll;

use kernel::new_mutex;

use kernel::of;

use kernel::platform;
@@ -67,20 +68,13 @@ unsafe impl Sync for TyrData {} 
fn issue_soft_reset(dev: &Device<Bound>, iomem: &Devres<IoMem>) -> Result {

    regs::GPU_CMD.write(dev, iomem, regs::GPU_CMD_SOFT_RESET)?;



    // TODO: We cannot poll, as there is no support in Rust currently, so we

    // sleep. Change this when read_poll_timeout() is implemented in Rust.

    kernel::time::delay::fsleep(time::Delta::from_millis(100));



    if regs::GPU_IRQ_RAWSTAT.read(dev, iomem)? & regs::GPU_IRQ_RAWSTAT_RESET_COMPLETED == 0 {

        dev_err!(dev, "GPU reset failed with errno\n");

        dev_err!(

            dev,

            "GPU_IRQ_RAWSTAT is {}\n",

            regs::GPU_IRQ_RAWSTAT.read(dev, iomem)?

        );



        return Err(EIO);

    }

    poll::read_poll_timeout(

        || regs::GPU_IRQ_RAWSTAT.read(dev, iomem),

        |status| *status & regs::GPU_IRQ_RAWSTAT_RESET_COMPLETED != 0,

        time::Delta::from_millis(1),

        time::Delta::from_millis(100),

    )

    .inspect_err(|_| dev_err!(dev, "GPU reset failed."))?;



    Ok(())

}

drivers/gpu/drm/tyr/gpu.rs

+9 −9
Original line number Diff line number Diff line
@@ -6,9 +6,10 @@ 
use kernel::device::Bound;

use kernel::device::Device;

use kernel::devres::Devres;

use kernel::io::poll;

use kernel::platform;

use kernel::prelude::*;

use kernel::time;

use kernel::time::Delta;

use kernel::transmute::AsBytes;

use kernel::uapi;
@@ -204,14 +205,13 @@ fn from(value: u32) -> Self { 
pub(crate) fn l2_power_on(dev: &Device<Bound>, iomem: &Devres<IoMem>) -> Result {

    regs::L2_PWRON_LO.write(dev, iomem, 1)?;



    // TODO: We cannot poll, as there is no support in Rust currently, so we

    // sleep. Change this when read_poll_timeout() is implemented in Rust.

    kernel::time::delay::fsleep(time::Delta::from_millis(100));



    if regs::L2_READY_LO.read(dev, iomem)? != 1 {

        dev_err!(dev, "Failed to power on the GPU\n");

        return Err(EIO);

    }

    poll::read_poll_timeout(

        || regs::L2_READY_LO.read(dev, iomem),

        |status| *status == 1,

        Delta::from_millis(1),

        Delta::from_millis(100),

    )

    .inspect_err(|_| dev_err!(dev, "Failed to power on the GPU."))?;



    Ok(())

}