Re: [PATCH 2/2] gpu: drm: tyr: use IoMem directly instead of Devres

["Eliot Courtney" <ecourtney@nvidia.com>]

On Tue May 26, 2026 at 8:01 AM JST, Danilo Krummrich wrote:
> Now that IoMem is lifetime-parameterized, use it directly in probe
> rather than wrapping it in Devres and Arc. The I/O memory mapping is
> only used during probe and not stored in driver data, so device-managed
> revocation is unnecessary.
>
> This removes the Devres access(dev) pattern from issue_soft_reset(),
> GpuInfo::new(), and l2_power_on(), simplifying register access.
>
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
> ---
>  drivers/gpu/drm/tyr/driver.rs | 19 ++++++-------------
>  drivers/gpu/drm/tyr/gpu.rs    | 13 +++----------
>  2 files changed, 9 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/tyr/driver.rs b/drivers/gpu/drm/tyr/driver.rs
> index 5f4c484f671f..b9a5cc5fc678 100644
> --- a/drivers/gpu/drm/tyr/driver.rs
> +++ b/drivers/gpu/drm/tyr/driver.rs
> @@ -6,11 +6,9 @@
>          OptionalClk, //
>      },
>      device::{
> -        Bound,
>          Core,
>          Device, //
>      },
> -    devres::Devres,
>      dma::{
>          Device as DmaDevice,
>          DmaMask, //
> @@ -30,7 +28,6 @@
>      sizes::SZ_2M,
>      sync::{
>          aref::ARef,
> -        Arc,
>          Mutex, //
>      },
>      time, //
> @@ -44,7 +41,7 @@
>      regs::gpu_control::*, //
>  };
>  
> -pub(crate) type IoMem = kernel::io::mem::IoMem<'static, SZ_2M>;
> +pub(crate) type IoMem<'a> = kernel::io::mem::IoMem<'a, SZ_2M>;
>  
>  pub(crate) struct TyrDrmDriver;
>  
> @@ -74,15 +71,11 @@ pub(crate) struct TyrDrmDeviceData {
>      pub(crate) gpu_info: GpuInfo,
>  }
>  
> -fn issue_soft_reset(dev: &Device<Bound>, iomem: &Devres<IoMem>) -> Result {
> -    let io = (*iomem).access(dev)?;
> -    io.write_reg(GPU_COMMAND::reset(ResetMode::SoftReset));
> +fn issue_soft_reset(dev: &Device, iomem: &IoMem<'_>) -> Result {
> +    iomem.write_reg(GPU_COMMAND::reset(ResetMode::SoftReset));
>  
>      poll::read_poll_timeout(
> -        || {
> -            let io = (*iomem).access(dev)?;
> -            Ok(io.read(GPU_IRQ_RAWSTAT))
> -        },
> +        || Ok(iomem.read(GPU_IRQ_RAWSTAT)),
>          |status| status.reset_completed(),
>          time::Delta::from_millis(1),
>          time::Delta::from_millis(100),
> @@ -123,12 +116,12 @@ fn probe<'bound>(
>          let sram_regulator = Regulator::<regulator::Enabled>::get(pdev.as_ref(), c"sram")?;
>  
>          let request = pdev.io_request_by_index(0).ok_or(ENODEV)?;
> -        let iomem = Arc::new(request.iomap_sized::<SZ_2M>()?.into_devres()?, GFP_KERNEL)?;
> +        let iomem = request.iomap_sized::<SZ_2M>()?;
>  
>          issue_soft_reset(pdev.as_ref(), &iomem)?;
>          gpu::l2_power_on(pdev.as_ref(), &iomem)?;
>  
> -        let gpu_info = GpuInfo::new(pdev.as_ref(), &iomem)?;
> +        let gpu_info = GpuInfo::new(&iomem)?;
>          gpu_info.log(pdev.as_ref());
>  
>          let pa_bits = MMU_FEATURES::from_raw(gpu_info.mmu_features)
> diff --git a/drivers/gpu/drm/tyr/gpu.rs b/drivers/gpu/drm/tyr/gpu.rs
> index 652556026f50..3acffefaf210 100644
> --- a/drivers/gpu/drm/tyr/gpu.rs
> +++ b/drivers/gpu/drm/tyr/gpu.rs
> @@ -9,7 +9,6 @@
>          Bound,
>          Device, //
>      },
> -    devres::Devres,
>      io::{
>          poll,
>          register::Array,
> @@ -40,9 +39,7 @@
>  pub(crate) struct GpuInfo(pub(crate) uapi::drm_panthor_gpu_info);
>  
>  impl GpuInfo {
> -    pub(crate) fn new(dev: &Device<Bound>, iomem: &Devres<IoMem>) -> Result<Self> {
> -        let io = (*iomem).access(dev)?;
> -
> +    pub(crate) fn new(io: &IoMem<'_>) -> Result<Self> {

Perhaps a future patch can remove this now unnecessary looking Result in
the return type.

Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>