Re: [PATCH v2 2/2] drm/tyr: use IoMem directly instead of Devres

[Boris Brezillon <boris.brezillon@collabora.com>]

On Fri, 29 May 2026 02:00:54 +0200
Danilo Krummrich <dakr@kernel.org> 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.
> 
> Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>
> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
>  drivers/gpu/drm/tyr/driver.rs | 19 ++++++-------------
>  drivers/gpu/drm/tyr/gpu.rs    | 17 +++++------------
>  2 files changed, 11 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tyr/driver.rs b/drivers/gpu/drm/tyr/driver.rs
> index 6276e9743c32..227ea2adccea 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..592b8bb16eba 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,
> @@ -40,10 +39,8 @@
>  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)?;
> -
> -        Ok(Self(uapi::drm_panthor_gpu_info {
> +    pub(crate) fn new(io: &IoMem<'_>) -> Self {
> +        Self(uapi::drm_panthor_gpu_info {
>              gpu_id: io.read(GPU_ID).into_raw(),
>              gpu_rev: io.read(REVIDR).into_raw(),
>              csf_id: io.read(CSF_ID).into_raw(),
> @@ -81,7 +78,7 @@ pub(crate) fn new(dev: &Device<Bound>, iomem: &Devres<IoMem>) -> Result<Self> {
>              pad: 0,
>              //GPU_FEATURES register is not available; it was introduced in arch 11.x.
>              gpu_features: 0,
> -        }))
> +        })
>      }
>  
>      pub(crate) fn log(&self, dev: &Device<Bound>) {
> @@ -163,15 +160,11 @@ struct GpuModels {
>  }];
>  
>  /// Powers on the l2 block.
> -pub(crate) fn l2_power_on(dev: &Device<Bound>, iomem: &Devres<IoMem>) -> Result {
> -    let io = (*iomem).access(dev)?;
> +pub(crate) fn l2_power_on(dev: &Device, io: &IoMem<'_>) -> Result {
>      io.write_reg(L2_PWRON_LO::zeroed().with_const_request::<1>());
>  
>      poll::read_poll_timeout(
> -        || {
> -            let io = (*iomem).access(dev)?;
> -            Ok(io.read(L2_READY_LO))
> -        },
> +        || Ok(io.read(L2_READY_LO)),
>          |status| status.ready() == 1,
>          Delta::from_millis(1),
>          Delta::from_millis(100),