Re: [PATCH v2 0/8] drm/panthor: Localize register access by component

[Steven Price <steven.price@arm.com>]

On 12/04/2026 15:29, Karunika Choo wrote:
> Hi all,
> 
> This series refactors the panthor register access paths so that each
> component uses its own local iomem base instead of relying on the
> global device mapping throughout the driver.
> 
> Today a number of register definitions and helpers are still expressed
> in terms of the full device register space, which makes it easy for one
> component to reach into another component's registers.
> 
> The series prepares the driver for a cleaner per-component layout in 3
> steps:
> - make the low-level GPU register helpers operate on an iomem pointer
>   rather than a panthor_device pointer
> - split register definitions and move cross-component accesses behind
>   helpers owned by the relevant component
> - convert GPU, PWR, firmware and MMU code to use component-local iomem
>   bases, while keeping IRQ handling on a dedicated IRQ-local base.
> 
> The end result is that register accesses become more obviously scoped to
> the component that owns them, cross-component register accesses are
> removed from callers, and the common IRQ helpers no longer depend on
> absolute register offsets.
> 
> No functional change is intended.

Generally this all looks fine, one minor comment (see patch 4), but
otherwise the series is:

Reviewed-by: Steven Price <steven.price@arm.com>

Thanks,
Steve

> v2:
> - Picked up Acks from Boris.
> - Moved GPU_ID definitions into panthor_gpu_regs.h and deleted
>   panthor_hw_regs.h
> - Fixed incorrect spelling of timestamp helper functions.
> - Changed IRQ request function to take an iomem pointer instead of an
>   offset.
> - Update panthor_gpu_info_init() to use the correct block-local iomem
>   pointers for register accesses.
> - Link to v1: https://lore.kernel.org/all/20260410164637.549145-1-karunika.choo@arm.com/
> 
> Kind regards,
> Karunika
> 
> Karunika Choo (8):
>   drm/panthor: Pass an iomem pointer to GPU register access helpers
>   drm/panthor: Split register definitions by components
>   drm/panthor: Replace cross-component register accesses with helpers
>   drm/panthor: Store IRQ register base iomem pointer in panthor_irq
>   drm/panthor: Use a local iomem base for GPU registers
>   drm/panthor: Use a local iomem base for PWR registers
>   drm/panthor: Use a local iomem base for firmware control registers
>   drm/panthor: Use a local iomem base for MMU AS registers
> 
>  drivers/gpu/drm/panthor/panthor_device.c   |  28 +-
>  drivers/gpu/drm/panthor/panthor_device.h   |  92 ++++---
>  drivers/gpu/drm/panthor/panthor_drv.c      |   7 +-
>  drivers/gpu/drm/panthor/panthor_fw.c       |  40 ++-
>  drivers/gpu/drm/panthor/panthor_fw.h       |   1 +
>  drivers/gpu/drm/panthor/panthor_fw_regs.h  |  29 ++
>  drivers/gpu/drm/panthor/panthor_gpu.c      | 101 +++++--
>  drivers/gpu/drm/panthor/panthor_gpu.h      |   6 +
>  drivers/gpu/drm/panthor/panthor_gpu_regs.h | 119 +++++++++
>  drivers/gpu/drm/panthor/panthor_heap.c     |   2 +-
>  drivers/gpu/drm/panthor/panthor_hw.c       |  54 ++--
>  drivers/gpu/drm/panthor/panthor_hw.h       |   2 +-
>  drivers/gpu/drm/panthor/panthor_mmu.c      |  46 ++--
>  drivers/gpu/drm/panthor/panthor_mmu_regs.h |  69 +++++
>  drivers/gpu/drm/panthor/panthor_pwr.c      |  93 ++++---
>  drivers/gpu/drm/panthor/panthor_pwr_regs.h |  79 ++++++
>  drivers/gpu/drm/panthor/panthor_regs.h     | 291 ---------------------
>  drivers/gpu/drm/panthor/panthor_sched.c    |   5 +-
>  18 files changed, 584 insertions(+), 480 deletions(-)
>  create mode 100644 drivers/gpu/drm/panthor/panthor_fw_regs.h
>  create mode 100644 drivers/gpu/drm/panthor/panthor_gpu_regs.h
>  create mode 100644 drivers/gpu/drm/panthor/panthor_mmu_regs.h
>  create mode 100644 drivers/gpu/drm/panthor/panthor_pwr_regs.h
>  delete mode 100644 drivers/gpu/drm/panthor/panthor_regs.h
> 
> --
> 2.43.0
>