On Thu, 28 May 2026 16:05:32 +0100 Karunika Choo <[email protected]> wrote:
> Mali v15 exposes a 64-bit GPU_ID register with a different field layout > from earlier GPUs. > > Add the register definitions and decoding helpers for the new format, > read GPU_WIDE_ID when the compatibility value indicates a v15 GPU, and > populate both the cached GPU_ID fields and the uAPI gpu_id_hi field. > > This allows userspace and the driver to identify v15 GPUs correctly. > > Signed-off-by: Karunika Choo <[email protected]> > --- > .../drm/panthor/panthor_gpu_discover_regs.h | 17 +++++++++ > drivers/gpu/drm/panthor/panthor_hw.c | 38 ++++++++++++++----- > include/uapi/drm/panthor_drm.h | 10 +++++ > 3 files changed, 56 insertions(+), 9 deletions(-) > create mode 100644 drivers/gpu/drm/panthor/panthor_gpu_discover_regs.h > > diff --git a/drivers/gpu/drm/panthor/panthor_gpu_discover_regs.h > b/drivers/gpu/drm/panthor/panthor_gpu_discover_regs.h > new file mode 100644 > index 000000000000..54bb104902ee > --- /dev/null > +++ b/drivers/gpu/drm/panthor/panthor_gpu_discover_regs.h > @@ -0,0 +1,17 @@ > +/* SPDX-License-Identifier: GPL-2.0 or MIT */ > +/* Copyright 2026 ARM Limited. All rights reserved. */ > + > +#ifndef __PANTHOR_GPU_DISCOVER_REGS_H__ > +#define __PANTHOR_GPU_DISCOVER_REGS_H__ > + > +#define GPU_WIDE_ID 0x0 > +#define GPU_WIDE_COMPAT 0xF > +#define GPU_WIDE_ARCH_MAJOR(x) (((x) & GENMASK(63, > 56)) >> 56) > +#define GPU_WIDE_ARCH_MINOR(x) (((x) & GENMASK(55, > 48)) >> 48) > +#define GPU_WIDE_ARCH_REV(x) (((x) & > GENMASK(47, 40)) >> 40) > +#define GPU_WIDE_PROD_MAJOR(x) (((x) & GENMASK(39, > 32)) >> 32) > +#define GPU_WIDE_VER_MAJOR(x) (((x) & > GENMASK(23, 16)) >> 16) > +#define GPU_WIDE_VER_MINOR(x) (((x) & > GENMASK(15, 8)) >> 8) > +#define GPU_WIDE_VER_STATUS(x) ((x) & GENMASK(7, 0)) > + > +#endif /* __PANTHOR_GPU_DISCOVER_REGS_H__ */ > diff --git a/drivers/gpu/drm/panthor/panthor_hw.c > b/drivers/gpu/drm/panthor/panthor_hw.c > index 3570e2889584..833d10cbb2d6 100644 > --- a/drivers/gpu/drm/panthor/panthor_hw.c > +++ b/drivers/gpu/drm/panthor/panthor_hw.c > @@ -9,6 +9,7 @@ > #include "panthor_device.h" > #include "panthor_device_io.h" > #include "panthor_gpu.h" > +#include "panthor_gpu_discover_regs.h" > #include "panthor_gpu_regs.h" > #include "panthor_hw.h" > #include "panthor_pwr.h" > @@ -297,18 +298,37 @@ static int panthor_hw_bind_device(struct panthor_device > *ptdev) > static int panthor_hw_gpu_id_init(struct panthor_device *ptdev) > { > struct panthor_gpu_id *gpu_id = &ptdev->gpu_id; > - ptdev->gpu_info.gpu_id = gpu_read(ptdev->iomem, GPU_ID); > + u32 gpu_id32 = gpu_read(ptdev->iomem, GPU_ID); > > - if (!ptdev->gpu_info.gpu_id) > + if (!gpu_id32) > return -ENXIO; > > - gpu_id->arch.major = GPU_ARCH_MAJOR(ptdev->gpu_info.gpu_id); > - gpu_id->arch.minor = GPU_ARCH_MINOR(ptdev->gpu_info.gpu_id); > - gpu_id->arch.rev = GPU_ARCH_REV(ptdev->gpu_info.gpu_id); > - gpu_id->prod_major = GPU_PROD_MAJOR(ptdev->gpu_info.gpu_id); > - gpu_id->ver.major = GPU_VER_MAJOR(ptdev->gpu_info.gpu_id); > - gpu_id->ver.minor = GPU_VER_MINOR(ptdev->gpu_info.gpu_id); > - gpu_id->ver.status = GPU_VER_STATUS(ptdev->gpu_info.gpu_id); > + ptdev->gpu_info.gpu_id = gpu_id32; > + > + gpu_id->arch.major = GPU_ARCH_MAJOR(gpu_id32); > + gpu_id->arch.minor = GPU_ARCH_MINOR(gpu_id32); > + gpu_id->arch.rev = GPU_ARCH_REV(gpu_id32); > + gpu_id->prod_major = GPU_PROD_MAJOR(gpu_id32); > + gpu_id->ver.major = GPU_VER_MAJOR(gpu_id32); > + gpu_id->ver.minor = GPU_VER_MINOR(gpu_id32); > + gpu_id->ver.status = GPU_VER_STATUS(gpu_id32); > + > + if (GPU_ARCH_MAJOR(gpu_id32) == GPU_WIDE_COMPAT) { > + u64 gpu_id64 = gpu_read64(ptdev->iomem, GPU_WIDE_ID); I know we currently assume that DISCOVER regs on v15 and GPU regs on older gens are starting at zero, but I'd prefer to make this explicit with something like: /* DISCOVER register block always starts at offset * zero, so does the GPU register block on older * GPUs. */ void __iomem *discover = ptdev->iomem; u64 gpu_id64 = gpu_read64(discover, GPU_WIDE_ID); > + if (!gpu_id64) > + return -ENXIO; > + > + ptdev->gpu_info.gpu_wide_id = gpu_id64; > + ptdev->gpu_info.gpu_id = 0; > + > + gpu_id->arch.major = GPU_WIDE_ARCH_MAJOR(gpu_id64); > + gpu_id->arch.minor = GPU_WIDE_ARCH_MINOR(gpu_id64); > + gpu_id->arch.rev = GPU_WIDE_ARCH_REV(gpu_id64); > + gpu_id->prod_major = GPU_WIDE_PROD_MAJOR(gpu_id64); > + gpu_id->ver.major = GPU_WIDE_VER_MAJOR(gpu_id64); > + gpu_id->ver.minor = GPU_WIDE_VER_MINOR(gpu_id64); > + gpu_id->ver.status = GPU_WIDE_VER_STATUS(gpu_id64); > + } I'd probably move the !has_wide_id() logic to an else branch instead of assigning unconditionally, and then fixing up if has_wide_id() is true: if (GPU_ARCH_MAJOR(gpu_id32) == GPU_WIDE_COMPAT) { u64 gpu_id64 = gpu_read64(ptdev->iomem, GPU_WIDE_ID); if (!gpu_id64) return -ENXIO; ptdev->gpu_info.gpu_wide_id = gpu_id64; gpu_id->arch.major = GPU_WIDE_ARCH_MAJOR(gpu_id64); gpu_id->arch.minor = GPU_WIDE_ARCH_MINOR(gpu_id64); gpu_id->arch.rev = GPU_WIDE_ARCH_REV(gpu_id64); gpu_id->prod_major = GPU_WIDE_PROD_MAJOR(gpu_id64); gpu_id->ver.major = GPU_WIDE_VER_MAJOR(gpu_id64); gpu_id->ver.minor = GPU_WIDE_VER_MINOR(gpu_id64); gpu_id->ver.status = GPU_WIDE_VER_STATUS(gpu_id64); } else { ptdev->gpu_info.gpu_id = gpu_id32; gpu_id->arch.major = GPU_ARCH_MAJOR(gpu_id32); gpu_id->arch.minor = GPU_ARCH_MINOR(gpu_id32); gpu_id->arch.rev = GPU_ARCH_REV(gpu_id32); gpu_id->prod_major = GPU_PROD_MAJOR(gpu_id32); gpu_id->ver.major = GPU_VER_MAJOR(gpu_id32); gpu_id->ver.minor = GPU_VER_MINOR(gpu_id32); gpu_id->ver.status = GPU_VER_STATUS(gpu_id32); } > > return 0; > } > diff --git a/include/uapi/drm/panthor_drm.h b/include/uapi/drm/panthor_drm.h > index 0e455d91e77d..04fc9f133152 100644 > --- a/include/uapi/drm/panthor_drm.h > +++ b/include/uapi/drm/panthor_drm.h > @@ -373,6 +373,16 @@ struct drm_panthor_gpu_info { > > /** @gpu_features: Bitmask describing supported GPU-wide features */ > __u64 gpu_features; > + > + /** @gpu_wide_id: 64-bit GPU_ID for v15 onwards. */ Specify that it's zero on v14- HW, and also update the gpu_id doc to mention it will be zero on v15+. > + __u64 gpu_wide_id; > +#define DRM_PANTHOR_WIDE_ARCH_MAJOR(x) (((x) >> 56) & 0xff) > +#define DRM_PANTHOR_WIDE_ARCH_MINOR(x) (((x) >> 48) & 0xff) > +#define DRM_PANTHOR_WIDE_ARCH_REV(x) (((x) >> 40) & 0xff) > +#define DRM_PANTHOR_WIDE_PRODUCT_MAJOR(x) (((x) >> 32) & 0xff) > +#define DRM_PANTHOR_WIDE_VERSION_MAJOR(x) (((x) >> 16) & 0xff) > +#define DRM_PANTHOR_WIDE_VERSION_MINOR(x) (((x) >> 8) & 0xff) > +#define DRM_PANTHOR_WIDE_VERSION_STATUS(x) ((x) & 0xff) > }; > > /**
