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Wed, 28 Oct 2026 08:58:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793203122; bh=LqMVoiCpP/7b83Vo3Et5H75tfBu+HMQvKifhWWwQWHs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uYlY4Uh4jnlAWKdoN9P59gsGZzFYI6dAx+dB+2bk+FjaM2QN+MM/m7xaaepTcjqRZ CF5JDH4tV/r8C9KvPjoRynYv1OaI/bMWkJmhoii6Hhf/cUMP/EYHbKQ5NO7Yvz0Mhw dmuyMO4rDgDTBM9l/tmedYHPi2guANz+DQ2QK5fI= Date: Wed, 28 Oct 2026 15:58:37 +0000 From: Liviu Dudau To: Karunika Choo Cc: dri-devel@lists.freedesktop.org, nd@arm.com, Boris Brezillon , Steven Price , linux-kernel@vger.kernel.org, Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Daniel Almeida , Alice Ryhl Subject: Re: [PATCH v1 04/27] drm/panthor: Add 64-bit GPU_ID decoding for v15 GPUs Message-ID: References: <20260922204535.2850094-1-karunika.choo@arm.com> <20260922204535.2850094-5-karunika.choo@arm.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260922204535.2850094-5-karunika.choo@arm.com> On Tue, Sep 22, 2026 at 09:44:58PM +0100, Karunika Choo 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_wide_id field. > > This allows userspace and the driver to identify v15 GPUs correctly. > > Signed-off-by: Karunika Choo Reviewed-by: Liviu Dudau Best regards, Liviu > --- > v1: > - Decode selected GPU_ID format after checking compatibility value. > - Document GPU_DISCOVER and GPU_CONTROL register offset differences > between GPUs. > - Fix mask generation in panthor_gpu_discover_regs.h > > .../drm/panthor/panthor_gpu_discover_regs.h | 19 +++++++++ > drivers/gpu/drm/panthor/panthor_hw.c | 42 +++++++++++++++---- > include/uapi/drm/panthor_drm.h | 13 ++++++ > 3 files changed, 65 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 0000000000000..e6bfe1fe2c68a > --- /dev/null > +++ b/drivers/gpu/drm/panthor/panthor_gpu_discover_regs.h > @@ -0,0 +1,19 @@ > +/* 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__ > + > +#include > + > +#define GPU_WIDE_ID 0x0 > +#define GPU_WIDE_COMPAT 0xF > +#define GPU_WIDE_ARCH_MAJOR(x) (((x) & GENMASK_U64(63, 56)) >> 56) > +#define GPU_WIDE_ARCH_MINOR(x) (((x) & GENMASK_U64(55, 48)) >> 48) > +#define GPU_WIDE_ARCH_REV(x) (((x) & GENMASK_U64(47, 40)) >> 40) > +#define GPU_WIDE_PROD_MAJOR(x) (((x) & GENMASK_U64(39, 32)) >> 32) > +#define GPU_WIDE_VER_MAJOR(x) (((x) & GENMASK_U64(23, 16)) >> 16) > +#define GPU_WIDE_VER_MINOR(x) (((x) & GENMASK_U64(15, 8)) >> 8) > +#define GPU_WIDE_VER_STATUS(x) ((x) & GENMASK_U64(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 2143e57d48106..40012ba7e23ca 100644 > --- a/drivers/gpu/drm/panthor/panthor_hw.c > +++ b/drivers/gpu/drm/panthor/panthor_hw.c > @@ -8,6 +8,7 @@ > > #include "panthor_device.h" > #include "panthor_gpu.h" > +#include "panthor_gpu_discover_regs.h" > #include "panthor_gpu_regs.h" > #include "panthor_hw.h" > #include "panthor_pwr.h" > @@ -296,18 +297,41 @@ 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); > + if (GPU_ARCH_MAJOR(gpu_id32) == GPU_WIDE_COMPAT) { > + /* > + * GPU_DISCOVER register block always starts at offset zero, > + * so does the GPU_CONTROL register block on pre-v15 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; > + > + 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 a2ff0f4ec6915..843a0b40e1d36 100644 > --- a/include/uapi/drm/panthor_drm.h > +++ b/include/uapi/drm/panthor_drm.h > @@ -376,6 +376,19 @@ 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 and later GPUs. @gpu_id is 0 when > + * this is populated. > + */ > + __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) > }; > > /** > -- > 2.43.0 > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯