From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B77E234888F for ; Tue, 28 Oct 2025 16:16:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761668201; cv=none; b=OBWoBB8+rYPnfCFjxqv3yLh9Wftp2oT/9ma1x1Z38JPc6mhKXClaYcBbz1yJv272J+eUqu7a5x2sDujOeUJ37STGLkJU/dIlnstq6Ar3nA/3g/cTojbh9hQ0WbvYfR0Z2GbuvdxY5xZjKTJ2BQ4flBjOczKYGb6p9JHI7z9FJ7U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761668201; c=relaxed/simple; bh=vvnZJk0kFGNJGHa0P24BYe6V1sQgrk9+DsQHuXQ2aiA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gRE5C4cULTXoSLySP5Din/EziG4rgGmqgw8T976cxXAw54frButinN+I84hpA1MBeqtE8kc62pJYFQk1womEgjhAUtCgLC5nkV76mufsawj148GwOB5NPRiPWMzA/aljF9kJvVyjWbmD6nRKYVo6Uyz9S1pVv598dps07uBG+Zg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6A088168F for ; Tue, 28 Oct 2025 09:16:31 -0700 (PDT) Received: from e110455-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 013703F63F for ; Tue, 28 Oct 2025 09:16:38 -0700 (PDT) Date: Tue, 28 Oct 2025 16:16:27 +0000 From: Liviu Dudau To: Karunika Choo Cc: dri-devel@lists.freedesktop.org, nd@arm.com, Boris Brezillon , Steven Price , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/8] drm/panthor: Add arch-specific panthor_hw binding Message-ID: References: <20251027161334.854650-1-karunika.choo@arm.com> <20251027161334.854650-2-karunika.choo@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20251027161334.854650-2-karunika.choo@arm.com> Hello, On Mon, Oct 27, 2025 at 04:13:27PM +0000, Karunika Choo wrote: > This patch adds the framework for binding to a specific panthor_hw > structure based on the architecture major value parsed from the GPU_ID > register. This is in preparation of enabling architecture-specific > behaviours based on GPU_ID. As such, it also splits the GPU_ID register > read operation into its own helper function. > > This framework allows a single panthor_hw structure to be shared across > multiple architectures should there be minimal changes between them via > the arch_min and arch_max field of the panthor_hw_entry structure, > instead of duplicating the structure across multiple architectures. > > Signed-off-by: Karunika Choo > --- > v2: > * merged GPU_ID refactoring patch with the arch-specific panthor_hw > binding patch (PATCH 01/10 and PATCH 02/10 in v1). > --- > drivers/gpu/drm/panthor/panthor_device.h | 4 ++ > drivers/gpu/drm/panthor/panthor_hw.c | 65 +++++++++++++++++++++++- > drivers/gpu/drm/panthor/panthor_hw.h | 6 +++ > 3 files changed, 74 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h > index a764111359d2..1457c1255f1f 100644 > --- a/drivers/gpu/drm/panthor/panthor_device.h > +++ b/drivers/gpu/drm/panthor/panthor_device.h > @@ -26,6 +26,7 @@ struct panthor_device; > struct panthor_gpu; > struct panthor_group_pool; > struct panthor_heap_pool; > +struct panthor_hw; > struct panthor_job; > struct panthor_mmu; > struct panthor_fw; > @@ -122,6 +123,9 @@ struct panthor_device { > /** @csif_info: Command stream interface information. */ > struct drm_panthor_csif_info csif_info; > > + /** @hw: GPU-specific data. */ > + struct panthor_hw *hw; > + > /** @gpu: GPU management data. */ > struct panthor_gpu *gpu; > > diff --git a/drivers/gpu/drm/panthor/panthor_hw.c b/drivers/gpu/drm/panthor/panthor_hw.c > index 4f2858114e5e..b6e7401327c3 100644 > --- a/drivers/gpu/drm/panthor/panthor_hw.c > +++ b/drivers/gpu/drm/panthor/panthor_hw.c > @@ -8,6 +8,28 @@ > #define GPU_PROD_ID_MAKE(arch_major, prod_major) \ > (((arch_major) << 24) | (prod_major)) > > +/** struct panthor_hw_entry - HW arch major to panthor_hw binding entry */ > +struct panthor_hw_entry { > + /** @arch_min: Minimum supported architecture major value (inclusive) */ > + u8 arch_min; > + > + /** @arch_max: Maximum supported architecture major value (inclusive) */ > + u8 arch_max; I'm not a big fan of this [min, max] range definition. I would expect that, unless a new panthor_hw_entry is defined, the one covering arch X will also cover arch X+1 automatically. With the current implementation we will have to add a patch extending arch_max for an existing panthor_hw_entry when a new GPU architecture is released that is compatible with the previous one at the panthor_hw level *and backport the patch* for older kernels if they can support that hardware. My suggestion is to drop this structure entirely and change panthor_hw_bind_device() to a cascade of if()s starting with the latest arch to have a struct panthor_hw defined. For this patch the function will actually just set ptdev->hw to panthor_hw_arch_v10 without any ifs. Also (this is my personal preference) I would merge patch 1/8 and 2/8 so that we don't have just empty structures defined. Best regards, Liviu > + > + /** @hwdev: Pointer to panthor_hw structure */ > + struct panthor_hw *hwdev; > +}; > + > +static struct panthor_hw panthor_hw_arch_v10 = {}; > + > +static struct panthor_hw_entry panthor_hw_match[] = { > + { > + .arch_min = 10, > + .arch_max = 13, > + .hwdev = &panthor_hw_arch_v10, > + }, > +}; > + > static char *get_gpu_model_name(struct panthor_device *ptdev) > { > const u32 gpu_id = ptdev->gpu_info.gpu_id; > @@ -62,7 +84,6 @@ static void panthor_gpu_info_init(struct panthor_device *ptdev) > { > unsigned int i; > > - ptdev->gpu_info.gpu_id = gpu_read(ptdev, GPU_ID); > ptdev->gpu_info.csf_id = gpu_read(ptdev, GPU_CSF_ID); > ptdev->gpu_info.gpu_rev = gpu_read(ptdev, GPU_REVID); > ptdev->gpu_info.core_features = gpu_read(ptdev, GPU_CORE_FEATURES); > @@ -117,8 +138,50 @@ static void panthor_hw_info_init(struct panthor_device *ptdev) > ptdev->gpu_info.tiler_present); > } > > +static int panthor_hw_bind_device(struct panthor_device *ptdev) > +{ > + struct panthor_hw *hdev = NULL; > + const u32 arch_major = GPU_ARCH_MAJOR(ptdev->gpu_info.gpu_id); > + int i = 0; > + > + for (i = 0; i < ARRAY_SIZE(panthor_hw_match); i++) { > + struct panthor_hw_entry *entry = &panthor_hw_match[i]; > + > + if (arch_major >= entry->arch_min && arch_major <= entry->arch_max) { > + hdev = entry->hwdev; > + break; > + } > + } > + > + if (!hdev) > + return -EOPNOTSUPP; > + > + ptdev->hw = hdev; > + > + return 0; > +} > + > +static int panthor_hw_gpu_id_init(struct panthor_device *ptdev) > +{ > + ptdev->gpu_info.gpu_id = gpu_read(ptdev, GPU_ID); > + if (!ptdev->gpu_info.gpu_id) > + return -ENXIO; > + > + return 0; > +} > + > int panthor_hw_init(struct panthor_device *ptdev) > { > + int ret = 0; > + > + ret = panthor_hw_gpu_id_init(ptdev); > + if (ret) > + return ret; > + > + ret = panthor_hw_bind_device(ptdev); > + if (ret) > + return ret; > + > panthor_hw_info_init(ptdev); > > return 0; > diff --git a/drivers/gpu/drm/panthor/panthor_hw.h b/drivers/gpu/drm/panthor/panthor_hw.h > index 0af6acc6aa6a..39752de3e7ad 100644 > --- a/drivers/gpu/drm/panthor/panthor_hw.h > +++ b/drivers/gpu/drm/panthor/panthor_hw.h > @@ -6,6 +6,12 @@ > > struct panthor_device; > > +/** > + * struct panthor_hw - GPU specific register mapping and functions > + */ > +struct panthor_hw { > +}; > + > int panthor_hw_init(struct panthor_device *ptdev); > > #endif /* __PANTHOR_HW_H__ */ > -- > 2.49.0 > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯