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 25E7514A619 for ; Fri, 1 May 2026 13:28:21 +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=1777642103; cv=none; b=sDdW9kqUt0dtperwV3y83MiHwBQoL98cvbrdttI1ndzJb5PIyzoO0BLX24po3ncoQx4xLe3ZnNBX9XSN1OA9LSIriaZXo1evxST0ZlF+ccKH4rE+2CzaS1gLs+A73cTl3O4GVLEOisaSBOgTX6+sxVz8CCQ8Oy2oxNW5IFsl8Q0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777642103; c=relaxed/simple; bh=ArffdoYQY7j7cEy/fEwUcR+TvqH/ui+Oi4DIkQxDb1w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UY4eFVzgLgDPwhZiWTKnZUpgtb1u/fuiWqjBBhwdO8Q9jIw/uV4lj7pm0wKS8F1EDg8ncQXSZDMCR4Dmt2XdFpQYEPkUr4q5tLG5IiXxHUu2pZDxn6E4E+Kx//P9ppULjHpBYuRetQZCzcBldefMy2oGW4GRJLfRQ9/4nLH6+V4= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=RQ2PQ7EO; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="RQ2PQ7EO" 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 28930176A; Fri, 1 May 2026 06:28:16 -0700 (PDT) Received: from [10.1.29.19] (e122027.cambridge.arm.com [10.1.29.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A9B2E3F62B; Fri, 1 May 2026 06:28:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777642101; bh=ArffdoYQY7j7cEy/fEwUcR+TvqH/ui+Oi4DIkQxDb1w=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=RQ2PQ7EO1uheuyndEOCGcWC5WAJklRlA1igyTmFl7VQsQHaPJX+D+0HxbAWMtGAra Lzx83cs7gOtTEZ+HZUA16MWeAoo0ewqQTrBfrPzUkfzYKljuIurBQr/qHxDtc2hpGL I8b28L747Fyj12wlToy+uGs24MnthO6cOM3i8QtQ= Message-ID: <7a8fad13-a7ba-4273-999c-a265d20858bb@arm.com> Date: Fri, 1 May 2026 14:28:17 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 04/10] drm/panthor: Extend the IRQ logic to allow fast/raw IRQ handlers To: Boris Brezillon , Liviu Dudau Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20260429-panthor-signal-from-irq-v1-0-4b92ae4142d2@collabora.com> <20260429-panthor-signal-from-irq-v1-4-4b92ae4142d2@collabora.com> From: Steven Price Content-Language: en-GB In-Reply-To: <20260429-panthor-signal-from-irq-v1-4-4b92ae4142d2@collabora.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 29/04/2026 10:38, Boris Brezillon wrote: > All drivers except panthor signal their fences from their interrupt > handler to minimize latency. We could do the same from the interrupt > handler, but the latency is still quite high in that case, so let's > allow components to choose the context they want their IRQ handler > to run in. > > This takes the form of an extra fast_handler() returning an irqreturn_t > reflecting the need to wake-up a thread or not. > A new PANTHOR_IRQ_ADV_HANDLER() macro taking this extra fast_handler > argument is added, PANTHOR_IRQ_HANDLER() is implemented as a wrapper > around PANTHOR_IRQ_ADV_HANDLER() with a default fast_handler > returning IRQ_WAKE_THREAD. The fast and slow handler are still assumed > to be mutually exclusive. In case a fast handler is provided, the > slow_handler is expected to be run when the event can't be processed > directly in the fast handler, or when the driver thinks it would be > beneficial to coalesce interrupts by polling in the thread rather than > re-enabling interrupts immediately. As Liviu pointed out this commit message isn't right, but the code change below looks fine. So with a fixed commit message: Reviewed-by: Steven Price > > Signed-off-by: Boris Brezillon > --- > drivers/gpu/drm/panthor/panthor_device.h | 5 ++--- > drivers/gpu/drm/panthor/panthor_fw.c | 1 + > drivers/gpu/drm/panthor/panthor_gpu.c | 1 + > drivers/gpu/drm/panthor/panthor_mmu.c | 1 + > drivers/gpu/drm/panthor/panthor_pwr.c | 1 + > 5 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h > index afa202546316..1c130b8394ab 100644 > --- a/drivers/gpu/drm/panthor/panthor_device.h > +++ b/drivers/gpu/drm/panthor/panthor_device.h > @@ -672,6 +672,7 @@ static inline void panthor_irq_disable_events(struct panthor_irq *pirq, u32 mask > static inline int > panthor_irq_request(struct panthor_device *ptdev, struct panthor_irq *pirq, > int irq, u32 mask, void __iomem *iomem, const char *name, > + irqreturn_t (*raw_handler)(int, void *data), > irqreturn_t (*threaded_handler)(int, void *data)) > { > const char *full_name; > @@ -687,9 +688,7 @@ panthor_irq_request(struct panthor_device *ptdev, struct panthor_irq *pirq, > if (!full_name) > return -ENOMEM; > > - return devm_request_threaded_irq(ptdev->base.dev, irq, > - panthor_irq_default_raw_handler, > - threaded_handler, > + return devm_request_threaded_irq(ptdev->base.dev, irq, raw_handler, threaded_handler, > IRQF_SHARED, full_name, pirq); > } > > diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c > index eaf599b0a887..8239a6951569 100644 > --- a/drivers/gpu/drm/panthor/panthor_fw.c > +++ b/drivers/gpu/drm/panthor/panthor_fw.c > @@ -1483,6 +1483,7 @@ int panthor_fw_init(struct panthor_device *ptdev) > > ret = panthor_irq_request(ptdev, &fw->irq, irq, 0, > ptdev->iomem + JOB_INT_BASE, "job", > + panthor_irq_default_raw_handler, > panthor_job_irq_threaded_handler); > if (ret) { > drm_err(&ptdev->base, "failed to request job irq"); > diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c > index ce208e384762..d0be758ea3e1 100644 > --- a/drivers/gpu/drm/panthor/panthor_gpu.c > +++ b/drivers/gpu/drm/panthor/panthor_gpu.c > @@ -177,6 +177,7 @@ int panthor_gpu_init(struct panthor_device *ptdev) > ret = panthor_irq_request(ptdev, &ptdev->gpu->irq, irq, > GPU_INTERRUPTS_MASK, > ptdev->iomem + GPU_INT_BASE, "gpu", > + panthor_irq_default_raw_handler, > panthor_gpu_irq_threaded_handler); > if (ret) > return ret; > diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c > index a0d0a9b2926f..2cb07933b629 100644 > --- a/drivers/gpu/drm/panthor/panthor_mmu.c > +++ b/drivers/gpu/drm/panthor/panthor_mmu.c > @@ -3260,6 +3260,7 @@ int panthor_mmu_init(struct panthor_device *ptdev) > ret = panthor_irq_request(ptdev, &mmu->irq, irq, > panthor_mmu_fault_mask(ptdev, ~0), > ptdev->iomem + MMU_INT_BASE, "mmu", > + panthor_irq_default_raw_handler, > panthor_mmu_irq_threaded_handler); > if (ret) > return ret; > diff --git a/drivers/gpu/drm/panthor/panthor_pwr.c b/drivers/gpu/drm/panthor/panthor_pwr.c > index 80cf78007896..1efb7f3482ba 100644 > --- a/drivers/gpu/drm/panthor/panthor_pwr.c > +++ b/drivers/gpu/drm/panthor/panthor_pwr.c > @@ -491,6 +491,7 @@ int panthor_pwr_init(struct panthor_device *ptdev) > err = panthor_irq_request( > ptdev, &pwr->irq, irq, PWR_INTERRUPTS_MASK, > pwr->iomem + PWR_INT_BASE, "pwr", > + panthor_irq_default_raw_handler, > panthor_pwr_irq_threaded_handler); > if (err) > return err; >