From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CB224FF886D for ; Wed, 29 Apr 2026 09:39:01 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 23A8F10EEFE; Wed, 29 Apr 2026 09:39:01 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="kuMMj3y8"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8CE2E10EEFE for ; Wed, 29 Apr 2026 09:38:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1777455535; bh=qOx2MQk3JW++3W1rDOThwqmi/jAY/AHbh2LtClX1Cos=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=kuMMj3y8FyQUnyWWlNTxQbHVMq7i/vvws5iDREODkkl42LCItLBa4oUENbpNpxomE IYlFP03g5zZAYCHqGCBftDCWXNmbmpAyX7jxQpbGJkWuWncTHuwpgSyn4d+EV9iybh Fq+Lq2islMuk5F9m1Lw+nylPkiXqHocNpeH/v3UrC40S7sioxEuTS+nsUZG/qCHWw/ 6QSRbwldvTqb5HaYQgZnKOUMPLGNzJj5v5+7KgyPEKfktp/KQ/CynYhItXJNDkU+1u YGTtURyu9fOG1uWL7RPUlMIfWVLgaEm5Ck6XIXZjKGRFrA6sXrRZKD+DBZVK3Msy7t YoSWFeLvzx6oA== Received: from [100.64.0.11] (unknown [100.64.0.11]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by bali.collaboradmins.com (Postfix) with ESMTPSA id D9ED617E0698; Wed, 29 Apr 2026 11:38:54 +0200 (CEST) From: Boris Brezillon Date: Wed, 29 Apr 2026 11:38:28 +0200 Subject: [PATCH 01/10] drm/panthor: Make panthor_irq::state a non-atomic field MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260429-panthor-signal-from-irq-v1-1-4b92ae4142d2@collabora.com> References: <20260429-panthor-signal-from-irq-v1-0-4b92ae4142d2@collabora.com> In-Reply-To: <20260429-panthor-signal-from-irq-v1-0-4b92ae4142d2@collabora.com> To: Steven Price , Liviu Dudau Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Boris Brezillon X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1777455534; l=4735; i=boris.brezillon@collabora.com; s=20260429; h=from:subject:message-id; bh=qOx2MQk3JW++3W1rDOThwqmi/jAY/AHbh2LtClX1Cos=; b=IJgw81UE8Vxn3TLGmluD/mdXMyXVI1Kg0V1mDYvdxUXP8qEeJCsWFsNEQurIX6LhtA9RTiWkk 2esLlrM2qCiDKmoZ5G81mLoKZsGX0QT3vJclY3rBAQoHvjTLn+FAUer X-Developer-Key: i=boris.brezillon@collabora.com; a=ed25519; pk=eN+ORdOgQY7d5U+0kA8h5bf67XdD8bhKbjD/TCHexSY= X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The only place where panthor_irq::state is accessed without panthor_irq::mask_lock held is in the prologue of _irq_suspend(), which is not really a fast-path. So let's simplify things by assuming panthor_irq::state must always be accessed with the mask_lock held, and add a scoped_guard() in _irq_suspend(). Signed-off-by: Boris Brezillon --- drivers/gpu/drm/panthor/panthor_device.h | 35 ++++++++++++++++---------------- 1 file changed, 17 insertions(+), 18 deletions(-) diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h index 4e4607bca7cc..3f91ba73829d 100644 --- a/drivers/gpu/drm/panthor/panthor_device.h +++ b/drivers/gpu/drm/panthor/panthor_device.h @@ -101,8 +101,12 @@ struct panthor_irq { */ spinlock_t mask_lock; - /** @state: one of &enum panthor_irq_state reflecting the current state. */ - atomic_t state; + /** + * @state: one of &enum panthor_irq_state reflecting the current state. + * + * Must be accessed with mask_lock held. + */ + enum panthor_irq_state state; }; /** @@ -510,18 +514,15 @@ const char *panthor_exception_name(struct panthor_device *ptdev, static irqreturn_t panthor_ ## __name ## _irq_raw_handler(int irq, void *data) \ { \ struct panthor_irq *pirq = data; \ - enum panthor_irq_state old_state; \ \ if (!gpu_read(pirq->iomem, INT_STAT)) \ return IRQ_NONE; \ \ guard(spinlock_irqsave)(&pirq->mask_lock); \ - old_state = atomic_cmpxchg(&pirq->state, \ - PANTHOR_IRQ_STATE_ACTIVE, \ - PANTHOR_IRQ_STATE_PROCESSING); \ - if (old_state != PANTHOR_IRQ_STATE_ACTIVE) \ + if (pirq->state != PANTHOR_IRQ_STATE_ACTIVE) \ return IRQ_NONE; \ \ + pirq->state = PANTHOR_IRQ_STATE_PROCESSING; \ gpu_write(pirq->iomem, INT_MASK, 0); \ return IRQ_WAKE_THREAD; \ } \ @@ -551,13 +552,10 @@ static irqreturn_t panthor_ ## __name ## _irq_threaded_handler(int irq, void *da } \ \ scoped_guard(spinlock_irqsave, &pirq->mask_lock) { \ - enum panthor_irq_state old_state; \ - \ - old_state = atomic_cmpxchg(&pirq->state, \ - PANTHOR_IRQ_STATE_PROCESSING, \ - PANTHOR_IRQ_STATE_ACTIVE); \ - if (old_state == PANTHOR_IRQ_STATE_PROCESSING) \ + if (pirq->state == PANTHOR_IRQ_STATE_PROCESSING) { \ + pirq->state = PANTHOR_IRQ_STATE_ACTIVE; \ gpu_write(pirq->iomem, INT_MASK, pirq->mask); \ + } \ } \ \ return ret; \ @@ -566,18 +564,19 @@ static irqreturn_t panthor_ ## __name ## _irq_threaded_handler(int irq, void *da static inline void panthor_ ## __name ## _irq_suspend(struct panthor_irq *pirq) \ { \ scoped_guard(spinlock_irqsave, &pirq->mask_lock) { \ - atomic_set(&pirq->state, PANTHOR_IRQ_STATE_SUSPENDING); \ + pirq->state = PANTHOR_IRQ_STATE_SUSPENDING; \ gpu_write(pirq->iomem, INT_MASK, 0); \ } \ synchronize_irq(pirq->irq); \ - atomic_set(&pirq->state, PANTHOR_IRQ_STATE_SUSPENDED); \ + scoped_guard(spinlock_irqsave, &pirq->mask_lock) \ + pirq->state = PANTHOR_IRQ_STATE_SUSPENDED; \ } \ \ static inline void panthor_ ## __name ## _irq_resume(struct panthor_irq *pirq) \ { \ guard(spinlock_irqsave)(&pirq->mask_lock); \ \ - atomic_set(&pirq->state, PANTHOR_IRQ_STATE_ACTIVE); \ + pirq->state = PANTHOR_IRQ_STATE_ACTIVE; \ gpu_write(pirq->iomem, INT_CLEAR, pirq->mask); \ gpu_write(pirq->iomem, INT_MASK, pirq->mask); \ } \ @@ -610,7 +609,7 @@ static inline void panthor_ ## __name ## _irq_enable_events(struct panthor_irq * * on the PROCESSING -> ACTIVE transition. \ * If the IRQ is suspended/suspending, the mask is restored at resume time. \ */ \ - if (atomic_read(&pirq->state) == PANTHOR_IRQ_STATE_ACTIVE) \ + if (pirq->state == PANTHOR_IRQ_STATE_ACTIVE) \ gpu_write(pirq->iomem, INT_MASK, pirq->mask); \ } \ \ @@ -624,7 +623,7 @@ static inline void panthor_ ## __name ## _irq_disable_events(struct panthor_irq * on the PROCESSING -> ACTIVE transition. \ * If the IRQ is suspended/suspending, the mask is restored at resume time. \ */ \ - if (atomic_read(&pirq->state) == PANTHOR_IRQ_STATE_ACTIVE) \ + if (pirq->state == PANTHOR_IRQ_STATE_ACTIVE) \ gpu_write(pirq->iomem, INT_MASK, pirq->mask); \ } -- 2.53.0