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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 BDB6BCD4F54 for ; Wed, 27 May 2026 22:14:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:References:Mime-Version:In-Reply-To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=xmNwprPA7hV2w0Jkxb+Nz3U2pfABHSvhMemy7L2s74M=; b=khHS9FbB97PP/wQgooRj5F9i9j TQGZaYyJruQm/XfXgFsOAGMAp+FYCeGwVmmUG2+S33mM15TJKQg9qAecl5SwLlEONV8DgXHnoZw5b MPzeXIq3vFKYkh5rO2ILvZichwqg1S+n9X2o4IaXx2FQ8Sv5KSLoSmRqM6ILl1BQbpog7rd1n+QId dm2Xa0cky9zqCgDx2C5NGU+mwzoE1lhRnKsW3ygZqIL6Un5s42Vzy09tM+S8nYJ8vqpQI39P/GIjB lBRyZXhT+sgWsvEj7j2svMXYvB+WRlrF13m9uk3LB/7b4mAzm+Skb+X8QguQLkYRUvBEYyMSK7GEY b2qwRabQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wSMW7-00000004mMx-0FkK; Wed, 27 May 2026 22:14:23 +0000 Received: from mail-pl1-x649.google.com ([2607:f8b0:4864:20::649]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wSMW2-00000004mL8-1BAb for linux-arm-kernel@lists.infradead.org; Wed, 27 May 2026 22:14:19 +0000 Received: by mail-pl1-x649.google.com with SMTP id d9443c01a7336-2bc7f9b2213so88117495ad.0 for ; Wed, 27 May 2026 15:14:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779920057; x=1780524857; darn=lists.infradead.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=xmNwprPA7hV2w0Jkxb+Nz3U2pfABHSvhMemy7L2s74M=; b=OzdjWcxq7Wp7AvwjplZraGjEjEY8mT1Iz8pVg1jJxVLpagB1t70WHSEMOwdUmHl++P AwmmgXPhfU0D4i+gXVNt8eCZIaNbUbwdApGU31RVUB5jewEfM4mrKkMLAvbMomuQq+hB j3IAe0RPIms4NfoYPCIlstCQzMqrEF9MfSHBC42uflRAUEU/3n1n1ZXQ/zyl+dIyGZOe uSkROHtdjXA3yk0e/jO5SY1/bdffbze4auNKrL9aTnxKC7K4CHfHuuEXjXQdMLa+xuze V0q6opqE+HKZSc4B7FGKnfTbLQeAG00iwTHqKBO/KGX34gf5YopCD6l+sTaoIhEcZfAz f9WA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779920057; x=1780524857; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=xmNwprPA7hV2w0Jkxb+Nz3U2pfABHSvhMemy7L2s74M=; b=eRJT0UCK20umjjr3Jm+YQpE2JiBusqrBVxTFKRe2caZ4FVF0HWas82NQDzNMA0xR1C 8j80cvHx69+EMOvgxvb9CDoyIbRzQ8sJOjh3nhhFj6OzKa5k+z6cns6dH3rFeBEPc0cc CtPO2tv7smAbZDyIal5CyAseZ2ANE4yW5EUC8s43D5n7sRKigLRqZnstzCMGQ5wKmr8t 5J6qo9KtWx4g34jVqHUHQ7AEZhZRGsTW/Jxygj1cyN0YleYHJj/mTTIjHtQ7/sXVQ/iK +eYmon1snqahq8NIiDH77630ct/BwG1HpvXCAMvX8sfKDuLsYmhtqtHvq6g9YY9yJLrX NH+Q== X-Forwarded-Encrypted: i=1; AFNElJ/b0/+nthxKPVPYkP+2dad0etDa4SK9NQ7QgtIbY6nw+T9ZmIpd7HEhW7WHBPUa0UC7pmft3XXxH0eSt2I56Bfs@lists.infradead.org X-Gm-Message-State: AOJu0YwyuhdFkQbqsgSsTEKL7qKM2ujpSXwI4Y7iMG/A/v++Jk7xnCEO GYh4Hn3oAPpKZwjnSGfr8eHOzAqlbSJY64xeXfTDJC2nRA0FaW1MDpMBWKl7EN1ia9FO0Tkgtju ryg== X-Received: from plbjw17.prod.google.com ([2002:a17:903:2791:b0:2bd:7970:c1cf]) (user=praan job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:2f90:b0:2bd:ef15:9fce with SMTP id d9443c01a7336-2beb063227emr277408735ad.20.1779920056662; Wed, 27 May 2026 15:14:16 -0700 (PDT) Date: Wed, 27 May 2026 22:13:58 +0000 In-Reply-To: <20260527221407.1756491-1-praan@google.com> Mime-Version: 1.0 References: <20260527221407.1756491-1-praan@google.com> X-Mailer: git-send-email 2.54.0.794.g4f17f83d09-goog Message-ID: <20260527221407.1756491-3-praan@google.com> Subject: [PATCH v7 02/11] iommu/arm-smmu-v3: Add a helper to drain cmd queues From: Pranjal Shrivastava To: iommu@lists.linux.dev Cc: Will Deacon , Joerg Roedel , Robin Murphy , Jason Gunthorpe , Mostafa Saleh , Nicolin Chen , Daniel Mentz , Ashish Mhetre , linux-arm-kernel@lists.infradead.org, Pranjal Shrivastava Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260527_151418_344273_D3DCDC19 X-CRM114-Status: GOOD ( 15.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Before we suspend SMMU, we want to ensure that all commands (especially ATC_INV) have been flushed by the CMDQ, i.e. the CMDQs are empty. Add a helper function that polls till the queues are dained. Reviewed-by: Nicolin Chen Signed-off-by: Pranjal Shrivastava --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 34 +++++++++++++++++++++ drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 3 ++ 2 files changed, 37 insertions(+) diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index 3dad2c2d3283..0e77ef1e4523 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -884,6 +884,40 @@ static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu, cmds->num, true); } +int arm_smmu_queue_poll_until_empty(struct arm_smmu_device *smmu, + struct arm_smmu_queue *q) +{ + struct arm_smmu_queue_poll qp; + struct arm_smmu_ll_queue *llq = &q->llq; + int ret = 0; + + queue_poll_init(smmu, &qp); + do { + if (queue_empty(llq)) + break; + + ret = queue_poll(&qp); + WRITE_ONCE(llq->cons, readl_relaxed(q->cons_reg)); + + } while (!ret); + + return ret; +} + +static int arm_smmu_drain_queues(struct arm_smmu_device *smmu) +{ + int ret; + + /* + * Since this is only called from the suspend callback where + * exclusive access is ensured as CMDQ_PROD_STOP_FLAG blocks new + * command submissions to the cmdq, we can skip the cmdq locking. + */ + ret = arm_smmu_queue_poll_until_empty(smmu, &smmu->cmdq.q); + + return ret; +} + static void arm_smmu_page_response(struct device *dev, struct iopf_fault *unused, struct iommu_page_response *resp) { diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h index 16353596e08a..c855ab4962ed 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -1165,6 +1165,9 @@ int arm_smmu_init_one_queue(struct arm_smmu_device *smmu, int arm_smmu_cmdq_init(struct arm_smmu_device *smmu, struct arm_smmu_cmdq *cmdq); +int arm_smmu_queue_poll_until_empty(struct arm_smmu_device *smmu, + struct arm_smmu_queue *q); + static inline bool arm_smmu_master_canwbs(struct arm_smmu_master *master) { return dev_iommu_fwspec_get(master->dev)->flags & -- 2.54.0.794.g4f17f83d09-goog