From patchwork Mon Apr 25 15:58:11 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sricharan Ramabadhran X-Patchwork-Id: 8930331 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 44BFB9F1C1 for ; Mon, 25 Apr 2016 16:01:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5103520165 for ; Mon, 25 Apr 2016 16:01:42 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1B329201EF for ; Mon, 25 Apr 2016 16:01:41 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1auivp-0007x0-0E; Mon, 25 Apr 2016 16:00:17 +0000 Received: from smtp.codeaurora.org ([198.145.29.96]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1auiuf-0005DE-Jj for linux-arm-kernel@lists.infradead.org; Mon, 25 Apr 2016 15:59:07 +0000 Received: from smtp.codeaurora.org (localhost [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 645A461347; Mon, 25 Apr 2016 15:58:44 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 2EF69612EE; Mon, 25 Apr 2016 15:58:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from blr-ubuntu-32.ap.qualcomm.com (unknown [202.46.23.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: sricharan@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id A04FA605B5; Mon, 25 Apr 2016 15:58:39 +0000 (UTC) From: Sricharan R To: will.deacon@arm.com, robin.murphy@arm.com, joro@8bytes.org, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, laurent.pinchart@ideasonboard.com Subject: [RFC 6/9] iommu: of: Handle IOMMU lookup failure with deferred probing or error Date: Mon, 25 Apr 2016 21:28:11 +0530 Message-Id: <1461599894-1969-7-git-send-email-sricharan@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1461599894-1969-1-git-send-email-sricharan@codeaurora.org> References: <1461599894-1969-1-git-send-email-sricharan@codeaurora.org> X-Virus-Scanned: ClamAV using ClamSMTP X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160425_085905_951377_5D60DF78 X-CRM114-Status: GOOD ( 16.65 ) X-Spam-Score: -2.9 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: sricharan@codeaurora.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Laurent Pinchart Failures to look up an IOMMU when parsing the DT iommus property need to be handled separately from the .of_xlate() failures to support deferred probing. The lack of a registered IOMMU can be caused by the lack of a driver for the IOMMU, the IOMMU device probe not having been performed yet, having been deferred, or having failed. The first case occurs when the device tree describes the bus master and IOMMU topology correctly but no device driver exists for the IOMMU yet or the device driver has not been compiled in. Return NULL, the caller will configure the device without an IOMMU. The second and third cases are handled by deferring the probe of the bus master device which will eventually get reprobed after the IOMMU. The last case is currently handled by deferring the probe of the bus master device as well. A mechanism to either configure the bus master device without an IOMMU or to fail the bus master device probe depending on whether the IOMMU is optional or mandatory would be a good enhancement. Signed-off-by: Laurent Pinchart --- drivers/iommu/of_iommu.c | 16 +++++++++++++--- drivers/of/device.c | 2 ++ 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c index 910826c..f722f55 100644 --- a/drivers/iommu/of_iommu.c +++ b/drivers/iommu/of_iommu.c @@ -189,8 +189,18 @@ struct iommu_ops *of_iommu_configure(struct device *dev, np = iommu_spec.np; ops = of_iommu_get_ops(np); - if (!ops || !ops->of_xlate || ops->of_xlate(dev, &iommu_spec)) + if (!ops) { + const struct of_device_id *oid; + + oid = of_match_node(&__iommu_of_table, np); + ops = oid ? ERR_PTR(-EPROBE_DEFER) : NULL; goto err_put_node; + } + + if (!ops->of_xlate || ops->of_xlate(dev, &iommu_spec)) { + ops = NULL; + goto err_put_node; + } of_node_put(np); idx++; @@ -200,7 +210,7 @@ struct iommu_ops *of_iommu_configure(struct device *dev, err_put_node: of_node_put(np); - return NULL; + return ops; } void __init of_iommu_init(void) @@ -211,7 +221,7 @@ void __init of_iommu_init(void) for_each_matching_node_and_match(np, matches, &match) { const of_iommu_init_fn init_fn = match->data; - if (init_fn(np)) + if (init_fn && init_fn(np)) pr_err("Failed to initialise IOMMU %s\n", of_node_full_name(np)); } diff --git a/drivers/of/device.c b/drivers/of/device.c index 494cdbe..57a5f2d 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -149,6 +149,8 @@ int of_dma_configure_ops(struct device *dev, struct device_node *np) coherent ? " " : " not "); iommu = of_iommu_configure(dev, np); + if (IS_ERR(iommu)) + return PTR_ERR(iommu); dev_dbg(dev, "device is%sbehind an iommu\n", iommu ? " " : " not ");