From patchwork Thu May 14 23:00:09 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Pinchart X-Patchwork-Id: 6410411 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 06B50C0432 for ; Thu, 14 May 2015 23:09:31 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 18EAA20444 for ; Thu, 14 May 2015 23:09:30 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3FCE620411 for ; Thu, 14 May 2015 23:09:29 +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 1Yt2Ck-0000rL-EK; Thu, 14 May 2015 23:06:14 +0000 Received: from galahad.ideasonboard.com ([2001:4b98:dc2:45:216:3eff:febb:480d]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Yt28m-0005PP-8e for linux-arm-kernel@lists.infradead.org; Thu, 14 May 2015 23:02:09 +0000 Received: from avalon.ideasonboard.com (dsl-hkibrasgw3-50ddcc-40.dhcp.inet.fi [80.221.204.40]) by galahad.ideasonboard.com (Postfix) with ESMTPSA id 6593D203B2; Fri, 15 May 2015 01:00:09 +0200 (CEST) From: Laurent Pinchart To: linux-kernel@vger.kernel.org Subject: [RFC/PATCH 8/9] iommu: of: Handle IOMMU lookup failure with deferred probing or error Date: Fri, 15 May 2015 02:00:09 +0300 Message-Id: <1431644410-2997-9-git-send-email-laurent.pinchart+renesas@ideasonboard.com> X-Mailer: git-send-email 2.3.6 In-Reply-To: <1431644410-2997-1-git-send-email-laurent.pinchart+renesas@ideasonboard.com> References: <1431644410-2997-1-git-send-email-laurent.pinchart+renesas@ideasonboard.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150514_160208_719355_30679043 X-CRM114-Status: GOOD ( 14.85 ) X-Spam-Score: -0.0 (/) Cc: Laura Abbott , Arnd Bergmann , Robin Murphy , Joreg Roedel , Will Deacon , iommu@lists.linux-foundation.org, Thierry Reding , Greg Kroah-Hartman , Grant Likely , Mitchel Humpherys , linux-arm-kernel@lists.infradead.org, Marek Szyprowski X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 b922ed4f9fb3..e98f19a3b740 100644 --- a/drivers/iommu/of_iommu.c +++ b/drivers/iommu/of_iommu.c @@ -170,8 +170,18 @@ 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++; @@ -181,7 +191,7 @@ 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) @@ -192,7 +202,7 @@ 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 3cb3f78a6d13..f4964ab21026 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -148,6 +148,8 @@ 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 ");