From patchwork Fri Feb 3 15:48:44 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sricharan Ramabadhran X-Patchwork-Id: 9554465 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 76FB460424 for ; Fri, 3 Feb 2017 15:49:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4F28528478 for ; Fri, 3 Feb 2017 15:49:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 43C9F2849C; Fri, 3 Feb 2017 15:49:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D5DE228478 for ; Fri, 3 Feb 2017 15:49:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751374AbdBCPtp (ORCPT ); Fri, 3 Feb 2017 10:49:45 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:57068 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751368AbdBCPtn (ORCPT ); Fri, 3 Feb 2017 10:49:43 -0500 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id AF1CA608C5; Fri, 3 Feb 2017 15:49:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1486136977; bh=FEmAqltm2SeGEP80bnduzxTECo9nIL2pr+tvDCdYMDM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c5g2EMEo+QDp8aJpJuL4Gogg0wj4afktMviyr7KHVhRvQ1ofS/+jArVKIJHGnWpUN UqEIb5HYJCGlNdDt3k/BhHbjgdwCzqTfuMeTrdzDZhjmC/oFx1pIsla2cni1PAmJbV CLX1uUatBBdhwYWg03AkHHap+OhymZZ1I4ONuH04= 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 56C0C607EB; Fri, 3 Feb 2017 15:49:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1486136976; bh=FEmAqltm2SeGEP80bnduzxTECo9nIL2pr+tvDCdYMDM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AXifXl7DruERQ8zwcaAOfO7CyvCUNyyf3l1eOKtr0nQlAwXy85R19g591K99MZCKC yMrPQ6RtOGv2oK6odJBxtqc8YE0KD+jdEUIchiurBURO7hU0A311eTEZq4gi9z6sYN rB0FVISIy2CXFZDIkHMFXUeMCYb2WT5mYoPz9Gj4= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 56C0C607EB Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=sricharan@codeaurora.org From: Sricharan R To: robin.murphy@arm.com, will.deacon@arm.com, joro@8bytes.org, lorenzo.pieralisi@arm.com, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, m.szyprowski@samsung.com, bhelgaas@google.com, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, tn@semihalf.com, hanjun.guo@linaro.org, okaya@codeaurora.org Cc: sricharan@codeaurora.org Subject: [PATCH V8 02/11] iommu/of: Prepare for deferred IOMMU configuration Date: Fri, 3 Feb 2017 21:18:44 +0530 Message-Id: <1486136933-20328-3-git-send-email-sricharan@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1486136933-20328-1-git-send-email-sricharan@codeaurora.org> References: <1486136933-20328-1-git-send-email-sricharan@codeaurora.org> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Robin Murphy IOMMU configuration represents unchanging properties of the hardware, and as such should only need happen once in a device's lifetime, but the necessary interaction with the IOMMU device and driver complicates exactly when that point should be. Since the only reasonable tool available for handling the inter-device dependency is probe deferral, we need to prepare of_iommu_configure() to run later than it is currently called (i.e. at driver probe rather than device creation), to handle being retried, and to tell whether a not-yet present IOMMU should be waited for or skipped (by virtue of having declared a built-in driver or not). Tested-by: Marek Szyprowski Signed-off-by: Robin Murphy --- drivers/iommu/of_iommu.c | 43 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 42 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c index ee49081..1f92d98 100644 --- a/drivers/iommu/of_iommu.c +++ b/drivers/iommu/of_iommu.c @@ -96,6 +96,19 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index, } EXPORT_SYMBOL_GPL(of_get_dma_window); +static bool of_iommu_driver_present(struct device_node *np) +{ + /* + * If the IOMMU still isn't ready by the time we reach init, assume + * it never will be. We don't want to defer indefinitely, nor attempt + * to dereference __iommu_of_table after it's been freed. + */ + if (system_state > SYSTEM_BOOTING) + return false; + + return of_match_node(&__iommu_of_table, np); +} + static const struct iommu_ops *of_iommu_xlate(struct device *dev, struct of_phandle_args *iommu_spec) { @@ -104,12 +117,20 @@ int of_get_dma_window(struct device_node *dn, const char *prefix, int index, int err; ops = iommu_get_instance(fwnode); - if (!ops || !ops->of_xlate) + if ((ops && !ops->of_xlate) || + (!ops && !of_iommu_driver_present(iommu_spec->np))) return NULL; err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops); if (err) return ERR_PTR(err); + /* + * The otherwise-empty fwspec handily serves to indicate the specific + * IOMMU device we're waiting for, which will be useful if we ever get + * a proper probe-ordering dependency mechanism in future. + */ + if (!ops) + return ERR_PTR(-EPROBE_DEFER); err = ops->of_xlate(dev, iommu_spec); if (err) @@ -186,14 +207,34 @@ const struct iommu_ops *of_iommu_configure(struct device *dev, struct device_node *master_np) { const struct iommu_ops *ops; + struct iommu_fwspec *fwspec = dev->iommu_fwspec; if (!master_np) return NULL; + if (fwspec) { + if (fwspec->ops) + return fwspec->ops; + + /* In the deferred case, start again from scratch */ + iommu_fwspec_free(dev); + } + if (dev_is_pci(dev)) ops = of_pci_iommu_init(to_pci_dev(dev), master_np); else ops = of_platform_iommu_init(dev, master_np); + /* + * If we have reason to believe the IOMMU driver missed the initial + * add_device callback for dev, replay it to get things in order. + */ + if (!IS_ERR_OR_NULL(ops) && ops->add_device && + dev->bus && !dev->iommu_group) { + int err = ops->add_device(dev); + + if (err) + ops = ERR_PTR(err); + } return IS_ERR(ops) ? NULL : ops; }