Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752271AbeAQHad (ORCPT + 1 other); Wed, 17 Jan 2018 02:30:33 -0500 Received: from mail-vk0-f65.google.com ([209.85.213.65]:39438 "EHLO mail-vk0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750969AbeAQHac (ORCPT ); Wed, 17 Jan 2018 02:30:32 -0500 X-Google-Smtp-Source: ACJfBotltJd8VwuCIO4NlSvYhEhJdWqf5WpJy80OyhRpD3WE0/j3wpvuLpzyqD44xdpeze9S8n+FCg== MIME-Version: 1.0 In-Reply-To: <5A5EF94E.7010806@rock-chips.com> References: <20180116132540.18939-1-jeffy.chen@rock-chips.com> <20180116132540.18939-12-jeffy.chen@rock-chips.com> <5A5EF94E.7010806@rock-chips.com> From: Tomasz Figa Date: Wed, 17 Jan 2018 16:30:08 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 11/13] iommu/rockchip: Use OF_IOMMU to attach devices automatically To: JeffyChen Cc: linux-kernel@vger.kernel.org, Ricky Liang , Robin Murphy , simon xue , Heiko Stuebner , "open list:ARM/Rockchip SoC..." , open@263.net, "list@263.net:IOMMU DRIVERS , Joerg Roedel ," Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Wed, Jan 17, 2018 at 4:20 PM, JeffyChen wrote: > Hi Tomasz, > > Thanks for your reply. > > > On 01/17/2018 01:44 PM, Tomasz Figa wrote: >> >> On Tue, Jan 16, 2018 at 10:25 PM, Jeffy Chen >> wrote: >>> >>> Converts the rockchip-iommu driver to use the OF_IOMMU infrastructure, >>> which allows attaching master devices to their IOMMUs automatically >>> according to DT properties. >>> >>> Signed-off-by: Jeffy Chen >>> --- >>> >>> Changes in v2: None >>> >>> drivers/iommu/rockchip-iommu.c | 116 >>> +++++++++++------------------------------ >>> 1 file changed, 31 insertions(+), 85 deletions(-) >>> >>> diff --git a/drivers/iommu/rockchip-iommu.c >>> b/drivers/iommu/rockchip-iommu.c >>> index 51e4f982c4a6..c2d3ac82184e 100644 >>> --- a/drivers/iommu/rockchip-iommu.c >>> +++ b/drivers/iommu/rockchip-iommu.c >> >> [snip] >>> >>> +static int rk_iommu_of_xlate(struct device *dev, >>> + struct of_phandle_args *args) >>> +{ >>> + struct platform_device *iommu_dev; >>> + >>> + iommu_dev = of_find_device_by_node(args->np); >>> + if (!iommu_dev) { >>> + dev_err(dev, "iommu %pOF not found\n", args->np); >>> + return -ENODEV; >>> + } >>> + >>> + dev->archdata.iommu = platform_get_drvdata(iommu_dev); >> >> >> This will work only if that iommu was already probed. Do we have any >> guarantees that this callback is not called earlier? > > in of_iommu.c, the of_iommu_xlate would check for fwnode before calling > this. Right, looks like deferred probe is handled there. > > but it's possible the probe failed after calling iommu_device_set_fwnode, so > i'll try to add some checks here, and maybe adjust probe() to prevent it > too. I think iommu_device_set_fwnode() is not enough for of_iommu_xlate() to find the IOMMU. The IOMMU is actually added to the IOMMU list by iommu_device_register(), which is last in the sequence, so I guess we should be fine. Best regards, Tomasz