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From:   Yong Wu <yong.wu@mediatek.com>
To:     Joerg Roedel <joro@8bytes.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Rob Herring <robh+dt@kernel.org>
CC:     Robin Murphy <robin.murphy@arm.com>,
        Tomasz Figa <tfiga@google.com>,
        Will Deacon <will.deacon@arm.com>,
        <linux-mediatek@lists.infradead.org>,
        <srv_heupstream@mediatek.com>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <iommu@lists.linux-foundation.org>, <arnd@arndb.de>,
        <yingjoe.chen@mediatek.com>, <yong.wu@mediatek.com>,
        <youlin.pei@mediatek.com>, Nicolas Boichat <drinkcat@chromium.org>
Subject: [PATCH 03/13] iommu/mediatek: Add probe_defer for smi-larb
Date:   Tue, 1 Jan 2019 12:51:06 +0800
Message-ID: <1546318276-18993-4-git-send-email-yong.wu@mediatek.com>
In-Reply-To: <1546318276-18993-1-git-send-email-yong.wu@mediatek.com>
References: <1546318276-18993-1-git-send-email-yong.wu@mediatek.com>
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Sender: linux-kernel-owner@vger.kernel.org
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The iommu consumer should use device_link to connect with the
smi-larb(supplier). then the smi-larb should run before the iommu
consumer. Here we delay the iommu driver until the smi driver is
ready, then all the iommu consumer always is after the smi driver.

When there is no this patch, if some consumer drivers run before
smi-larb, the supplier link_status is DL_DEV_NO_DRIVER(0) in the
device_link_add, then device_links_driver_bound will use WARN_ON
to complain that the link_status of supplier is not right.

This is a preparing patch for adding device_link.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 drivers/iommu/mtk_iommu.c    | 2 +-
 drivers/iommu/mtk_iommu_v1.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 36526c9..202e41b 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -645,7 +645,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 			id = i;
 
 		plarbdev = of_find_device_by_node(larbnode);
-		if (!plarbdev)
+		if (!plarbdev || !plarbdev->dev.driver)
 			return -EPROBE_DEFER;
 		data->smi_imu.larb_imu[id].dev = &plarbdev->dev;
 
diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index f8b8275..9386aee 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -601,7 +601,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 			plarbdev = of_platform_device_create(
 						larb_spec.np, NULL,
 						platform_bus_type.dev_root);
-			if (!plarbdev) {
+			if (!plarbdev || !plarbdev->dev.driver) {
 				of_node_put(larb_spec.np);
 				return -EPROBE_DEFER;
 			}
-- 
1.9.1