linux-kernel - [PATCH 2/2] iommu/rockchip: ignore isp mmu reset operation

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Date:   Fri, 21 Jul 2017 09:35:21 +0800
From:   Simon Xue <xxm@...k-chips.com>
To:     Joerg Roedel <joro@...tes.org>, Heiko Stuebner <heiko@...ech.de>
Cc:     linux-rockchip@...ts.infradead.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Simon <xxm@...k-chips.com>
Subject: [PATCH 2/2] iommu/rockchip: ignore isp mmu reset operation

From: Simon <xxm@...k-chips.com>

ISP mmu can't support reset operation, it won't get the
expected result when reset, but rest functions work normally.
Add this patch as a WA for this issue.

Signed-off-by: Simon <xxm@...k-chips.com>
---
 drivers/iommu/rockchip-iommu.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index b38283e..47c00b9 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -92,6 +92,7 @@ struct rk_iommu {
 	int num_mmu;
 	int *irq;
 	int num_irq;
+	bool reset_disabled;
 	struct iommu_device iommu;
 	struct list_head node; /* entry in rk_iommu_domain.iommus */
 	struct iommu_domain *domain; /* domain to which iommu is attached */
@@ -415,6 +416,9 @@ static int rk_iommu_force_reset(struct rk_iommu *iommu)
 	int ret, i;
 	u32 dte_addr;
 
+	if (iommu->reset_disabled)
+		return 0;
+
 	/*
 	 * Check if register DTE_ADDR is working by writing DTE_ADDR_DUMMY
 	 * and verifying that upper 5 nybbles are read back.
@@ -1177,6 +1181,9 @@ static int rk_iommu_probe(struct platform_device *pdev)
 		}
 	}
 
+	iommu->reset_disabled = device_property_read_bool(dev,
+					"rk_iommu,disable_reset_quirk");
+
 	err = iommu_device_sysfs_add(&iommu->iommu, dev, NULL, dev_name(dev));
 	if (err)
 		return err;
-- 
1.9.1