iommu/rockchip: ignore isp mmu reset operation

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 Xue <xxm@rock-chips.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index e2852b041231167f4e19e332f61895403407fdac..78ea341c7c75d35b98281bf88a163f9389eea498 100644 (file)
--- 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.
@@ -1180,6 +1184,9 @@ static int rk_iommu_probe(struct platform_device *pdev)
                }
        }
 
+       iommu->reset_disabled = device_property_read_bool(dev,
+                                       "rockchip,disable-mmu-reset");
+
        err = iommu_device_sysfs_add(&iommu->iommu, dev, NULL, dev_name(dev));
        if (err)
                return err;