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SubjectRe: [RFC 1/2] iommu/arm-smmu-v3: Remove bypass in arm_smmu_reset_device
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On 23/04/18 12:45, Yisheng Xie wrote:
> Add a bypass parameter in arm_smmu_device to keep whether smmu device
> should pypass or not, so parameter bypass in arm_smmu_reset_device can
> be removed.

Given that the GBPA configuration implied by the bypass argument here is
only there to avoid initialising a full stream table when the firmware
is terminally broken, I wonder if it would make sense to simply skip
allocating a stream table at all in that case. Then we could just base
the subsequent SMMUEN/GPBA decision on whether strtab_cfg.strtab is
valid or not.

Robin.

> This should not have any functional change, but prepare for later patch.
>
> Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
> ---
> drivers/iommu/arm-smmu-v3.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 1d64710..044df6e 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -587,6 +587,8 @@ struct arm_smmu_device {
>
> u32 sync_count;
>
> + bool bypass;
> +
> /* IOMMU core code handle */
> struct iommu_device iommu;
> };
> @@ -2384,7 +2386,7 @@ static int arm_smmu_device_disable(struct arm_smmu_device *smmu)
> return ret;
> }
>
> -static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
> +static int arm_smmu_device_reset(struct arm_smmu_device *smmu)
> {
> int ret;
> u32 reg, enables;
> @@ -2487,7 +2489,7 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
>
>
> /* Enable the SMMU interface, or ensure bypass */
> - if (!bypass || disable_bypass) {
> + if (!smmu->bypass || disable_bypass) {
> enables |= CR0_SMMUEN;
> } else {
> ret = arm_smmu_update_gbpa(smmu, 0, GBPA_ABORT);
> @@ -2778,7 +2780,6 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> resource_size_t ioaddr;
> struct arm_smmu_device *smmu;
> struct device *dev = &pdev->dev;
> - bool bypass;
>
> smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
> if (!smmu) {
> @@ -2796,7 +2797,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> }
>
> /* Set bypass mode according to firmware probing result */
> - bypass = !!ret;
> + smmu->bypass = !!ret;
>
> /* Base address */
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> @@ -2842,7 +2843,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> platform_set_drvdata(pdev, smmu);
>
> /* Reset the device */
> - ret = arm_smmu_device_reset(smmu, bypass);
> + ret = arm_smmu_device_reset(smmu);
> if (ret)
> return ret;
>
>

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