Subject: [PATCH v2 21/22] iommu/tegra: smmu: Support Multiple ASID

From: [email-masked] (Stephen Warren)
Date: Thu, 18 Jul 2013 14:43:06 -0600

On 07/05/2013 04:44 AM, Hiroshi Doyu wrote:
> Support Multiple Address Space(AS). Tegra SMMU can have multiple
> ASes. We reserve 2 of them for static assignment, AS[0] for system
> default, AS[1] for AHB clusters as protected domain from others, where
> there are many traditional pheripheral devices like USB, SD/MMC. They
> should be isolated from some smart devices like host1x for system
> robustness. Even if smart devices behaves wrongly, the traditional
> devices(SD/MMC, USB) wouldn't be affected, and the system could
> continue most likely.

> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c

>  static int smmu_iommu_add_device(struct device *dev)
>  {
>  	int err;
> -	struct dma_iommu_mapping *map = smmu_handle->map[SYSTEM_DEFAULT];
> +	u64 swgroup;
> +	struct dma_iommu_mapping *map = NULL;
> +
> +	swgroup = smmu_of_get_memory_client(dev);
> +	switch (swgroup) {
> +	case TEGRA_SWGROUP_BIT(PPCS):
> +		map = smmu_handle->map[SYSTEM_PROTECTED];
> +		break;
> +	default:
> +		map = smmu_handle->map[SYSTEM_DEFAULT];

I already mentioned this, but just for completeness: What is
smmu->num_as <= SYSTEM_DEFAULT?