gpu: host1x: Use SMMU on Tegra124 and Tegra210

	}

}

static bool host1x_wants_iommu(struct host1x *host1x)

{

	/*

	 * If we support addressing a maximum of 32 bits of physical memory

	 * and if the host1x firewall is enabled, there's no need to enable

	 * IOMMU support. This can happen for example on Tegra20, Tegra30

	 * and Tegra114.

	 *

	 * Tegra124 and later can address up to 34 bits of physical memory and

	 * many platforms come equipped with more than 2 GiB of system memory,

	 * which requires crossing the 4 GiB boundary. But there's a catch: on

	 * SoCs before Tegra186 (i.e. Tegra124 and Tegra210), the host1x can

	 * only address up to 32 bits of memory in GATHER opcodes, which means

	 * that command buffers need to either be in the first 2 GiB of system

	 * memory (which could quickly lead to memory exhaustion), or command

	 * buffers need to be treated differently from other buffers (which is

	 * not possible with the current ABI).

	 *

	 * A third option is to use the IOMMU in these cases to make sure all

	 * buffers will be mapped into a 32-bit IOVA space that host1x can

	 * address. This allows all of the system memory to be used and works

	 * within the limitations of the host1x on these SoCs.

	 *

	 * In summary, default to enable IOMMU on Tegra124 and later. For any

	 * of the earlier SoCs, only use the IOMMU for additional safety when

	 * the host1x firewall is disabled.

	 */

	if (host1x->info->dma_mask <= DMA_BIT_MASK(32)) {

		if (IS_ENABLED(CONFIG_TEGRA_HOST1X_FIREWALL))

			return false;

	}

	return true;

}

static struct iommu_domain *host1x_iommu_attach(struct host1x *host)

{

	struct iommu_domain *domain = iommu_get_domain_for_dev(host->dev);

	int err;

	/*

	 * If the host1x firewall is enabled, there's no need to enable IOMMU

	 * support. Similarly, if host1x is already attached to an IOMMU (via

	 * the DMA API), don't try to attach again.

	 * We may not always want to enable IOMMU support (for example if the

	 * host1x firewall is already enabled and we don't support addressing

	 * more than 32 bits of physical memory), so check for that first.

	 *

	 * Similarly, if host1x is already attached to an IOMMU (via the DMA

	 * API), don't try to attach again.

	 */

	if (IS_ENABLED(CONFIG_TEGRA_HOST1X_FIREWALL) || domain)

	if (!host1x_wants_iommu(host) || domain)

		return domain;

	host->group = iommu_group_get(host->dev);