diff options
Diffstat (limited to 'include/linux/iommu.h')
| -rw-r--r-- | include/linux/iommu.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 20b592dec335..6f53ad74fa0d 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -1103,4 +1103,25 @@ static inline void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_m #endif /* CONFIG_IOMMU_DMA */ +/* + * Newer generations of Tegra SoCs require devices' stream IDs to be directly programmed into + * some registers. These are always paired with a Tegra SMMU or ARM SMMU, for which the contents + * of the struct iommu_fwspec are known. Use this helper to formalize access to these internals. + */ +#define TEGRA_STREAM_ID_BYPASS 0x7f + +static inline bool tegra_dev_iommu_get_stream_id(struct device *dev, u32 *stream_id) +{ +#ifdef CONFIG_IOMMU_API + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); + + if (fwspec && fwspec->num_ids == 1) { + *stream_id = fwspec->ids[0] & 0xffff; + return true; + } +#endif + + return false; +} + #endif /* __LINUX_IOMMU_H */ |