[PATCH v3 04/17] dma-mapping: Add check if IOVA can be used

Leon Romanovsky
2024-11-10T13:47:55Z

From: Leon Romanovsky <leonro@nvidia.com>

This patch adds a check if IOVA can be used for the specific
transaction.

In the new API a DMA mapping transaction is identified by a
struct dma_iova_state, which holds some recomputed information
for the transaction which does not change for each page being
mapped.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
include/linux/dma-mapping.h | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 1524da363734..6075e0708deb 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -76,6 +76,20 @@

#define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))

+struct dma_iova_state {
+ size_t __size;
+};
+
+/*
+ * Use the high bit to mark if we used swiotlb for one or more ranges.
+ */
+#define DMA_IOVA_USE_SWIOTLB (1ULL << 63)
+
+static inline size_t dma_iova_size(struct dma_iova_state *state)
+{
+ return state->__size & ~DMA_IOVA_USE_SWIOTLB;
+}
+
#ifdef CONFIG_DMA_API_DEBUG
void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr);
void debug_dma_map_single(struct device *dev, const void *addr,
@@ -281,6 +295,25 @@ static inline int dma_mmap_noncontiguous(struct device *dev,
}
#endif /* CONFIG_HAS_DMA */

+#ifdef CONFIG_IOMMU_DMA
+/**
+ * dma_use_iova - check if the IOVA API is used for this state
+ * @state: IOVA state
+ *
+ * Return %true if the DMA transfers uses the dma_iova_*() calls or %false if
+ * they can't be used.
+ */
+static inline bool dma_use_iova(struct dma_iova_state *state)
+{
+ return state->__size != 0;
+}
+#else /* CONFIG_IOMMU_DMA */
+static inline bool dma_use_iova(struct dma_iova_state *state)
+{
+ return false;
+}
+#endif /* CONFIG_IOMMU_DMA */
+
#if defined(CONFIG_HAS_DMA) && defined(CONFIG_DMA_NEED_SYNC)
void __dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
enum dma_data_direction dir);
--
2.47.0