[dpdk-dev] [PATCH 3/7] mem: add function for setting DMA mask

[Alejandro Lucero <alejandro.lucero@netronome.com>]

This patch adds the possibility of setting a dma mask to be used
once the memory initialization is done.

This is currently needed when IOVA mode is set by PCI related
code and an x86 IOMMU hardware unit is present. Current code calls
rte_mem_check_dma_mask but it is wrong to do so at that point
because the memory has not been initialized yet.

Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
---
 lib/librte_eal/common/eal_common_memory.c  | 10 ++++++++++
 lib/librte_eal/common/include/rte_memory.h | 10 ++++++++++
 lib/librte_eal/rte_eal_version.map         |  1 +
 3 files changed, 21 insertions(+)

diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
index e0f08f39a..24b72fcb0 100644
--- a/lib/librte_eal/common/eal_common_memory.c
+++ b/lib/librte_eal/common/eal_common_memory.c
@@ -480,6 +480,16 @@ rte_mem_check_dma_mask(uint8_t maskbits)
 	return 0;
 }
 
+/* set dma mask to use when memory initialization is done */
+void __rte_experimental
+rte_mem_set_dma_mask(uint8_t maskbits)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+
+	mcfg->dma_maskbits = mcfg->dma_maskbits == 0 ? maskbits :
+			     RTE_MIN(mcfg->dma_maskbits, maskbits);
+}
+
 /* return the number of memory channels */
 unsigned rte_memory_get_nchannel(void)
 {
diff --git a/lib/librte_eal/common/include/rte_memory.h b/lib/librte_eal/common/include/rte_memory.h
index ad3f3cfb0..eff028db1 100644
--- a/lib/librte_eal/common/include/rte_memory.h
+++ b/lib/librte_eal/common/include/rte_memory.h
@@ -466,6 +466,16 @@ unsigned rte_memory_get_nrank(void);
 /* check memsegs iovas are within a range based on dma mask */
 int __rte_experimental rte_mem_check_dma_mask(uint8_t maskbits);
 
+/**
+ *  * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ *  Set dma mask to use once memory initialization is done.
+ *  Previous function rte_mem_check_dma_mask can not be used
+ *  safely until memory has been initialized.
+ */
+void __rte_experimental rte_mem_set_dma_mask(uint8_t maskbits);
+
 /**
  * Drivers based on uio will not load unless physical
  * addresses are obtainable. It is only possible to get
diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map
index ef8126a97..ae24b5c73 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -296,6 +296,7 @@ EXPERIMENTAL {
 	rte_devargs_remove;
 	rte_devargs_type_count;
 	rte_mem_check_dma_mask;
+	rte_mem_set_dma_mask;
 	rte_eal_cleanup;
 	rte_fbarray_attach;
 	rte_fbarray_destroy;
-- 
2.17.1