[dpdk-dev] [PATCH v2 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  | 16 ++++++++++++++++
 lib/librte_eal/common/include/rte_memory.h | 10 ++++++++++
 lib/librte_eal/rte_eal_version.map         |  1 +
 3 files changed, 27 insertions(+)

diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
index e0f08f39a..cc4f1d80f 100644
--- a/lib/librte_eal/common/eal_common_memory.c
+++ b/lib/librte_eal/common/eal_common_memory.c
@@ -480,6 +480,22 @@ rte_mem_check_dma_mask(uint8_t maskbits)
 	return 0;
 }
 
+/*
+ * Set dma mask to use when memory initialization is done.
+ *
+ * This function should ONLY be used by code executed before the memory
+ * initialization. PMDs should use rte_mem_check_dma_mask if addressing
+ * limitations by the device.
+ */
+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..abbfe2364 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 4eb16ee3b..51ee948ba 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -334,6 +334,7 @@ EXPERIMENTAL {
 	rte_mem_event_callback_register;
 	rte_mem_event_callback_unregister;
 	rte_mem_iova2virt;
+	rte_mem_set_dma_mask;
 	rte_mem_virt2memseg;
 	rte_mem_virt2memseg_list;
 	rte_memseg_contig_walk;
-- 
2.17.1