Changes between Initial Version and Version 1 of dma_driver

Timestamp:

Oct 8, 2014, 5:19:14 PM (10 years ago)

Author:

alain

Comment:

--

dma_driver

@@ +1 @@
+= GIET-VM / DMA Driver =
+
+[[PageOutline]]
+
+The [source:soft/giet_vm/giet_drivers/dma_driver.c dma_driver.c] and [source:soft/giet_vm/giet_drivers/dma_driver.h dma_driver.h] files define the DMA driver. 
+
+This ''vci_multi_dma'' component is a multi-channels DMA controller, that can replicated in all clusters (''internal'' peripheral).
+
+There is  (NB_CLUSTERS * NB_DMA_CHANNELS) channels, indexed by a global index:
+        dma_id = cluster_xy * NB_DMA_CHANNELS + local_index
+
+A DMA channel is a private ressource allocated to a given processor. It is exclusively used by the kernet to speedup data transfers, and
+there is no lock protecting exclusive access to the channel. As the kernel uses a polling policy on the DMA_STATUS register to detect
+transfer completion, the DMA IRQ is not used.
+
+The virtual base address of the segment associated to a channel is:
+    SEG_DMA_BASE + cluster_xy * PERI_CLUSTER_INCREMENT + DMA_SPAN * local_index
+
+The SEG_DMA_BASE virtual address and PERI_CLUSTER_INCREMENT values must be defined in the hard_config.h file.