From 803c874abe1358998ab65a8cca728684ebb50a13 Mon Sep 17 00:00:00 2001 From: Chris Metcalf Date: Fri, 2 Aug 2013 12:24:42 -0400 Subject: [PATCH] tile: support LSI MEGARAID SAS HBA hybrid dma_ops The LSI MEGARAID SAS HBA suffers from the problem where it can do 64-bit DMA to streaming buffers but not to consistent buffers. In other words, 64-bit DMA is used for disk data transfers and 32-bit DMA must be used for control message transfers. According to LSI, the firmware is not fully functional yet. This change implements a kind of hybrid dma_ops to support this. Note that on most other platforms, the 64-bit DMA addressing space is the same as the 32-bit DMA space and they overlap the physical memory space. No special arrangement is needed to support this kind of mixed DMA capability. On TILE-Gx, the 64-bit DMA space is completely separate from the 32-bit DMA space. Due to the use of the IOMMU, the 64-bit DMA space doesn't overlap the physical memory space. On the other hand, the 32-bit DMA space overlaps the physical memory space under 4GB. The separate address spaces make it necessary to have separate dma_ops. Signed-off-by: Chris Metcalf --- Reading git-format-patch failed