From: Jake Moilanen Date: Thu, 29 Mar 2007 13:44:02 +0000 (-0500) Subject: [POWERPC] DMA 4GB boundary protection X-Git-Tag: v2.6.22-rc1~1109^2~117 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=569975591c5530fdc9c7a3c45122e5e46f075a74;p=pandora-kernel.git [POWERPC] DMA 4GB boundary protection There are many adapters which cannot handle DMAing across any 4 GB boundary. For instance, the latest Emulex adapters. This normally is not an issue as firmware gives dma-windows under 4gigs. However, some of the new System-P boxes have dma-windows above 4gigs, and this present a problem. During initialization of the IOMMU tables, the last entry at each 4GB boundary is marked as used. Thus no mappings can cross the boundary. If a table ends at a 4GB boundary, the entry is not marked as used. A boot option to remove this 4GB protection is given w/ protect4gb=off. This exposes the potential issue for driver and hardware development purposes. Signed-off-by: Jake Moilanen Acked-by: Olof Johansson Signed-off-by: Paul Mackerras --- Reading git-diff-tree failed