Benjamin Herrenschmidt wrote:
Sounds good. Thanks!Note, that these smaller sub-host-page-sized mappings might pollute the address space causing full aligned host-page-size maps to become scarce... Maybe there's a clever way to keep those in their own segment of the address space?We already have a large vs. small split in the iommu virtual space to alleviate this (though it's not a hard constraint, we can still get into the "other" side if the default one is full). Try that patch and let me know:
Seems to be working! :)
Index: linux-work/arch/powerpc/kernel/iommu.c =================================================================== --- linux-work.orig/arch/powerpc/kernel/iommu.c 2007-12-21 10:39:39.000000000 +1100 +++ linux-work/arch/powerpc/kernel/iommu.c 2007-12-21 10:46:18.000000000 +1100 @@ -278,6 +278,7 @@ int iommu_map_sg(struct iommu_table *tbl unsigned long flags; struct scatterlist *s, *outs, *segstart; int outcount, incount, i; + unsigned int align; unsigned long handle;BUG_ON(direction == DMA_NONE);@@ -309,7 +310,11 @@ int iommu_map_sg(struct iommu_table *tbl /* Allocate iommu entries for that segment */ vaddr = (unsigned long) sg_virt(s); npages = iommu_num_pages(vaddr, slen); - entry = iommu_range_alloc(tbl, npages, &handle, mask >> IOMMU_PAGE_SHIFT, 0); + align = 0; + if (IOMMU_PAGE_SHIFT < PAGE_SHIFT && (vaddr & ~PAGE_MASK) == 0) + align = PAGE_SHIFT - IOMMU_PAGE_SHIFT; + entry = iommu_range_alloc(tbl, npages, &handle, + mask >> IOMMU_PAGE_SHIFT, align);DBG(" - vaddr: %lx, size: %lx\n", vaddr, slen); @@ -572,7 +577,7 @@ dma_addr_t iommu_map_single(struct iommu{ dma_addr_t dma_handle = DMA_ERROR_CODE; unsigned long uaddr; - unsigned int npages; + unsigned int npages, align;BUG_ON(direction == DMA_NONE); @@ -580,8 +585,13 @@ dma_addr_t iommu_map_single(struct iommunpages = iommu_num_pages(uaddr, size);if (tbl) {+ align = 0; + if (IOMMU_PAGE_SHIFT < PAGE_SHIFT && + ((unsigned long)vaddr & ~PAGE_MASK) == 0) + align = PAGE_SHIFT - IOMMU_PAGE_SHIFT; + dma_handle = iommu_alloc(tbl, vaddr, npages, direction, - mask >> IOMMU_PAGE_SHIFT, 0); + mask >> IOMMU_PAGE_SHIFT, align); if (dma_handle == DMA_ERROR_CODE) { if (printk_ratelimit()) { printk(KERN_INFO "iommu_alloc failed, "
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
- Follow-Ups:
- Re: iommu dma mapping alignment requirements
- From: Benjamin Herrenschmidt <[email protected]>
- Re: iommu dma mapping alignment requirements
- References:
- iommu dma mapping alignment requirements
- From: Steve Wise <[email protected]>
- Re: iommu dma mapping alignment requirements
- From: Benjamin Herrenschmidt <[email protected]>
- Re: iommu dma mapping alignment requirements
- From: Steve Wise <[email protected]>
- Re: iommu dma mapping alignment requirements
- From: Benjamin Herrenschmidt <[email protected]>
- Re: iommu dma mapping alignment requirements
- From: Steve Wise <[email protected]>
- Re: iommu dma mapping alignment requirements
- From: Benjamin Herrenschmidt <[email protected]>
- iommu dma mapping alignment requirements
- Prev by Date: Re: [PATCH 3/3] pci: Remove pci_enable_device_bars()
- Next by Date: Re: Linux 2.6.24-rc6
- Previous by thread: Re: iommu dma mapping alignment requirements
- Next by thread: Re: iommu dma mapping alignment requirements
- Index(es):
 |