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Message-Id: <1277235772-26757-15-git-send-email-konrad.wilk@oracle.com>
Date: Tue, 22 Jun 2010 15:42:47 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: linux-kernel@...r.kernel.org, fujita.tomonori@....ntt.co.jp,
iommu@...ts.linux-foundation.org, albert_herranz@...oo.es,
x86@...nel.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Subject: [PATCH 14/19] swiotlb-xen: Add 'xen_swiotlb_init' function.
We utilize the alloc_bootmem to allocate any memory (even
past the 4GB) and then follow it with a xen kernel
to replace the memory pointed by the virtual address with memory
that is under the 4GB mark.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
---
lib/swiotlb-xen.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 67 insertions(+), 1 deletions(-)
diff --git a/lib/swiotlb-xen.c b/lib/swiotlb-xen.c
index e0f944e..3c5bfde 100644
--- a/lib/swiotlb-xen.c
+++ b/lib/swiotlb-xen.c
@@ -33,10 +33,10 @@
*
*/
+#include <linux/bootmem.h>
#include <linux/dma-mapping.h>
#include <xen/page.h>
#include <xen/xen-ops.h>
-
/*
* Used to do a quick range check in swiotlb_tbl_unmap_single and
* swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
@@ -44,6 +44,7 @@
*/
static char *xen_io_tlb_start, *xen_io_tlb_end;
+static unsigned long xen_io_tlb_nslabs;
/* Temporary scaffolding. Will be removed later. */
void
@@ -124,6 +125,70 @@ xen_map_single(struct device *hwdev, phys_addr_t phys, size_t size,
return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir);
}
+static int max_dma_bits = 32;
+
+static int
+xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
+{
+ int i, rc;
+ int dma_bits;
+
+ dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
+
+ i = 0;
+ do {
+ int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
+
+ do {
+ rc = xen_create_contiguous_region(
+ (unsigned long)buf + (i << IO_TLB_SHIFT),
+ get_order(slabs << IO_TLB_SHIFT),
+ dma_bits);
+ } while (rc && dma_bits++ < max_dma_bits);
+ if (rc)
+ return rc;
+
+ i += slabs;
+ } while (i < nslabs);
+ return 0;
+}
+
+void __init xen_swiotlb_init(int verbose)
+{
+ unsigned long bytes;
+ int rc;
+
+ xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
+ xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
+
+ bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
+
+ /*
+ * Get IO TLB memory from any location.
+ */
+ xen_io_tlb_start = alloc_bootmem(bytes);
+ if (!xen_io_tlb_start)
+ panic("Cannot allocate SWIOTLB buffer");
+
+ xen_io_tlb_end = xen_io_tlb_start + bytes;
+ /*
+ * And replace that memory with pages under 4GB.
+ */
+ rc = xen_swiotlb_fixup(xen_io_tlb_start,
+ bytes,
+ xen_io_tlb_nslabs);
+ if (rc)
+ goto error;
+
+ swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
+
+ return;
+error:
+ panic("DMA(%d): Failed to exchange pages allocated for DMA with Xen! "\
+ "We either don't have the permission or you do not have enough"\
+ "free memory under 4GB!\n", rc);
+}
+
void *
xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags)
@@ -177,6 +242,7 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
}
EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);
+
/*
* Map a single buffer of the indicated size for DMA in streaming mode. The
* physical address to use is returned.
--
1.7.0.1
--
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