5d2efba64b
The 10Gigabit ethernet device drivers appear to be able to chew up all 256MB of TCE mappings on pSeries systems, as evidenced by numerous error messages: iommu_alloc failed, tbl c0000000010d5c48 vaddr c0000000d875eff0 npages 1 Some experimentation indicates that this is essentially because one 1500 byte ethernet MTU gets mapped as a 64K DMA region when the large 64K pages are enabled. Thus, it doesn't take much to exhaust all of the available DMA mappings for a high-speed card. This patch changes the iommu allocator to work with its own unique, distinct page size. Although the patch is long, its actually quite simple: it just #defines a distinct IOMMU_PAGE_SIZE and then uses this in all the places that matter. As a side effect, it also dramatically improves network performance on platforms with H-calls on iommu translation inserts/removes (since we no longer call it 16 times for a 1500 bytes packet when the iommu HW is still 4k). In the future, we might want to make the IOMMU_PAGE_SIZE a variable in the iommu_table instance, thus allowing support for different HW page sizes in the iommu itself. Signed-off-by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
50 lines
1.6 KiB
C
50 lines
1.6 KiB
C
/*
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* Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
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* Rewrite, cleanup:
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* Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _ASM_POWERPC_TCE_H
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#define _ASM_POWERPC_TCE_H
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#ifdef __KERNEL__
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#include <asm/iommu.h>
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/*
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* Tces come in two formats, one for the virtual bus and a different
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* format for PCI
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*/
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#define TCE_VB 0
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#define TCE_PCI 1
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/* TCE page size is 4096 bytes (1 << 12) */
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#define TCE_SHIFT 12
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#define TCE_PAGE_SIZE (1 << TCE_SHIFT)
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#define TCE_ENTRY_SIZE 8 /* each TCE is 64 bits */
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#define TCE_RPN_MASK 0xfffffffffful /* 40-bit RPN (4K pages) */
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#define TCE_RPN_SHIFT 12
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#define TCE_VALID 0x800 /* TCE valid */
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#define TCE_ALLIO 0x400 /* TCE valid for all lpars */
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#define TCE_PCI_WRITE 0x2 /* write from PCI allowed */
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#define TCE_PCI_READ 0x1 /* read from PCI allowed */
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#define TCE_VB_WRITE 0x1 /* write from VB allowed */
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_TCE_H */
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