linux_dsm_epyc7002/include/asm-powerpc/iommu.h
Linas Vepstas 5d2efba64b [POWERPC] Use 4kB iommu pages even on 64kB-page systems
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>
2006-11-01 14:52:48 +11:00

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C

/*
* Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
* Rewrite, cleanup:
* Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _ASM_IOMMU_H
#define _ASM_IOMMU_H
#ifdef __KERNEL__
#include <linux/compiler.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <asm/types.h>
#include <asm/bitops.h>
#define IOMMU_PAGE_SHIFT 12
#define IOMMU_PAGE_SIZE (ASM_CONST(1) << IOMMU_PAGE_SHIFT)
#define IOMMU_PAGE_MASK (~((1 << IOMMU_PAGE_SHIFT) - 1))
#define IOMMU_PAGE_ALIGN(addr) _ALIGN_UP(addr, IOMMU_PAGE_SIZE)
#ifndef __ASSEMBLY__
/* Pure 2^n version of get_order */
static __inline__ __attribute_const__ int get_iommu_order(unsigned long size)
{
return __ilog2((size - 1) >> IOMMU_PAGE_SHIFT) + 1;
}
#endif /* __ASSEMBLY__ */
/*
* IOMAP_MAX_ORDER defines the largest contiguous block
* of dma space we can get. IOMAP_MAX_ORDER = 13
* allows up to 2**12 pages (4096 * 4096) = 16 MB
*/
#define IOMAP_MAX_ORDER 13
struct iommu_table {
unsigned long it_busno; /* Bus number this table belongs to */
unsigned long it_size; /* Size of iommu table in entries */
unsigned long it_offset; /* Offset into global table */
unsigned long it_base; /* mapped address of tce table */
unsigned long it_index; /* which iommu table this is */
unsigned long it_type; /* type: PCI or Virtual Bus */
unsigned long it_blocksize; /* Entries in each block (cacheline) */
unsigned long it_hint; /* Hint for next alloc */
unsigned long it_largehint; /* Hint for large allocs */
unsigned long it_halfpoint; /* Breaking point for small/large allocs */
spinlock_t it_lock; /* Protects it_map */
unsigned long *it_map; /* A simple allocation bitmap for now */
};
struct scatterlist;
struct device_node;
#ifdef CONFIG_PPC_MULTIPLATFORM
/* Walks all buses and creates iommu tables */
extern void iommu_setup_pSeries(void);
extern void iommu_setup_dart(void);
/* Frees table for an individual device node */
extern void iommu_free_table(struct device_node *dn);
#endif /* CONFIG_PPC_MULTIPLATFORM */
/* Initializes an iommu_table based in values set in the passed-in
* structure
*/
extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
int nid);
extern int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
struct scatterlist *sglist, int nelems, unsigned long mask,
enum dma_data_direction direction);
extern void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
int nelems, enum dma_data_direction direction);
extern void *iommu_alloc_coherent(struct iommu_table *tbl, size_t size,
dma_addr_t *dma_handle, unsigned long mask,
gfp_t flag, int node);
extern void iommu_free_coherent(struct iommu_table *tbl, size_t size,
void *vaddr, dma_addr_t dma_handle);
extern dma_addr_t iommu_map_single(struct iommu_table *tbl, void *vaddr,
size_t size, unsigned long mask,
enum dma_data_direction direction);
extern void iommu_unmap_single(struct iommu_table *tbl, dma_addr_t dma_handle,
size_t size, enum dma_data_direction direction);
extern void iommu_init_early_pSeries(void);
extern void iommu_init_early_iSeries(void);
extern void iommu_init_early_dart(void);
#ifdef CONFIG_PCI
extern void pci_iommu_init(void);
extern void pci_direct_iommu_init(void);
#else
static inline void pci_iommu_init(void) { }
#endif
extern void alloc_dart_table(void);
#endif /* __KERNEL__ */
#endif /* _ASM_IOMMU_H */