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05c6cfb9dce0d13d37e9d007ee6a4af36f1c0a58
android_kernel_xiaomi_sm8450/arch/powerpc/include/asm/iommu.h
Alexey Kardashevskiy 05c6cfb9dc powerpc/iommu/powernv: Release replaced TCE 
At the moment writing new TCE value to the IOMMU table fails with EBUSY
if there is a valid entry already. However PAPR specification allows
the guest to write new TCE value without clearing it first.

Another problem this patch is addressing is the use of pool locks for
external IOMMU users such as VFIO. The pool locks are to protect
DMA page allocator rather than entries and since the host kernel does
not control what pages are in use, there is no point in pool locks and
exchange()+put_page(oldtce) is sufficient to avoid possible races.

This adds an exchange() callback to iommu_table_ops which does the same
thing as set() plus it returns replaced TCE and DMA direction so
the caller can release the pages afterwards. The exchange() receives
a physical address unlike set() which receives linear mapping address;
and returns a physical address as the clear() does.

This implements exchange() for P5IOC2/IODA/IODA2. This adds a requirement
for a platform to have exchange() implemented in order to support VFIO.

This replaces iommu_tce_build() and iommu_clear_tce() with
a single iommu_tce_xchg().

This makes sure that TCE permission bits are not set in TCE passed to
IOMMU API as those are to be calculated by platform code from
DMA direction.

This moves SetPageDirty() to the IOMMU code to make it work for both
VFIO ioctl interface in in-kernel TCE acceleration (when it becomes
available later).

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
[aw: for the vfio related changes]
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-06-11 15:16:49 +10:00

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/*
* 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 <linux/bitops.h>
#include <asm/machdep.h>
#include <asm/types.h>
#include <asm/pci-bridge.h>
#define IOMMU_PAGE_SHIFT_4K 12
#define IOMMU_PAGE_SIZE_4K (ASM_CONST(1) << IOMMU_PAGE_SHIFT_4K)
#define IOMMU_PAGE_MASK_4K (~((1 << IOMMU_PAGE_SHIFT_4K) - 1))
#define IOMMU_PAGE_ALIGN_4K(addr) _ALIGN_UP(addr, IOMMU_PAGE_SIZE_4K)
#define IOMMU_PAGE_SIZE(tblptr) (ASM_CONST(1) << (tblptr)->it_page_shift)
#define IOMMU_PAGE_MASK(tblptr) (~((1 << (tblptr)->it_page_shift) - 1))
#define IOMMU_PAGE_ALIGN(addr, tblptr) _ALIGN_UP(addr, IOMMU_PAGE_SIZE(tblptr))
/* Boot time flags */
extern int iommu_is_off;
extern int iommu_force_on;
struct iommu_table_ops {
/*
* When called with direction==DMA_NONE, it is equal to clear().
* uaddr is a linear map address.
*/
int (*set)(struct iommu_table *tbl,
long index, long npages,
unsigned long uaddr,
enum dma_data_direction direction,
struct dma_attrs *attrs);
#ifdef CONFIG_IOMMU_API
/*
* Exchanges existing TCE with new TCE plus direction bits;
* returns old TCE and DMA direction mask.
* @tce is a physical address.
*/
int (*exchange)(struct iommu_table *tbl,
long index,
unsigned long *hpa,
enum dma_data_direction *direction);
#endif
void (*clear)(struct iommu_table *tbl,
long index, long npages);
/* get() returns a physical address */
unsigned long (*get)(struct iommu_table *tbl, long index);
void (*flush)(struct iommu_table *tbl);
};
/* These are used by VIO */
extern struct iommu_table_ops iommu_table_lpar_multi_ops;
extern struct iommu_table_ops iommu_table_pseries_ops;
/*
* 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
#define IOMMU_POOL_HASHBITS 2
#define IOMMU_NR_POOLS (1 << IOMMU_POOL_HASHBITS)
struct iommu_pool {
unsigned long start;
unsigned long end;
unsigned long hint;
spinlock_t lock;
} ____cacheline_aligned_in_smp;
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 poolsize;
unsigned long nr_pools;
struct iommu_pool large_pool;
struct iommu_pool pools[IOMMU_NR_POOLS];
unsigned long *it_map; /* A simple allocation bitmap for now */
unsigned long it_page_shift;/* table iommu page size */
struct list_head it_group_list;/* List of iommu_table_group_link */
struct iommu_table_ops *it_ops;
};
/* Pure 2^n version of get_order */
static inline __attribute_const__
int get_iommu_order(unsigned long size, struct iommu_table *tbl)
{
return __ilog2((size - 1) >> tbl->it_page_shift) + 1;
}
struct scatterlist;
static inline void set_iommu_table_base(struct device *dev, void *base)
{
dev->archdata.dma_data.iommu_table_base = base;
}
static inline void *get_iommu_table_base(struct device *dev)
{
return dev->archdata.dma_data.iommu_table_base;
}
/* Frees table for an individual device node */
extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
/* 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);
#define IOMMU_TABLE_GROUP_MAX_TABLES 1
struct iommu_table_group;
struct iommu_table_group_ops {
/* Switch ownership from platform code to external user (e.g. VFIO) */
void (*take_ownership)(struct iommu_table_group *table_group);
/* Switch ownership from external user (e.g. VFIO) back to core */
void (*release_ownership)(struct iommu_table_group *table_group);
};
struct iommu_table_group_link {
struct list_head next;
struct rcu_head rcu;
struct iommu_table_group *table_group;
};
struct iommu_table_group {
struct iommu_group *group;
struct iommu_table *tables[IOMMU_TABLE_GROUP_MAX_TABLES];
struct iommu_table_group_ops *ops;
};
#ifdef CONFIG_IOMMU_API
extern void iommu_register_group(struct iommu_table_group *table_group,
int pci_domain_number, unsigned long pe_num);
extern int iommu_add_device(struct device *dev);
extern void iommu_del_device(struct device *dev);
extern int __init tce_iommu_bus_notifier_init(void);
extern long iommu_tce_xchg(struct iommu_table *tbl, unsigned long entry,
unsigned long *hpa, enum dma_data_direction *direction);
#else
static inline void iommu_register_group(struct iommu_table_group *table_group,
int pci_domain_number,
unsigned long pe_num)
{
}
static inline int iommu_add_device(struct device *dev)
{
return 0;
}
static inline void iommu_del_device(struct device *dev)
{
}
static inline int __init tce_iommu_bus_notifier_init(void)
{
return 0;
}
#endif /* !CONFIG_IOMMU_API */
extern int ppc_iommu_map_sg(struct device *dev, struct iommu_table *tbl,
struct scatterlist *sglist, int nelems,
unsigned long mask,
enum dma_data_direction direction,
struct dma_attrs *attrs);
extern void ppc_iommu_unmap_sg(struct iommu_table *tbl,
struct scatterlist *sglist,
int nelems,
enum dma_data_direction direction,
struct dma_attrs *attrs);
extern void *iommu_alloc_coherent(struct device *dev, 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_page(struct device *dev, struct iommu_table *tbl,
struct page *page, unsigned long offset,
size_t size, unsigned long mask,
enum dma_data_direction direction,
struct dma_attrs *attrs);
extern void iommu_unmap_page(struct iommu_table *tbl, dma_addr_t dma_handle,
size_t size, enum dma_data_direction direction,
struct dma_attrs *attrs);
extern void iommu_init_early_pSeries(void);
extern void iommu_init_early_dart(struct pci_controller_ops *controller_ops);
extern void iommu_init_early_pasemi(void);
extern void alloc_dart_table(void);
#if defined(CONFIG_PPC64) && defined(CONFIG_PM)
static inline void iommu_save(void)
{
if (ppc_md.iommu_save)
ppc_md.iommu_save();
}
static inline void iommu_restore(void)
{
if (ppc_md.iommu_restore)
ppc_md.iommu_restore();
}
#endif
/* The API to support IOMMU operations for VFIO */
extern int iommu_tce_clear_param_check(struct iommu_table *tbl,
unsigned long ioba, unsigned long tce_value,
unsigned long npages);
extern int iommu_tce_put_param_check(struct iommu_table *tbl,
unsigned long ioba, unsigned long tce);
extern void iommu_flush_tce(struct iommu_table *tbl);
extern int iommu_take_ownership(struct iommu_table *tbl);
extern void iommu_release_ownership(struct iommu_table *tbl);
extern enum dma_data_direction iommu_tce_direction(unsigned long tce);
extern unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir);
#endif /* __KERNEL__ */
#endif /* _ASM_IOMMU_H */
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