include/linux/iova.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (c) 2006, Intel Corporation.
 *
 * Copyright (C) 2006-2008 Intel Corporation
 * Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 */

#ifndef _IOVA_H_
#define _IOVA_H_

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/rbtree.h>
#include <linux/atomic.h>
#include <linux/dma-mapping.h>

/* iova structure */
struct iova {
    struct rb_node node;
    unsigned long pfn_hi; /* Highest allocated pfn */
    unsigned long pfn_lo; /* Lowest allocated pfn */
};

struct iova_magazine;
struct iova_cpu_rcache;

#define IOVA_RANGE_CACHE_MAX_SIZE 6 /* log of max cached IOVA range size (in pages) */
#define MAX_GLOBAL_MAGS 32          /* magazines per bin */

struct iova_rcache {
    spinlock_t lock;
    unsigned long depot_size;
    struct iova_magazine *depot[MAX_GLOBAL_MAGS];
    struct iova_cpu_rcache __percpu *cpu_rcaches;
};

struct iova_domain;

/* Call-Back from IOVA code into IOMMU drivers */
typedef void (*iova_flush_cb)(struct iova_domain *domain);

/* Destructor for per-entry data */
typedef void (*iova_entry_dtor)(unsigned long data);

/* Number of entries per Flush Queue */
#define IOVA_FQ_SIZE 256

/* Timeout (in ms) after which entries are flushed from the Flush-Queue */
#define IOVA_FQ_TIMEOUT 10

/* Flush Queue entry for defered flushing */
struct iova_fq_entry {
    unsigned long iova_pfn;
    unsigned long pages;
    unsigned long data;
    u64 counter; /* Flush counter when this entrie was added */
};

/* Per-CPU Flush Queue structure */
struct iova_fq {
    struct iova_fq_entry entries[IOVA_FQ_SIZE];
    unsigned head, tail;
    spinlock_t lock;
};

/* holds all the iova translations for a domain */
struct iova_domain {
    spinlock_t iova_rbtree_lock;   /* Lock to protect update of rbtree */
    struct rb_root rbroot;         /* iova domain rbtree root */
    struct rb_node *cached_node;   /* Save last alloced node */
    struct rb_node *cached32_node; /* Save last 32-bit alloced node */
    unsigned long granule;         /* pfn granularity for this domain */
    unsigned long start_pfn;       /* Lower limit for this domain */
    unsigned long dma_32bit_pfn;
    unsigned long max32_alloc_size; /* Size of last failed allocation */
    struct iova_fq __percpu *fq;    /* Flush Queue */

    atomic64_t fq_flush_start_cnt; /* Number of TLB flushes that
                     have been started */

    atomic64_t fq_flush_finish_cnt; /* Number of TLB flushes that
                     have been finished */

    struct iova anchor;                                    /* rbtree lookup anchor */
    struct iova_rcache rcaches[IOVA_RANGE_CACHE_MAX_SIZE]; /* IOVA range caches */

    iova_flush_cb flush_cb; /* Call-Back function to flush IOMMU
                 TLBs */

    iova_entry_dtor entry_dtor; /* IOMMU driver specific destructor for
                    iova entry */

    struct timer_list fq_timer; /* Timer to regularily empty the
                    flush-queues */
    atomic_t fq_timer_on;       /* 1 when timer is active, 0
                      when not */
    bool best_fit;
};

static inline unsigned long iova_size(struct iova *iova)
{
    return iova->pfn_hi - iova->pfn_lo + 1;
}

static inline unsigned long iova_shift(struct iova_domain *iovad)
{
    return __ffs(iovad->granule);
}

static inline unsigned long iova_mask(struct iova_domain *iovad)
{
    return iovad->granule - 1;
}

static inline size_t iova_offset(struct iova_domain *iovad, dma_addr_t iova)
{
    return iova & iova_mask(iovad);
}

static inline size_t iova_align(struct iova_domain *iovad, size_t size)
{
    return ALIGN(size, iovad->granule);
}

static inline dma_addr_t iova_dma_addr(struct iova_domain *iovad, struct iova *iova)
{
    return (dma_addr_t)iova->pfn_lo << iova_shift(iovad);
}

static inline unsigned long iova_pfn(struct iova_domain *iovad, dma_addr_t iova)
{
    return iova >> iova_shift(iovad);
}

#if IS_ENABLED(CONFIG_IOMMU_IOVA)
int iova_cache_get(void);
void iova_cache_put(void);

struct iova *alloc_iova_mem(void);
void free_iova_mem(struct iova *iova);
void free_iova(struct iova_domain *iovad, unsigned long pfn);
void __free_iova(struct iova_domain *iovad, struct iova *iova);
struct iova *alloc_iova(struct iova_domain *iovad, unsigned long size, unsigned long limit_pfn, bool size_aligned);
void free_iova_fast(struct iova_domain *iovad, unsigned long pfn, unsigned long size);
void queue_iova(struct iova_domain *iovad, unsigned long pfn, unsigned long pages, unsigned long data);
unsigned long alloc_iova_fast(struct iova_domain *iovad, unsigned long size, unsigned long limit_pfn,
                              bool flush_rcache);
struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo, unsigned long pfn_hi);
void copy_reserved_iova(struct iova_domain *from, struct iova_domain *to);
void init_iova_domain(struct iova_domain *iovad, unsigned long granule, unsigned long start_pfn);
bool has_iova_flush_queue(struct iova_domain *iovad);
int init_iova_flush_queue(struct iova_domain *iovad, iova_flush_cb flush_cb, iova_entry_dtor entry_dtor);
struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn);
void put_iova_domain(struct iova_domain *iovad);
struct iova *split_and_remove_iova(struct iova_domain *iovad, struct iova *iova, unsigned long pfn_lo,
                                   unsigned long pfn_hi);
void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad);
#else
static inline int iova_cache_get(void)
{
    return -ENOTSUPP;
}

static inline void iova_cache_put(void)
{
}

static inline struct iova *alloc_iova_mem(void)
{
    return NULL;
}

static inline void free_iova_mem(struct iova *iova)
{
}

static inline void free_iova(struct iova_domain *iovad, unsigned long pfn)
{
}

static inline void __free_iova(struct iova_domain *iovad, struct iova *iova)
{
}

static inline struct iova *alloc_iova(struct iova_domain *iovad, unsigned long size, unsigned long limit_pfn,
                                      bool size_aligned)
{
    return NULL;
}

static inline void free_iova_fast(struct iova_domain *iovad, unsigned long pfn, unsigned long size)
{
}

static inline void queue_iova(struct iova_domain *iovad, unsigned long pfn, unsigned long pages, unsigned long data)
{
}

static inline unsigned long alloc_iova_fast(struct iova_domain *iovad, unsigned long size, unsigned long limit_pfn,
                                            bool flush_rcache)
{
    return 0;
}

static inline struct iova *reserve_iova(struct iova_domain *iovad, unsigned long pfn_lo, unsigned long pfn_hi)
{
    return NULL;
}

static inline void copy_reserved_iova(struct iova_domain *from, struct iova_domain *to)
{
}

static inline void init_iova_domain(struct iova_domain *iovad, unsigned long granule, unsigned long start_pfn)
{
}

static inline bool has_iova_flush_queue(struct iova_domain *iovad)
{
    return false;
}

static inline int init_iova_flush_queue(struct iova_domain *iovad, iova_flush_cb flush_cb, iova_entry_dtor entry_dtor)
{
    return -ENODEV;
}

static inline struct iova *find_iova(struct iova_domain *iovad, unsigned long pfn)
{
    return NULL;
}

static inline void put_iova_domain(struct iova_domain *iovad)
{
}

static inline struct iova *split_and_remove_iova(struct iova_domain *iovad, struct iova *iova, unsigned long pfn_lo,
                                                 unsigned long pfn_hi)
{
    return NULL;
}

static inline void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *iovad)
{
}
#endif

#endif