115 lines
3.2 KiB
C
115 lines
3.2 KiB
C
#ifndef _LINUX_MEMREMAP_H_
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#define _LINUX_MEMREMAP_H_
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#include <linux/mm.h>
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#include <linux/ioport.h>
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#include <linux/percpu-refcount.h>
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struct resource;
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struct device;
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/**
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* struct vmem_altmap - pre-allocated storage for vmemmap_populate
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* @base_pfn: base of the entire dev_pagemap mapping
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* @reserve: pages mapped, but reserved for driver use (relative to @base)
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* @free: free pages set aside in the mapping for memmap storage
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* @align: pages reserved to meet allocation alignments
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* @alloc: track pages consumed, private to vmemmap_populate()
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*/
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struct vmem_altmap {
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const unsigned long base_pfn;
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const unsigned long reserve;
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unsigned long free;
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unsigned long align;
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unsigned long alloc;
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};
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unsigned long vmem_altmap_offset(struct vmem_altmap *altmap);
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void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
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#if defined(CONFIG_SPARSEMEM_VMEMMAP) && defined(CONFIG_ZONE_DEVICE)
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struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start);
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#else
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static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
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{
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return NULL;
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}
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#endif
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/**
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* struct dev_pagemap - metadata for ZONE_DEVICE mappings
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* @altmap: pre-allocated/reserved memory for vmemmap allocations
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* @res: physical address range covered by @ref
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* @ref: reference count that pins the devm_memremap_pages() mapping
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* @dev: host device of the mapping for debug
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*/
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struct dev_pagemap {
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struct vmem_altmap *altmap;
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const struct resource *res;
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struct percpu_ref *ref;
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struct device *dev;
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};
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#ifdef CONFIG_ZONE_DEVICE
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void *devm_memremap_pages(struct device *dev, struct resource *res,
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struct percpu_ref *ref, struct vmem_altmap *altmap);
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struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
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#else
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static inline void *devm_memremap_pages(struct device *dev,
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struct resource *res, struct percpu_ref *ref,
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struct vmem_altmap *altmap)
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{
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/*
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* Fail attempts to call devm_memremap_pages() without
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* ZONE_DEVICE support enabled, this requires callers to fall
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* back to plain devm_memremap() based on config
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*/
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WARN_ON_ONCE(1);
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return ERR_PTR(-ENXIO);
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}
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static inline struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
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{
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return NULL;
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}
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#endif
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/**
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* get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
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* @pfn: page frame number to lookup page_map
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* @pgmap: optional known pgmap that already has a reference
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*
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* @pgmap allows the overhead of a lookup to be bypassed when @pfn lands in the
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* same mapping.
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*/
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static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
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struct dev_pagemap *pgmap)
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{
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const struct resource *res = pgmap ? pgmap->res : NULL;
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resource_size_t phys = PFN_PHYS(pfn);
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/*
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* In the cached case we're already holding a live reference so
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* we can simply do a blind increment
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*/
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if (res && phys >= res->start && phys <= res->end) {
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percpu_ref_get(pgmap->ref);
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return pgmap;
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}
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/* fall back to slow path lookup */
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rcu_read_lock();
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pgmap = find_dev_pagemap(phys);
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if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
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pgmap = NULL;
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rcu_read_unlock();
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return pgmap;
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}
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static inline void put_dev_pagemap(struct dev_pagemap *pgmap)
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{
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if (pgmap)
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percpu_ref_put(pgmap->ref);
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}
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#endif /* _LINUX_MEMREMAP_H_ */
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