fd195c49fb
Version 6 of the ARM architecture introduces the concept of 16MB pages (supersections) and 36-bit (40-bit actually, but nobody uses this) physical addresses. 36-bit addressed memory and I/O and ARMv6 can only be mapped using supersections and the requirement on these is that both virtual and physical addresses be 16MB aligned. In trying to add support for ioremap() of 36-bit I/O, we run into the issue that get_vm_area() allows for a maximum of 512K alignment via the IOREMAP_MAX_ORDER constant. To work around this, we can: - Allocate a larger VM area than needed (size + (1ul << IOREMAP_MAX_ORDER)) and then align the pointer ourselves, but this ends up with 512K of wasted VM per ioremap(). - Provide a new __get_vm_area_aligned() API and make __get_vm_area() sit on top of this. I did this and it works but I don't like the idea adding another VM API just for this one case. - My preferred solution which is to allow the architecture to override the IOREMAP_MAX_ORDER constant with it's own version. Signed-off-by: Deepak Saxena <dsaxena@plexity.net> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
63 lines
1.8 KiB
C
63 lines
1.8 KiB
C
#ifndef _LINUX_VMALLOC_H
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#define _LINUX_VMALLOC_H
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#include <linux/spinlock.h>
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#include <asm/page.h> /* pgprot_t */
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/* bits in vm_struct->flags */
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#define VM_IOREMAP 0x00000001 /* ioremap() and friends */
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#define VM_ALLOC 0x00000002 /* vmalloc() */
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#define VM_MAP 0x00000004 /* vmap()ed pages */
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/* bits [20..32] reserved for arch specific ioremap internals */
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/*
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* Maximum alignment for ioremap() regions.
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* Can be overriden by arch-specific value.
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*/
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#ifndef IOREMAP_MAX_ORDER
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#define IOREMAP_MAX_ORDER (7 + PAGE_SHIFT) /* 128 pages */
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#endif
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struct vm_struct {
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void *addr;
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unsigned long size;
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unsigned long flags;
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struct page **pages;
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unsigned int nr_pages;
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unsigned long phys_addr;
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struct vm_struct *next;
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};
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/*
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* Highlevel APIs for driver use
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*/
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extern void *vmalloc(unsigned long size);
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extern void *vmalloc_exec(unsigned long size);
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extern void *vmalloc_32(unsigned long size);
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extern void *__vmalloc(unsigned long size, unsigned int __nocast gfp_mask, pgprot_t prot);
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extern void *__vmalloc_area(struct vm_struct *area, unsigned int __nocast gfp_mask, pgprot_t prot);
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extern void vfree(void *addr);
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extern void *vmap(struct page **pages, unsigned int count,
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unsigned long flags, pgprot_t prot);
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extern void vunmap(void *addr);
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/*
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* Lowlevel-APIs (not for driver use!)
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*/
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extern struct vm_struct *get_vm_area(unsigned long size, unsigned long flags);
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extern struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
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unsigned long start, unsigned long end);
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extern struct vm_struct *remove_vm_area(void *addr);
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extern struct vm_struct *__remove_vm_area(void *addr);
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extern int map_vm_area(struct vm_struct *area, pgprot_t prot,
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struct page ***pages);
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extern void unmap_vm_area(struct vm_struct *area);
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/*
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* Internals. Dont't use..
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*/
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extern rwlock_t vmlist_lock;
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extern struct vm_struct *vmlist;
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#endif /* _LINUX_VMALLOC_H */
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