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ARM: dma-mapping: split out vmregion code from dma coherent mapping code
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Greg Ungerer <gerg@uclinux.org>
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Russell King
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Nov 24, 2009
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,131 @@ | ||
| #include <linux/spinlock.h> | ||
| #include <linux/list.h> | ||
| #include <linux/slab.h> | ||
|
|
||
| #include "vmregion.h" | ||
|
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||
| /* | ||
| * VM region handling support. | ||
| * | ||
| * This should become something generic, handling VM region allocations for | ||
| * vmalloc and similar (ioremap, module space, etc). | ||
| * | ||
| * I envisage vmalloc()'s supporting vm_struct becoming: | ||
| * | ||
| * struct vm_struct { | ||
| * struct vmregion region; | ||
| * unsigned long flags; | ||
| * struct page **pages; | ||
| * unsigned int nr_pages; | ||
| * unsigned long phys_addr; | ||
| * }; | ||
| * | ||
| * get_vm_area() would then call vmregion_alloc with an appropriate | ||
| * struct vmregion head (eg): | ||
| * | ||
| * struct vmregion vmalloc_head = { | ||
| * .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list), | ||
| * .vm_start = VMALLOC_START, | ||
| * .vm_end = VMALLOC_END, | ||
| * }; | ||
| * | ||
| * However, vmalloc_head.vm_start is variable (typically, it is dependent on | ||
| * the amount of RAM found at boot time.) I would imagine that get_vm_area() | ||
| * would have to initialise this each time prior to calling vmregion_alloc(). | ||
| */ | ||
|
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| struct arm_vmregion * | ||
| arm_vmregion_alloc(struct arm_vmregion_head *head, size_t size, gfp_t gfp) | ||
| { | ||
| unsigned long addr = head->vm_start, end = head->vm_end - size; | ||
| unsigned long flags; | ||
| struct arm_vmregion *c, *new; | ||
|
|
||
| if (head->vm_end - head->vm_start < size) { | ||
| printk(KERN_WARNING "%s: allocation too big (requested %#x)\n", | ||
| __func__, size); | ||
| goto out; | ||
| } | ||
|
|
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| new = kmalloc(sizeof(struct arm_vmregion), gfp); | ||
| if (!new) | ||
| goto out; | ||
|
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| spin_lock_irqsave(&head->vm_lock, flags); | ||
|
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| list_for_each_entry(c, &head->vm_list, vm_list) { | ||
| if ((addr + size) < addr) | ||
| goto nospc; | ||
| if ((addr + size) <= c->vm_start) | ||
| goto found; | ||
| addr = c->vm_end; | ||
| if (addr > end) | ||
| goto nospc; | ||
| } | ||
|
|
||
| found: | ||
| /* | ||
| * Insert this entry _before_ the one we found. | ||
| */ | ||
| list_add_tail(&new->vm_list, &c->vm_list); | ||
| new->vm_start = addr; | ||
| new->vm_end = addr + size; | ||
| new->vm_active = 1; | ||
|
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| spin_unlock_irqrestore(&head->vm_lock, flags); | ||
| return new; | ||
|
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| nospc: | ||
| spin_unlock_irqrestore(&head->vm_lock, flags); | ||
| kfree(new); | ||
| out: | ||
| return NULL; | ||
| } | ||
|
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||
| static struct arm_vmregion *__arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr) | ||
| { | ||
| struct arm_vmregion *c; | ||
|
|
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| list_for_each_entry(c, &head->vm_list, vm_list) { | ||
| if (c->vm_active && c->vm_start == addr) | ||
| goto out; | ||
| } | ||
| c = NULL; | ||
| out: | ||
| return c; | ||
| } | ||
|
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| struct arm_vmregion *arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr) | ||
| { | ||
| struct arm_vmregion *c; | ||
| unsigned long flags; | ||
|
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| spin_lock_irqsave(&head->vm_lock, flags); | ||
| c = __arm_vmregion_find(head, addr); | ||
| spin_unlock_irqrestore(&head->vm_lock, flags); | ||
| return c; | ||
| } | ||
|
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||
| struct arm_vmregion *arm_vmregion_find_remove(struct arm_vmregion_head *head, unsigned long addr) | ||
| { | ||
| struct arm_vmregion *c; | ||
| unsigned long flags; | ||
|
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| spin_lock_irqsave(&head->vm_lock, flags); | ||
| c = __arm_vmregion_find(head, addr); | ||
| if (c) | ||
| c->vm_active = 0; | ||
| spin_unlock_irqrestore(&head->vm_lock, flags); | ||
| return c; | ||
| } | ||
|
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| void arm_vmregion_free(struct arm_vmregion_head *head, struct arm_vmregion *c) | ||
| { | ||
| unsigned long flags; | ||
|
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| spin_lock_irqsave(&head->vm_lock, flags); | ||
| list_del(&c->vm_list); | ||
| spin_unlock_irqrestore(&head->vm_lock, flags); | ||
|
|
||
| kfree(c); | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,29 @@ | ||
| #ifndef VMREGION_H | ||
| #define VMREGION_H | ||
|
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| #include <linux/spinlock.h> | ||
| #include <linux/list.h> | ||
|
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| struct page; | ||
|
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| struct arm_vmregion_head { | ||
| spinlock_t vm_lock; | ||
| struct list_head vm_list; | ||
| unsigned long vm_start; | ||
| unsigned long vm_end; | ||
| }; | ||
|
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| struct arm_vmregion { | ||
| struct list_head vm_list; | ||
| unsigned long vm_start; | ||
| unsigned long vm_end; | ||
| struct page *vm_pages; | ||
| int vm_active; | ||
| }; | ||
|
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| struct arm_vmregion *arm_vmregion_alloc(struct arm_vmregion_head *, size_t, gfp_t); | ||
| struct arm_vmregion *arm_vmregion_find(struct arm_vmregion_head *, unsigned long); | ||
| struct arm_vmregion *arm_vmregion_find_remove(struct arm_vmregion_head *, unsigned long); | ||
| void arm_vmregion_free(struct arm_vmregion_head *, struct arm_vmregion *); | ||
|
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||
| #endif |