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>
diff --git a/arch/arm/mm/vmregion.c b/arch/arm/mm/vmregion.c
new file mode 100644
index 0000000..19e09bdb
--- /dev/null
+++ b/arch/arm/mm/vmregion.c
@@ -0,0 +1,131 @@
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include "vmregion.h"
+
+/*
+ * 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().
+ */
+
+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;
+ }
+
+ new = kmalloc(sizeof(struct arm_vmregion), gfp);
+ if (!new)
+ goto out;
+
+ spin_lock_irqsave(&head->vm_lock, flags);
+
+ 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;
+
+ spin_unlock_irqrestore(&head->vm_lock, flags);
+ return new;
+
+ nospc:
+ spin_unlock_irqrestore(&head->vm_lock, flags);
+ kfree(new);
+ out:
+ return NULL;
+}
+
+static struct arm_vmregion *__arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr)
+{
+ struct arm_vmregion *c;
+
+ 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;
+}
+
+struct arm_vmregion *arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr)
+{
+ struct arm_vmregion *c;
+ unsigned long flags;
+
+ spin_lock_irqsave(&head->vm_lock, flags);
+ c = __arm_vmregion_find(head, addr);
+ spin_unlock_irqrestore(&head->vm_lock, flags);
+ return c;
+}
+
+struct arm_vmregion *arm_vmregion_find_remove(struct arm_vmregion_head *head, unsigned long addr)
+{
+ struct arm_vmregion *c;
+ unsigned long flags;
+
+ 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;
+}
+
+void arm_vmregion_free(struct arm_vmregion_head *head, struct arm_vmregion *c)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&head->vm_lock, flags);
+ list_del(&c->vm_list);
+ spin_unlock_irqrestore(&head->vm_lock, flags);
+
+ kfree(c);
+}