#include <linux/device.h>
#include <linux/export.h>
#include <linux/ioport.h>
+#include <linux/list.h>
#include <linux/slab.h>
#ifdef CONFIG_X86
return (type & types) ? 0 : 1;
}
EXPORT_SYMBOL_GPL(acpi_dev_filter_resource_type);
+
+struct reserved_region {
+ struct list_head node;
+ u64 start;
+ u64 end;
+};
+
+static LIST_HEAD(reserved_io_regions);
+static LIST_HEAD(reserved_mem_regions);
+
+static int request_range(u64 start, u64 end, u8 space_id, unsigned long flags,
+ char *desc)
+{
+ unsigned int length = end - start + 1;
+ struct resource *res;
+
+ res = space_id == ACPI_ADR_SPACE_SYSTEM_IO ?
+ request_region(start, length, desc) :
+ request_mem_region(start, length, desc);
+ if (!res)
+ return -EIO;
+
+ res->flags &= ~flags;
+ return 0;
+}
+
+static int add_region_before(u64 start, u64 end, u8 space_id,
+ unsigned long flags, char *desc,
+ struct list_head *head)
+{
+ struct reserved_region *reg;
+ int error;
+
+ reg = kmalloc(sizeof(*reg), GFP_KERNEL);
+ if (!reg)
+ return -ENOMEM;
+
+ error = request_range(start, end, space_id, flags, desc);
+ if (error)
+ return error;
+
+ reg->start = start;
+ reg->end = end;
+ list_add_tail(®->node, head);
+ return 0;
+}
+
+/**
+ * acpi_reserve_region - Reserve an I/O or memory region as a system resource.
+ * @start: Starting address of the region.
+ * @length: Length of the region.
+ * @space_id: Identifier of address space to reserve the region from.
+ * @flags: Resource flags to clear for the region after requesting it.
+ * @desc: Region description (for messages).
+ *
+ * Reserve an I/O or memory region as a system resource to prevent others from
+ * using it. If the new region overlaps with one of the regions (in the given
+ * address space) already reserved by this routine, only the non-overlapping
+ * parts of it will be reserved.
+ *
+ * Returned is either 0 (success) or a negative error code indicating a resource
+ * reservation problem. It is the code of the first encountered error, but the
+ * routine doesn't abort until it has attempted to request all of the parts of
+ * the new region that don't overlap with other regions reserved previously.
+ *
+ * The resources requested by this routine are never released.
+ */
+int acpi_reserve_region(u64 start, unsigned int length, u8 space_id,
+ unsigned long flags, char *desc)
+{
+ struct list_head *regions;
+ struct reserved_region *reg;
+ u64 end = start + length - 1;
+ int ret = 0, error = 0;
+
+ if (space_id == ACPI_ADR_SPACE_SYSTEM_IO)
+ regions = &reserved_io_regions;
+ else if (space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+ regions = &reserved_mem_regions;
+ else
+ return -EINVAL;
+
+ if (list_empty(regions))
+ return add_region_before(start, end, space_id, flags, desc, regions);
+
+ list_for_each_entry(reg, regions, node)
+ if (reg->start == end + 1) {
+ /* The new region can be prepended to this one. */
+ ret = request_range(start, end, space_id, flags, desc);
+ if (!ret)
+ reg->start = start;
+
+ return ret;
+ } else if (reg->start > end) {
+ /* No overlap. Add the new region here and get out. */
+ return add_region_before(start, end, space_id, flags,
+ desc, ®->node);
+ } else if (reg->end == start - 1) {
+ goto combine;
+ } else if (reg->end >= start) {
+ goto overlap;
+ }
+
+ /* The new region goes after the last existing one. */
+ return add_region_before(start, end, space_id, flags, desc, regions);
+
+ overlap:
+ /*
+ * The new region overlaps an existing one.
+ *
+ * The head part of the new region immediately preceding the existing
+ * overlapping one can be combined with it right away.
+ */
+ if (reg->start > start) {
+ error = request_range(start, reg->start - 1, space_id, flags, desc);
+ if (error)
+ ret = error;
+ else
+ reg->start = start;
+ }
+
+ combine:
+ /*
+ * The new region is adjacent to an existing one. If it extends beyond
+ * that region all the way to the next one, it is possible to combine
+ * all three of them.
+ */
+ while (reg->end < end) {
+ struct reserved_region *next = NULL;
+ u64 a = reg->end + 1, b = end;
+
+ if (!list_is_last(®->node, regions)) {
+ next = list_next_entry(reg, node);
+ if (next->start <= end)
+ b = next->start - 1;
+ }
+ error = request_range(a, b, space_id, flags, desc);
+ if (!error) {
+ if (next && next->start == b + 1) {
+ reg->end = next->end;
+ list_del(&next->node);
+ kfree(next);
+ } else {
+ reg->end = end;
+ break;
+ }
+ } else if (next) {
+ if (!ret)
+ ret = error;
+
+ reg = next;
+ } else {
+ break;
+ }
+ }
+
+ return ret ? ret : error;
+}
+EXPORT_SYMBOL_GPL(acpi_reserve_region);
projects / cascardo / linux.git / blobdiff