resource: Add resource set range and size helpers

[ Upstream commit 9fb6fef0fb49124291837af1da5028f79d53f98e ]

Setting the end address for a resource with a given size lacks a helper and
is therefore coded manually unlike the getter side which has a helper for
resource size calculation. Also, almost all callsites that calculate the
end address for a resource also set the start address right before it like
this:

  res->start = start_addr;
  res->end = res->start + size - 1;

Add resource_set_range(res, start_addr, size) that sets the start address
and calculates the end address to simplify this often repeated fragment.

Also add resource_set_size() for the cases where setting the start address
of the resource is not necessary but mention in its kerneldoc that
resource_set_range() is preferred when setting both addresses.

Link: https://lore.kernel.org/r/20240614100606.15830-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Stable-dep-of: 11721c45a826 ("PCI: Use resource_set_range() that correctly sets ->end")
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 25d768d48970..d10749797f18 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -216,6 +216,38 @@ struct resource *lookup_resource(struct resource *root, resource_size_t start);
 int adjust_resource(struct resource *res, resource_size_t start,
 		    resource_size_t size);
 resource_size_t resource_alignment(struct resource *res);
+
+/**
+ * resource_set_size - Calculate resource end address from size and start
+ * @res: Resource descriptor
+ * @size: Size of the resource
+ *
+ * Calculate the end address for @res based on @size.
+ *
+ * Note: The start address of @res must be set when calling this function.
+ * Prefer resource_set_range() if setting both the start address and @size.
+ */
+static inline void resource_set_size(struct resource *res, resource_size_t size)
+{
+	res->end = res->start + size - 1;
+}
+
+/**
+ * resource_set_range - Set resource start and end addresses
+ * @res: Resource descriptor
+ * @start: Start address for the resource
+ * @size: Size of the resource
+ *
+ * Set @res start address and calculate the end address based on @size.
+ */
+static inline void resource_set_range(struct resource *res,
+				      resource_size_t start,
+				      resource_size_t size)
+{
+	res->start = start;
+	resource_set_size(res, size);
+}
+
 static inline resource_size_t resource_size(const struct resource *res)
 {
 	return res->end - res->start + 1;