cxl/regs: Clarify when a 'struct cxl_register_map' is input vs output

The @Map parameter to cxl_probe_X_registers() is filled in with the
mapping parameters of the register block. The @Map parameter to
cxl_map_X_registers() only reads that information to perform the
mapping. Mark @Map const for cxl_map_X_registers() to clarify that it is
only an input to those helpers.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/168679258103.3436160.4941603739448763855.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Author: djbw

drivers/cxl/core/regs.c

@@ -200,10 +200,10 @@ void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
 }
 
 int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
-			   struct cxl_register_map *map, unsigned long map_mask)
+			   const struct cxl_register_map *map, unsigned long map_mask)
 {
 	struct mapinfo {
-		struct cxl_reg_map *rmap;
+		const struct cxl_reg_map *rmap;
 		void __iomem **addr;
 	} mapinfo[] = {
 		{ &map->component_map.hdm_decoder, &regs->hdm_decoder },
@@ -233,11 +233,11 @@ EXPORT_SYMBOL_NS_GPL(cxl_map_component_regs, CXL);
 
 int cxl_map_device_regs(struct device *dev,
 			struct cxl_device_regs *regs,
-			struct cxl_register_map *map)
+			const struct cxl_register_map *map)
 {
 	resource_size_t phys_addr = map->resource;
 	struct mapinfo {
-		struct cxl_reg_map *rmap;
+		const struct cxl_reg_map *rmap;
 		void __iomem **addr;
 	} mapinfo[] = {
 		{ &map->device_map.status, &regs->status, },

drivers/cxl/cxl.h

@@ -254,10 +254,10 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
 void cxl_probe_device_regs(struct device *dev, void __iomem *base,
 			   struct cxl_device_reg_map *map);
 int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
-			   struct cxl_register_map *map,
+			   const struct cxl_register_map *map,
 			   unsigned long map_mask);
 int cxl_map_device_regs(struct device *dev, struct cxl_device_regs *regs,
-			struct cxl_register_map *map);
+			const struct cxl_register_map *map);
 
 enum cxl_regloc_type;
 int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,