---
include/linux/iosys-map.h | 45 +++++++++++++++++++++++++++++++--------
1 file changed, 36 insertions(+), 9 deletions(-)
diff --git a/include/linux/iosys-map.h b/include/linux/iosys-map.h
index 4b8406ee8bc4..ec81ed995c59 100644
--- a/include/linux/iosys-map.h
+++ b/include/linux/iosys-map.h
@@ -6,6 +6,7 @@
#ifndef __IOSYS_MAP_H__
#define __IOSYS_MAP_H__
+#include <linux/compiler_types.h>
#include <linux/io.h>
#include <linux/string.h>
@@ -333,6 +334,26 @@ static inline void iosys_map_memset(struct iosys_map *dst, size_t offset,
memset(dst->vaddr + offset, value, len);
}
+#ifdef CONFIG_64BIT
+#define __iosys_map_rd_io_u64_case(val_, vaddr_iomem_) \
+ u64: val_ = readq(vaddr_iomem_)
+#else
+#define __iosys_map_rd_io_u64_case(val_, vaddr_iomem_) \
+ u64: memcpy_fromio(&(val_), vaddr_iomem_, sizeof(u64))
+#endif
+
+#define __iosys_map_rd_io(val__, vaddr_iomem__, type__) _Generic(val__, \
+ u8: val__ = readb(vaddr_iomem__), \
+ u16: val__ = readw(vaddr_iomem__), \
+ u32: val__ = readl(vaddr_iomem__), \
+ __iosys_map_rd_io_u64_case(val__, vaddr_iomem__))
+
+#define __iosys_map_rd_sys(val__, vaddr__, type__) ({ \
+ compiletime_assert(sizeof(type__) <= sizeof(u64), \
+ "Unsupported access size for __iosys_map_rd_sys()"); \
+ val__ = READ_ONCE(*((type__ *)vaddr__)); \
+})
+
/**
* iosys_map_rd - Read a C-type value from the iosys_map
*
@@ -340,16 +361,21 @@ static inline void iosys_map_memset(struct iosys_map *dst, size_t offset,
* @offset__: The offset from which to read
* @type__: Type of the value being read
*
- * Read a C type value from iosys_map, handling possible un-aligned accesses to
- * the mapping.
+ * Read a C type value (u8, u16, u32 and u64) from iosys_map. For other types or
+ * if pointer may be unaligned (and problematic for the architecture supported),
+ * use iosys_map_memcpy_from().
*
* Returns:
* The value read from the mapping.
*/
-#define iosys_map_rd(map__, offset__, type__) ({ \
- type__ val; \
- iosys_map_memcpy_from(&val, map__, offset__, sizeof(val)); \
- val; \
+#define iosys_map_rd(map__, offset__, type__) ({ \
+ type__ val; \
+ if ((map__)->is_iomem) { \
+ __iosys_map_rd_io(val, (map__)->vaddr_iomem + (offset__), type__);\
+ } else { \
+ __iosys_map_rd_sys(val, (map__)->vaddr + (offset__), type__); \
+ } \
+ val; \
})
/**
@@ -379,9 +405,10 @@ static inline void iosys_map_memset(struct iosys_map *dst, size_t offset,
*
* Read a value from iosys_map considering its layout is described by a C struct
* starting at @struct_offset__. The field offset and size is calculated and its
- * value read handling possible un-aligned memory accesses. For example: suppose
- * there is a @struct foo defined as below and the value ``foo.field2.inner2``
- * needs to be read from the iosys_map:
+ * value read. If the field access would incur in un-aligned access, then either
+ * iosys_map_memcpy_from() needs to be used or the architecture must support it.
+ * For example: suppose there is a @struct foo defined as below and the value
+ * ``foo.field2.inner2`` needs to be read from the iosys_map:
*
* .. code-block:: c
*
