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-rw-r--r--include/linux/hw_bitfield.h61
-rw-r--r--include/linux/string.h13
2 files changed, 64 insertions, 10 deletions
diff --git a/include/linux/hw_bitfield.h b/include/linux/hw_bitfield.h
new file mode 100644
index 00000000000..6e74d902ed3
--- /dev/null
+++ b/include/linux/hw_bitfield.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2025, Collabora Ltd.
+ */
+
+#ifndef _LINUX_HW_BITFIELD_H
+#define _LINUX_HW_BITFIELD_H
+
+#include <linux/bitfield.h>
+#include <linux/build_bug.h>
+
+/**
+ * FIELD_PREP_WM16() - prepare a bitfield element with a mask in the upper half
+ * @_mask: shifted mask defining the field's length and position
+ * @_val: value to put in the field
+ *
+ * FIELD_PREP_WM16() masks and shifts up the value, as well as bitwise ORs the
+ * result with the mask shifted up by 16.
+ *
+ * This is useful for a common design of hardware registers where the upper
+ * 16-bit half of a 32-bit register is used as a write-enable mask. In such a
+ * register, a bit in the lower half is only updated if the corresponding bit
+ * in the upper half is high.
+ */
+#define FIELD_PREP_WM16(_mask, _val) \
+ ({ \
+ typeof(_val) __val = _val; \
+ typeof(_mask) __mask = _mask; \
+ __BF_FIELD_CHECK(__mask, ((u16)0U), __val, \
+ "HWORD_UPDATE: "); \
+ (((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) | \
+ ((__mask) << 16); \
+ })
+
+/**
+ * FIELD_PREP_WM16_CONST() - prepare a constant bitfield element with a mask in
+ * the upper half
+ * @_mask: shifted mask defining the field's length and position
+ * @_val: value to put in the field
+ *
+ * FIELD_PREP_WM16_CONST() masks and shifts up the value, as well as bitwise ORs
+ * the result with the mask shifted up by 16.
+ *
+ * This is useful for a common design of hardware registers where the upper
+ * 16-bit half of a 32-bit register is used as a write-enable mask. In such a
+ * register, a bit in the lower half is only updated if the corresponding bit
+ * in the upper half is high.
+ *
+ * Unlike FIELD_PREP_WM16(), this is a constant expression and can therefore
+ * be used in initializers. Error checking is less comfortable for this
+ * version.
+ */
+#define FIELD_PREP_WM16_CONST(_mask, _val) \
+ ( \
+ FIELD_PREP_CONST(_mask, _val) | \
+ (BUILD_BUG_ON_ZERO((u64)(_mask) > U16_MAX) + \
+ ((_mask) << 16)) \
+ )
+
+
+#endif /* _LINUX_HW_BITFIELD_H */
diff --git a/include/linux/string.h b/include/linux/string.h
index 850356d7c3f..986499dfc70 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -43,12 +43,8 @@ extern int strcmp(const char *,const char *);
#ifndef __HAVE_ARCH_STRNCMP
extern int strncmp(const char *,const char *,__kernel_size_t);
#endif
-#ifndef __HAVE_ARCH_STRCASECMP
int strcasecmp(const char *s1, const char *s2);
-#endif
-#ifndef __HAVE_ARCH_STRNCASECMP
-extern int strncasecmp(const char *s1, const char *s2, __kernel_size_t len);
-#endif
+int strncasecmp(const char *s1, const char *s2, __kernel_size_t len);
#ifndef __HAVE_ARCH_STRCHR
extern char * strchr(const char *,int);
#endif
@@ -63,7 +59,7 @@ extern char * strchr(const char *,int);
* @c: character to search for
* Return: position of @c in @s, or end of @s if not found
*/
-const char *strchrnul(const char *s, int c);
+char *strchrnul(const char *s, int c);
#ifndef __HAVE_ARCH_STRRCHR
extern char * strrchr(const char *,int);
@@ -75,6 +71,7 @@ extern char * strstr(const char *,const char *);
#ifndef __HAVE_ARCH_STRNSTR
extern char *strnstr(const char *, const char *, size_t);
#endif
+char *strcasestr(const char *, const char *);
#ifndef __HAVE_ARCH_STRLEN
extern __kernel_size_t strlen(const char *);
#endif
@@ -107,10 +104,6 @@ extern char * strndup(const char *, size_t);
extern const char *strdup_const(const char *s);
extern void kfree_const(const void *x);
-#ifndef __HAVE_ARCH_STRSWAB
-extern char * strswab(const char *);
-#endif
-
#ifndef __HAVE_ARCH_MEMSET
extern void * memset(void *,int,__kernel_size_t);
#endif