Merge patch series "Linux compat improvements and CCF prep"

Casey Connolly <[email protected]> says:

This series implements various improvements to Linux header
compatibility, largely in preparation for a full port of Linux CCF but
many of these changes would also be helpful when porting other drivers.

Beside the basic header/compat stuff there are a few larger patches:

Patch 1 adds the "%pOF" format specifier to vsprintf, this behaves the
same as it does in Linux printing the name of the ofnode, but notably it
expects an ofnode pointer rather than a device_node.

Patch 2 adds an option to skip doing a full DM scan pre-relocation.
Some platforms like Qualcomm don't actually need devices to be probed
prior to relocation, it is also quite slow to scan the entire FDT before
caches are up. This option gets us to main loop 30-50% faster.

Unfortunately it isn't possible to totally skip DM since U-Boot will
panic if it can't find a serial port, but the serial uclass code will
bind the serial port itself by reading /chosen/stdout-path, however any
dependencies like clocks won't be found so this should only be enabled
if the serial driver gracefully handles missing clocks.

Patch 3 adds [k]strdup_const(), this works the same as the Linux version
saving a small amount of memory by avoiding duplicating strings stored
in .rodata, this is particularly useful for CCF.

Patch 4 adds 64-bit versions of some 32-bit ofnode utilities functions,
making it possible to parse 64-bit arrays.

Patch 6 provides a simple implementation of kref, this will be used
by CCF.

Patch 9 adds devm_krealloc() support to devres, it relies on storing
allocation sizes in the devres struct which will add a small overhead.

Link: https://lore.kernel.org/r/[email protected]

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/math64.h b/include/linux/math64.h
index eaa9fd5b968..70a7ee3ff1d 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -257,4 +257,23 @@ static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
 }
 #endif /* mul_u64_u32_div */
 
+/**
+ * abs_diff - return absolute value of the difference between the arguments
+ * @a: the first argument
+ * @b: the second argument
+ *
+ * @a and @b have to be of the same type. With this restriction we compare
+ * signed to signed and unsigned to unsigned. The result is the subtraction
+ * the smaller of the two from the bigger, hence result is always a positive
+ * value.
+ *
+ * Return: an absolute value of the difference between the @a and @b.
+ */
+#define abs_diff(a, b) ({			\
+	typeof(a) __a = (a);			\
+	typeof(b) __b = (b);			\
+	(void)(&__a == &__b);			\
+	__a > __b ? (__a - __b) : (__b - __a);	\
+})
+
 #endif /* _LINUX_MATH64_H */