X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=include%2Fbitfield.h;h=579a69c856dac6affb982e2973a199dd1f31793a;hb=37db55b7e9dbbc25e4179ec5b7be8e286e47a44d;hp=ec4815c8e05179508c00cce24655acd7382ba62e;hpb=1ad6364eeb4f578e423081d1748e8a3fdf1ab01d;p=oweals%2Fu-boot.git

diff --git a/include/bitfield.h b/include/bitfield.h
index ec4815c8e0..579a69c856 100644
--- a/include/bitfield.h
+++ b/include/bitfield.h
@@ -1,7 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Copyright 2013 Broadcom Corporation.
- *
- * SPDX-License-Identifier:      GPL-2.0+
  */
 
 /*
@@ -27,6 +26,12 @@
  * old = bitfield_extract(old_reg_val, 10, 5);
  * new_reg_val = bitfield_replace(old_reg_val, 10, 5, new);
  *
+ * or
+ *
+ * mask = bitfield_mask(10, 5);
+ * old = bitfield_extract_by_mask(old_reg_val, mask);
+ * new_reg_val = bitfield_replace_by_mask(old_reg_val, mask, new);
+ *
  * The numbers 10 and 5 could for example come from data
  * tables which describe all bitfields in all registers.
  */
@@ -54,5 +59,31 @@ static inline uint bitfield_replace(uint reg_val, uint shift, uint width,
 {
 	uint mask = bitfield_mask(shift, width);
 
-	return (reg_val & ~mask) | (bitfield_val << shift);
+	return (reg_val & ~mask) | ((bitfield_val << shift) & mask);
+}
+
+/* Produces a shift of the bitfield given a mask */
+static inline uint bitfield_shift(uint mask)
+{
+	return mask ? ffs(mask) - 1 : 0;
+}
+
+/* Extract the value of a bitfield found within a given register value */
+static inline uint bitfield_extract_by_mask(uint reg_val, uint mask)
+{
+	uint shift = bitfield_shift(mask);
+
+	return (reg_val & mask) >> shift;
+}
+
+/*
+ * Replace the value of a bitfield found within a given register value
+ * Returns the newly modified uint value with the replaced field.
+ */
+static inline uint bitfield_replace_by_mask(uint reg_val, uint mask,
+					    uint bitfield_val)
+{
+	uint shift = bitfield_shift(mask);
+
+	return (reg_val & ~mask) | ((bitfield_val << shift) & mask);
 }