@@ -148,6 +148,96 @@ struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc,
}
EXPORT_SYMBOL_GPL(gpiochip_get_desc);
+/**
+ * bitmap_get_value - get a value of n-bits from the memory region
+ * @map: address to the bitmap memory region
+ * @start: bit offset of the n-bit value
+ * @nbits: size of value in bits (must be between 1 and BITS_PER_LONG inclusive).
+ *
+ * Returns value of nbits located at the @start bit offset within the @map
+ * memory region.
+ */
+unsigned long bitmap_get_value(const unsigned long *map,
+ unsigned long start,
+ unsigned long nbits)
+{
+ const size_t index = BIT_WORD(start);
+ const unsigned long offset = start % BITS_PER_LONG;
+ const unsigned long ceiling = round_up(start + 1, BITS_PER_LONG);
+ const unsigned long space = ceiling - start;
+ unsigned long value_low, value_high;
+
+ if (space >= nbits)
+ return (map[index] >> offset) & GENMASK(nbits - 1, 0);
+ else {
+ value_low = map[index] & BITMAP_FIRST_WORD_MASK(start);
+ value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits);
+ return (value_low >> offset) | (value_high << space);
+ }
+}
+EXPORT_SYMBOL_GPL(bitmap_get_value);
+
+/**
+ * bitmap_set_value - set value within a memory region
+ * @map: address to the bitmap memory region
+ * @nbits: size of map in bits
+ * @value: value of clump
+ * @value_width: size of value in bits (must be between 1 and BITS_PER_LONG inclusive)
+ * @start: bit offset of the value
+ */
+void bitmap_set_value(unsigned long *map, unsigned long nbits,
+ unsigned long value, unsigned long value_width,
+ unsigned long start)
+{
+ const unsigned long index = BIT_WORD(start);
+ const unsigned long length = BIT_WORD(nbits);
+ const unsigned long offset = start % BITS_PER_LONG;
+ const unsigned long ceiling = round_up(start + 1, BITS_PER_LONG);
+ const unsigned long space = ceiling - start;
+
+ value &= GENMASK(value_width - 1, 0);
+
+ if (space >= value_width) {
+ map[index] &= ~(GENMASK(value_width - 1, 0) << offset);
+ map[index] |= value << offset;
+ } else {
+ map[index + 0] &= ~BITMAP_FIRST_WORD_MASK(start);
+ map[index + 0] |= value << offset;
+
+ if (index + 1 >= length)
+ return;
+
+ map[index + 1] &= ~BITMAP_LAST_WORD_MASK(start + value_width);
+ map[index + 1] |= value >> space;
+ }
+}
+EXPORT_SYMBOL_GPL(bitmap_set_value);
+
+/**
+ * find_next_clump - find next clump with set bits in a memory region
+ * @clump: location to store copy of found clump
+ * @addr: address to base the search on
+ * @size: bitmap size in number of bits
+ * @offset: bit offset at which to start searching
+ * @clump_size: clump size in bits
+ *
+ * Returns the bit offset for the next set clump; the found clump value is
+ * copied to the location pointed by @clump. If no bits are set, returns @size.
+ */
+unsigned long find_next_clump(unsigned long *clump, const unsigned long *addr,
+ unsigned long size, unsigned long offset,
+ unsigned long clump_size)
+{
+ offset = find_next_bit(addr, size, offset);
+ if (offset == size)
+ return size;
+
+ offset = rounddown(offset, clump_size);
+ *clump = bitmap_get_value(addr, offset, clump_size);
+ return offset;
+}
+EXPORT_SYMBOL_GPL(find_next_clump);
+
/**
* desc_to_gpio - convert a GPIO descriptor to the integer namespace
* @desc: GPIO descriptor
@@ -141,6 +141,34 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce);
int gpiod_hog(struct gpio_desc *desc, const char *name,
unsigned long lflags, enum gpiod_flags dflags);
+unsigned long bitmap_get_value(const unsigned long *map,
+ unsigned long start,
+ unsigned long nbits);
+
+void bitmap_set_value(unsigned long *map, unsigned long nbits,
+ unsigned long value, unsigned long value_width,
+ unsigned long start);
+
+unsigned long find_next_clump(unsigned long *clump, const unsigned long *addr,
+ unsigned long size, unsigned long offset,
+ unsigned long clump_size);
+
+#define find_first_clump(clump, bits, size, clump_size) \
+ find_next_clump((clump), (bits), (size), 0, (clump_size))
+
+/**
+ * for_each_set_nbits - iterate over bitmap for each clump with set bits
+ * @start: bit offset to start search and to store the current iteration offset
+ * @clump: location to store copy of current 8-bit clump
+ * @bits: bitmap address to base the search on
+ * @size: bitmap size in number of bits
+ * @clump_size: clump size in bits
+ */
+#define for_each_set_nbits(start, clump, bits, size, clump_size) \
+ for ((start) = find_first_clump(&(clump), (bits), (size), (clump_size)); \
+ (start) < (size); \
+ (start) = find_next_clump(&(clump), (bits), (size), (start) + (clump_size), (clump_size)))
+
/*
* Return the GPIO number of the passed descriptor relative to its chip
*/