[PATCH v7 0/8] Introduce the for_each_set_clump8 macro

[PATCH v7 0/8] Introduce the for_each_set_clump8 macro

[William Breathitt Gray]

Changes in v7:
  - Pass bitmap_set_value8 'value' parameter by value
  - Remove bitmap_set_value8 final mask operation; users beware: values
    greater than 8 bits may clobber bitmap

While adding GPIO get_multiple/set_multiple callback support for various
drivers, I noticed a pattern of looping manifesting that would be useful
standardized as a macro.

This patchset introduces the for_each_set_clump8 macro and utilizes it
in several GPIO drivers. The for_each_set_clump macro8 facilitates a
for-loop syntax that iterates over a memory region entire groups of set
bits at a time.

For example, suppose you would like to iterate over a 32-bit integer 8
bits at a time, skipping over 8-bit groups with no set bit, where
XXXXXXXX represents the current 8-bit group:

    Example:        10111110 00000000 11111111 00110011
    First loop:     10111110 00000000 11111111 XXXXXXXX
    Second loop:    10111110 00000000 XXXXXXXX 00110011
    Third loop:     XXXXXXXX 00000000 11111111 00110011

Each iteration of the loop returns the next 8-bit group that has at
least one set bit.

The for_each_set_clump8 macro has four parameters:

    * start: set to the bit offset of the current clump
    * clump: set to the current clump value
    * bits: bitmap to search within
    * size: bitmap size in number of bits

In this version of the patchset, the for_each_set_clump macro has been
reimplemented and simplified based on the suggestions provided by Rasmus
Villemoes and Andy Shevchenko in the version 4 submission.

In particular, the function of the for_each_set_clump macro has been
restricted to handle only 8-bit clumps; the drivers that use the
for_each_set_clump macro only handle 8-bit ports so a generic
for_each_set_clump implementation is not necessary. Thus, a solution for
odd-sized clumps (e.g. 3-bit, 7-bit, etc.) mismatching word boundaries
can be postponed until a driver appears that actually requires a generic
for_each_set_clump implementation.

In addition, the bitmap_get_value8 and bitmap_set_value8 functions are
introduced to get and set 8-bit values respectively. Their use is based
on the behavior suggested in the patchset version 4 review. Similarly,
the implementation of the find_next_clump function has been simplified
in order for the function to match the syntax and use of the
find_next_bit function.

William Breathitt Gray (8):
  bitops: Introduce the for_each_set_clump8 macro
  lib/test_bitmap.c: Add for_each_set_clump8 test cases
  gpio: 104-dio-48e: Utilize for_each_set_clump8 macro
  gpio: 104-idi-48: Utilize for_each_set_clump8 macro
  gpio: gpio-mm: Utilize for_each_set_clump8 macro
  gpio: ws16c48: Utilize for_each_set_clump8 macro
  gpio: pci-idio-16: Utilize for_each_set_clump8 macro
  gpio: pcie-idio-24: Utilize for_each_set_clump8 macro

 drivers/gpio/gpio-104-dio-48e.c   |  71 ++++++-------------
 drivers/gpio/gpio-104-idi-48.c    |  36 ++--------
 drivers/gpio/gpio-gpio-mm.c       |  71 ++++++-------------
 drivers/gpio/gpio-pci-idio-16.c   |  73 +++++++-------------
 drivers/gpio/gpio-pcie-idio-24.c  | 109 +++++++++++-------------------
 drivers/gpio/gpio-ws16c48.c       |  71 ++++++-------------
 include/asm-generic/bitops/find.h |  14 ++++
 include/linux/bitops.h            |   5 ++
 lib/find_bit.c                    |  63 +++++++++++++++++
 lib/test_bitmap.c                 |  65 ++++++++++++++++++
 10 files changed, 279 insertions(+), 299 deletions(-)

-- 
2.20.1

[PATCH v7 1/8] bitops: Introduce the for_each_set_clump8 macro

[William Breathitt Gray]

This macro iterates for each 8-bit group of bits (clump) with set bits,
within a bitmap memory region. For each iteration, "start" is set to the
bit offset of the found clump, while the respective clump value is
stored to the location pointed by "clump". Additionally, the
bitmap_get_value8 and bitmap_set_value8 functions are introduced to
respectively get and set an 8-bit value in a bitmap memory region.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 include/asm-generic/bitops/find.h | 14 +++++++
 include/linux/bitops.h            |  5 +++
 lib/find_bit.c                    | 63 +++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+)

diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h
index 8a1ee10014de..61c496ae94cf 100644
--- a/include/asm-generic/bitops/find.h
+++ b/include/asm-generic/bitops/find.h
@@ -80,4 +80,18 @@ extern unsigned long find_first_zero_bit(const unsigned long *addr,
 
 #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
 
+unsigned int bitmap_get_value8(const unsigned long *const bitmap,
+			       const unsigned int start);
+
+void bitmap_set_value8(unsigned long *const bitmap,
+		       const unsigned long value,
+		       const unsigned int start);
+
+unsigned int find_next_clump8(unsigned long *const clump,
+			      const unsigned long *const addr,
+			      unsigned int offset, const unsigned int size);
+
+#define find_first_clump8(clump, bits, size) \
+	find_next_clump8((clump), (bits), 0, (size))
+
 #endif /*_ASM_GENERIC_BITOPS_FIND_H_ */
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 705f7c442691..61c10f20079e 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -40,6 +40,11 @@ extern unsigned long __sw_hweight64(__u64 w);
 	     (bit) < (size);					\
 	     (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
 
+#define for_each_set_clump8(start, clump, bits, size) \
+	for ((start) = find_first_clump8(&(clump), (bits), (size)); \
+	     (start) < (size); \
+	     (start) = find_next_clump8(&(clump), (bits), (start) + 8, (size)))
+
 static inline int get_bitmask_order(unsigned int count)
 {
 	int order;
diff --git a/lib/find_bit.c b/lib/find_bit.c
index ee3df93ba69a..97d96e65a3d9 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -218,3 +218,66 @@ EXPORT_SYMBOL(find_next_bit_le);
 #endif
 
 #endif /* __BIG_ENDIAN */
+
+/**
+ * bitmap_get_value8 - get an 8-bit value within a memory region
+ * @bitmap: address to the bitmap memory region
+ * @start: bit offset of the 8-bit value
+ *
+ * Returns the 8-bit value located at the @start bit offset within the @bitmap
+ * memory region.
+ */
+unsigned int bitmap_get_value8(const unsigned long *const bitmap,
+			       const unsigned int start)
+{
+	const size_t index = BIT_WORD(start);
+	const unsigned int offset = start % BITS_PER_LONG;
+
+	return (bitmap[index] >> offset) & 0xFF;
+}
+EXPORT_SYMBOL(bitmap_get_value8);
+
+/**
+ * bitmap_set_value8 - set an 8-bit value within a memory region
+ * @bitmap: address to the bitmap memory region
+ * @value: the 8-bit value
+ * @start: bit offset of the 8-bit value
+ */
+void bitmap_set_value8(unsigned long *const bitmap,
+		       const unsigned long value,
+		       const unsigned int start)
+{
+	const size_t index = BIT_WORD(start);
+	const unsigned int offset = start % BITS_PER_LONG;
+	const unsigned long mask = GENMASK(7, offset);
+
+	bitmap[index] &= ~mask;
+	bitmap[index] |= value << offset;
+}
+EXPORT_SYMBOL(bitmap_set_value8);
+
+/**
+ * find_next_clump8 - find next 8-bit clump with set bits in a memory region
+ * @clump: location to store copy of found clump
+ * @addr: address to base the search on
+ * @offset: bit offset at which to start searching
+ * @size: bitmap size in number of 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 int find_next_clump8(unsigned long *const clump,
+			      const unsigned long *const addr,
+			      unsigned int offset, const unsigned int size)
+{
+	for (; offset < size; offset += 8) {
+		*clump = bitmap_get_value8(addr, offset);
+		if (!*clump)
+			continue;
+
+		return offset;
+	}
+
+	return size;
+}
+EXPORT_SYMBOL(find_next_clump8);
-- 
2.20.1

[PATCH v7 2/8] lib/test_bitmap.c: Add for_each_set_clump8 test cases

[William Breathitt Gray]

The introduction of the for_each_set_clump8 macro warrants test cases to
verify the implementation. This patch adds test case checks for whether
an out-of-bounds clump index is returned, a zero clump is returned, or
the returned clump value differs from the expected clump value.

Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 lib/test_bitmap.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 6cd7d0740005..66ddb3fb98cb 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -88,6 +88,36 @@ __check_eq_u32_array(const char *srcfile, unsigned int line,
 	return true;
 }
 
+static bool __init __check_eq_clump8(const char *srcfile, unsigned int line,
+				    const unsigned int offset,
+				    const unsigned int size,
+				    const unsigned char *const clump_exp,
+				    const unsigned long *const clump)
+{
+	unsigned long exp;
+
+	if (offset >= size) {
+		pr_warn("[%s:%u] bit offset for clump out-of-bounds: expected less than %u, got %u\n",
+			srcfile, line, size, offset);
+		return false;
+	}
+
+	exp = clump_exp[offset / 8];
+	if (!exp) {
+		pr_warn("[%s:%u] bit offset for zero clump: expected nonzero clump, got bit offset %u with clump value 0",
+			srcfile, line, offset);
+		return false;
+	}
+
+	if (*clump != exp) {
+		pr_warn("[%s:%u] expected clump value of 0x%lX, got clump value of 0x%lX",
+			srcfile, line, exp, *clump);
+		return false;
+	}
+
+	return true;
+}
+
 #define __expect_eq(suffix, ...)					\
 	({								\
 		int result = 0;						\
@@ -104,6 +134,7 @@ __check_eq_u32_array(const char *srcfile, unsigned int line,
 #define expect_eq_bitmap(...)		__expect_eq(bitmap, ##__VA_ARGS__)
 #define expect_eq_pbl(...)		__expect_eq(pbl, ##__VA_ARGS__)
 #define expect_eq_u32_array(...)	__expect_eq(u32_array, ##__VA_ARGS__)
+#define expect_eq_clump8(...)		__expect_eq(clump8, ##__VA_ARGS__)
 
 static void __init test_zero_clear(void)
 {
@@ -361,6 +392,39 @@ static void noinline __init test_mem_optimisations(void)
 	}
 }
 
+static const unsigned char clump_exp[] __initconst = {
+	0x01,	/* 1 bit set */
+	0x02,	/* non-edge 1 bit set */
+	0x00,	/* zero bits set */
+	0x28,	/* 3 bits set across 4-bit boundary */
+	0x28,	/* Repeated clump */
+	0x0F,	/* 4 bits set */
+	0xFF,	/* all bits set */
+	0x05,	/* non-adjacent 2 bits set */
+};
+
+static void __init test_for_each_set_clump8(void)
+{
+#define CLUMP_EXP_NUMBITS 64
+	DECLARE_BITMAP(bits, CLUMP_EXP_NUMBITS);
+	unsigned int start;
+	unsigned long clump;
+
+	/* set bitmap to test case */
+	bitmap_zero(bits, CLUMP_EXP_NUMBITS);
+	bitmap_set(bits, 0, 1);		/* 0x01 */
+	bitmap_set(bits, 8, 1);		/* 0x02 */
+	bitmap_set(bits, 27, 3);	/* 0x28 */
+	bitmap_set(bits, 35, 3);	/* 0x28 */
+	bitmap_set(bits, 40, 4);	/* 0x0F */
+	bitmap_set(bits, 48, 8);	/* 0xFF */
+	bitmap_set(bits, 56, 1);	/* 0x05 - part 1 */
+	bitmap_set(bits, 58, 1);	/* 0x05 - part 2 */
+
+	for_each_set_clump8(start, clump, bits, CLUMP_EXP_NUMBITS)
+		expect_eq_clump8(start, CLUMP_EXP_NUMBITS, clump_exp, &clump);
+}
+
 static int __init test_bitmap_init(void)
 {
 	test_zero_clear();
@@ -369,6 +433,7 @@ static int __init test_bitmap_init(void)
 	test_bitmap_arr32();
 	test_bitmap_parselist();
 	test_mem_optimisations();
+	test_for_each_set_clump8();
 
 	if (failed_tests == 0)
 		pr_info("all %u tests passed\n", total_tests);
-- 
2.20.1

[PATCH v7 3/8] gpio: 104-dio-48e: Utilize for_each_set_clump8 macro

[William Breathitt Gray]

Replace verbose implementation in get_multiple/set_multiple callbacks
with for_each_set_clump8 macro to simplify code and improve clarity.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-104-dio-48e.c | 71 ++++++++++-----------------------
 1 file changed, 20 insertions(+), 51 deletions(-)

diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c
index 92c8f944bf64..1093a1403d77 100644
--- a/drivers/gpio/gpio-104-dio-48e.c
+++ b/drivers/gpio/gpio-104-dio-48e.c
@@ -183,46 +183,25 @@ static int dio48e_gpio_get(struct gpio_chip *chip, unsigned offset)
 	return !!(port_state & mask);
 }
 
+static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
+
 static int dio48e_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
 	unsigned long *bits)
 {
 	struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
-	size_t i;
-	static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
-	const unsigned int gpio_reg_size = 8;
-	unsigned int bits_offset;
-	size_t word_index;
-	unsigned int word_offset;
-	unsigned long word_mask;
-	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
+	unsigned int offset;
+	unsigned long gpio_mask;
+	unsigned int port_addr;
 	unsigned long port_state;
 
 	/* clear bits array to a clean slate */
 	bitmap_zero(bits, chip->ngpio);
 
-	/* get bits are evaluated a gpio port register at a time */
-	for (i = 0; i < ARRAY_SIZE(ports); i++) {
-		/* gpio offset in bits array */
-		bits_offset = i * gpio_reg_size;
-
-		/* word index for bits array */
-		word_index = BIT_WORD(bits_offset);
-
-		/* gpio offset within current word of bits array */
-		word_offset = bits_offset % BITS_PER_LONG;
-
-		/* mask of get bits for current gpio within current word */
-		word_mask = mask[word_index] & (port_mask << word_offset);
-		if (!word_mask) {
-			/* no get bits in this port so skip to next one */
-			continue;
-		}
-
-		/* read bits from current gpio port */
-		port_state = inb(dio48egpio->base + ports[i]);
+	for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
+		port_addr = dio48egpio->base + ports[offset / 8];
+		port_state = inb(port_addr) & gpio_mask;
 
-		/* store acquired bits at respective bits array offset */
-		bits[word_index] |= (port_state << word_offset) & word_mask;
+		bitmap_set_value8(bits, port_state, offset);
 	}
 
 	return 0;
@@ -252,37 +231,27 @@ static void dio48e_gpio_set_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
-	unsigned int i;
-	const unsigned int gpio_reg_size = 8;
-	unsigned int port;
-	unsigned int out_port;
+	unsigned int offset;
+	unsigned long gpio_mask;
+	size_t index;
+	unsigned int port_addr;
 	unsigned int bitmask;
 	unsigned long flags;
 
-	/* set bits are evaluated a gpio register size at a time */
-	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
-		/* no more set bits in this mask word; skip to the next word */
-		if (!mask[BIT_WORD(i)]) {
-			i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
-			continue;
-		}
+	for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
+		index = offset / 8;
+		port_addr = dio48egpio->base + ports[index];
 
-		port = i / gpio_reg_size;
-		out_port = (port > 2) ? port + 1 : port;
-		bitmask = mask[BIT_WORD(i)] & bits[BIT_WORD(i)];
+		bitmask = bitmap_get_value8(bits, offset) & gpio_mask;
 
 		raw_spin_lock_irqsave(&dio48egpio->lock, flags);
 
 		/* update output state data and set device gpio register */
-		dio48egpio->out_state[port] &= ~mask[BIT_WORD(i)];
-		dio48egpio->out_state[port] |= bitmask;
-		outb(dio48egpio->out_state[port], dio48egpio->base + out_port);
+		dio48egpio->out_state[index] &= ~gpio_mask;
+		dio48egpio->out_state[index] |= bitmask;
+		outb(dio48egpio->out_state[index], port_addr);
 
 		raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);
-
-		/* prepare for next gpio register set */
-		mask[BIT_WORD(i)] >>= gpio_reg_size;
-		bits[BIT_WORD(i)] >>= gpio_reg_size;
 	}
 }
 
-- 
2.20.1

[PATCH v7 4/8] gpio: 104-idi-48: Utilize for_each_set_clump8 macro

[William Breathitt Gray]

Replace verbose implementation in get_multiple/set_multiple callbacks
with for_each_set_clump8 macro to simplify code and improve clarity.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-104-idi-48.c | 36 +++++++---------------------------
 1 file changed, 7 insertions(+), 29 deletions(-)

diff --git a/drivers/gpio/gpio-104-idi-48.c b/drivers/gpio/gpio-104-idi-48.c
index 88dc6f2449f6..d58382958bd5 100644
--- a/drivers/gpio/gpio-104-idi-48.c
+++ b/drivers/gpio/gpio-104-idi-48.c
@@ -93,42 +93,20 @@ static int idi_48_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
 	unsigned long *bits)
 {
 	struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
-	size_t i;
+	unsigned int offset;
+	unsigned long gpio_mask;
 	static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
-	const unsigned int gpio_reg_size = 8;
-	unsigned int bits_offset;
-	size_t word_index;
-	unsigned int word_offset;
-	unsigned long word_mask;
-	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
+	unsigned int port_addr;
 	unsigned long port_state;
 
 	/* clear bits array to a clean slate */
 	bitmap_zero(bits, chip->ngpio);
 
-	/* get bits are evaluated a gpio port register at a time */
-	for (i = 0; i < ARRAY_SIZE(ports); i++) {
-		/* gpio offset in bits array */
-		bits_offset = i * gpio_reg_size;
+	for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
+		port_addr = idi48gpio->base + ports[offset / 8];
+		port_state = inb(port_addr) & gpio_mask;
 
-		/* word index for bits array */
-		word_index = BIT_WORD(bits_offset);
-
-		/* gpio offset within current word of bits array */
-		word_offset = bits_offset % BITS_PER_LONG;
-
-		/* mask of get bits for current gpio within current word */
-		word_mask = mask[word_index] & (port_mask << word_offset);
-		if (!word_mask) {
-			/* no get bits in this port so skip to next one */
-			continue;
-		}
-
-		/* read bits from current gpio port */
-		port_state = inb(idi48gpio->base + ports[i]);
-
-		/* store acquired bits at respective bits array offset */
-		bits[word_index] |= (port_state << word_offset) & word_mask;
+		bitmap_set_value8(bits, port_state, offset);
 	}
 
 	return 0;
-- 
2.20.1

[PATCH v7 5/8] gpio: gpio-mm: Utilize for_each_set_clump8 macro

[William Breathitt Gray]

Replace verbose implementation in get_multiple/set_multiple callbacks
with for_each_set_clump8 macro to simplify code and improve clarity.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-gpio-mm.c | 71 +++++++++++--------------------------
 1 file changed, 20 insertions(+), 51 deletions(-)

diff --git a/drivers/gpio/gpio-gpio-mm.c b/drivers/gpio/gpio-gpio-mm.c
index 8c150fd68d9d..ad80f874e004 100644
--- a/drivers/gpio/gpio-gpio-mm.c
+++ b/drivers/gpio/gpio-gpio-mm.c
@@ -172,46 +172,25 @@ static int gpiomm_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	return !!(port_state & mask);
 }
 
+static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
+
 static int gpiomm_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
 	unsigned long *bits)
 {
 	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
-	size_t i;
-	static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
-	const unsigned int gpio_reg_size = 8;
-	unsigned int bits_offset;
-	size_t word_index;
-	unsigned int word_offset;
-	unsigned long word_mask;
-	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
+	unsigned int offset;
+	unsigned long gpio_mask;
+	unsigned int port_addr;
 	unsigned long port_state;
 
 	/* clear bits array to a clean slate */
 	bitmap_zero(bits, chip->ngpio);
 
-	/* get bits are evaluated a gpio port register at a time */
-	for (i = 0; i < ARRAY_SIZE(ports); i++) {
-		/* gpio offset in bits array */
-		bits_offset = i * gpio_reg_size;
-
-		/* word index for bits array */
-		word_index = BIT_WORD(bits_offset);
-
-		/* gpio offset within current word of bits array */
-		word_offset = bits_offset % BITS_PER_LONG;
-
-		/* mask of get bits for current gpio within current word */
-		word_mask = mask[word_index] & (port_mask << word_offset);
-		if (!word_mask) {
-			/* no get bits in this port so skip to next one */
-			continue;
-		}
-
-		/* read bits from current gpio port */
-		port_state = inb(gpiommgpio->base + ports[i]);
+	for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
+		port_addr = gpiommgpio->base + ports[offset / 8];
+		port_state = inb(port_addr) & gpio_mask;
 
-		/* store acquired bits at respective bits array offset */
-		bits[word_index] |= (port_state << word_offset) & word_mask;
+		bitmap_set_value8(bits, port_state, offset);
 	}
 
 	return 0;
@@ -242,37 +221,27 @@ static void gpiomm_gpio_set_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
-	unsigned int i;
-	const unsigned int gpio_reg_size = 8;
-	unsigned int port;
-	unsigned int out_port;
+	unsigned int offset;
+	unsigned long gpio_mask;
+	size_t index;
+	unsigned int port_addr;
 	unsigned int bitmask;
 	unsigned long flags;
 
-	/* set bits are evaluated a gpio register size at a time */
-	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
-		/* no more set bits in this mask word; skip to the next word */
-		if (!mask[BIT_WORD(i)]) {
-			i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
-			continue;
-		}
+	for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
+		index = offset / 8;
+		port_addr = gpiommgpio->base + ports[index];
 
-		port = i / gpio_reg_size;
-		out_port = (port > 2) ? port + 1 : port;
-		bitmask = mask[BIT_WORD(i)] & bits[BIT_WORD(i)];
+		bitmask = bitmap_get_value8(bits, offset) & gpio_mask;
 
 		spin_lock_irqsave(&gpiommgpio->lock, flags);
 
 		/* update output state data and set device gpio register */
-		gpiommgpio->out_state[port] &= ~mask[BIT_WORD(i)];
-		gpiommgpio->out_state[port] |= bitmask;
-		outb(gpiommgpio->out_state[port], gpiommgpio->base + out_port);
+		gpiommgpio->out_state[index] &= ~gpio_mask;
+		gpiommgpio->out_state[index] |= bitmask;
+		outb(gpiommgpio->out_state[index], port_addr);
 
 		spin_unlock_irqrestore(&gpiommgpio->lock, flags);
-
-		/* prepare for next gpio register set */
-		mask[BIT_WORD(i)] >>= gpio_reg_size;
-		bits[BIT_WORD(i)] >>= gpio_reg_size;
 	}
 }
 
-- 
2.20.1

[PATCH v7 6/8] gpio: ws16c48: Utilize for_each_set_clump8 macro

[William Breathitt Gray]

Replace verbose implementation in get_multiple/set_multiple callbacks
with for_each_set_clump8 macro to simplify code and improve clarity.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-ws16c48.c | 71 ++++++++++---------------------------
 1 file changed, 19 insertions(+), 52 deletions(-)

diff --git a/drivers/gpio/gpio-ws16c48.c b/drivers/gpio/gpio-ws16c48.c
index 5cf3697bfb15..48cb9aa740b5 100644
--- a/drivers/gpio/gpio-ws16c48.c
+++ b/drivers/gpio/gpio-ws16c48.c
@@ -134,42 +134,19 @@ static int ws16c48_gpio_get_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
-	const unsigned int gpio_reg_size = 8;
-	size_t i;
-	const size_t num_ports = chip->ngpio / gpio_reg_size;
-	unsigned int bits_offset;
-	size_t word_index;
-	unsigned int word_offset;
-	unsigned long word_mask;
-	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
+	unsigned int offset;
+	unsigned long gpio_mask;
+	unsigned int port_addr;
 	unsigned long port_state;
 
 	/* clear bits array to a clean slate */
 	bitmap_zero(bits, chip->ngpio);
 
-	/* get bits are evaluated a gpio port register at a time */
-	for (i = 0; i < num_ports; i++) {
-		/* gpio offset in bits array */
-		bits_offset = i * gpio_reg_size;
+	for_each_set_clump8(offset, gpio_mask, mask, chip->ngpio) {
+		port_addr = ws16c48gpio->base + offset / 8;
+		port_state = inb(port_addr) & gpio_mask;
 
-		/* word index for bits array */
-		word_index = BIT_WORD(bits_offset);
-
-		/* gpio offset within current word of bits array */
-		word_offset = bits_offset % BITS_PER_LONG;
-
-		/* mask of get bits for current gpio within current word */
-		word_mask = mask[word_index] & (port_mask << word_offset);
-		if (!word_mask) {
-			/* no get bits in this port so skip to next one */
-			continue;
-		}
-
-		/* read bits from current gpio port */
-		port_state = inb(ws16c48gpio->base + i);
-
-		/* store acquired bits at respective bits array offset */
-		bits[word_index] |= (port_state << word_offset) & word_mask;
+		bitmap_set_value8(bits, port_state, offset);
 	}
 
 	return 0;
@@ -203,39 +180,29 @@ static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
-	unsigned int i;
-	const unsigned int gpio_reg_size = 8;
-	unsigned int port;
-	unsigned int iomask;
+	unsigned int offset;
+	unsigned long gpio_mask;
+	size_t index;
+	unsigned int port_addr;
 	unsigned int bitmask;
 	unsigned long flags;
 
-	/* set bits are evaluated a gpio register size at a time */
-	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
-		/* no more set bits in this mask word; skip to the next word */
-		if (!mask[BIT_WORD(i)]) {
-			i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
-			continue;
-		}
-
-		port = i / gpio_reg_size;
+	for_each_set_clump8(offset, gpio_mask, mask, chip->ngpio) {
+		index = offset / 8;
+		port_addr = ws16c48gpio->base + index;
 
 		/* mask out GPIO configured for input */
-		iomask = mask[BIT_WORD(i)] & ~ws16c48gpio->io_state[port];
-		bitmask = iomask & bits[BIT_WORD(i)];
+		gpio_mask &= ~ws16c48gpio->io_state[index];
+		bitmask = bitmap_get_value8(bits, offset) & gpio_mask;
 
 		raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
 
 		/* update output state data and set device gpio register */
-		ws16c48gpio->out_state[port] &= ~iomask;
-		ws16c48gpio->out_state[port] |= bitmask;
-		outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
+		ws16c48gpio->out_state[index] &= ~gpio_mask;
+		ws16c48gpio->out_state[index] |= bitmask;
+		outb(ws16c48gpio->out_state[index], port_addr);
 
 		raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
-
-		/* prepare for next gpio register set */
-		mask[BIT_WORD(i)] >>= gpio_reg_size;
-		bits[BIT_WORD(i)] >>= gpio_reg_size;
 	}
 }
 
-- 
2.20.1

[PATCH v7 7/8] gpio: pci-idio-16: Utilize for_each_set_clump8 macro

[William Breathitt Gray]

Replace verbose implementation in get_multiple/set_multiple callbacks
with for_each_set_clump8 macro to simplify code and improve clarity.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-pci-idio-16.c | 73 ++++++++++++---------------------
 1 file changed, 26 insertions(+), 47 deletions(-)

diff --git a/drivers/gpio/gpio-pci-idio-16.c b/drivers/gpio/gpio-pci-idio-16.c
index 6b7349783223..f115b923ae98 100644
--- a/drivers/gpio/gpio-pci-idio-16.c
+++ b/drivers/gpio/gpio-pci-idio-16.c
@@ -108,45 +108,23 @@ static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
-	size_t i;
-	const unsigned int gpio_reg_size = 8;
-	unsigned int bits_offset;
-	size_t word_index;
-	unsigned int word_offset;
-	unsigned long word_mask;
-	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
-	unsigned long port_state;
+	unsigned int offset;
+	unsigned long gpio_mask;
 	void __iomem *ports[] = {
 		&idio16gpio->reg->out0_7, &idio16gpio->reg->out8_15,
 		&idio16gpio->reg->in0_7, &idio16gpio->reg->in8_15,
 	};
+	void __iomem *port_addr;
+	unsigned long port_state;
 
 	/* clear bits array to a clean slate */
 	bitmap_zero(bits, chip->ngpio);
 
-	/* get bits are evaluated a gpio port register at a time */
-	for (i = 0; i < ARRAY_SIZE(ports); i++) {
-		/* gpio offset in bits array */
-		bits_offset = i * gpio_reg_size;
-
-		/* word index for bits array */
-		word_index = BIT_WORD(bits_offset);
-
-		/* gpio offset within current word of bits array */
-		word_offset = bits_offset % BITS_PER_LONG;
+	for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
+		port_addr = ports[offset / 8];
+		port_state = ioread8(port_addr) & gpio_mask;
 
-		/* mask of get bits for current gpio within current word */
-		word_mask = mask[word_index] & (port_mask << word_offset);
-		if (!word_mask) {
-			/* no get bits in this port so skip to next one */
-			continue;
-		}
-
-		/* read bits from current gpio port */
-		port_state = ioread8(ports[i]);
-
-		/* store acquired bits at respective bits array offset */
-		bits[word_index] |= (port_state << word_offset) & word_mask;
+		bitmap_set_value8(bits, port_state, offset);
 	}
 
 	return 0;
@@ -186,30 +164,31 @@ static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
+	unsigned int offset;
+	unsigned long gpio_mask;
+	void __iomem *ports[] = {
+		&idio16gpio->reg->out0_7, &idio16gpio->reg->out8_15,
+	};
+	size_t index;
+	void __iomem *port_addr;
+	unsigned int bitmask;
 	unsigned long flags;
 	unsigned int out_state;
 
-	raw_spin_lock_irqsave(&idio16gpio->lock, flags);
+	for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
+		index = offset / 8;
+		port_addr = ports[index];
 
-	/* process output lines 0-7 */
-	if (*mask & 0xFF) {
-		out_state = ioread8(&idio16gpio->reg->out0_7) & ~*mask;
-		out_state |= *mask & *bits;
-		iowrite8(out_state, &idio16gpio->reg->out0_7);
-	}
+		bitmask = bitmap_get_value8(bits, offset) & gpio_mask;
+
+		raw_spin_lock_irqsave(&idio16gpio->lock, flags);
 
-	/* shift to next output line word */
-	*mask >>= 8;
+		out_state = ioread8(port_addr) & ~gpio_mask;
+		out_state |= bitmask;
+		iowrite8(out_state, port_addr);
 
-	/* process output lines 8-15 */
-	if (*mask & 0xFF) {
-		*bits >>= 8;
-		out_state = ioread8(&idio16gpio->reg->out8_15) & ~*mask;
-		out_state |= *mask & *bits;
-		iowrite8(out_state, &idio16gpio->reg->out8_15);
+		raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
 	}
-
-	raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
 }
 
 static void idio_16_irq_ack(struct irq_data *data)
-- 
2.20.1

[PATCH v7 8/8] gpio: pcie-idio-24: Utilize for_each_set_clump8 macro

[William Breathitt Gray]

Replace verbose implementation in get_multiple/set_multiple callbacks
with for_each_set_clump8 macro to simplify code and improve clarity.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
---
 drivers/gpio/gpio-pcie-idio-24.c | 109 ++++++++++++-------------------
 1 file changed, 40 insertions(+), 69 deletions(-)

diff --git a/drivers/gpio/gpio-pcie-idio-24.c b/drivers/gpio/gpio-pcie-idio-24.c
index 52f1647a46fd..1cfe39fb8e9e 100644
--- a/drivers/gpio/gpio-pcie-idio-24.c
+++ b/drivers/gpio/gpio-pcie-idio-24.c
@@ -198,52 +198,34 @@ static int idio_24_gpio_get_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct idio_24_gpio *const idio24gpio = gpiochip_get_data(chip);
-	size_t i;
-	const unsigned int gpio_reg_size = 8;
-	unsigned int bits_offset;
-	size_t word_index;
-	unsigned int word_offset;
-	unsigned long word_mask;
-	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
-	unsigned long port_state;
+	unsigned int offset;
+	unsigned long gpio_mask;
 	void __iomem *ports[] = {
 		&idio24gpio->reg->out0_7, &idio24gpio->reg->out8_15,
 		&idio24gpio->reg->out16_23, &idio24gpio->reg->in0_7,
 		&idio24gpio->reg->in8_15, &idio24gpio->reg->in16_23,
 	};
+	size_t index;
+	unsigned long port_state;
 	const unsigned long out_mode_mask = BIT(1);
 
 	/* clear bits array to a clean slate */
 	bitmap_zero(bits, chip->ngpio);
 
-	/* get bits are evaluated a gpio port register at a time */
-	for (i = 0; i < ARRAY_SIZE(ports) + 1; i++) {
-		/* gpio offset in bits array */
-		bits_offset = i * gpio_reg_size;
-
-		/* word index for bits array */
-		word_index = BIT_WORD(bits_offset);
-
-		/* gpio offset within current word of bits array */
-		word_offset = bits_offset % BITS_PER_LONG;
-
-		/* mask of get bits for current gpio within current word */
-		word_mask = mask[word_index] & (port_mask << word_offset);
-		if (!word_mask) {
-			/* no get bits in this port so skip to next one */
-			continue;
-		}
+	for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
+		index = offset / 8;
 
 		/* read bits from current gpio port (port 6 is TTL GPIO) */
-		if (i < 6)
-			port_state = ioread8(ports[i]);
+		if (index < 6)
+			port_state = ioread8(ports[index]);
 		else if (ioread8(&idio24gpio->reg->ctl) & out_mode_mask)
 			port_state = ioread8(&idio24gpio->reg->ttl_out0_7);
 		else
 			port_state = ioread8(&idio24gpio->reg->ttl_in0_7);
 
-		/* store acquired bits at respective bits array offset */
-		bits[word_index] |= (port_state << word_offset) & word_mask;
+		port_state &= gpio_mask;
+
+		bitmap_set_value8(bits, port_state, offset);
 	}
 
 	return 0;
@@ -294,59 +276,48 @@ static void idio_24_gpio_set_multiple(struct gpio_chip *chip,
 	unsigned long *mask, unsigned long *bits)
 {
 	struct idio_24_gpio *const idio24gpio = gpiochip_get_data(chip);
-	size_t i;
-	unsigned long bits_offset;
+	unsigned int offset;
 	unsigned long gpio_mask;
-	const unsigned int gpio_reg_size = 8;
-	const unsigned long port_mask = GENMASK(gpio_reg_size, 0);
-	unsigned long flags;
-	unsigned int out_state;
 	void __iomem *ports[] = {
 		&idio24gpio->reg->out0_7, &idio24gpio->reg->out8_15,
 		&idio24gpio->reg->out16_23
 	};
+	size_t index;
+	unsigned int bitmask;
+	unsigned long flags;
+	unsigned int out_state;
 	const unsigned long out_mode_mask = BIT(1);
-	const unsigned int ttl_offset = 48;
-	const size_t ttl_i = BIT_WORD(ttl_offset);
-	const unsigned int word_offset = ttl_offset % BITS_PER_LONG;
-	const unsigned long ttl_mask = (mask[ttl_i] >> word_offset) & port_mask;
-	const unsigned long ttl_bits = (bits[ttl_i] >> word_offset) & ttl_mask;
-
-	/* set bits are processed a gpio port register at a time */
-	for (i = 0; i < ARRAY_SIZE(ports); i++) {
-		/* gpio offset in bits array */
-		bits_offset = i * gpio_reg_size;
-
-		/* check if any set bits for current port */
-		gpio_mask = (*mask >> bits_offset) & port_mask;
-		if (!gpio_mask) {
-			/* no set bits for this port so move on to next port */
-			continue;
-		}
 
-		raw_spin_lock_irqsave(&idio24gpio->lock, flags);
+	for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
+		index = offset / 8;
 
-		/* process output lines */
-		out_state = ioread8(ports[i]) & ~gpio_mask;
-		out_state |= (*bits >> bits_offset) & gpio_mask;
-		iowrite8(out_state, ports[i]);
+		bitmask = bitmap_get_value8(bits, offset) & gpio_mask;
 
-		raw_spin_unlock_irqrestore(&idio24gpio->lock, flags);
-	}
+		raw_spin_lock_irqsave(&idio24gpio->lock, flags);
 
-	/* check if setting TTL lines and if they are in output mode */
-	if (!ttl_mask || !(ioread8(&idio24gpio->reg->ctl) & out_mode_mask))
-		return;
+		/* read bits from current gpio port (port 6 is TTL GPIO) */
+		if (index < 6) {
+			out_state = ioread8(ports[index]);
+		} else if (ioread8(&idio24gpio->reg->ctl) & out_mode_mask) {
+			out_state = ioread8(&idio24gpio->reg->ttl_out0_7);
+		} else {
+			/* skip TTL GPIO if set for input */
+			raw_spin_unlock_irqrestore(&idio24gpio->lock, flags);
+			continue;
+		}
 
-	/* handle TTL output */
-	raw_spin_lock_irqsave(&idio24gpio->lock, flags);
+		/* set requested bit states */
+		out_state &= ~gpio_mask;
+		out_state |= bitmask;
 
-	/* process output lines */
-	out_state = ioread8(&idio24gpio->reg->ttl_out0_7) & ~ttl_mask;
-	out_state |= ttl_bits;
-	iowrite8(out_state, &idio24gpio->reg->ttl_out0_7);
+		/* write bits for current gpio port (port 6 is TTL GPIO) */
+		if (index < 6)
+			iowrite8(out_state, ports[index]);
+		else
+			iowrite8(out_state, &idio24gpio->reg->ttl_out0_7);
 
-	raw_spin_unlock_irqrestore(&idio24gpio->lock, flags);
+		raw_spin_unlock_irqrestore(&idio24gpio->lock, flags);
+	}
 }
 
 static void idio_24_irq_ack(struct irq_data *data)
-- 
2.20.1

Re: [PATCH v7 1/8] bitops: Introduce the for_each_set_clump8 macro

[Andy Shevchenko]

On Sat, Jan 12, 2019 at 3:47 AM William Breathitt Gray
<vilhelm.gray@gmail.com> wrote:
>
> This macro iterates for each 8-bit group of bits (clump) with set bits,
> within a bitmap memory region. For each iteration, "start" is set to the
> bit offset of the found clump, while the respective clump value is
> stored to the location pointed by "clump". Additionally, the
> bitmap_get_value8 and bitmap_set_value8 functions are introduced to
> respectively get and set an 8-bit value in a bitmap memory region.

> +unsigned int bitmap_get_value8(const unsigned long *const bitmap,
> +                              const unsigned int start);

Hmm... Shouldn't be returned value of type unsigned long for sake of
consistency?

> +/**
> + * bitmap_set_value8 - set an 8-bit value within a memory region
> + * @bitmap: address to the bitmap memory region

> + * @value: the 8-bit value

Put the same warning here as you did in cover letter

> + * @start: bit offset of the 8-bit value
> + */
> +void bitmap_set_value8(unsigned long *const bitmap,
> +                      const unsigned long value,
> +                      const unsigned int start)
> +{
> +       const size_t index = BIT_WORD(start);
> +       const unsigned int offset = start % BITS_PER_LONG;
> +       const unsigned long mask = GENMASK(7, offset);
> +
> +       bitmap[index] &= ~mask;
> +       bitmap[index] |= value << offset;
> +}


-- 
With Best Regards,
Andy Shevchenko