Introduce the for_each_set_nbits macro

PATCH Superseded Syed Nayyar Waris 7 participants 19 messages Mar 6, 2021 – Apr 2, 2021 1 message not in the archive

Subsystems (5)

GPIO Generic include/asm header files Arm/Zynq architecture Xilinx GPIO driver +1 more subsystems

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Syed Nayyar Waris

author

2021-03-06 14:02 UTC #0 lore raw

v3 cover Introduce the for_each_set_nbits macro

Hello Bartosz,

Since this patchset primarily affects GPIO drivers, would you like to pick it up through your GPIO tree?

This patchset introduces a new generic version of for_each_set_nbits. The previous version of for_each_set_clump8 used a fixed size 8-bit clump, but the new generic version can work with clump of any size but less than or equal to BITS_PER_LONG. The patchset utilizes the new macro in several GPIO drivers.

The earlier 8-bit for_each_set_clump8 facilitated 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.

But with the new for_each_set_nbits the clump size can be different from 8 bits. Moreover, the clump can be split at word boundary in situations where word size is not multiple of clump size. Following are examples showing the working of new macro for clump sizes of 24 bits and 6 bits.

Example 1:
clump size: 24 bits, Number of clumps (or ports): 10
bitmap stores the bit information from where successive clumps are retrieved.

     /* bitmap memory region */
        0x00aa0000ff000000;  /* Most significant bits */
        0xaaaaaa0000ff0000;
        0x000000aa000000aa;
        0xbbbbabcdeffedcba;  /* Least significant bits */

Different iterations of for_each_set_nbits:-
'offset' is the bit position and 'clump' is the 24 bit clump from the above bitmap.

Iteration first:        offset: 0 clump: 0xfedcba
Iteration second:       offset: 24 clump: 0xabcdef
Iteration third:        offset: 48 clump: 0xaabbbb
Iteration fourth:       offset: 96 clump: 0xaa
Iteration fifth:        offset: 144 clump: 0xff
Iteration sixth:        offset: 168 clump: 0xaaaaaa
Iteration seventh:      offset: 216 clump: 0xff

Loop breaks because in the end the remaining bits (0x00aa) size was less than clump size of 24 bits.

In above example it can be seen that in iteration third, the 24 bit clump that was retrieved was split between bitmap[0] and bitmap[1]. This example also shows that 24 bit zeroes if present in between, were skipped (preserving the previous for_each_set_macro8 behaviour).

Example 2:
clump size = 6 bits, Number of clumps (or ports) = 3.

     /* bitmap memory region */
        0x00aa0000ff000000;  /* Most significant bits */
        0xaaaaaa0000ff0000;
        0x0f00000000000000;
        0x0000000000000ac0;  /* Least significant bits */

Different iterations of for_each_set_nbits:
'offset' is the bit position and 'clump' is the 6 bit clump from the above bitmap.
Iteration first: offset: 6 clump: 0x2b
Loop breaks because 6 * 3 = 18 bits traversed in bitmap. Here 6 * 3 is clump size * no. of clumps.

Changes in v3:
- [Patch 1/3]: Rename for_each_set_clump to for_each_set_nbits.
- [Patch 1/3]: Shift function definitions outside 'ifdef CONFIG_DEBUG_FS' macro guard to resolve build (linking) error in xilinx Patch[3/3].
- [Patch 2/3]: Rename for_each_set_clump to for_each_set_nbits.

Changes in v2:
- [Patch 1/3]: Shift the macros and related functions to gpiolib inside gpio/. Reduce the visibilty of 'for_each_set_clump' to gpio.
- [Patch 1/3]: Remove __builtin_unreachable and simply use return statement.
- Remove tests from lib/test_bitmap.c as 'for_each_set_clump' is now localised inside gpio/ only.

Syed Nayyar Waris (3):
gpiolib: Introduce the for_each_set_nbits macro
gpio: thunderx: Utilize for_each_set_nbits macro
gpio: xilinx: Utilize generic bitmap_get_value and _set_value

 drivers/gpio/gpio-thunderx.c | 13 ++++--
 drivers/gpio/gpio-xilinx.c   | 63 ++++++++++++-------------
 drivers/gpio/gpiolib.c       | 90 ++++++++++++++++++++++++++++++++++++
 drivers/gpio/gpiolib.h       | 28 +++++++++++
 4 files changed, 158 insertions(+), 36 deletions(-)

base-commit: e71ba9452f0b5b2e8dc8aa5445198cd9214a6a62

Signature · 1 line

2.29.0

Syed Nayyar Waris

author

2021-03-06 14:04 UTC #1 lore raw

PATCH v3 1/3 gpiolib: Introduce the for_each_set_nbits macro

This macro iterates for each 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_value() and bitmap_set_value() functions are introduced to respectively get and set a value of n-bits in a bitmap memory region. The n-bits can have any size from 1 to BITS_PER_LONG. size less than 1 or more than BITS_PER_LONG causes undefined behaviour. Moreover, during setting value of n-bit in bitmap, if a situation arise that the width of next n-bit is exceeding the word boundary, then it will divide itself such that some portion of it is stored in that word, while the remaining portion is stored in the next higher word. Similar situation occurs while retrieving the value from bitmap.

Cc Linus Walleij <[email protected]>

Cc Bartosz Gołaszewski <[email protected]>

Cc Arnd Bergmann <[email protected]>

Cc Andy Shevchenko <[email protected]>

Signed-off-by Syed Nayyar Waris <[email protected]>

Acked-by William Breathitt Gray <[email protected]>

---
 drivers/gpio/gpiolib.c | 90 ++++++++++++++++++++++++++++++++++++++++++
 drivers/gpio/gpiolib.h | 28 +++++++++++++
 2 files changed, 118 insertions(+)

drivers/gpio/gpiolib.c +90 -0

index b02cc2abd3b6..1e3cfc6bc73f 100644
@@ -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

drivers/gpio/gpiolib.h +28 -0

index 30bc3f80f83e..af79784dfce3 100644
@@ -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
  */

Signature · 1 line

2.29.0

Syed Nayyar Waris

author

2021-03-06 14:06 UTC #2 lore raw

PATCH v3 2/3 gpio: thunderx: Utilize for_each_set_nbits macro

In reply to Syed Nayyar Waris

This patch reimplements the thunderx_gpio_set_multiple function in drivers/gpio/gpio-thunderx.c to use the new for_each_set_nbits macro. Instead of looping for each bank in thunderx_gpio_set_multiple function, now we can skip bank which is not set and save cycles.

Cc Robert Richter <[email protected]>

Cc Bartosz Golaszewski <[email protected]>

Signed-off-by Syed Nayyar Waris <[email protected]>

Acked-by William Breathitt Gray <[email protected]>

---
 drivers/gpio/gpio-thunderx.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

drivers/gpio/gpio-thunderx.c +8 -5

index 9f66deab46ea..4349e7393a1d 100644
@@ -16,7 +16,7 @@
 #include <linux/pci.h>
 #include <linux/spinlock.h>
 #include <asm-generic/msi.h>
-
+#include "gpiolib.h"
 
 #define GPIO_RX_DAT	0x0
 #define GPIO_TX_SET	0x8

@@ -275,12 +275,15 @@ static void thunderx_gpio_set_multiple(struct gpio_chip *chip,
 				       unsigned long *bits)
 {
 	int bank;
-	u64 set_bits, clear_bits;
+	unsigned long set_bits, clear_bits, gpio_mask;
+	unsigned long offset;
+
 	struct thunderx_gpio *txgpio = gpiochip_get_data(chip);
 
-	for (bank = 0; bank <= chip->ngpio / 64; bank++) {
-		set_bits = bits[bank] & mask[bank];
-		clear_bits = ~bits[bank] & mask[bank];
+	for_each_set_nbits(offset, gpio_mask, mask, chip->ngpio, 64) {
+		bank = offset / 64;
+		set_bits = bits[bank] & gpio_mask;
+		clear_bits = ~bits[bank] & gpio_mask;
 		writeq(set_bits, txgpio->register_base + (bank * GPIO_2ND_BANK) + GPIO_TX_SET);
 		writeq(clear_bits, txgpio->register_base + (bank * GPIO_2ND_BANK) + GPIO_TX_CLR);
 	}

Signature · 1 line

2.29.0

Syed Nayyar Waris

author

2021-03-06 14:07 UTC #3 lore raw

PATCH v3 3/3 gpio: xilinx: Utilize generic bitmap_get_value and _set_value

In reply to Syed Nayyar Waris

This patch reimplements the xgpio_set_multiple() function in drivers/gpio/gpio-xilinx.c to use the new generic functions:
bitmap_get_value() and bitmap_set_value(). The code is now simpler to read and understand. Moreover, instead of looping for each bit in xgpio_set_multiple() function, now we can check each channel at a time and save cycles.

Cc Bartosz Golaszewski <[email protected]>

Cc Michal Simek <[email protected]>

Signed-off-by Syed Nayyar Waris <[email protected]>

Acked-by William Breathitt Gray <[email protected]>

---
 drivers/gpio/gpio-xilinx.c | 63 +++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 31 deletions(-)

drivers/gpio/gpio-xilinx.c +32 ~~-31~~

index be539381fd82..8445e69cf37b 100644
@@ -15,6 +15,7 @@
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/slab.h>
+#include "gpiolib.h"
 
 /* Register Offset Definitions */
 #define XGPIO_DATA_OFFSET   (0x0)	/* Data register  */

@@ -141,37 +142,37 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
 {
 	unsigned long flags;
 	struct xgpio_instance *chip = gpiochip_get_data(gc);
-	int index = xgpio_index(chip, 0);
-	int offset, i;
-
-	spin_lock_irqsave(&chip->gpio_lock[index], flags);
-
-	/* Write to GPIO signals */
-	for (i = 0; i < gc->ngpio; i++) {
-		if (*mask == 0)
-			break;
-		/* Once finished with an index write it out to the register */
-		if (index !=  xgpio_index(chip, i)) {
-			xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-				       index * XGPIO_CHANNEL_OFFSET,
-				       chip->gpio_state[index]);
-			spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
-			index =  xgpio_index(chip, i);
-			spin_lock_irqsave(&chip->gpio_lock[index], flags);
-		}
-		if (__test_and_clear_bit(i, mask)) {
-			offset =  xgpio_offset(chip, i);
-			if (test_bit(i, bits))
-				chip->gpio_state[index] |= BIT(offset);
-			else
-				chip->gpio_state[index] &= ~BIT(offset);
-		}
-	}
-
-	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-		       index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
-
-	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
+	u32 *const state = chip->gpio_state;
+	unsigned int *const width = chip->gpio_width;
+
+	DECLARE_BITMAP(old, 64);
+	DECLARE_BITMAP(new, 64);
+	DECLARE_BITMAP(changed, 64);
+
+	spin_lock_irqsave(&chip->gpio_lock[0], flags);
+	spin_lock(&chip->gpio_lock[1]);
+
+	bitmap_set_value(old, 64, state[0], width[0], 0);
+	bitmap_set_value(old, 64, state[1], width[1], width[0]);
+	bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+	bitmap_set_value(old, 64, state[0], 32, 0);
+	bitmap_set_value(old, 64, state[1], 32, 32);
+	state[0] = bitmap_get_value(new, 0, width[0]);
+	state[1] = bitmap_get_value(new, width[0], width[1]);
+	bitmap_set_value(new, 64, state[0], 32, 0);
+	bitmap_set_value(new, 64, state[1], 32, 32);
+	bitmap_xor(changed, old, new, 64);
+
+	if (((u32 *)changed)[0])
+		xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET,
+				state[0]);
+	if (((u32 *)changed)[1])
+		xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
+				XGPIO_CHANNEL_OFFSET, state[1]);
+
+	spin_unlock(&chip->gpio_lock[1]);
+	spin_unlock_irqrestore(&chip->gpio_lock[0], flags);
 }
 
 /**

Signature · 1 line

2.29.0

Michal Simek

2021-03-08 07:14 UTC #4 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 87 lines · Syed Nayyar Waris

Cc Bartosz Golaszewski <[email protected]>

Cc Michal Simek <[email protected]>

Signed-off-by Syed Nayyar Waris <[email protected]>

Acked-by William Breathitt Gray <[email protected]>

---
 drivers/gpio/gpio-xilinx.c | 63 +++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 31 deletions(-)

drivers/gpio/gpio-xilinx.c +25 ~~-31~~

index be539381fd82..8445e69cf37b 100644
@@ -15,6 +15,7 @@
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/slab.h>
+#include "gpiolib.h"
 
 /* Register Offset Definitions */
 #define XGPIO_DATA_OFFSET   (0x0)	/* Data register  */

@@ -141,37 +142,37 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
 {
 	unsigned long flags;
 	struct xgpio_instance *chip = gpiochip_get_data(gc);
-	int index = xgpio_index(chip, 0);
-	int offset, i;
-
-	spin_lock_irqsave(&chip->gpio_lock[index], flags);
-
-	/* Write to GPIO signals */
-	for (i = 0; i < gc->ngpio; i++) {
-		if (*mask == 0)
-			break;
-		/* Once finished with an index write it out to the register */
-		if (index !=  xgpio_index(chip, i)) {
-			xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-				       index * XGPIO_CHANNEL_OFFSET,
-				       chip->gpio_state[index]);
-			spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
-			index =  xgpio_index(chip, i);
-			spin_lock_irqsave(&chip->gpio_lock[index], flags);
-		}
-		if (__test_and_clear_bit(i, mask)) {
-			offset =  xgpio_offset(chip, i);
-			if (test_bit(i, bits))
-				chip->gpio_state[index] |= BIT(offset);
-			else
-				chip->gpio_state[index] &= ~BIT(offset);
-		}
-	}
-
-	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-		       index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
-
-	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
+	u32 *const state = chip->gpio_state;
+	unsigned int *const width = chip->gpio_width;
+
+	DECLARE_BITMAP(old, 64);
+	DECLARE_BITMAP(new, 64);
+	DECLARE_BITMAP(changed, 64);
+
+	spin_lock_irqsave(&chip->gpio_lock[0], flags);
+	spin_lock(&chip->gpio_lock[1]);
+
+	bitmap_set_value(old, 64, state[0], width[0], 0);
+	bitmap_set_value(old, 64, state[1], width[1], width[0]);
+	bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+	bitmap_set_value(old, 64, state[0], 32, 0);
+	bitmap_set_value(old, 64, state[1], 32, 32);
+	state[0] = bitmap_get_value(new, 0, width[0]);
+	state[1] = bitmap_get_value(new, width[0], width[1]);
+	bitmap_set_value(new, 64, state[0], 32, 0);
+	bitmap_set_value(new, 64, state[1], 32, 32);
+	bitmap_xor(changed, old, new, 64);
+
+	if (((u32 *)changed)[0])
+		xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET,

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 178

Quoted 10 lines

drivers/gpio/gpio-xilinx.c +7 -0

+				state[0]);
+	if (((u32 *)changed)[1])
+		xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
+				XGPIO_CHANNEL_OFFSET, state[1]);
+
+	spin_unlock(&chip->gpio_lock[1]);
+	spin_unlock_irqrestore(&chip->gpio_lock[0], flags);
 }
 
 /**

Srinivas N: Can you please test this code?

Thanks,
Michal

Bartosz Golaszewski

2021-03-26 17:28 UTC #5 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 99 lines · Michal Simek

Quoted 95 lines · Syed Nayyar Waris

Cc Bartosz Golaszewski <[email protected]>

Cc Michal Simek <[email protected]>

Signed-off-by Syed Nayyar Waris <[email protected]>

Acked-by William Breathitt Gray <[email protected]>

---
 drivers/gpio/gpio-xilinx.c | 63 +++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 31 deletions(-)

drivers/gpio/gpio-xilinx.c +32 ~~-31~~

index be539381fd82..8445e69cf37b 100644
@@ -15,6 +15,7 @@
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/slab.h>
+#include "gpiolib.h"
 
 /* Register Offset Definitions */
 #define XGPIO_DATA_OFFSET   (0x0)    /* Data register  */

@@ -141,37 +142,37 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
 {
      unsigned long flags;
      struct xgpio_instance *chip = gpiochip_get_data(gc);
-     int index = xgpio_index(chip, 0);
-     int offset, i;
-
-     spin_lock_irqsave(&chip->gpio_lock[index], flags);
-
-     /* Write to GPIO signals */
-     for (i = 0; i < gc->ngpio; i++) {
-             if (*mask == 0)
-                     break;
-             /* Once finished with an index write it out to the register */
-             if (index !=  xgpio_index(chip, i)) {
-                     xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-                                    index * XGPIO_CHANNEL_OFFSET,
-                                    chip->gpio_state[index]);
-                     spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
-                     index =  xgpio_index(chip, i);
-                     spin_lock_irqsave(&chip->gpio_lock[index], flags);
-             }
-             if (__test_and_clear_bit(i, mask)) {
-                     offset =  xgpio_offset(chip, i);
-                     if (test_bit(i, bits))
-                             chip->gpio_state[index] |= BIT(offset);
-                     else
-                             chip->gpio_state[index] &= ~BIT(offset);
-             }
-     }
-
-     xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-                    index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
-
-     spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
+     u32 *const state = chip->gpio_state;
+     unsigned int *const width = chip->gpio_width;
+
+     DECLARE_BITMAP(old, 64);
+     DECLARE_BITMAP(new, 64);
+     DECLARE_BITMAP(changed, 64);
+
+     spin_lock_irqsave(&chip->gpio_lock[0], flags);
+     spin_lock(&chip->gpio_lock[1]);
+
+     bitmap_set_value(old, 64, state[0], width[0], 0);
+     bitmap_set_value(old, 64, state[1], width[1], width[0]);
+     bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+     bitmap_set_value(old, 64, state[0], 32, 0);
+     bitmap_set_value(old, 64, state[1], 32, 32);
+     state[0] = bitmap_get_value(new, 0, width[0]);
+     state[1] = bitmap_get_value(new, width[0], width[1]);
+     bitmap_set_value(new, 64, state[0], 32, 0);
+     bitmap_set_value(new, 64, state[1], 32, 32);
+     bitmap_xor(changed, old, new, 64);
+
+     if (((u32 *)changed)[0])
+             xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET,
+                             state[0]);
+     if (((u32 *)changed)[1])
+             xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
+                             XGPIO_CHANNEL_OFFSET, state[1]);
+
+     spin_unlock(&chip->gpio_lock[1]);
+     spin_unlock_irqrestore(&chip->gpio_lock[0], flags);
 }

Quoted 7 lines

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 178
Quoted 2 lines
drivers/gpio/gpio-xilinx.c +0 -0
 /**
Srinivas N: Can you please test this code?
Thanks,
Michal

Hey, any chance of getting that Tested-by?

Bart

Srinivas Neeli

2021-03-31 15:27 UTC #6 lore raw

RE: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Hi,

Quoted 126 lines

-----Original Message-----
From: Bartosz Golaszewski <[email protected]>
Sent: Friday, March 26, 2021 10:58 PM
To: Michal Simek <[email protected]>
Cc: Syed Nayyar Waris <[email protected]>; Srinivas Neeli <[email protected]>; Andy Shevchenko <[email protected]>; William Breathitt Gray <[email protected]>; Arnd Bergmann <[email protected]>; Robert Richter <[email protected]>; Linus Walleij <[email protected]>; Masahiro Yamada <[email protected]>; Andrew Morton <[email protected]>; Zhang Rui <[email protected]>; Daniel Lezcano <[email protected]>; Amit Kucheria <[email protected]>; Linux-Arch <[email protected]>; linux-gpio <[email protected]>; LKML <linux- [email protected]>; arm-soc <[email protected]>; linux-pm <[email protected]>; Srinivas Goud <[email protected]>
Subject: Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 105 lines · Michal Simek

Quoted 88 lines · Syed Nayyar Waris

Cc Bartosz Golaszewski <[email protected]>

Cc Michal Simek <[email protected]>

Signed-off-by Syed Nayyar Waris <[email protected]>

Acked-by William Breathitt Gray <[email protected]>

---
 drivers/gpio/gpio-xilinx.c | 63
+++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 31 deletions(-)

drivers/gpio/gpio-xilinx.c +25 ~~-31~~

index be539381fd82..8445e69cf37b 100644
@@ -15,6 +15,7 @@
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/slab.h>
+#include "gpiolib.h"
 
 /* Register Offset Definitions */
 #define XGPIO_DATA_OFFSET   (0x0)    /* Data register  */

@@ -141,37 +142,37 @@ static void xgpio_set_multiple(struct
 gpio_chip *gc, unsigned long *mask,  {
      unsigned long flags;
      struct xgpio_instance *chip = gpiochip_get_data(gc);
-     int index = xgpio_index(chip, 0);
-     int offset, i;
-
-     spin_lock_irqsave(&chip->gpio_lock[index], flags);
-
-     /* Write to GPIO signals */
-     for (i = 0; i < gc->ngpio; i++) {
-             if (*mask == 0)
-                     break;
-             /* Once finished with an index write it out to the register */
-             if (index !=  xgpio_index(chip, i)) {
-                     xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-                                    index * XGPIO_CHANNEL_OFFSET,
-                                    chip->gpio_state[index]);
-                     spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
-                     index =  xgpio_index(chip, i);
-                     spin_lock_irqsave(&chip->gpio_lock[index], flags);
-             }
-             if (__test_and_clear_bit(i, mask)) {
-                     offset =  xgpio_offset(chip, i);
-                     if (test_bit(i, bits))
-                             chip->gpio_state[index] |= BIT(offset);
-                     else
-                             chip->gpio_state[index] &= ~BIT(offset);
-             }
-     }
-
-     xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-                    index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
-
-     spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
+     u32 *const state = chip->gpio_state;
+     unsigned int *const width = chip->gpio_width;
+
+     DECLARE_BITMAP(old, 64);
+     DECLARE_BITMAP(new, 64);
+     DECLARE_BITMAP(changed, 64);
+
+     spin_lock_irqsave(&chip->gpio_lock[0], flags);
+     spin_lock(&chip->gpio_lock[1]);
+
+     bitmap_set_value(old, 64, state[0], width[0], 0);
+     bitmap_set_value(old, 64, state[1], width[1], width[0]);
+     bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+     bitmap_set_value(old, 64, state[0], 32, 0);
+     bitmap_set_value(old, 64, state[1], 32, 32);
+     state[0] = bitmap_get_value(new, 0, width[0]);
+     state[1] = bitmap_get_value(new, width[0], width[1]);
+     bitmap_set_value(new, 64, state[0], 32, 0);
+     bitmap_set_value(new, 64, state[1], 32, 32);
+     bitmap_xor(changed, old, new, 64);
+
+     if (((u32 *)changed)[0])
+             xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET,

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct · line 178

Quoted 10 lines

drivers/gpio/gpio-xilinx.c +7 -0

+                             state[0]);
+     if (((u32 *)changed)[1])
+             xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
+                             XGPIO_CHANNEL_OFFSET, state[1]);
+
+     spin_unlock(&chip->gpio_lock[1]);
+     spin_unlock_irqrestore(&chip->gpio_lock[0], flags);
 }
 
 /**

Srinivas N: Can you please test this code?

Quoted 4 lines

Quoted 2 lines
Thanks,
Michal
Hey, any chance of getting that Tested-by?

I tested patches with few modifications in code (spin_lock handling and merge conflict). functionality wise it's working fine.

Quoted 2 lines

Bart

Syed Nayyar Waris

author

2021-04-01 11:17 UTC #7 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 129 lines · Srinivas Neeli

Hi,

Quoted 126 lines

Quoted 105 lines · Michal Simek

Quoted 88 lines · Syed Nayyar Waris

Cc Bartosz Golaszewski <[email protected]>

Cc Michal Simek <[email protected]>

Signed-off-by Syed Nayyar Waris <[email protected]>

Acked-by William Breathitt Gray <[email protected]>

---
 drivers/gpio/gpio-xilinx.c | 63
+++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 31 deletions(-)

drivers/gpio/gpio-xilinx.c +25 ~~-31~~

index be539381fd82..8445e69cf37b 100644
@@ -15,6 +15,7 @@
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/slab.h>
+#include "gpiolib.h"
 
 /* Register Offset Definitions */
 #define XGPIO_DATA_OFFSET   (0x0)    /* Data register  */

@@ -141,37 +142,37 @@ static void xgpio_set_multiple(struct
 gpio_chip *gc, unsigned long *mask,  {
      unsigned long flags;
      struct xgpio_instance *chip = gpiochip_get_data(gc);
-     int index = xgpio_index(chip, 0);
-     int offset, i;
-
-     spin_lock_irqsave(&chip->gpio_lock[index], flags);
-
-     /* Write to GPIO signals */
-     for (i = 0; i < gc->ngpio; i++) {
-             if (*mask == 0)
-                     break;
-             /* Once finished with an index write it out to the register */
-             if (index !=  xgpio_index(chip, i)) {
-                     xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-                                    index * XGPIO_CHANNEL_OFFSET,
-                                    chip->gpio_state[index]);
-                     spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
-                     index =  xgpio_index(chip, i);
-                     spin_lock_irqsave(&chip->gpio_lock[index], flags);
-             }
-             if (__test_and_clear_bit(i, mask)) {
-                     offset =  xgpio_offset(chip, i);
-                     if (test_bit(i, bits))
-                             chip->gpio_state[index] |= BIT(offset);
-                     else
-                             chip->gpio_state[index] &= ~BIT(offset);
-             }
-     }
-
-     xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-                    index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
-
-     spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
+     u32 *const state = chip->gpio_state;
+     unsigned int *const width = chip->gpio_width;
+
+     DECLARE_BITMAP(old, 64);
+     DECLARE_BITMAP(new, 64);
+     DECLARE_BITMAP(changed, 64);
+
+     spin_lock_irqsave(&chip->gpio_lock[0], flags);
+     spin_lock(&chip->gpio_lock[1]);
+
+     bitmap_set_value(old, 64, state[0], width[0], 0);
+     bitmap_set_value(old, 64, state[1], width[1], width[0]);
+     bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+     bitmap_set_value(old, 64, state[0], 32, 0);
+     bitmap_set_value(old, 64, state[1], 32, 32);
+     state[0] = bitmap_get_value(new, 0, width[0]);
+     state[1] = bitmap_get_value(new, width[0], width[1]);
+     bitmap_set_value(new, 64, state[0], 32, 0);
+     bitmap_set_value(new, 64, state[1], 32, 32);
+     bitmap_xor(changed, old, new, 64);
+
+     if (((u32 *)changed)[0])
+             xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET,

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct · line 178

Quoted 10 lines

drivers/gpio/gpio-xilinx.c +7 -0

+                             state[0]);
+     if (((u32 *)changed)[1])
+             xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
+                             XGPIO_CHANNEL_OFFSET, state[1]);
+
+     spin_unlock(&chip->gpio_lock[1]);
+     spin_unlock_irqrestore(&chip->gpio_lock[0], flags);
 }
 
 /**

Srinivas N: Can you please test this code?

Quoted 9 lines

Quoted 4 lines
Quoted 2 lines
Thanks,
Michal
Hey, any chance of getting that Tested-by?
I tested patches with few modifications in code (spin_lock handling and merge conflict). functionality wise it's working fine.
Quoted 2 lines
Bart

Hi Bartosz,

May I please know the URL of the tree that you are using. I had been using the tree below for submitting this patchset on GPIO to you.
https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git

I think I am using the wrong tree. On which tree should I base my patches on for my next (v4) submission? Should I use the tree below? :
https://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux.git

Regards
Syed Nayyar Waris

_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Bartosz Golaszewski

2021-04-01 12:53 UTC #8 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 147 lines · Syed Nayyar Waris

Quoted 129 lines · Srinivas Neeli
Hi,
Quoted 126 lines
-----Original Message-----
From: Bartosz Golaszewski <[email protected]>
Sent: Friday, March 26, 2021 10:58 PM
To: Michal Simek <[email protected]>
Cc: Syed Nayyar Waris <[email protected]>; Srinivas Neeli <[email protected]>; Andy Shevchenko <[email protected]>; William Breathitt Gray <[email protected]>; Arnd Bergmann <[email protected]>; Robert Richter <[email protected]>; Linus Walleij <[email protected]>; Masahiro Yamada <[email protected]>; Andrew Morton <[email protected]>; Zhang Rui <[email protected]>; Daniel Lezcano <[email protected]>; Amit Kucheria <[email protected]>; Linux-Arch <[email protected]>; linux-gpio <[email protected]>; LKML <linux- [email protected]>; arm-soc <[email protected]>; linux-pm <[email protected]>; Srinivas Goud <[email protected]>
Subject: Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value
Quoted 105 lines · Michal Simek
Quoted 88 lines · Syed Nayyar Waris
This patch reimplements the xgpio_set_multiple() function in drivers/gpio/gpio-xilinx.c to use the new generic functions:
bitmap_get_value() and bitmap_set_value(). The code is now simpler to read and understand. Moreover, instead of looping for each bit in xgpio_set_multiple() function, now we can check each channel at a time and save cycles.
Cc Bartosz Golaszewski <[email protected]>
Cc Michal Simek <[email protected]>
Signed-off-by Syed Nayyar Waris <[email protected]>
Acked-by William Breathitt Gray <[email protected]>
---
 drivers/gpio/gpio-xilinx.c | 63
+++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 31 deletions(-)
drivers/gpio/gpio-xilinx.c +25 ~~-31~~
index be539381fd82..8445e69cf37b 100644
@@ -15,6 +15,7 @@
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/slab.h>
+#include "gpiolib.h"
 
 /* Register Offset Definitions */
 #define XGPIO_DATA_OFFSET   (0x0)    /* Data register  */
@@ -141,37 +142,37 @@ static void xgpio_set_multiple(struct
 gpio_chip *gc, unsigned long *mask,  {
      unsigned long flags;
      struct xgpio_instance *chip = gpiochip_get_data(gc);
-     int index = xgpio_index(chip, 0);
-     int offset, i;
-
-     spin_lock_irqsave(&chip->gpio_lock[index], flags);
-
-     /* Write to GPIO signals */
-     for (i = 0; i < gc->ngpio; i++) {
-             if (*mask == 0)
-                     break;
-             /* Once finished with an index write it out to the register */
-             if (index !=  xgpio_index(chip, i)) {
-                     xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-                                    index * XGPIO_CHANNEL_OFFSET,
-                                    chip->gpio_state[index]);
-                     spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
-                     index =  xgpio_index(chip, i);
-                     spin_lock_irqsave(&chip->gpio_lock[index], flags);
-             }
-             if (__test_and_clear_bit(i, mask)) {
-                     offset =  xgpio_offset(chip, i);
-                     if (test_bit(i, bits))
-                             chip->gpio_state[index] |= BIT(offset);
-                     else
-                             chip->gpio_state[index] &= ~BIT(offset);
-             }
-     }
-
-     xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
-                    index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
-
-     spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
+     u32 *const state = chip->gpio_state;
+     unsigned int *const width = chip->gpio_width;
+
+     DECLARE_BITMAP(old, 64);
+     DECLARE_BITMAP(new, 64);
+     DECLARE_BITMAP(changed, 64);
+
+     spin_lock_irqsave(&chip->gpio_lock[0], flags);
+     spin_lock(&chip->gpio_lock[1]);
+
+     bitmap_set_value(old, 64, state[0], width[0], 0);
+     bitmap_set_value(old, 64, state[1], width[1], width[0]);
+     bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+     bitmap_set_value(old, 64, state[0], 32, 0);
+     bitmap_set_value(old, 64, state[1], 32, 32);
+     state[0] = bitmap_get_value(new, 0, width[0]);
+     state[1] = bitmap_get_value(new, width[0], width[1]);
+     bitmap_set_value(new, 64, state[0], 32, 0);
+     bitmap_set_value(new, 64, state[1], 32, 32);
+     bitmap_xor(changed, old, new, 64);
+
+     if (((u32 *)changed)[0])
+             xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET,
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct · line 178
Quoted 10 lines
drivers/gpio/gpio-xilinx.c +7 -0
+                             state[0]);
+     if (((u32 *)changed)[1])
+             xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
+                             XGPIO_CHANNEL_OFFSET, state[1]);
+
+     spin_unlock(&chip->gpio_lock[1]);
+     spin_unlock_irqrestore(&chip->gpio_lock[0], flags);
 }
 
 /**
Srinivas N: Can you please test this code?
Quoted 9 lines
Quoted 4 lines
Quoted 2 lines
Thanks,
Michal
Hey, any chance of getting that Tested-by?
I tested patches with few modifications in code (spin_lock handling and merge conflict). functionality wise it's working fine.
Quoted 2 lines
Bart
Hi Bartosz,
May I please know the URL of the tree that you are using. I had been using the tree below for submitting this patchset on GPIO to you.
https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git

Quoted 7 lines

I think I am using the wrong tree. On which tree should I base my patches on for my next (v4) submission? Should I use the tree below? :
https://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux.git
Regards
Syed Nayyar Waris

Yes this is the one. Please address new issues raised by reviewers.

Bart

_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Andy Shevchenko

2021-03-26 17:58 UTC #9 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

In reply to Syed Nayyar Waris

Quoted 7 lines · Syed Nayyar Waris

This patch reimplements the xgpio_set_multiple() function in drivers/gpio/gpio-xilinx.c to use the new generic functions:
bitmap_get_value() and bitmap_set_value(). The code is now simpler to read and understand. Moreover, instead of looping for each bit in xgpio_set_multiple() function, now we can check each channel at a time and save cycles.

...

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,

Quoted 4 lines

drivers/gpio/gpio-xilinx.c +3 -0

+       u32 *const state = chip->gpio_state;
+       unsigned int *const width = chip->gpio_width;
 
+

Extra blank line.

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 153

Quoted 6 lines

drivers/gpio/gpio-xilinx.c +5 -0

+       DECLARE_BITMAP(old, 64);
+       DECLARE_BITMAP(new, 64);
+       DECLARE_BITMAP(changed, 64);
 
+       spin_lock_irqsave(&chip->gpio_lock[0], flags);
+       spin_lock(&chip->gpio_lock[1]);

I understand why this is done at the top of the function in the original code. I do not understand why you put some operations under spin lock.

Have you checked what each of these spin locks protects? Please check and try to lock as minimum as possible.

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 165

Quoted 11 lines

drivers/gpio/gpio-xilinx.c +11 -0

+       bitmap_set_value(old, 64, state[0], width[0], 0);
+       bitmap_set_value(old, 64, state[1], width[1], width[0]);
+       bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+       bitmap_set_value(old, 64, state[0], 32, 0);
+       bitmap_set_value(old, 64, state[1], 32, 32);
+       state[0] = bitmap_get_value(new, 0, width[0]);
+       state[1] = bitmap_get_value(new, width[0], width[1]);
+       bitmap_set_value(new, 64, state[0], 32, 0);
+       bitmap_set_value(new, 64, state[1], 32, 32);
+       bitmap_xor(changed, old, new, 64);

Original code and this is cryptic. Can you add a few comments explaining what is going on here?

Quoted 2 lines

drivers/gpio/gpio-xilinx.c +2 -0

+       spin_unlock(&chip->gpio_lock[1]);
+       spin_unlock_irqrestore(&chip->gpio_lock[0], flags);

Signature · 2 lines

With Best Regards,
Andy Shevchenko

Syed Nayyar Waris

author

2021-04-02 09:40 UTC #10 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 47 lines · Andy Shevchenko

Quoted 7 lines · Syed Nayyar Waris
This patch reimplements the xgpio_set_multiple() function in drivers/gpio/gpio-xilinx.c to use the new generic functions:
bitmap_get_value() and bitmap_set_value(). The code is now simpler to read and understand. Moreover, instead of looping for each bit in xgpio_set_multiple() function, now we can check each channel at a time and save cycles.
...
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
Quoted 4 lines
drivers/gpio/gpio-xilinx.c +3 -0
+       u32 *const state = chip->gpio_state;
+       unsigned int *const width = chip->gpio_width;
 
+
Extra blank line.
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 153
Quoted 6 lines
drivers/gpio/gpio-xilinx.c +5 -0
+       DECLARE_BITMAP(old, 64);
+       DECLARE_BITMAP(new, 64);
+       DECLARE_BITMAP(changed, 64);
 
+       spin_lock_irqsave(&chip->gpio_lock[0], flags);
+       spin_lock(&chip->gpio_lock[1]);
I understand why this is done at the top of the function in the original code. I do not understand why you put some operations under spin lock.
Have you checked what each of these spin locks protects? Please check and try to lock as minimum as possible.
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 165
Quoted 11 lines
drivers/gpio/gpio-xilinx.c +11 -0
+       bitmap_set_value(old, 64, state[0], width[0], 0);
+       bitmap_set_value(old, 64, state[1], width[1], width[0]);
+       bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+       bitmap_set_value(old, 64, state[0], 32, 0);
+       bitmap_set_value(old, 64, state[1], 32, 32);
+       state[0] = bitmap_get_value(new, 0, width[0]);
+       state[1] = bitmap_get_value(new, width[0], width[1]);
+       bitmap_set_value(new, 64, state[0], 32, 0);
+       bitmap_set_value(new, 64, state[1], 32, 32);
+       bitmap_xor(changed, old, new, 64);
Original code and this is cryptic. Can you add a few comments explaining what is going on here?

Quoted 6 lines

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 175
Quoted 2 lines
drivers/gpio/gpio-xilinx.c +2 -0
+       spin_unlock(&chip->gpio_lock[1]);
+       spin_unlock_irqrestore(&chip->gpio_lock[0], flags);
--
With Best Regards,
Andy Shevchenko

Have removed the extra line and added comments. Regarding locking - I see that now there is just a single lock available instead of 2 locks. Have made necessary changes. Thanks
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/gpio/gpio-xilinx.c?id=37ef334680800263b32bb96a5156a4b47f0244a2

Regards

Syed Nayyar Waris

Andy Shevchenko

2021-03-26 18:02 UTC #11 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

In reply to Syed Nayyar Waris

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 160

Quoted 2 lines · Syed Nayyar Waris

drivers/gpio/gpio-xilinx.c +2 -0

+       bitmap_set_value(old, 64, state[0], 32, 0);
+       bitmap_set_value(old, 64, state[1], 32, 32);

Isn't it effectively bitnap_from_arr32() ?

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 164

Quoted 2 lines

drivers/gpio/gpio-xilinx.c +2 -0

+       bitmap_set_value(new, 64, state[0], 32, 0);
+       bitmap_set_value(new, 64, state[1], 32, 32);

Ditto.

Signature · 2 lines

With Best Regards,
Andy Shevchenko

Syed Nayyar Waris

author

2021-03-26 22:13 UTC #12 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 8 lines · Andy Shevchenko

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 160
Quoted 2 lines · Syed Nayyar Waris
drivers/gpio/gpio-xilinx.c +2 -0
+       bitmap_set_value(old, 64, state[0], 32, 0);
+       bitmap_set_value(old, 64, state[1], 32, 32);
Isn't it effectively bitnap_from_arr32() ?

Quoted 8 lines

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 164
Quoted 2 lines
drivers/gpio/gpio-xilinx.c +2 -0
+       bitmap_set_value(new, 64, state[0], 32, 0);
+       bitmap_set_value(new, 64, state[1], 32, 32);
Ditto.
--
With Best Regards,
Andy Shevchenko

Hi Andy,

With bitmap_set_value() we are also specifying the offset (or start) position too. so that the remainder of the array remains unaffected. I think it would not be feasible to use bitmap_from/to_arr32() here.

Regards
Syed Nayyar Waris

A message that is not in the archive (sent off-list or not yet received): CAHp75VfDZbJjCOEGdHc=-D6W8_7m2=CinXj-itwn6hvoVqdWYQ@mail.gmail.com

William Breathitt Gray

2021-03-27 12:02 UTC #14 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 24 lines · Andy Shevchenko

Quoted 22 lines · Syed Nayyar Waris
Quoted 2 lines · Andy Shevchenko
On Sat, Mar 6, 2021 at 4:08 PM Syed Nayyar Waris <[email protected]>
Quoted 6 lines · wrote:
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 160
Quoted 3 lines
drivers/gpio/gpio-xilinx.c +2 -0
+       bitmap_set_value(old, 64, state[0], 32, 0);
+       bitmap_set_value(old, 64, state[1], 32, 32);
Isn't it effectively bitnap_from_arr32() ?
Quoted 8 lines
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 164
Quoted 2 lines
drivers/gpio/gpio-xilinx.c +2 -0
+       bitmap_set_value(new, 64, state[0], 32, 0);
+       bitmap_set_value(new, 64, state[1], 32, 32);
Ditto.
--
With Best Regards,
Andy Shevchenko
Hi Andy,

Quoted 7 lines

Quoted 3 lines
With bitmap_set_value() we are also specifying the offset (or start) position too. so that the remainder of the array remains unaffected. I think it would not be feasible to use bitmap_from/to_arr32() here.
You have hard coded start and nbits parameters to 32. How is it not the same?

Would these four lines become something like this:

	bitmap_from_arr32(old, state, 64);
	...
	bitmap_from_arr32(new, state, 64);

Sincerely,

William Breathitt Gray

Andy Shevchenko

2021-03-27 16:36 UTC #15 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 22 lines · William Breathitt Gray

Quoted 21 lines · Andy Shevchenko
Quoted 18 lines · Syed Nayyar Waris
Quoted 1 line · Andy Shevchenko
On Sat, Mar 6, 2021 at 4:08 PM Syed Nayyar Waris <[email protected]>
Quoted 10 lines · wrote:
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 160
Quoted 3 lines
drivers/gpio/gpio-xilinx.c +2 -0
+       bitmap_set_value(old, 64, state[0], 32, 0);
+       bitmap_set_value(old, 64, state[1], 32, 32);
Isn't it effectively bitnap_from_arr32() ?
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 164
Quoted 2 lines
drivers/gpio/gpio-xilinx.c +2 -0
+       bitmap_set_value(new, 64, state[0], 32, 0);
+       bitmap_set_value(new, 64, state[1], 32, 32);
Ditto.
With bitmap_set_value() we are also specifying the offset (or start) position too. so that the remainder of the array remains unaffected. I think it would not be feasible to use bitmap_from/to_arr32() here.

Quoted 8 lines

Quoted 2 lines
You have hard coded start and nbits parameters to 32. How is it not the same?
Would these four lines become something like this:
        bitmap_from_arr32(old, state, 64);
        ...
        bitmap_from_arr32(new, state, 64);

This is my understanding, but I might miss something. I mean driver specifics that make my proposal incorrect.

Signature · 2 lines

With Best Regards,
Andy Shevchenko

Syed Nayyar Waris

author

2021-04-01 17:51 UTC #16 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 34 lines · Andy Shevchenko

Quoted 22 lines · William Breathitt Gray
Quoted 21 lines · Andy Shevchenko
Quoted 18 lines · Syed Nayyar Waris
Quoted 1 line · Andy Shevchenko
On Sat, Mar 6, 2021 at 4:08 PM Syed Nayyar Waris <[email protected]>
Quoted 10 lines · wrote:
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 160
Quoted 3 lines
drivers/gpio/gpio-xilinx.c +2 -0
+       bitmap_set_value(old, 64, state[0], 32, 0);
+       bitmap_set_value(old, 64, state[1], 32, 32);
Isn't it effectively bitnap_from_arr32() ?
drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 164
Quoted 2 lines
drivers/gpio/gpio-xilinx.c +2 -0
+       bitmap_set_value(new, 64, state[0], 32, 0);
+       bitmap_set_value(new, 64, state[1], 32, 32);
Ditto.
With bitmap_set_value() we are also specifying the offset (or start) position too. so that the remainder of the array remains unaffected. I think it would not be feasible to use bitmap_from/to_arr32() here.
Quoted 8 lines
Quoted 2 lines
You have hard coded start and nbits parameters to 32. How is it not the same?
Would these four lines become something like this:
        bitmap_from_arr32(old, state, 64);
        ...
        bitmap_from_arr32(new, state, 64);

Quoted 6 lines

This is my understanding, but I might miss something. I mean driver specifics that make my proposal incorrect.
--
With Best Regards,
Andy Shevchenko

I initially (incorrectly) thought that all of the bitmap_set_value() statements have to be replaced. But now I realised, only those specific bitmap_set_value() calls containing 32 bits width have to replaced.

I will incorporate the above review comments in my next v4 submission.

Regards
Syed Nayyar Waris

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linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Andy Shevchenko

2021-03-29 15:25 UTC #17 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

In reply to Syed Nayyar Waris

Quoted 6 lines · Syed Nayyar Waris

This patch reimplements the xgpio_set_multiple() function in drivers/gpio/gpio-xilinx.c to use the new generic functions:
bitmap_get_value() and bitmap_set_value(). The code is now simpler to read and understand. Moreover, instead of looping for each bit in xgpio_set_multiple() function, now we can check each channel at a time and save cycles.

...

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 145

Quoted 1 line

drivers/gpio/gpio-xilinx.c +1 -0
+	u32 *const state = chip->gpio_state;

Looking at this... What's the point of the const here?

Am I right that this tells: pointer is a const, while the data underneath can be modified?

drivers/gpio/gpio-xilinx.c static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, · line 146

Quoted 1 line

drivers/gpio/gpio-xilinx.c +1 -0
+	unsigned int *const width = chip->gpio_width;

Ditto.

Putting const:s here and there for sake of the const is not good practice. It makes code harder to read.

Signature · 2 lines

With Best Regards,
Andy Shevchenko

Syed Nayyar Waris

author

2021-04-01 17:48 UTC #18 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

Quoted 20 lines · Andy Shevchenko

Quoted 6 lines · Syed Nayyar Waris
This patch reimplements the xgpio_set_multiple() function in drivers/gpio/gpio-xilinx.c to use the new generic functions:
bitmap_get_value() and bitmap_set_value(). The code is now simpler to read and understand. Moreover, instead of looping for each bit in xgpio_set_multiple() function, now we can check each channel at a time and save cycles.
...
Quoted 1 line
+ u32 *const state = chip->gpio_state;
Looking at this... What's the point of the const here?
Am I right that this tells: pointer is a const, while the data underneath can be modified?
Quoted 1 line
+ unsigned int *const width = chip->gpio_width;

Quoted 9 lines

Ditto.
Putting const:s here and there for sake of the const is not good practice. It makes code harder to read.
--
With Best Regards,
Andy Shevchenko

Okay. I will incorporate your comments in my next submission. Thank You.

Regards
Syed Nayyar Waris

_______________________________________________
linux-arm-kernel mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Syed Nayyar Waris

author

2021-04-02 10:07 UTC #19 lore raw

Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

In reply to Andy Shevchenko

Quoted 9 lines · Andy Shevchenko

Quoted 6 lines · Syed Nayyar Waris
This patch reimplements the xgpio_set_multiple() function in drivers/gpio/gpio-xilinx.c to use the new generic functions:
bitmap_get_value() and bitmap_set_value(). The code is now simpler to read and understand. Moreover, instead of looping for each bit in xgpio_set_multiple() function, now we can check each channel at a time and save cycles.

Quoted 8 lines

...
Quoted 1 line
+ u32 *const state = chip->gpio_state;
Looking at this... What's the point of the const here?
Am I right that this tells: pointer is a const, while the data underneath can be modified?

Yes you are right and the data underneath can be modified. I have removed the 'const' in v4

Quoted 7 lines

Quoted 2 lines
+ unsigned int *const width = chip->gpio_width;
Ditto.
Putting const:s here and there for sake of the const is not good practice. It makes code harder to read.

Okay.

Quoted 6 lines

--
With Best Regards,
Andy Shevchenko