Re: [PATCH v4 4/4] gpio: xilinx: Utilize for_each_set_clump macro
From: William Breathitt Gray <hidden>
Date: 2020-05-02 19:04:12
Also in:
linux-gpio, lkml
On Sun, May 03, 2020 at 12:21:54AM +0530, Syed Nayyar Waris wrote:
quoted hunk ↗ jump to hunk
This patch reimplements the xgpio_set_multiple function in drivers/gpio/gpio-xilinx.c to use the new for_each_set_clump macro. Instead of looping for each bit in xgpio_set_multiple function, now we can check each channel at a time and save cycles. Cc: Linus Walleij <redacted> Cc: Bartosz Golaszewski <redacted> Cc: Michal Simek <redacted> Signed-off-by: Syed Nayyar Waris <redacted> Signed-off-by: William Breathitt Gray <redacted> --- Changes in v4: - Minor change: Hardcode value for better code readability. Changes in v3: - No change. Changes in v2: - No change. drivers/gpio/gpio-xilinx.c | 64 ++++++++++++++++++++------------------ 1 file changed, 34 insertions(+), 30 deletions(-)diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c index 67f9f82e0db0..67c5eeaf1bb9 100644 --- a/drivers/gpio/gpio-xilinx.c +++ b/drivers/gpio/gpio-xilinx.c@@ -136,39 +136,43 @@ static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val) static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask, unsigned long *bits) { - unsigned long flags; + unsigned long flags[2]; 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); - } + u32 *const state = chip->gpio_state; + unsigned int *const width = chip->gpio_width; + const unsigned long state_size = 32; + const unsigned long total_state_bits = state_size * 2;
Hello Syed, I don't think there's much need for these two variables either. You can remove the state_size and total_state_bits variables, and instead inline 32 and 64 directly in your code below. William Breathitt Gray
+ unsigned long offset, clump;
+ size_t index;
+
+ DECLARE_BITMAP(old, 64);
+ DECLARE_BITMAP(new, 64);
+ DECLARE_BITMAP(changed, 64);
+
+ spin_lock_irqsave(&chip->gpio_lock[0], flags[0]);
+ spin_lock_irqsave(&chip->gpio_lock[1], flags[1]);
+
+ bitmap_set_value(old, state[0], 0, width[0]);
+ bitmap_set_value(old, state[1], width[0], width[1]);
+ bitmap_replace(new, old, bits, mask, gc->ngpio);
+
+ bitmap_set_value(old, state[0], 0, state_size);
+ bitmap_set_value(old, state[1], state_size, state_size);
+ state[0] = bitmap_get_value(new, 0, width[0]);
+ state[1] = bitmap_get_value(new, width[0], width[1]);
+ bitmap_set_value(new, state[0], 0, state_size);
+ bitmap_set_value(new, state[1], state_size, state_size);
+ bitmap_xor(changed, old, new, total_state_bits);
+
+ for_each_set_clump(offset, clump, changed, total_state_bits, state_size) {
+ index = offset / state_size;
+ xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
+ index * XGPIO_CHANNEL_OFFSET,
+ state[index]);
}
- xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
- index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
-
- spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
+ spin_unlock_irqrestore(&chip->gpio_lock[1], flags[1]);
+ spin_unlock_irqrestore(&chip->gpio_lock[0], flags[0]);
}
/**
--
2.26.2