On Sat, Mar 6, 2021 at 4:08 PM Syed Nayyar Waris [off-list ref] wrote:

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.

...

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

+

Extra blank line.

+       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.

+       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?

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

-- 
With Best Regards,
Andy Shevchenko

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