Messages in this thread | | | From | Andy Shevchenko <> | Date | Fri, 26 Mar 2021 19:57:35 +0200 | Subject | Re: [PATCH v3 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value |
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On Sat, Mar 6, 2021 at 4:08 PM Syed Nayyar Waris <syednwaris@gmail.com> 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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