linux-kernel - Re: [PATCH v2 2/3] gpio: thunderx: Utilize for_each_set

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Date:   Sun, 14 Feb 2021 15:46:14 +0900
From:   William Breathitt Gray <vilhelm.gray@...il.com>
To:     Syed Nayyar Waris <syednwaris@...il.com>
Cc:     bgolaszewski@...libre.com, andriy.shevchenko@...ux.intel.com,
        michal.simek@...inx.com, arnd@...db.de, rrichter@...vell.com,
        linus.walleij@...aro.org, yamada.masahiro@...ionext.com,
        akpm@...ux-foundation.org, rui.zhang@...el.com,
        daniel.lezcano@...aro.org, amit.kucheria@...durent.com,
        linux-arch@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH v2 2/3] gpio: thunderx: Utilize for_each_set_clump macro

On Fri, Feb 12, 2021 at 06:51:04PM +0530, Syed Nayyar Waris wrote:
> This patch reimplements the thunderx_gpio_set_multiple function in
> drivers/gpio/gpio-thunderx.c to use the new for_each_set_clump 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: William Breathitt Gray <vilhelm.gray@...il.com>
> Cc: Robert Richter <rrichter@...vell.com>
> Cc: Bartosz Golaszewski <bgolaszewski@...libre.com>
> Signed-off-by: Syed Nayyar Waris <syednwaris@...il.com>

Acked-by: William Breathitt Gray <vilhelm.gray@...il.com>

> ---
>  drivers/gpio/gpio-thunderx.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-thunderx.c b/drivers/gpio/gpio-thunderx.c
> index 9f66deab46ea..0398b2d2af4b 100644
> --- a/drivers/gpio/gpio-thunderx.c
> +++ b/drivers/gpio/gpio-thunderx.c
> @@ -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_clump(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);
>  	}
> -- 
> 2.29.0
> 

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