| Message ID | 20200424123050.GA5653@syed |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On Fri, Apr 24, 2020 at 06:00:50PM +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: Robert Richter <rrichter@marvell.com> > Cc: Linus Walleij <linus.walleij@linaro.org> > Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> > Signed-off-by: Syed Nayyar Waris <syednwaris@gmail.com> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> > --- > drivers/gpio/gpio-thunderx.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpio/gpio-thunderx.c b/drivers/gpio/gpio-thunderx.c > index 9f66dea..74aea25 100644 > --- a/drivers/gpio/gpio-thunderx.c > +++ b/drivers/gpio/gpio-thunderx.c > @@ -275,12 +275,16 @@ static void thunderx_gpio_set_multiple(struct gpio_chip *chip, > unsigned long *bits) > { > int bank; > - u64 set_bits, clear_bits; > + u64 set_bits, clear_bits, gpio_mask; > + const unsigned long bank_size = 64; > + 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, bank_size) { > + bank = offset / bank_size; > + 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); > } > -- > 2.7.4 We noticed in the original code that this set_multiple callback does not appear to work correctly on systems where BITS_PER_LONG == 32. On those systems, the bits and mask values are 32-bit, but the for loop jumps 64 bits at a time -- that means the loop is skipping the upper 32 gpio lines of every iteration. Is the gpio-thunderx driver only intended for 64-bit systems? Or this behavior a bug? William Breathitt Gray
On Fri, Apr 24, 2020 at 09:55:47AM -0400, William Breathitt Gray wrote: > On Fri, Apr 24, 2020 at 06:00:50PM +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: Robert Richter <rrichter@marvell.com> > > Cc: Linus Walleij <linus.walleij@linaro.org> > > Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> > > Signed-off-by: Syed Nayyar Waris <syednwaris@gmail.com> > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> > > --- > > drivers/gpio/gpio-thunderx.c | 12 ++++++++---- > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/gpio/gpio-thunderx.c b/drivers/gpio/gpio-thunderx.c > > index 9f66dea..74aea25 100644 > > --- a/drivers/gpio/gpio-thunderx.c > > +++ b/drivers/gpio/gpio-thunderx.c > > @@ -275,12 +275,16 @@ static void thunderx_gpio_set_multiple(struct gpio_chip *chip, > > unsigned long *bits) > > { > > int bank; > > - u64 set_bits, clear_bits; > > + u64 set_bits, clear_bits, gpio_mask; > > + const unsigned long bank_size = 64; > > + 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, bank_size) { > > + bank = offset / bank_size; > > + 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); > > } > > -- > > 2.7.4 > > We noticed in the original code that this set_multiple callback does not > appear to work correctly on systems where BITS_PER_LONG == 32. On those > systems, the bits and mask values are 32-bit, but the for loop jumps 64 > bits at a time -- that means the loop is skipping the upper 32 gpio > lines of every iteration. > > Is the gpio-thunderx driver only intended for 64-bit systems? Or this > behavior a bug? > > William Breathitt Gray Nevermind, I spoke too soon; I see there's a depends on 64BIT line in the Kconfig for GPIO_THUNDERX. William Breathitt Gray
diff --git a/drivers/gpio/gpio-thunderx.c b/drivers/gpio/gpio-thunderx.c index 9f66dea..74aea25 100644 --- a/drivers/gpio/gpio-thunderx.c +++ b/drivers/gpio/gpio-thunderx.c @@ -275,12 +275,16 @@ static void thunderx_gpio_set_multiple(struct gpio_chip *chip, unsigned long *bits) { int bank; - u64 set_bits, clear_bits; + u64 set_bits, clear_bits, gpio_mask; + const unsigned long bank_size = 64; + 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, bank_size) { + bank = offset / bank_size; + 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); }