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gpio: mmio: Make pin2mask() a private business
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The vtable call pin2mask() was introducing a vtable function call
in every gpiochip callback for a generic MMIO GPIO chip. This was
not exactly efficient. (Maybe link-time optimization could get rid of
it, I don't know.)

After removing all external calls into this API we can make it a
boolean flag in the struct gpio_chip call and sink the function into
the gpio-mmio driver yielding encapsulation and potential speedups.

Cc: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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Linus Walleij committed Oct 25, 2017
1 parent b3222f7 commit 24efd94
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Showing 2 changed files with 23 additions and 30 deletions.
45 changes: 19 additions & 26 deletions drivers/gpio/gpio-mmio.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -126,20 +126,16 @@ static unsigned long bgpio_read32be(void __iomem *reg)
return ioread32be(reg);
}

static unsigned long bgpio_pin2mask(struct gpio_chip *gc, unsigned int pin)
static unsigned long bgpio_line2mask(struct gpio_chip *gc, unsigned int line)
{
return BIT(pin);
}

static unsigned long bgpio_pin2mask_be(struct gpio_chip *gc,
unsigned int pin)
{
return BIT(gc->bgpio_bits - 1 - pin);
if (gc->be_bits)
return BIT(gc->bgpio_bits - 1 - line);
return BIT(line);
}

static int bgpio_get_set(struct gpio_chip *gc, unsigned int gpio)
{
unsigned long pinmask = gc->pin2mask(gc, gpio);
unsigned long pinmask = bgpio_line2mask(gc, gpio);

if (gc->bgpio_dir & pinmask)
return !!(gc->read_reg(gc->reg_set) & pinmask);
Expand All @@ -149,7 +145,7 @@ static int bgpio_get_set(struct gpio_chip *gc, unsigned int gpio)

static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
{
return !!(gc->read_reg(gc->reg_dat) & gc->pin2mask(gc, gpio));
return !!(gc->read_reg(gc->reg_dat) & bgpio_line2mask(gc, gpio));
}

static void bgpio_set_none(struct gpio_chip *gc, unsigned int gpio, int val)
Expand All @@ -158,7 +154,7 @@ static void bgpio_set_none(struct gpio_chip *gc, unsigned int gpio, int val)

static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
unsigned long mask = gc->pin2mask(gc, gpio);
unsigned long mask = bgpio_line2mask(gc, gpio);
unsigned long flags;

spin_lock_irqsave(&gc->bgpio_lock, flags);
Expand All @@ -176,7 +172,7 @@ static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
int val)
{
unsigned long mask = gc->pin2mask(gc, gpio);
unsigned long mask = bgpio_line2mask(gc, gpio);

if (val)
gc->write_reg(gc->reg_set, mask);
Expand All @@ -186,7 +182,7 @@ static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,

static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
unsigned long mask = gc->pin2mask(gc, gpio);
unsigned long mask = bgpio_line2mask(gc, gpio);
unsigned long flags;

spin_lock_irqsave(&gc->bgpio_lock, flags);
Expand Down Expand Up @@ -216,9 +212,9 @@ static void bgpio_multiple_get_masks(struct gpio_chip *gc,
break;
if (__test_and_clear_bit(i, mask)) {
if (test_bit(i, bits))
*set_mask |= gc->pin2mask(gc, i);
*set_mask |= bgpio_line2mask(gc, i);
else
*clear_mask |= gc->pin2mask(gc, i);
*clear_mask |= bgpio_line2mask(gc, i);
}
}
}
Expand Down Expand Up @@ -294,7 +290,7 @@ static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)

spin_lock_irqsave(&gc->bgpio_lock, flags);

gc->bgpio_dir &= ~gc->pin2mask(gc, gpio);
gc->bgpio_dir &= ~bgpio_line2mask(gc, gpio);
gc->write_reg(gc->reg_dir, gc->bgpio_dir);

spin_unlock_irqrestore(&gc->bgpio_lock, flags);
Expand All @@ -305,7 +301,7 @@ static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
static int bgpio_get_dir(struct gpio_chip *gc, unsigned int gpio)
{
/* Return 0 if output, 1 of input */
return !(gc->read_reg(gc->reg_dir) & gc->pin2mask(gc, gpio));
return !(gc->read_reg(gc->reg_dir) & bgpio_line2mask(gc, gpio));
}

static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
Expand All @@ -316,7 +312,7 @@ static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)

spin_lock_irqsave(&gc->bgpio_lock, flags);

gc->bgpio_dir |= gc->pin2mask(gc, gpio);
gc->bgpio_dir |= bgpio_line2mask(gc, gpio);
gc->write_reg(gc->reg_dir, gc->bgpio_dir);

spin_unlock_irqrestore(&gc->bgpio_lock, flags);
Expand All @@ -330,7 +326,7 @@ static int bgpio_dir_in_inv(struct gpio_chip *gc, unsigned int gpio)

spin_lock_irqsave(&gc->bgpio_lock, flags);

gc->bgpio_dir |= gc->pin2mask(gc, gpio);
gc->bgpio_dir |= bgpio_line2mask(gc, gpio);
gc->write_reg(gc->reg_dir, gc->bgpio_dir);

spin_unlock_irqrestore(&gc->bgpio_lock, flags);
Expand All @@ -346,7 +342,7 @@ static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)

spin_lock_irqsave(&gc->bgpio_lock, flags);

gc->bgpio_dir &= ~gc->pin2mask(gc, gpio);
gc->bgpio_dir &= ~bgpio_line2mask(gc, gpio);
gc->write_reg(gc->reg_dir, gc->bgpio_dir);

spin_unlock_irqrestore(&gc->bgpio_lock, flags);
Expand All @@ -357,12 +353,11 @@ static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
static int bgpio_get_dir_inv(struct gpio_chip *gc, unsigned int gpio)
{
/* Return 0 if output, 1 if input */
return !!(gc->read_reg(gc->reg_dir) & gc->pin2mask(gc, gpio));
return !!(gc->read_reg(gc->reg_dir) & bgpio_line2mask(gc, gpio));
}

static int bgpio_setup_accessors(struct device *dev,
struct gpio_chip *gc,
bool bit_be,
bool byte_be)
{

Expand Down Expand Up @@ -406,8 +401,6 @@ static int bgpio_setup_accessors(struct device *dev,
return -EINVAL;
}

gc->pin2mask = bit_be ? bgpio_pin2mask_be : bgpio_pin2mask;

return 0;
}

Expand Down Expand Up @@ -531,8 +524,8 @@ int bgpio_init(struct gpio_chip *gc, struct device *dev,
if (ret)
return ret;

ret = bgpio_setup_accessors(dev, gc, flags & BGPIOF_BIG_ENDIAN,
flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
gc->be_bits = !!(flags & BGPIOF_BIG_ENDIAN);
ret = bgpio_setup_accessors(dev, gc, flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
if (ret)
return ret;

Expand Down
8 changes: 4 additions & 4 deletions include/linux/gpio/driver.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -67,9 +67,9 @@ struct module;
* registers.
* @read_reg: reader function for generic GPIO
* @write_reg: writer function for generic GPIO
* @pin2mask: some generic GPIO controllers work with the big-endian bits
* notation, e.g. in a 8-bits register, GPIO7 is the least significant
* bit. This callback assigns the right bit mask.
* @be_bits: if the generic GPIO has big endian bit order (bit 31 is representing
* line 0, bit 30 is line 1 ... bit 0 is line 31) this is set to true by the
* generic GPIO core. It is for internal housekeeping only.
* @reg_dat: data (in) register for generic GPIO
* @reg_set: output set register (out=high) for generic GPIO
* @reg_clr: output clear register (out=low) for generic GPIO
Expand Down Expand Up @@ -151,7 +151,7 @@ struct gpio_chip {
#if IS_ENABLED(CONFIG_GPIO_GENERIC)
unsigned long (*read_reg)(void __iomem *reg);
void (*write_reg)(void __iomem *reg, unsigned long data);
unsigned long (*pin2mask)(struct gpio_chip *gc, unsigned int pin);
bool be_bits;
void __iomem *reg_dat;
void __iomem *reg_set;
void __iomem *reg_clr;
Expand Down

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