Re: [PATCHv3 1/7] basic_mmio_gpio: remove runtime width/endianness evaluation

[Grant Likely <grant.likely@secretlab.ca>]

On Mon, Apr 11, 2011 at 12:21:48PM +0100, Jamie Iles wrote:
> Remove endianness/width calculations at runtime by installing function
> pointers for bit-to-mask conversion and register accessors.
> 
> Reported-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Jamie Iles <jamie@jamieiles.com>
> Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
> Cc: Grant Likely <grant.likely@secretlab.ca>

Merged, thanks.

g.

> ---
>  drivers/gpio/basic_mmio_gpio.c |  136 +++++++++++++++++++++++++++-------------
>  1 files changed, 92 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c
> index 3addea6..e935a24 100644
> --- a/drivers/gpio/basic_mmio_gpio.c
> +++ b/drivers/gpio/basic_mmio_gpio.c
> @@ -63,6 +63,10 @@ o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`
>  
>  struct bgpio_chip {
>  	struct gpio_chip gc;
> +
> +	unsigned long (*read_reg)(void __iomem *reg);
> +	void (*write_reg)(void __iomem *reg, unsigned long data);
> +
>  	void __iomem *reg_dat;
>  	void __iomem *reg_set;
>  	void __iomem *reg_clr;
> @@ -74,7 +78,7 @@ struct bgpio_chip {
>  	 * Some GPIO controllers work with the big-endian bits notation,
>  	 * e.g. in a 8-bits register, GPIO7 is the least significant bit.
>  	 */
> -	int big_endian_bits;
> +	unsigned long (*pin2mask)(struct bgpio_chip *bgc, unsigned int pin);
>  
>  	/*
>  	 * Used to lock bgpio_chip->data. Also, this is needed to keep
> @@ -91,70 +95,77 @@ static struct bgpio_chip *to_bgpio_chip(struct gpio_chip *gc)
>  	return container_of(gc, struct bgpio_chip, gc);
>  }
>  
> -static unsigned long bgpio_in(struct bgpio_chip *bgc)
> +static void bgpio_write8(void __iomem *reg, unsigned long data)
>  {
> -	switch (bgc->bits) {
> -	case 8:
> -		return __raw_readb(bgc->reg_dat);
> -	case 16:
> -		return __raw_readw(bgc->reg_dat);
> -	case 32:
> -		return __raw_readl(bgc->reg_dat);
> -#if BITS_PER_LONG >= 64
> -	case 64:
> -		return __raw_readq(bgc->reg_dat);
> -#endif
> -	}
> -	return -EINVAL;
> +	__raw_writeb(data, reg);
>  }
>  
> -static void bgpio_out(struct bgpio_chip *bgc, void __iomem *reg,
> -		      unsigned long data)
> +static unsigned long bgpio_read8(void __iomem *reg)
>  {
> -	switch (bgc->bits) {
> -	case 8:
> -		__raw_writeb(data, reg);
> -		return;
> -	case 16:
> -		__raw_writew(data, reg);
> -		return;
> -	case 32:
> -		__raw_writel(data, reg);
> -		return;
> +	return __raw_readb(reg);
> +}
> +
> +static void bgpio_write16(void __iomem *reg, unsigned long data)
> +{
> +	__raw_writew(data, reg);
> +}
> +
> +static unsigned long bgpio_read16(void __iomem *reg)
> +{
> +	return __raw_readw(reg);
> +}
> +
> +static void bgpio_write32(void __iomem *reg, unsigned long data)
> +{
> +	__raw_writel(data, reg);
> +}
> +
> +static unsigned long bgpio_read32(void __iomem *reg)
> +{
> +	return __raw_readl(reg);
> +}
> +
>  #if BITS_PER_LONG >= 64
> -	case 64:
> -		__raw_writeq(data, reg);
> -		return;
> -#endif
> -	}
> +static void bgpio_write64(void __iomem *reg, unsigned long data)
> +{
> +	__raw_writeq(data, reg);
>  }
>  
> +static unsigned long bgpio_read64(void __iomem *reg)
> +{
> +	return __raw_readq(reg);
> +}
> +#endif /* BITS_PER_LONG >= 64 */
> +
>  static unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin)
>  {
> -	if (bgc->big_endian_bits)
> -		return 1 << (bgc->bits - 1 - pin);
> -	else
> -		return 1 << pin;
> +	return 1 << pin;
> +}
> +
> +static unsigned long bgpio_pin2mask_be(struct bgpio_chip *bgc,
> +				       unsigned int pin)
> +{
> +	return 1 << (bgc->bits - 1 - pin);
>  }
>  
>  static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
>  {
>  	struct bgpio_chip *bgc = to_bgpio_chip(gc);
>  
> -	return bgpio_in(bgc) & bgpio_pin2mask(bgc, gpio);
> +	return bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio);
>  }
>  
>  static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>  {
>  	struct bgpio_chip *bgc = to_bgpio_chip(gc);
> -	unsigned long mask = bgpio_pin2mask(bgc, gpio);
> +	unsigned long mask = bgc->pin2mask(bgc, gpio);
>  	unsigned long flags;
>  
>  	if (bgc->reg_set) {
>  		if (val)
> -			bgpio_out(bgc, bgc->reg_set, mask);
> +			bgc->write_reg(bgc->reg_set, mask);
>  		else
> -			bgpio_out(bgc, bgc->reg_clr, mask);
> +			bgc->write_reg(bgc->reg_clr, mask);
>  		return;
>  	}
>  
> @@ -165,7 +176,7 @@ static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>  	else
>  		bgc->data &= ~mask;
>  
> -	bgpio_out(bgc, bgc->reg_dat, bgc->data);
> +	bgc->write_reg(bgc->reg_dat, bgc->data);
>  
>  	spin_unlock_irqrestore(&bgc->lock, flags);
>  }
> @@ -181,9 +192,44 @@ static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
>  	return 0;
>  }
>  
> -static int __devinit bgpio_probe(struct platform_device *pdev)
> +static int bgpio_setup_accessors(struct platform_device *pdev,
> +				 struct bgpio_chip *bgc)
>  {
>  	const struct platform_device_id *platid = platform_get_device_id(pdev);
> +
> +	switch (bgc->bits) {
> +	case 8:
> +		bgc->read_reg	= bgpio_read8;
> +		bgc->write_reg	= bgpio_write8;
> +		break;
> +	case 16:
> +		bgc->read_reg	= bgpio_read16;
> +		bgc->write_reg	= bgpio_write16;
> +		break;
> +	case 32:
> +		bgc->read_reg	= bgpio_read32;
> +		bgc->write_reg	= bgpio_write32;
> +		break;
> +#if BITS_PER_LONG >= 64
> +	case 64:
> +		bgc->read_reg	= bgpio_read64;
> +		bgc->write_reg	= bgpio_write64;
> +		break;
> +#endif /* BITS_PER_LONG >= 64 */
> +	default:
> +		dev_err(&pdev->dev, "unsupported data width %u bits\n",
> +			bgc->bits);
> +		return -EINVAL;
> +	}
> +
> +	bgc->pin2mask = strcmp(platid->name, "basic-mmio-gpio-be") ?
> +		bgpio_pin2mask : bgpio_pin2mask_be;
> +
> +	return 0;
> +}
> +
> +static int __devinit bgpio_probe(struct platform_device *pdev)
> +{
>  	struct device *dev = &pdev->dev;
>  	struct bgpio_pdata *pdata = dev_get_platdata(dev);
>  	struct bgpio_chip *bgc;
> @@ -232,9 +278,11 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
>  	spin_lock_init(&bgc->lock);
>  
>  	bgc->bits = bits;
> -	bgc->big_endian_bits = !strcmp(platid->name, "basic-mmio-gpio-be");
> -	bgc->data = bgpio_in(bgc);
> +	ret = bgpio_setup_accessors(pdev, bgc);
> +	if (ret)
> +		return ret;
>  
> +	bgc->data = bgc->read_reg(bgc->reg_dat);
>  	bgc->gc.ngpio = bits;
>  	bgc->gc.direction_input = bgpio_dir_in;
>  	bgc->gc.direction_output = bgpio_dir_out;
> -- 
> 1.7.4.2
>