Re: [PATCH] drm/i915: remove confusing GPIO vs PCH_GPIO

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 05 Jul 2018, Lucas De Marchi <lucas.demarchi@intel.com> wrote:
> Instead of defining all registers twice, define just a PCH_GPIO_BASE
> that has the same address as PCH_GPIO_A and use that to calculate all
> the others. This also brings VLV and !HAS_GMCH_DISPLAY in line, doing
> the same thing.
>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
>
> As discussed on https://patchwork.freedesktop.org/patch/225388/.
>
>  drivers/gpu/drm/i915/gvt/handlers.c |  2 +-
>  drivers/gpu/drm/i915/i915_reg.h     | 37 +++++++++++++++--------------
>  drivers/gpu/drm/i915/intel_i2c.c    | 15 ++++++------
>  3 files changed, 27 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
> index e39492aaff6c..e25a74fe753b 100644
> --- a/drivers/gpu/drm/i915/gvt/handlers.c
> +++ b/drivers/gpu/drm/i915/gvt/handlers.c
> @@ -2084,7 +2084,7 @@ static int init_generic_mmio_info(struct intel_gvt *gvt)
>  
>  	MMIO_F(PCH_GMBUS0, 4 * 4, 0, 0, 0, D_ALL, gmbus_mmio_read,
>  		gmbus_mmio_write);
> -	MMIO_F(PCH_GPIOA, 6 * 4, F_UNALIGN, 0, 0, D_ALL, NULL, NULL);
> +	MMIO_F(_MMIO(PCH_GPIO_BASE), 6 * 4, F_UNALIGN, 0, 0, D_ALL, NULL, NULL);
>  	MMIO_F(_MMIO(0xe4f00), 0x28, 0, 0, 0, D_ALL, NULL, NULL);
>  
>  	MMIO_F(_MMIO(_PCH_DPB_AUX_CH_CTL), 6 * 4, 0, 0, 0, D_PRE_SKL, NULL,
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index dc953ee7e3b3..11503ed60832 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -3045,18 +3045,6 @@ enum i915_power_well_id {
>  /*
>   * GPIO regs
>   */
> -#define GPIOA			_MMIO(0x5010)
> -#define GPIOB			_MMIO(0x5014)
> -#define GPIOC			_MMIO(0x5018)
> -#define GPIOD			_MMIO(0x501c)
> -#define GPIOE			_MMIO(0x5020)
> -#define GPIOF			_MMIO(0x5024)
> -#define GPIOG			_MMIO(0x5028)
> -#define GPIOH			_MMIO(0x502c)
> -#define GPIOJ			_MMIO(0x5034)
> -#define GPIOK			_MMIO(0x5038)
> -#define GPIOL			_MMIO(0x503C)
> -#define GPIOM			_MMIO(0x5040)
>  # define GPIO_CLOCK_DIR_MASK		(1 << 0)
>  # define GPIO_CLOCK_DIR_IN		(0 << 1)
>  # define GPIO_CLOCK_DIR_OUT		(1 << 1)
> @@ -7625,12 +7613,25 @@ enum {
>  #define   ICP_TC_HPD_LONG_DETECT(tc_port)	(2 << (tc_port) * 4)
>  #define   ICP_TC_HPD_SHORT_DETECT(tc_port)	(1 << (tc_port) * 4)
>  
> -#define PCH_GPIOA               _MMIO(0xc5010)
> -#define PCH_GPIOB               _MMIO(0xc5014)
> -#define PCH_GPIOC               _MMIO(0xc5018)
> -#define PCH_GPIOD               _MMIO(0xc501c)
> -#define PCH_GPIOE               _MMIO(0xc5020)
> -#define PCH_GPIOF               _MMIO(0xc5024)
> +#define GPIO_OFFSET		0x5010u
> +#define PCH_GPIO_BASE		(0xc0000u + GPIO_OFFSET)
> +#define VLV_GPIO_BASE		(VLV_DISPLAY_BASE + GPIO_OFFSET)
> +
> +enum i915_gpio {
> +	GPIOA = 0,
> +	GPIOB,
> +	GPIOC,
> +	GPIOD,
> +	GPIOE,
> +	GPIOF,
> +	GPIOG,
> +	GPIOH,
> +	__GPIOI_UNUSED,
> +	GPIOJ,
> +	GPIOK,
> +	GPIOL,
> +	GPIOM,
> +};

Is this the right place for the enum? The file is about registers,
i915_gpio becomes a GPIO identifier not unline pipe, transcoder, or
port.

Please add a macro to access the registers, indexed using i915_gpio, in
terms of dev_priv->gpio_mmio_base. Something like:

#define GPIO(gpio)	_MMIO(dev_priv->gpio_mmio_base + GPIO_OFFSET + 4 * (gpio))

Please use that in code instead of spreading register offset arithmetics
outside of this file.

Please note that there are other registers that use gpio_mmio_base
defined in this file, and they will be broken by the change of adding
GPIO_OFFSET directly into gpio_mmio_base! I don't care which way you do
it, but take it into account.

Overall I like the idea.

BR,
Jani.


>  
>  #define PCH_GMBUS0		_MMIO(0xc5100)
>  #define PCH_GMBUS1		_MMIO(0xc5104)
> diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
> index 97606c1be70d..bb1040275d4b 100644
> --- a/drivers/gpu/drm/i915/intel_i2c.c
> +++ b/drivers/gpu/drm/i915/intel_i2c.c
> @@ -37,7 +37,7 @@
>  
>  struct gmbus_pin {
>  	const char *name;
> -	i915_reg_t reg;
> +	enum i915_gpio gpio;
>  };
>  
>  /* Map gmbus pin pairs to names and registers. */
> @@ -121,8 +121,7 @@ bool intel_gmbus_is_valid_pin(struct drm_i915_private *dev_priv,
>  	else
>  		size = ARRAY_SIZE(gmbus_pins);
>  
> -	return pin < size &&
> -		i915_mmio_reg_valid(get_gmbus_pin(dev_priv, pin)->reg);
> +	return pin < size && get_gmbus_pin(dev_priv, pin)->name;
>  }
>  
>  /* Intel GPIO access functions */
> @@ -293,7 +292,7 @@ intel_gpio_setup(struct intel_gmbus *bus, unsigned int pin)
>  	algo = &bus->bit_algo;
>  
>  	bus->gpio_reg = _MMIO(dev_priv->gpio_mmio_base +
> -			      i915_mmio_reg_offset(get_gmbus_pin(dev_priv, pin)->reg));
> +			      4 * get_gmbus_pin(dev_priv, pin)->gpio);
>  	bus->adapter.algo_data = algo;
>  	algo->setsda = set_data;
>  	algo->setscl = set_clock;
> @@ -775,11 +774,11 @@ int intel_setup_gmbus(struct drm_i915_private *dev_priv)
>  		return 0;
>  
>  	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> -		dev_priv->gpio_mmio_base = VLV_DISPLAY_BASE;
> +		dev_priv->gpio_mmio_base = VLV_GPIO_BASE;
>  	else if (!HAS_GMCH_DISPLAY(dev_priv))
> -		dev_priv->gpio_mmio_base =
> -			i915_mmio_reg_offset(PCH_GPIOA) -
> -			i915_mmio_reg_offset(GPIOA);
> +		dev_priv->gpio_mmio_base = PCH_GPIO_BASE;
> +	else
> +		dev_priv->gpio_mmio_base = GPIO_OFFSET;
>  
>  	mutex_init(&dev_priv->gmbus_mutex);
>  	init_waitqueue_head(&dev_priv->gmbus_wait_queue);

-- 
Jani Nikula, Intel Open Source Graphics Center
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