Re: [PATCH 1/7] drm/i915: create macros for the "unclaimed register" checks

[Ben Widawsky <ben@bwidawsk.net>]

On Fri, 25 Jan 2013 18:57:36 -0200
Paulo Zanoni <przanoni@gmail.com> wrote:

> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> This avoids polluting i915_write##x and also allows us to reuse code
> on i915_read##x.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c |   24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 9cc8f87..ae0a55a 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1224,6 +1224,20 @@ ilk_dummy_write(struct drm_i915_private *dev_priv)
>  	I915_WRITE_NOTRACE(MI_MODE, 0);
>  }
>  
> +#define UNCLAIMED_REG_CLEAR(dev_priv, reg) \
> +	if (IS_HASWELL(dev_priv->dev) && \
> +	    (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) { \
> +		DRM_ERROR("Unknown unclaimed register before writing to %x\n", reg); \
> +		I915_WRITE_NOTRACE(GEN7_ERR_INT, ERR_INT_MMIO_UNCLAIMED); \
> +	}
> +

You don't really need the if here, do you? I think the way it worked
originally was fine.

> +#define UNCLAIMED_REG_CHECK(dev_priv, reg) \
> +	if (IS_HASWELL(dev_priv->dev) && \
> +	    (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) { \
> +		DRM_ERROR("Unclaimed write to %x\n", reg); \
> +		writel(ERR_INT_MMIO_UNCLAIMED, dev_priv->regs + GEN7_ERR_INT);	\
> +	}
> +
>  #define __i915_read(x, y) \
>  u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
>  	u##x val = 0; \

I suppose you could add some 'unlikely' predictions in another patch if
you wanted. I really don't know what the consensus is on using those
these day.

> @@ -1262,10 +1276,7 @@ void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
>  	} \
>  	if (IS_GEN5(dev_priv->dev)) \
>  		ilk_dummy_write(dev_priv); \
> -	if (IS_HASWELL(dev_priv->dev) && (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) { \
> -		DRM_ERROR("Unknown unclaimed register before writing to %x\n", reg); \
> -		I915_WRITE_NOTRACE(GEN7_ERR_INT, ERR_INT_MMIO_UNCLAIMED); \
> -	} \
> +	UNCLAIMED_REG_CLEAR(dev_priv, reg); \
>  	if (IS_VALLEYVIEW(dev_priv->dev) && IS_DISPLAYREG(reg)) { \
>  		write##y(val, dev_priv->regs + reg + 0x180000);		\
>  	} else {			\

Here's what I meant above, you replace 2 lines of code with 4 from the
macro. (Including an extra MMIO read).

> @@ -1274,10 +1285,7 @@ void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
>  	if (unlikely(__fifo_ret)) { \
>  		gen6_gt_check_fifodbg(dev_priv); \
>  	} \
> -	if (IS_HASWELL(dev_priv->dev) && (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) { \
> -		DRM_ERROR("Unclaimed write to %x\n", reg); \
> -		writel(ERR_INT_MMIO_UNCLAIMED, dev_priv->regs + GEN7_ERR_INT);	\
> -	} \
> +	UNCLAIMED_REG_CHECK(dev_priv, reg); \
>  }
>  __i915_write(8, b)
>  __i915_write(16, w)



-- 
Ben Widawsky, Intel Open Source Technology Center