Re: [PATCH 18/62] drm/i915/bdw: Make gen8_gmch_probe

[Imre Deak <imre.deak@intel.com>]

On Sat, 2013-11-02 at 21:07 -0700, Ben Widawsky wrote:
> Probing gen8 is similar to gen6. To make the code cleaner and more
> maintainable however we can use the probe functions to split it out.
> 
> v2: Rebased on top of update gtt probe infrastructure.
> 
> v3: Rebased on top of Kenneth' Graunke's ->pte_encode refactoring.
> 
> V4: Resolve conflicts with Ben's latest ppgtt patches, also switch to
> gen < 8 testing instead of gen <= 7.
> 
> v5: Resolve conflicts with address space vfunc changes in upstream.
> 
> Signed-off-by: Ben Widawsky <ben@bwidawsk.net> (v1)
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 92 +++++++++++++++++++++++++++----------
>  1 file changed, 68 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 19016b7..c6d38d0 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -892,6 +892,66 @@ static inline size_t gen8_get_stolen_size(u16 bdw_gmch_ctl)
>  	return bdw_gmch_ctl << 25; /* 32 MB units */
>  }
>  
> +static int ggtt_probe_common(struct drm_device *dev,
> +			     size_t gtt_size)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	phys_addr_t gtt_bus_addr;
> +	int ret;
> +
> +	/* For Modern GENs the PTEs and register space are split in the BAR */
> +	gtt_bus_addr = pci_resource_start(dev->pdev, 0) +
> +		(pci_resource_len(dev->pdev, 0) / 2);
> +
> +	dev_priv->gtt.gsm = ioremap_wc(gtt_bus_addr, gtt_size);
> +	if (!dev_priv->gtt.gsm) {
> +		DRM_ERROR("Failed to map the gtt page table\n");
> +		return -ENOMEM;
> +	}
> +
> +	ret = setup_scratch_page(dev);
> +	if (ret) {
> +		DRM_ERROR("Scratch setup failed\n");
> +		/* iounmap will also get called at remove, but meh */
> +		iounmap(dev_priv->gtt.gsm);
> +	}
> +
> +	return ret;
> +}
> +
> +static int gen8_gmch_probe(struct drm_device *dev,
> +			   size_t *gtt_total,
> +			   size_t *stolen,
> +			   phys_addr_t *mappable_base,
> +			   unsigned long *mappable_end)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	unsigned int gtt_size;
> +	u16 snb_gmch_ctl;
> +	int ret;
> +
> +	/* TODO: We're not aware of mappable constraints on gen8 yet */
> +	*mappable_base = pci_resource_start(dev->pdev, 2);
> +	*mappable_end = pci_resource_len(dev->pdev, 2);
> +
> +	if (!pci_set_dma_mask(dev->pdev, DMA_BIT_MASK(40)))
> +		pci_set_consistent_dma_mask(dev->pdev, DMA_BIT_MASK(40));

Not that this would be a practical problem, but according to bspec the
maximum physical address size is 39 bits for all PTE formats. Is that a
documentation error? (SNB supported 40 bits)

Other than this the patch looks ok to me:
Reviewed-by: Imre Deak <imre.deak@intel.com>

> +
> +	pci_read_config_word(dev->pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
> +
> +	*stolen = gen8_get_stolen_size(snb_gmch_ctl);
> +
> +	gtt_size = gen8_get_total_gtt_size(snb_gmch_ctl);
> +	*gtt_total = (gtt_size / 8) << PAGE_SHIFT;
> +
> +	ret = ggtt_probe_common(dev, gtt_size);
> +
> +	dev_priv->gtt.base.clear_range = NULL;
> +	dev_priv->gtt.base.insert_entries = NULL;
> +
> +	return ret;
> +}
> +
>  static int gen6_gmch_probe(struct drm_device *dev,
>  			   size_t *gtt_total,
>  			   size_t *stolen,
> @@ -899,7 +959,6 @@ static int gen6_gmch_probe(struct drm_device *dev,
>  			   unsigned long *mappable_end)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> -	phys_addr_t gtt_bus_addr;
>  	unsigned int gtt_size;
>  	u16 snb_gmch_ctl;
>  	int ret;
> @@ -920,30 +979,12 @@ static int gen6_gmch_probe(struct drm_device *dev,
>  		pci_set_consistent_dma_mask(dev->pdev, DMA_BIT_MASK(40));
>  	pci_read_config_word(dev->pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
>  
> -	if (IS_GEN8(dev)) {
> -		gtt_size = gen8_get_total_gtt_size(snb_gmch_ctl);
> -		*gtt_total = (gtt_size / 8) << PAGE_SHIFT;
> -		*stolen = gen8_get_stolen_size(snb_gmch_ctl);
> -	} else {
> -		gtt_size = gen6_get_total_gtt_size(snb_gmch_ctl);
> -		*gtt_total = (gtt_size / sizeof(gen6_gtt_pte_t)) << PAGE_SHIFT;
> -		*stolen = gen6_get_stolen_size(snb_gmch_ctl);
> -	}
> -
> -	/* For Modern GENs the PTEs and register space are split in the BAR */
> -	gtt_bus_addr = pci_resource_start(dev->pdev, 0) +
> -		(pci_resource_len(dev->pdev, 0) / 2);
> -
> -	dev_priv->gtt.gsm = ioremap_wc(gtt_bus_addr, gtt_size);
> -	if (!dev_priv->gtt.gsm) {
> -		DRM_ERROR("Failed to map the gtt page table\n");
> -		return -ENOMEM;
> +	*stolen = gen6_get_stolen_size(snb_gmch_ctl);
>  
> -	}
> +	gtt_size = gen6_get_total_gtt_size(snb_gmch_ctl);
> +	*gtt_total = (gtt_size / sizeof(gen6_gtt_pte_t)) << PAGE_SHIFT;
>  
> -	ret = setup_scratch_page(dev);
> -	if (ret)
> -		DRM_ERROR("Scratch setup failed\n");
> +	ret = ggtt_probe_common(dev, gtt_size);
>  
>  	dev_priv->gtt.base.clear_range = gen6_ggtt_clear_range;
>  	dev_priv->gtt.base.insert_entries = gen6_ggtt_insert_entries;
> @@ -997,7 +1038,7 @@ int i915_gem_gtt_init(struct drm_device *dev)
>  	if (INTEL_INFO(dev)->gen <= 5) {
>  		gtt->gtt_probe = i915_gmch_probe;
>  		gtt->base.cleanup = i915_gmch_remove;
> -	} else {
> +	} else if (INTEL_INFO(dev)->gen < 8) {
>  		gtt->gtt_probe = gen6_gmch_probe;
>  		gtt->base.cleanup = gen6_gmch_remove;
>  		if (IS_HASWELL(dev) && dev_priv->ellc_size)
> @@ -1010,6 +1051,9 @@ int i915_gem_gtt_init(struct drm_device *dev)
>  			gtt->base.pte_encode = ivb_pte_encode;
>  		else
>  			gtt->base.pte_encode = snb_pte_encode;
> +	} else {
> +		dev_priv->gtt.gtt_probe = gen8_gmch_probe;
> +		dev_priv->gtt.base.cleanup = gen6_gmch_remove;
>  	}
>  
>  	ret = gtt->gtt_probe(dev, &gtt->base.total, &gtt->stolen_size,