Re: [PATCH 4/4] drm/i915: BIOS and power context stolen mem handling for VLV

[Ben Widawsky <ben@bwidawsk.net>]

On Thu, May 02, 2013 at 10:48:10AM -0700, Jesse Barnes wrote:
> But we need to get the right stolen base and make pre-allocated objects
> for BIOS stuff so we don't clobber it.  If the BIOS hasn't allocated a
> power context, we allocate one here too, from stolen space as required
> by the docs.
> 
> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
> ---
>  drivers/gpu/drm/i915/i915_drv.h        |    2 +
>  drivers/gpu/drm/i915/i915_gem_stolen.c |   78 +++++++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/i915_reg.h        |    1 +
>  3 files changed, 80 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 3ac71db..5e9ea36 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1055,6 +1055,8 @@ typedef struct drm_i915_private {
>  
>  	struct i915_gpu_error gpu_error;
>  
> +	struct drm_i915_gem_object *vlv_pctx;
> +
>  	/* list of fbdev register on this device */
>  	struct intel_fbdev *fbdev;
>  
> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
> index 67d3510..c06056a 100644
> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
> @@ -62,7 +62,10 @@ static unsigned long i915_stolen_to_physical(struct drm_device *dev)
>  	 * its value of TOLUD.
>  	 */
>  	base = 0;
> -	if (INTEL_INFO(dev)->gen >= 6) {
> +	if (IS_VALLEYVIEW(dev)) {
> +		pci_read_config_dword(pdev, 0x5c, &base);
> +		base &= ((1<<19) - 1);
> +	} if (INTEL_INFO(dev)->gen >= 6) {

else if

>  		/* Read Base Data of Stolen Memory Register (BDSM) directly.
>  		 * Note that there is also a MCHBAR miror at 0x1080c0 or
>  		 * we could use device 2:0x5c instead.
> @@ -172,14 +175,82 @@ void i915_gem_stolen_cleanup_compression(struct drm_device *dev)
>  	dev_priv->cfb_size = 0;
>  }
>  
> +static void valleyview_setup_pctx(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_i915_gem_object *pctx;
> +	unsigned long pctx_paddr;
> +	u32 pcbr;
> +	int pctx_size = 24*1024;
> +
> +	pcbr = I915_READ(VLV_PCBR);
> +	if (pcbr) {
> +		/* BIOS set it up already, grab the pre-alloc'd space */
> +		int pcbr_offset;
> +
> +		pcbr_offset = (pcbr & (~4095)) - dev_priv->mm.stolen_base;
s/4095/PAGE_MASK?
> +		pctx = i915_gem_object_create_stolen_for_preallocated(dev_priv->dev,
> +								      pcbr_offset,
> +								      pcbr_offset,
> +								      pctx_size);

Can you remind me how we can get away with the assumption that gtt
offset has a 1:1 mapping with the stolen offset?

> +		/* We don't need to track it since we don't own it */
> +		return;
> +	}
> +
> +	/*
> +	 * From the Gunit register HAS:
> +	 * The Gfx driver is expected to program this register and ensure
> +	 * proper allocation within Gfx stolen memory.  For example, this
> +	 * register should be programmed such than the PCBR range does not
> +	 * overlap with other ranges, such as the frame buffer, protected
> +	 * memory, or any other relevant ranges.
> +	 */
> +	pctx = i915_gem_object_create_stolen(dev, pctx_size);
> +	if (!pctx) {
> +		DRM_DEBUG("not enough stolen space for PCTX, disabling\n");
> +		return;
> +	}
> +
> +	dev_priv->vlv_pctx = pctx;
> +	pctx_paddr = dev_priv->mm.stolen_base + pctx->stolen->start;
> +	I915_WRITE(VLV_PCBR, pctx_paddr);

Does the powerctx need to be reinitialized after GPU reset?

> +}

> +
> +static void valleyview_cleanup_pctx(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +
> +	if (!dev_priv->vlv_pctx)
> +		return;
> +
> +	i915_gem_object_release_stolen(dev_priv->vlv_pctx);
> +	I915_WRITE(VLV_PCBR, 0);
> +}
> +
>  void i915_gem_cleanup_stolen(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
>  	i915_gem_stolen_cleanup_compression(dev);
> +	if (IS_VALLEYVIEW(dev))
> +		valleyview_cleanup_pctx(dev);
>  	drm_mm_takedown(&dev_priv->mm.stolen);
>  }
>  
> +/* On VLV make sure we create pre-alloc'd objects for BIOS bits */
> +static void valleyview_init_bios_stolen(struct drm_i915_private *dev_priv)
> +{
> +	struct drm_i915_gem_object *bios_stolen;
> +	int bios_offset;
> +
> +	/* Top 1M of stolen space is used by firmware */
> +	bios_offset = dev_priv->gtt.stolen_size - 1024*1024;
> +	bios_stolen = i915_gem_object_create_stolen_for_preallocated(dev_priv->dev,
> +								     bios_offset,
> +								     bios_offset,
> +								     1024*1024);
> +}
> +
>  int i915_gem_init_stolen(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -194,6 +265,11 @@ int i915_gem_init_stolen(struct drm_device *dev)
>  	/* Basic memrange allocator for stolen space */
>  	drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_size);

I think you should chop off the 1MB here instead of making a stolen
object which we don't want to use or touch
>  
> +	if (IS_VALLEYVIEW(dev)) {
> +		valleyview_init_bios_stolen(dev_priv);
> +		valleyview_setup_pctx(dev);
       drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_size - 1K); 
} else {
        drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_size);
}
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index b5d87bd..1cc43ce 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -700,6 +700,7 @@
>  #define VLV_IIR		(VLV_DISPLAY_BASE + 0x20a4)
>  #define VLV_IMR		(VLV_DISPLAY_BASE + 0x20a8)
>  #define VLV_ISR		(VLV_DISPLAY_BASE + 0x20ac)
> +#define VLV_PCBR	(VLV_DISPLAY_BASE + 0x2120)
>  #define   I915_PIPE_CONTROL_NOTIFY_INTERRUPT		(1<<18)
>  #define   I915_DISPLAY_PORT_INTERRUPT			(1<<17)
>  #define   I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT	(1<<15)
> -- 
> 1.7.10.4
> 
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-- 
Ben Widawsky, Intel Open Source Technology Center