[Intel-gfx] [PATCH 04/11] drm/i915/context: CXT_SIZE register offsets added

[Eric Anholt]

On Tue, 14 Feb 2012 22:09:11 +0100, Ben Widawsky <ben at bwidawsk.net> wrote:
> From: Ben Widawsky <bwidawsk at gmail.com>
> 
> The GPUs can have different default context layouts, and the sizes could
> vary based on platform or BIOS. In order to back the context object with
> a properly sized BO, we must read this register in order to find out a
> sufficient size.
> 
> Thankfully (sarcarm!), the register moves and changes meanings
> throughout generations.
> 
> CTX and CXT differences are intentional as that is how it is in the
> documentation (prior to GEN6 it was CXT).
> 
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> ---
>  drivers/gpu/drm/i915/i915_reg.h |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 0c785af..5e61e79 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -1361,6 +1361,19 @@
>   */
>  #define CCID			0x2180
>  #define   CCID_EN		(1<<0)
> +#define CXT_SIZE		0x21a0
> +#define GEN6_CXT_RENDER_SIZE ((I915_READ(CXT_SIZE) >> 12) & 0x3f)
> +#define GEN6_CXT_EXTENDED_SIZE ((I915_READ(CXT_SIZE) >> 6) & 0x3f)
> +#define GEN6_CXT_PIPELINE_SIZE ((I915_READ(CXT_SIZE) >> 0) & 0x3f)
> +#define GEN6_CXT_TOTAL_SIZE (GEN6_CXT_RENDER_SIZE + GEN6_CXT_EXTENDED_SIZE + GEN6_CXT_PIPELINE_SIZE)
> +#define GEN7_CTX_SIZE		0x21a8
> +#define GEN7_CTX_RENDER_SIZE ((I915_READ(GEN7_CTX_SIZE) >> 16) & 0x3f)
> +#define GEN7_CTX_EXTENDED_SIZE ((I915_READ(GEN7_CTX_SIZE) >> 9) & 0x7f)
> +#define GEN7_CTX_GT1_SIZE ((I915_READ(GEN7_CTX_SIZE) >> 6) & 0x7)
> +#define GEN7_CTX_VFSTATE_SIZE ((I915_READ(GEN7_CTX_SIZE) >> 0) & 0x3f)
> +#define GEN7_CTX_TOTAL_SIZE (GEN7_CTX_RENDER_SIZE + GEN7_CTX_EXTENDED_SIZE \
> +			    + GEN7_CTX_GT1_SIZE + GEN7_CTX_VFSTATE_SIZE)
> +

I was surprised to see register reads in i915_reg.h definitions.  I'd
rather see this folded into the one callsite, and just the reg numbers
in i915_reg.h.

There's a bit of a discrepancy here -- CXT vs CTX.  The docs appear to
actually use CXT, which I will probably never type successfully since
contexts are "ctx" all over my other code.  Still, consistently using
the docs' spelling is probably better than inconsistently using it :)
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