Re: [PATCH 03/71] drm/i915/chv: PPAT setup for Cherryview

Barbalho, Rafael
2014-05-01T13:35:09Z

> -----Original Message-----
> From: Intel-gfx [mailto:intel-gfx-bounces@lists.freedesktop.org] On Behalf
> Of ville.syrjala@linux.intel.com
> Sent: Wednesday, April 09, 2014 11:28 AM
> To: intel-gfx@lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH 03/71] drm/i915/chv: PPAT setup for Cherryview
>
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Ignore the cache bits in PPAT and just set the snoop bit where appropriate.
> BDW WB is mapped to snooped access, while all other modes are mapped to
> non-snooped access.
>
> The hardware supposedly ignores everything except the snoop bit in the
> PPAT entries.
>
> Additionally the hardware actually enforces snooping for all page table
> accesses, and thus the snoop bit is ignored for PDEs.
>
> v2: Rebased on top of the bdw resume fix to reload the ppat entries.
>
> v3: Rebase on top of the i915_gem_gtt.h header extraction.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (v1)
> Acked-by: Ben Widawsky <ben@bwidawsk.net>
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---

Reviewed-by: Rafael Barbalho <rafael.barbalho@intel.com>

> drivers/gpu/drm/i915/i915_gem_gtt.c | 43
> +++++++++++++++++++++++++++++++++----
> drivers/gpu/drm/i915/i915_gem_gtt.h | 1 +
> 2 files changed, 40 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c
> b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 4467974..3e4d1f0 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -30,7 +30,8 @@
> #include "i915_trace.h"
> #include "intel_drv.h"
>
> -static void gen8_setup_private_ppat(struct drm_i915_private *dev_priv);
> +static void bdw_setup_private_ppat(struct drm_i915_private *dev_priv);
> +static void chv_setup_private_ppat(struct drm_i915_private *dev_priv);
>
> bool intel_enable_ppgtt(struct drm_device *dev, bool full) { @@ -1315,7
> +1316,11 @@ void i915_gem_restore_gtt_mappings(struct drm_device
> *dev)
>
>
> if (INTEL_INFO(dev)->gen >= 8) {
> - gen8_setup_private_ppat(dev_priv);
> + if (IS_CHERRYVIEW(dev))
> + chv_setup_private_ppat(dev_priv);
> + else
> + bdw_setup_private_ppat(dev_priv);
> +
> return;
> }
>
> @@ -1787,7 +1792,7 @@ static int ggtt_probe_common(struct drm_device
> *dev,
> /* The GGTT and PPGTT need a private PPAT setup in order to handle
> cacheability
> * bits. When using advanced contexts each context stores its own PAT, but
> * writing this data shouldn't be harmful even in those cases. */ -static void
> gen8_setup_private_ppat(struct drm_i915_private *dev_priv)
> +static void bdw_setup_private_ppat(struct drm_i915_private *dev_priv)
> {
> uint64_t pat;
>
> @@ -1806,6 +1811,33 @@ static void gen8_setup_private_ppat(struct
> drm_i915_private *dev_priv)
> I915_WRITE(GEN8_PRIVATE_PAT + 4, pat >> 32); }
>
> +static void chv_setup_private_ppat(struct drm_i915_private *dev_priv) {
> + uint64_t pat;
> +
> + /*
> + * Map WB on BDW to snooped on CHV.
> + *
> + * Only the snoop bit has meaning for CHV, the rest is
> + * ignored.
> + *
> + * Note that the harware enforces snooping for all page
> + * table accesses. The snoop bit is actually ignored for
> + * PDEs.
> + */
> + pat = GEN8_PPAT(0, CHV_PPAT_SNOOP) |
> + GEN8_PPAT(1, 0) |
> + GEN8_PPAT(2, 0) |
> + GEN8_PPAT(3, 0) |
> + GEN8_PPAT(4, CHV_PPAT_SNOOP) |
> + GEN8_PPAT(5, CHV_PPAT_SNOOP) |
> + GEN8_PPAT(6, CHV_PPAT_SNOOP) |
> + GEN8_PPAT(7, CHV_PPAT_SNOOP);
> +
> + I915_WRITE(GEN8_PRIVATE_PAT, pat);
> + I915_WRITE(GEN8_PRIVATE_PAT + 4, pat >> 32); }
> +
> static int gen8_gmch_probe(struct drm_device *dev,
> size_t *gtt_total,
> size_t *stolen,
> @@ -1831,7 +1863,10 @@ static int gen8_gmch_probe(struct drm_device
> *dev,
> gtt_size = gen8_get_total_gtt_size(snb_gmch_ctl);
> *gtt_total = (gtt_size / sizeof(gen8_gtt_pte_t)) << PAGE_SHIFT;
>
> - gen8_setup_private_ppat(dev_priv);
> + if (IS_CHERRYVIEW(dev))
> + chv_setup_private_ppat(dev_priv);
> + else
> + bdw_setup_private_ppat(dev_priv);
>
> ret = ggtt_probe_common(dev, gtt_size);
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h
> b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index b5e8ac0..cfca023 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
> @@ -95,6 +95,7 @@ typedef gen8_gtt_pte_t gen8_ppgtt_pde_t;
> #define PPAT_CACHED_INDEX _PAGE_PAT /* WB LLCeLLC */
> #define PPAT_DISPLAY_ELLC_INDEX _PAGE_PCD /* WT eLLC */
>
> +#define CHV_PPAT_SNOOP (1<<6)
> #define GEN8_PPAT_AGE(x) (x<<4)
> #define GEN8_PPAT_LLCeLLC (3<<2)
> #define GEN8_PPAT_LLCELLC (2<<2)
> --
> 1.8.3.2
>
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