Quoting Tvrtko Ursulin (2018-12-03 11:46:11)
> From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
>
> To enable later verification of GT workaround state at various stages of
> driver lifetime, we record the list of applicable ones per platforms to a
> list, from which they are also applied.
>
> The added data structure is a simple array of register, mask and value
> items, which is allocated on demand as workarounds are added to the list.
>
> This is a temporary implementation which later in the series gets fused
> with the existing per context workaround list handling. It is separated at
> this stage since the following patch fixes a bug which needs to be as easy
> to backport as possible.
>
> Also, since in the following patch we will be adding a new class of
> workarounds (per engine) which can be applied from interrupt context, we
> straight away make the provision for safe read-modify-write cycle.
>
> v2:
> * Change dev_priv to i915 along the init path. (Chris Wilson)
> * API rename. (Chris Wilson)
>
> v3:
> * Remove explicit list size tracking in favour of growing the allocation
> in power of two chunks. (Chris Wilson)
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> # v2
> ---
> drivers/gpu/drm/i915/i915_drv.c | 1 +
> drivers/gpu/drm/i915/i915_drv.h | 2 +
> drivers/gpu/drm/i915/i915_gem.c | 4 +-
> drivers/gpu/drm/i915/intel_workarounds.c | 491 +++++++++++++++--------
> drivers/gpu/drm/i915/intel_workarounds.h | 23 +-
> 5 files changed, 353 insertions(+), 168 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index e39016713464..ee5116b62cd2 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1453,6 +1453,7 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
>
> intel_uncore_sanitize(dev_priv);
>
> + intel_gt_init_workarounds(dev_priv);
> i915_gem_load_init_fences(dev_priv);
>
> /* On the 945G/GM, the chipset reports the MSI capability on the
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 43ac6873a2bb..9ddbcc1f3554 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -69,6 +69,7 @@
> #include "intel_ringbuffer.h"
> #include "intel_uncore.h"
> #include "intel_wopcm.h"
> +#include "intel_workarounds.h"
> #include "intel_uc.h"
>
> #include "i915_gem.h"
> @@ -1652,6 +1653,7 @@ struct drm_i915_private {
> int dpio_phy_iosf_port[I915_NUM_PHYS_VLV];
>
> struct i915_workarounds workarounds;
> + struct i915_wa_list gt_wa_list;
>
> struct i915_frontbuffer_tracking fb_tracking;
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index c55b1f75c980..6333a7d6af5a 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -5334,7 +5334,7 @@ int i915_gem_init_hw(struct drm_i915_private *dev_priv)
> I915_WRITE(MI_PREDICATE_RESULT_2, IS_HSW_GT3(dev_priv) ?
> LOWER_SLICE_ENABLED : LOWER_SLICE_DISABLED);
>
> - intel_gt_workarounds_apply(dev_priv);
> + intel_gt_apply_workarounds(dev_priv);
>
> i915_gem_init_swizzling(dev_priv);
>
> @@ -5706,6 +5706,8 @@ void i915_gem_fini(struct drm_i915_private *dev_priv)
> i915_gem_contexts_fini(dev_priv);
> mutex_unlock(&dev_priv->drm.struct_mutex);
>
> + intel_wa_list_free(&dev_priv->gt_wa_list);
> +
> intel_cleanup_gt_powersave(dev_priv);
>
> intel_uc_fini_misc(dev_priv);
> diff --git a/drivers/gpu/drm/i915/intel_workarounds.c b/drivers/gpu/drm/i915/intel_workarounds.c
> index e5cd6c6c66c3..f05f13547034 100644
> --- a/drivers/gpu/drm/i915/intel_workarounds.c
> +++ b/drivers/gpu/drm/i915/intel_workarounds.c
> @@ -48,6 +48,18 @@
> * - Public functions to init or apply the given workaround type.
> */
>
> +static void wa_init_start(struct i915_wa_list *wal, const char *name)
> +{
> + wal->name = name;
> +}
> +
> +static void wa_init_finish(struct i915_wa_list *wal)
> +{
> + if (wal->count)
> + DRM_DEBUG_DRIVER("Initialized %u %s workarounds\n",
> + wal->count, wal->name);
Does this become if (!wal->count) return; later?
> +}
> +
> static void wa_add(struct drm_i915_private *i915,
> i915_reg_t reg, const u32 mask, const u32 val)
> {
> @@ -575,160 +587,240 @@ int intel_ctx_workarounds_emit(struct i915_request *rq)
> return 0;
> }
>
> -static void bdw_gt_workarounds_apply(struct drm_i915_private *dev_priv)
> +static void
> +wal_add(struct i915_wa_list *wal, const struct i915_wa *wa)
> +{
> + const unsigned int grow = 1 << 4;
> +
> + GEM_BUG_ON(!is_power_of_2(grow));
> +
> + if (IS_ALIGNED(wal->count, grow)) { /* Either uninitialized or full. */
Neat.
> + struct i915_wa *list;
> +
> + list = kcalloc(ALIGN(wal->count + 1, grow), sizeof(*wa),
> + GFP_KERNEL);
(Quietly comments on the calloc here ;)
> + if (!list) {
> + DRM_ERROR("No space for workaround init!\n");
> + return;
> + }
> +
> + if (wal->list)
> + memcpy(list, wal->list, sizeof(*wa) * wal->count);
> +
> + wal->list = list;
> + }
> +
> + memcpy(&wal->list[wal->count], wa, sizeof(*wa));
> + wal->count++;
I'd push for
wal->list[wal->count++] = wa;
Might as well use static type checking.
> +struct i915_wa_list {
> + const char *name;
> + unsigned int count;
> + struct i915_wa *list;
Oh well, didn't save anything after all.
-Chris
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