[PATCH 17/18] drm/i915: Ironlake rc6 can use context interfaces

[Ben Widawsky <ben@bwidawsk.net>]

Use the context interfaces to create the power context.  Assuming we
have a default context, there should be no need to switch to
the render context anymore as the default context should already serve
this purpose.

As a double cautionary measure we check the CCID to make sure everything
looks kosher, and don't enable RC6 if it doesn't.

There is an important difference in logic when switching to the context
interface. The old code use MI_SUSPEND_FLUSH before MI_SET_CONTEXT which was an
ILK specific workaround I remember seeing in old docs but can no longer find.
That workaround is not implemented in the standard context code.

PS. I think there is a double mutex_unlock in the existing error path

CC: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
 drivers/gpu/drm/i915/i915_debugfs.c  |    8 +--
 drivers/gpu/drm/i915/i915_drv.h      |    3 +-
 drivers/gpu/drm/i915/i915_reg.h      |    1 +
 drivers/gpu/drm/i915/intel_display.c |   89 +++-------------------------------
 4 files changed, 10 insertions(+), 91 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index fdb7cce..6c98d18 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1372,13 +1372,7 @@ static int i915_context_status(struct seq_file *m, void *unused)
 
 	if (dev_priv->pwrctx) {
 		seq_printf(m, "power context ");
-		describe_obj(m, dev_priv->pwrctx);
-		seq_printf(m, "\n");
-	}
-
-	if (dev_priv->renderctx) {
-		seq_printf(m, "render context ");
-		describe_obj(m, dev_priv->renderctx);
+		describe_obj(m, dev_priv->pwrctx->obj);
 		seq_printf(m, "\n");
 	}
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 003b62e..1329b1f 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -352,8 +352,7 @@ typedef struct drm_i915_private {
 	drm_dma_handle_t *status_page_dmah;
 	uint32_t counter;
 	drm_local_map_t hws_map;
-	struct drm_i915_gem_object *pwrctx;
-	struct drm_i915_gem_object *renderctx;
+	struct i915_hw_context *pwrctx;
 
 	struct resource mch_res;
 
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 6b6d685..4965638 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1360,6 +1360,7 @@
  * Logical Context regs
  */
 #define CCID			0x2180
+#define CCID_MASK		0xfffff000
 #define   CCID_EN		(1<<0)
 #define CXT_SIZE		0x21a0
 #define GEN6_CXT_POWER_SIZE(cxt_reg)	((cxt_reg >> 24) & 0x3f)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index de1ba19..4ef968a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7948,42 +7948,6 @@ static const struct drm_mode_config_funcs intel_mode_funcs = {
 	.output_poll_changed = intel_fb_output_poll_changed,
 };
 
-static struct drm_i915_gem_object *
-intel_alloc_context_page(struct drm_device *dev)
-{
-	struct drm_i915_gem_object *ctx;
-	int ret;
-
-	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
-
-	ctx = i915_gem_alloc_object(dev, 4096);
-	if (!ctx) {
-		DRM_DEBUG("failed to alloc power context, RC6 disabled\n");
-		return NULL;
-	}
-
-	ret = i915_gem_object_pin(ctx, 4096, true);
-	if (ret) {
-		DRM_ERROR("failed to pin power context: %d\n", ret);
-		goto err_unref;
-	}
-
-	ret = i915_gem_object_set_to_gtt_domain(ctx, 1);
-	if (ret) {
-		DRM_ERROR("failed to set-domain on power context: %d\n", ret);
-		goto err_unpin;
-	}
-
-	return ctx;
-
-err_unpin:
-	i915_gem_object_unpin(ctx);
-err_unref:
-	drm_gem_object_unreference(&ctx->base);
-	mutex_unlock(&dev->struct_mutex);
-	return NULL;
-}
-
 bool ironlake_set_drps(struct drm_device *dev, u8 val)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -8667,15 +8631,8 @@ static void ironlake_teardown_rc6(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	if (dev_priv->renderctx) {
-		i915_gem_object_unpin(dev_priv->renderctx);
-		drm_gem_object_unreference(&dev_priv->renderctx->base);
-		dev_priv->renderctx = NULL;
-	}
-
 	if (dev_priv->pwrctx) {
-		i915_gem_object_unpin(dev_priv->pwrctx);
-		drm_gem_object_unreference(&dev_priv->pwrctx->base);
+		i915_context_destroy_anonymous(dev_priv->pwrctx);
 		dev_priv->pwrctx = NULL;
 	}
 }
@@ -8704,13 +8661,11 @@ static int ironlake_setup_rc6(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	if (dev_priv->renderctx == NULL)
-		dev_priv->renderctx = intel_alloc_context_page(dev);
-	if (!dev_priv->renderctx)
-		return -ENOMEM;
+	if (dev_priv->ring[RCS].default_context == NULL)
+		return -EIO;
 
 	if (dev_priv->pwrctx == NULL)
-		dev_priv->pwrctx = intel_alloc_context_page(dev);
+		dev_priv->pwrctx = i915_context_alloc_anonymous(dev);
 	if (!dev_priv->pwrctx) {
 		ironlake_teardown_rc6(dev);
 		return -ENOMEM;
@@ -8737,43 +8692,13 @@ void ironlake_enable_rc6(struct drm_device *dev)
 		return;
 	}
 
-	/*
-	 * GPU can automatically power down the render unit if given a page
-	 * to save state.
-	 */
-	ret = BEGIN_LP_RING(6);
-	if (ret) {
-		ironlake_teardown_rc6(dev);
-		mutex_unlock(&dev->struct_mutex);
-		return;
-	}
-
-	OUT_RING(MI_SUSPEND_FLUSH | MI_SUSPEND_FLUSH_EN);
-	OUT_RING(MI_SET_CONTEXT);
-	OUT_RING(dev_priv->renderctx->gtt_offset |
-		 MI_MM_SPACE_GTT |
-		 MI_SAVE_EXT_STATE_EN |
-		 MI_RESTORE_EXT_STATE_EN |
-		 MI_RESTORE_INHIBIT);
-	OUT_RING(MI_SUSPEND_FLUSH);
-	OUT_RING(MI_NOOP);
-	OUT_RING(MI_FLUSH);
-	ADVANCE_LP_RING();
-
-	/*
-	 * Wait for the command parser to advance past MI_SET_CONTEXT. The HW
-	 * does an implicit flush, combined with MI_FLUSH above, it should be
-	 * safe to assume that renderctx is valid
-	 */
-	ret = intel_wait_ring_idle(LP_RING(dev_priv));
-	if (ret) {
-		DRM_ERROR("failed to enable ironlake power power savings\n");
-		ironlake_teardown_rc6(dev);
+	if ((I915_READ(CCID) & CCID_MASK) == 0) {
+		DRM_ERROR("RC6 could not be enabled\n");
 		mutex_unlock(&dev->struct_mutex);
 		return;
 	}
 
-	I915_WRITE(PWRCTXA, dev_priv->pwrctx->gtt_offset | PWRCTX_EN);
+	I915_WRITE(PWRCTXA, dev_priv->pwrctx->obj->gtt_offset | PWRCTX_EN);
 	I915_WRITE(RSTDBYCTL, I915_READ(RSTDBYCTL) & ~RCX_SW_EXIT);
 	mutex_unlock(&dev->struct_mutex);
 }
-- 
1.7.9.4