From 8384cdd8b83af2a6b432a2fd4f56459a3c316329 Mon Sep 17 00:00:00 2001
From: Ben Widawsky <benjamin.widawsky@intel.com>
Date: Wed, 18 Sep 2013 19:03:18 -0700
Subject: drm/i915: Do remaps for all contexts
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On both Ivybridge and Haswell, row remapping information is saved and
restored with context. This means, we never actually properly supported
the l3 remapping because our sysfs interface is asynchronous (and not
tied to any context), and the known faulty HW would be reused by the
next context to run.

Not that due to the asynchronous nature of the sysfs entry, there is no
point modifying the registers for the existing context. Instead we set a
flag for all contexts to load the correct remapping information on the
next run. Interested clients can use debugfs to determine whether or not
the row has been remapped.

One could propose at this point that we just do the remapping in the
kernel. I guess since we have to maintain the sysfs interface anyway,
I'm not sure how useful it is, and I do like keeping the policy in
userspace; (it wasn't my original decision to make the
interface the way it is, so I'm not attached).

v2: Force a context switch when we have a remap on the next switch.
(Ville)
Don't let userspace use the interface with disabled contexts.

v3: Don't force a context switch, just let it nop
Improper context slice remap initialization, 1<<1 instead of 1<<i, but I
rewrote it to avoid a second round of confusion.
Error print moved to error path (All Ville)
Added a comment on why the slice remap initialization happens.

CC: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 3ccfd19dea7c5c85aa4b1f929a97a02b026ab356)
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c     |    8 ++++++
 drivers/gpu/drm/i915/i915_drv.h         |    1 
 drivers/gpu/drm/i915/i915_gem_context.c |   22 +++++++++++++++----
 drivers/gpu/drm/i915/i915_sysfs.c       |   37 ++++++++++++--------------------
 4 files changed, 41 insertions(+), 27 deletions(-)

--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -145,6 +145,13 @@ describe_obj(struct seq_file *m, struct
 		seq_printf(m, " (%s)", obj->ring->name);
 }
 
+static void describe_ctx(struct seq_file *m, struct i915_hw_context *ctx)
+{
+	seq_putc(m, ctx->is_initialized ? 'I' : 'i');
+	seq_putc(m, ctx->remap_slice ? 'R' : 'r');
+	seq_putc(m, ' ');
+}
+
 static int i915_gem_object_list_info(struct seq_file *m, void *data)
 {
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
@@ -1463,6 +1470,7 @@ static int i915_context_status(struct se
 
 	list_for_each_entry(ctx, &dev_priv->context_list, link) {
 		seq_puts(m, "HW context ");
+		describe_ctx(m, ctx);
 		for_each_ring(ring, dev_priv, i)
 			if (ring->default_context == ctx)
 				seq_printf(m, "(default context %s) ", ring->name);
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -601,6 +601,7 @@ struct i915_hw_context {
 	struct kref ref;
 	int id;
 	bool is_initialized;
+	uint8_t remap_slice;
 	struct drm_i915_file_private *file_priv;
 	struct intel_ring_buffer *ring;
 	struct drm_i915_gem_object *obj;
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -181,6 +181,10 @@ create_hw_context(struct drm_device *dev
 
 	ctx->file_priv = file_priv;
 	ctx->id = ret;
+	/* NB: Mark all slices as needing a remap so that when the context first
+	 * loads it will restore whatever remap state already exists. If there
+	 * is no remap info, it will be a NOP. */
+	ctx->remap_slice = (1 << NUM_L3_SLICES(dev)) - 1;
 
 	return ctx;
 
@@ -394,11 +398,11 @@ static int do_switch(struct i915_hw_cont
 	struct intel_ring_buffer *ring = to->ring;
 	struct i915_hw_context *from = ring->last_context;
 	u32 hw_flags = 0;
-	int ret;
+	int ret, i;
 
 	BUG_ON(from != NULL && from->obj != NULL && from->obj->pin_count == 0);
 
-	if (from == to)
+	if (from == to && !to->remap_slice)
 		return 0;
 
 	ret = i915_gem_obj_ggtt_pin(to->obj, CONTEXT_ALIGN, false, false);
@@ -421,8 +425,6 @@ static int do_switch(struct i915_hw_cont
 
 	if (!to->is_initialized || is_default_context(to))
 		hw_flags |= MI_RESTORE_INHIBIT;
-	else if (WARN_ON_ONCE(from == to)) /* not yet expected */
-		hw_flags |= MI_FORCE_RESTORE;
 
 	ret = mi_set_context(ring, to, hw_flags);
 	if (ret) {
@@ -430,6 +432,18 @@ static int do_switch(struct i915_hw_cont
 		return ret;
 	}
 
+	for (i = 0; i < MAX_L3_SLICES; i++) {
+		if (!(to->remap_slice & (1<<i)))
+			continue;
+
+		ret = i915_gem_l3_remap(ring, i);
+		/* If it failed, try again next round */
+		if (ret)
+			DRM_DEBUG_DRIVER("L3 remapping failed\n");
+		else
+			to->remap_slice &= ~(1<<i);
+	}
+
 	/* The backing object for the context is done after switching to the
 	 * *next* context. Therefore we cannot retire the previous context until
 	 * the next context has already started running. In fact, the below code
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -118,9 +118,8 @@ i915_l3_read(struct file *filp, struct k
 	struct drm_minor *dminor = container_of(dev, struct drm_minor, kdev);
 	struct drm_device *drm_dev = dminor->dev;
 	struct drm_i915_private *dev_priv = drm_dev->dev_private;
-	uint32_t misccpctl;
 	int slice = (int)(uintptr_t)attr->private;
-	int i, ret;
+	int ret;
 
 	count = round_down(count, 4);
 
@@ -134,26 +133,13 @@ i915_l3_read(struct file *filp, struct k
 	if (ret)
 		return ret;
 
-	if (IS_HASWELL(drm_dev)) {
-		if (dev_priv->l3_parity.remap_info[slice])
-			memcpy(buf,
-			       dev_priv->l3_parity.remap_info[slice] + (offset/4),
-			       count);
-		else
-			memset(buf, 0, count);
-
-		goto out;
-	}
-
-	misccpctl = I915_READ(GEN7_MISCCPCTL);
-	I915_WRITE(GEN7_MISCCPCTL, misccpctl & ~GEN7_DOP_CLOCK_GATE_ENABLE);
+	if (dev_priv->l3_parity.remap_info[slice])
+		memcpy(buf,
+		       dev_priv->l3_parity.remap_info[slice] + (offset/4),
+		       count);
+	else
+		memset(buf, 0, count);
 
-	for (i = 0; i < count; i += 4)
-		*((uint32_t *)(&buf[i])) = I915_READ(GEN7_L3LOG_BASE + offset + i);
-
-	I915_WRITE(GEN7_MISCCPCTL, misccpctl);
-
-out:
 	mutex_unlock(&drm_dev->struct_mutex);
 
 	return count;
@@ -168,6 +154,7 @@ i915_l3_write(struct file *filp, struct
 	struct drm_minor *dminor = container_of(dev, struct drm_minor, kdev);
 	struct drm_device *drm_dev = dminor->dev;
 	struct drm_i915_private *dev_priv = drm_dev->dev_private;
+	struct i915_hw_context *ctx;
 	u32 *temp = NULL; /* Just here to make handling failures easy */
 	int slice = (int)(uintptr_t)attr->private;
 	int ret;
@@ -176,6 +163,9 @@ i915_l3_write(struct file *filp, struct
 	if (ret)
 		return ret;
 
+	if (dev_priv->hw_contexts_disabled)
+		return -ENXIO;
+
 	ret = i915_mutex_lock_interruptible(drm_dev);
 	if (ret)
 		return ret;
@@ -204,8 +194,9 @@ i915_l3_write(struct file *filp, struct
 
 	memcpy(dev_priv->l3_parity.remap_info[slice] + (offset/4), buf, count);
 
-	if (i915_gem_l3_remap(&dev_priv->ring[RCS], slice))
-		count = 0;
+	/* NB: We defer the remapping until we switch to the context */
+	list_for_each_entry(ctx, &dev_priv->context_list, link)
+		ctx->remap_slice |= (1<<slice);
 
 	mutex_unlock(&drm_dev->struct_mutex);