[PATCH v2] drm/i915/mocs: Program MOCS for all engines on init

[Peter Antoine <peter.antoine@intel.com>]

Allow for the MOCS to be programmed for all engines.
Currently we program the MOCS when the first render batch
goes through. This works on most platforms but fails on
platforms that do not run a render batch early,
i.e. headless servers. The patch now programs all initialised engines
on init and the RCS is programmed again within the initial batch. This
is done for predictable consistency with regards to the hardware
context.

Hardware context loading sets the values of the MOCS for RCS
and L3CC. Programming them from within the batch makes sure that
the render context is valid, no matter what the previous state of
the saved-context was.

Signed-off-by: Peter Antoine <peter.antoine@intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c   |   3 +
 drivers/gpu/drm/i915/intel_mocs.c | 138 ++++++++++++++++++++++++++++++++++----
 drivers/gpu/drm/i915/intel_mocs.h |   1 +
 3 files changed, 130 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index b854af2..05c9fcb 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -32,6 +32,7 @@
 #include "i915_vgpu.h"
 #include "i915_trace.h"
 #include "intel_drv.h"
+#include "intel_mocs.h"
 #include <linux/shmem_fs.h>
 #include <linux/slab.h>
 #include <linux/swap.h>
@@ -4882,6 +4883,8 @@ i915_gem_init_hw(struct drm_device *dev)
 			goto out;
 	}
 
+	intel_program_mocs_engines(dev);
+
 	/* We can't enable contexts until all firmware is loaded */
 	if (HAS_GUC_UCODE(dev)) {
 		ret = intel_guc_ucode_load(dev);
diff --git a/drivers/gpu/drm/i915/intel_mocs.c b/drivers/gpu/drm/i915/intel_mocs.c
index fed7bea..cd01682 100644
--- a/drivers/gpu/drm/i915/intel_mocs.c
+++ b/drivers/gpu/drm/i915/intel_mocs.c
@@ -128,9 +128,9 @@ static const struct drm_i915_mocs_entry broxton_mocs_table[] = {
 
 /**
  * get_mocs_settings()
- * @dev:        DRM device.
+ * @dev:	DRM device.
  * @table:      Output table that will be made to point at appropriate
- *              MOCS values for the device.
+ *	      MOCS values for the device.
  *
  * This function will return the values of the MOCS table that needs to
  * be programmed for the platform. It will return the values that need
@@ -179,6 +179,48 @@ static i915_reg_t mocs_register(enum intel_ring_id ring, int index)
 }
 
 /**
+ * program_mocs_control_table() - emit the mocs control table
+ * @req:	Request to set up the MOCS table for.
+ * @table:	The values to program into the control regs.
+ * @ring:	The engine for whom to emit the registers.
+ *
+ * This function simply emits a MI_LOAD_REGISTER_IMM command for the
+ * given table starting at the given address.
+ *
+ * Return: 0 on success, otherwise the error status.
+ */
+static int program_mocs_control_table(struct drm_device *dev,
+				   const struct drm_i915_mocs_table *table,
+				   enum intel_ring_id ring)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	unsigned int index;
+
+	if (WARN_ON(table->size > GEN9_NUM_MOCS_ENTRIES))
+		return -ENODEV;
+
+	for (index = 0; index < table->size; index++) {
+		I915_WRITE(mocs_register(ring, index),
+			table->table[index].control_value);
+	}
+
+	/*
+	 * Ok, now set the unused entries to uncached. These entries
+	 * are officially undefined and no contract for the contents
+	 * and settings is given for these entries.
+	 *
+	 * Entry 0 in the table is uncached - so we are just writing
+	 * that value to all the used entries.
+	 */
+	for (; index < GEN9_NUM_MOCS_ENTRIES; index++) {
+		I915_WRITE(mocs_register(ring, index),
+					table->table[0].control_value);
+	}
+
+	return 0;
+}
+
+/**
  * emit_mocs_control_table() - emit the mocs control table
  * @req:	Request to set up the MOCS table for.
  * @table:	The values to program into the control regs.
@@ -302,6 +344,84 @@ static int emit_mocs_l3cc_table(struct drm_i915_gem_request *req,
 }
 
 /**
+ * program_mocs_l3cc_table() - program the mocs control table
+ * @dev:      The the device to be programmed.
+ * @table:    The values to program into the control regs.
+ *
+ * This function simply programs the mocs registers for the given table
+ * starting at the given address. This register set is  programmed in pairs.
+ *
+ * These registers may get programmed more than once, it is simpler to
+ * re-program 32 registers than maintain the state of when they were programmed.
+ * We are always reprogramming with the same values and this only on context
+ * start.
+ *
+ * Return: Nothing.
+ */
+static void program_mocs_l3cc_table(struct drm_device *dev,
+			      struct drm_i915_mocs_table *table)
+{
+	unsigned int count;
+	unsigned int i;
+	u32 value;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 filler = (table->table[0].l3cc_value & 0xffff) |
+			((table->table[0].l3cc_value & 0xffff) << 16);
+
+	for (i = 0, count = 0; i < table->size / 2; i++, count += 2) {
+		value = (table->table[count].l3cc_value & 0xffff) |
+			((table->table[count + 1].l3cc_value & 0xffff) << 16);
+
+		I915_WRITE(GEN9_LNCFCMOCS(i), value);
+	}
+
+	if (table->size & 0x01) {
+		/* Odd table size - 1 left over */
+		value = (table->table[count].l3cc_value & 0xffff) |
+			((table->table[0].l3cc_value & 0xffff) << 16);
+	} else
+		value = filler;
+
+	/*
+	 * Now set the rest of the table to uncached - use entry 0 as this
+	 * will be uncached. Leave the last pair as initialised as they are
+	 * reserved by the hardware.
+	 */
+	for (; i < (GEN9_NUM_MOCS_ENTRIES / 2); i++) {
+		I915_WRITE(GEN9_LNCFCMOCS(i), value);
+		value = filler;
+	}
+}
+
+/*
+ * intel_program_mocs_engines() - program all the MOCS register.
+ *
+ * This function will program the MOCS registers with the correct values.
+ * For the initialised engines, this means that some of the MOCS hw registers
+ * will be left at the hardware defaults.
+ *
+ * Return: Nothing.
+ */
+void intel_program_mocs_engines(struct drm_device *dev)
+{
+	struct drm_i915_mocs_table t;
+
+	if (get_mocs_settings(dev, &t)) {
+		struct drm_i915_private *dev_priv = dev->dev_private;
+		struct intel_engine_cs *ring;
+		enum intel_ring_id ring_id;
+
+		/* Program the control registers */
+		for_each_ring(ring, dev_priv, ring_id) {
+			program_mocs_control_table(dev, &t, ring_id);
+		}
+
+		/* Now program the l3cc registers */
+		program_mocs_l3cc_table(dev, &t);
+	}
+}
+
+/**
  * intel_rcs_context_init_mocs() - program the MOCS register.
  * @req:	Request to set up the MOCS tables for.
  *
@@ -323,16 +443,10 @@ int intel_rcs_context_init_mocs(struct drm_i915_gem_request *req)
 	int ret;
 
 	if (get_mocs_settings(req->ring->dev, &t)) {
-		struct drm_i915_private *dev_priv = req->i915;
-		struct intel_engine_cs *ring;
-		enum intel_ring_id ring_id;
-
-		/* Program the control registers */
-		for_each_ring(ring, dev_priv, ring_id) {
-			ret = emit_mocs_control_table(req, &t, ring_id);
-			if (ret)
-				return ret;
-		}
+		/* Program the RCS control registers */
+		ret = emit_mocs_control_table(req, &t, RCS);
+		if (ret)
+			return ret;
 
 		/* Now program the l3cc registers */
 		ret = emit_mocs_l3cc_table(req, &t);
diff --git a/drivers/gpu/drm/i915/intel_mocs.h b/drivers/gpu/drm/i915/intel_mocs.h
index 76e45b1..d20e16d 100644
--- a/drivers/gpu/drm/i915/intel_mocs.h
+++ b/drivers/gpu/drm/i915/intel_mocs.h
@@ -53,5 +53,6 @@
 #include "i915_drv.h"
 
 int intel_rcs_context_init_mocs(struct drm_i915_gem_request *req);
+void intel_program_mocs_engines(struct drm_device *dev);
 
 #endif
-- 
1.9.1

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