drm/i915: Added Programming of the MOCS

This change adds the programming of the MOCS registers to the gen 9+
platforms. The set of MOCS configuration entries introduced by this
patch is intended to be minimal but sufficient to cover the needs of
current userspace - i.e. a good set of defaults. It is expected to be
extended in the future to provide further default values or to allow
userspace to redefine its private MOCS tables based on its demand for
additional caching configurations. In this setup, userspace should
only utilize the first N entries, higher entries are reserved for
future use.

It creates a fixed register set that is programmed across the different
engines so that all engines have the same table. This is done as the
main RCS context only holds the registers for itself and the shared
L3 values. By trying to keep the registers consistent across the
different engines it should make the programming for the registers
consistent.

v2:
-'static const' for private data structures and style changes.(Matt Turner)
v3:
- Make the tables "slightly" more readable. (Damien Lespiau)
- Updated tables fix performance regression.
v4:
- Code formatting. (Chris Wilson)
- re-privatised mocs code. (Daniel Vetter)
v5:
- Changed the name of a function. (Chris Wilson)
v6:
- re-based
- Added Mesa table entry (skylake & broxton) (Francisco Jerez)
- Tidied up the readability defines (Francisco Jerez)
- NUMBER of entries defines wrong. (Jim Bish)
- Added comments to clear up the meaning of the tables (Jim Bish)
Signed-off-by: Peter Antoine <peter.antoine@intel.com>

v7 (Francisco Jerez):
- Don't write L3-specific MOCS_ESC/SCC values into the e/LLC control
  tables.  Prefix L3-specific defines consistently with L3_ and
  e/LLC-specific defines with LE_ to avoid this kind of confusion in
  the future.
- Change L3CC WT define back to RESERVED (matches my hardware
  documentation and the original patch, probably a misunderstanding
  of my own previous comment).
- Drop Android tables, define new minimal tables more suitable for the
  open source stack.
- Add comment that the MOCS tables are part of the kernel ABI.
- Move intel_logical_ring_begin() and _advance() calls one level down
  (Chris Wilson).
- Minor formatting and style fixes.
v8 (Francisco Jerez):
- Add table size sanity check to emit_mocs_control/l3cc_table() (Chris
  Wilson).
- Add comment about undefined entries being implicitly set to uncached
  for forwards compatibility.
v9 (Francisco Jerez):
- Minor style fixes.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Acked-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/Makefile

@@ -36,6 +36,7 @@ i915-y += i915_cmd_parser.o \
 	  i915_trace_points.o \
 	  intel_hotplug.o \
 	  intel_lrc.o \
+	  intel_mocs.o \
 	  intel_ringbuffer.o \
 	  intel_uncore.o
 

drivers/gpu/drm/i915/i915_reg.h

@@ -7902,4 +7902,13 @@ enum skl_disp_power_wells {
 #define _PALETTE_A (dev_priv->info.display_mmio_offset + 0xa000)
 #define _PALETTE_B (dev_priv->info.display_mmio_offset + 0xa800)
 
+/* MOCS (Memory Object Control State) registers */
+#define GEN9_LNCFCMOCS0		0xb020	/* L3 Cache Control base */
+
+#define GEN9_GFX_MOCS_0		0xc800	/* Graphics MOCS base register*/
+#define GEN9_MFX0_MOCS_0	0xc900	/* Media 0 MOCS base register*/
+#define GEN9_MFX1_MOCS_0	0xca00	/* Media 1 MOCS base register*/
+#define GEN9_VEBOX_MOCS_0	0xcb00	/* Video MOCS base register*/
+#define GEN9_BLT_MOCS_0		0xcc00	/* Blitter MOCS base register*/
+
 #endif /* _I915_REG_H_ */

drivers/gpu/drm/i915/intel_lrc.c

@@ -135,6 +135,7 @@
 #include <drm/drmP.h>
 #include <drm/i915_drm.h>
 #include "i915_drv.h"
+#include "intel_mocs.h"
 
 #define GEN9_LR_CONTEXT_RENDER_SIZE (22 * PAGE_SIZE)
 #define GEN8_LR_CONTEXT_RENDER_SIZE (20 * PAGE_SIZE)
@@ -772,8 +773,7 @@ static int logical_ring_prepare(struct drm_i915_gem_request *req, int bytes)
  *
  * Return: non-zero if the ringbuffer is not ready to be written to.
  */
-static int intel_logical_ring_begin(struct drm_i915_gem_request *req,
-				    int num_dwords)
+int intel_logical_ring_begin(struct drm_i915_gem_request *req, int num_dwords)
 {
 	struct drm_i915_private *dev_priv;
 	int ret;
@@ -1670,6 +1670,14 @@ static int gen8_init_rcs_context(struct drm_i915_gem_request *req)
 	if (ret)
 		return ret;
 
+	ret = intel_rcs_context_init_mocs(req);
+	/*
+	 * Failing to program the MOCS is non-fatal.The system will not
+	 * run at peak performance. So generate an error and carry on.
+	 */
+	if (ret)
+		DRM_ERROR("MOCS failed to program: expect performance issues.\n");
+
 	return intel_lr_context_render_state_init(req);
 }
 

drivers/gpu/drm/i915/intel_lrc.h

@@ -42,6 +42,7 @@ int intel_logical_ring_reserve_space(struct drm_i915_gem_request *request);
 void intel_logical_ring_stop(struct intel_engine_cs *ring);
 void intel_logical_ring_cleanup(struct intel_engine_cs *ring);
 int intel_logical_rings_init(struct drm_device *dev);
+int intel_logical_ring_begin(struct drm_i915_gem_request *req, int num_dwords);
 
 int logical_ring_flush_all_caches(struct drm_i915_gem_request *req);
 /**

drivers/gpu/drm/i915/intel_mocs.c

+/*
+ * Copyright (c) 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions: *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "intel_mocs.h"
+#include "intel_lrc.h"
+#include "intel_ringbuffer.h"
+
+/* structures required */
+struct drm_i915_mocs_entry {
+	u32 control_value;
+	u16 l3cc_value;
+};
+
+struct drm_i915_mocs_table {
+	u32 size;
+	const struct drm_i915_mocs_entry *table;
+};
+
+/* Defines for the tables (XXX_MOCS_0 - XXX_MOCS_63) */
+#define LE_CACHEABILITY(value)	((value) << 0)
+#define LE_TGT_CACHE(value)	((value) << 2)
+#define LE_LRUM(value)		((value) << 4)
+#define LE_AOM(value)		((value) << 6)
+#define LE_RSC(value)		((value) << 7)
+#define LE_SCC(value)		((value) << 8)
+#define LE_PFM(value)		((value) << 11)
+#define LE_SCF(value)		((value) << 14)
+
+/* Defines for the tables (LNCFMOCS0 - LNCFMOCS31) - two entries per word */
+#define L3_ESC(value)		((value) << 0)
+#define L3_SCC(value)		((value) << 1)
+#define L3_CACHEABILITY(value)	((value) << 4)
+
+/* Helper defines */
+#define GEN9_NUM_MOCS_ENTRIES	62  /* 62 out of 64 - 63 & 64 are reserved. */
+
+/* (e)LLC caching options */
+#define LE_PAGETABLE		0
+#define LE_UC			1
+#define LE_WT			2
+#define LE_WB			3
+
+/* L3 caching options */
+#define L3_DIRECT		0
+#define L3_UC			1
+#define L3_RESERVED		2
+#define L3_WB			3
+
+/* Target cache */
+#define ELLC			0
+#define LLC			1
+#define LLC_ELLC		2
+
+/*
+ * MOCS tables
+ *
+ * These are the MOCS tables that are programmed across all the rings.
+ * The control value is programmed to all the rings that support the
+ * MOCS registers. While the l3cc_values are only programmed to the
+ * LNCFCMOCS0 - LNCFCMOCS32 registers.
+ *
+ * These tables are intended to be kept reasonably consistent across
+ * platforms. However some of the fields are not applicable to all of
+ * them.
+ *
+ * Entries not part of the following tables are undefined as far as
+ * userspace is concerned and shouldn't be relied upon.  For the time
+ * being they will be implicitly initialized to the strictest caching
+ * configuration (uncached) to guarantee forwards compatibility with
+ * userspace programs written against more recent kernels providing
+ * additional MOCS entries.
+ *
+ * NOTE: These tables MUST start with being uncached and the length
+ *       MUST be less than 63 as the last two registers are reserved
+ *       by the hardware.  These tables are part of the kernel ABI and
+ *       may only be updated incrementally by adding entries at the
+ *       end.
+ */
+static const struct drm_i915_mocs_entry skylake_mocs_table[] = {
+	/* { 0x00000009, 0x0010 } */
+	{ (LE_CACHEABILITY(LE_UC) | LE_TGT_CACHE(LLC_ELLC) | LE_LRUM(0) |
+	   LE_AOM(0) | LE_RSC(0) | LE_SCC(0) | LE_PFM(0) | LE_SCF(0)),
+	  (L3_ESC(0) | L3_SCC(0) | L3_CACHEABILITY(L3_UC)) },
+	/* { 0x00000038, 0x0030 } */
+	{ (LE_CACHEABILITY(LE_PAGETABLE) | LE_TGT_CACHE(LLC_ELLC) | LE_LRUM(3) |
+	   LE_AOM(0) | LE_RSC(0) | LE_SCC(0) | LE_PFM(0) | LE_SCF(0)),
+	  (L3_ESC(0) | L3_SCC(0) | L3_CACHEABILITY(L3_WB)) },
+	/* { 0x0000003b, 0x0030 } */
+	{ (LE_CACHEABILITY(LE_WB) | LE_TGT_CACHE(LLC_ELLC) | LE_LRUM(3) |
+	   LE_AOM(0) | LE_RSC(0) | LE_SCC(0) | LE_PFM(0) | LE_SCF(0)),
+	  (L3_ESC(0) | L3_SCC(0) | L3_CACHEABILITY(L3_WB)) }
+};
+
+/* NOTE: the LE_TGT_CACHE is not used on Broxton */
+static const struct drm_i915_mocs_entry broxton_mocs_table[] = {
+	/* { 0x00000009, 0x0010 } */
+	{ (LE_CACHEABILITY(LE_UC) | LE_TGT_CACHE(LLC_ELLC) | LE_LRUM(0) |
+	   LE_AOM(0) | LE_RSC(0) | LE_SCC(0) | LE_PFM(0) | LE_SCF(0)),
+	  (L3_ESC(0) | L3_SCC(0) | L3_CACHEABILITY(L3_UC)) },
+	/* { 0x00000038, 0x0030 } */
+	{ (LE_CACHEABILITY(LE_PAGETABLE) | LE_TGT_CACHE(LLC_ELLC) | LE_LRUM(3) |
+	   LE_AOM(0) | LE_RSC(0) | LE_SCC(0) | LE_PFM(0) | LE_SCF(0)),
+	  (L3_ESC(0) | L3_SCC(0) | L3_CACHEABILITY(L3_WB)) },
+	/* { 0x0000003b, 0x0030 } */
+	{ (LE_CACHEABILITY(LE_WB) | LE_TGT_CACHE(LLC_ELLC) | LE_LRUM(3) |
+	   LE_AOM(0) | LE_RSC(0) | LE_SCC(0) | LE_PFM(0) | LE_SCF(0)),
+	  (L3_ESC(0) | L3_SCC(0) | L3_CACHEABILITY(L3_WB)) }
+};
+
+/**
+ * get_mocs_settings()
+ * @dev:        DRM device.
+ * @table:      Output table that will be made to point at appropriate
+ *              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
+ * to be programmed and if they need to be programmed.
+ *
+ * Return: true if there are applicable MOCS settings for the device.
+ */
+static bool get_mocs_settings(struct drm_device *dev,
+			      struct drm_i915_mocs_table *table)
+{
+	bool result = false;
+
+	if (IS_SKYLAKE(dev)) {
+		table->size  = ARRAY_SIZE(skylake_mocs_table);
+		table->table = skylake_mocs_table;
+		result = true;
+	} else if (IS_BROXTON(dev)) {
+		table->size  = ARRAY_SIZE(broxton_mocs_table);
+		table->table = broxton_mocs_table;
+		result = true;
+	} else {
+		WARN_ONCE(INTEL_INFO(dev)->gen >= 9,
+			  "Platform that should have a MOCS table does not.\n");
+	}
+
+	return result;
+}
+
+/**
+ * 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.
+ * @reg_base:	The base for the engine that needs to be programmed.
+ *
+ * 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 emit_mocs_control_table(struct drm_i915_gem_request *req,
+				   const struct drm_i915_mocs_table *table,
+				   u32 reg_base)
+{
+	struct intel_ringbuffer *ringbuf = req->ringbuf;
+	unsigned int index;
+	int ret;
+
+	if (WARN_ON(table->size > GEN9_NUM_MOCS_ENTRIES))
+		return -ENODEV;
+
+	ret = intel_logical_ring_begin(req, 2 + 2 * GEN9_NUM_MOCS_ENTRIES);
+	if (ret) {
+		DRM_DEBUG("intel_logical_ring_begin failed %d\n", ret);
+		return ret;
+	}
+
+	intel_logical_ring_emit(ringbuf,
+				MI_LOAD_REGISTER_IMM(GEN9_NUM_MOCS_ENTRIES));
+
+	for (index = 0; index < table->size; index++) {
+		intel_logical_ring_emit(ringbuf, reg_base + index * 4);
+		intel_logical_ring_emit(ringbuf,
+					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++) {
+		intel_logical_ring_emit(ringbuf, reg_base + index * 4);
+		intel_logical_ring_emit(ringbuf, table->table[0].control_value);
+	}
+
+	intel_logical_ring_emit(ringbuf, MI_NOOP);
+	intel_logical_ring_advance(ringbuf);
+
+	return 0;
+}
+
+/**
+ * emit_mocs_l3cc_table() - emit the mocs control table
+ * @req:	Request to set up the MOCS table for.
+ * @table:	The values to program into the control regs.
+ *
+ * This function simply emits a MI_LOAD_REGISTER_IMM command for the
+ * given table starting at the given address. This register set is
+ * programmed in pairs.
+ *
+ * Return: 0 on success, otherwise the error status.
+ */
+static int emit_mocs_l3cc_table(struct drm_i915_gem_request *req,
+				const struct drm_i915_mocs_table *table)
+{
+	struct intel_ringbuffer *ringbuf = req->ringbuf;
+	unsigned int count;
+	unsigned int i;
+	u32 value;
+	u32 filler = (table->table[0].l3cc_value & 0xffff) |
+			((table->table[0].l3cc_value & 0xffff) << 16);
+	int ret;
+
+	if (WARN_ON(table->size > GEN9_NUM_MOCS_ENTRIES))
+		return -ENODEV;
+
+	ret = intel_logical_ring_begin(req, 2 + GEN9_NUM_MOCS_ENTRIES);
+	if (ret) {
+		DRM_DEBUG("intel_logical_ring_begin failed %d\n", ret);
+		return ret;
+	}
+
+	intel_logical_ring_emit(ringbuf,
+			MI_LOAD_REGISTER_IMM(GEN9_NUM_MOCS_ENTRIES / 2));
+
+	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);
+
+		intel_logical_ring_emit(ringbuf, GEN9_LNCFCMOCS0 + i * 4);
+		intel_logical_ring_emit(ringbuf, 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 uninitialised as
+	 * they are reserved by the hardware.
+	 */
+	for (; i < GEN9_NUM_MOCS_ENTRIES / 2; i++) {
+		intel_logical_ring_emit(ringbuf, GEN9_LNCFCMOCS0 + i * 4);
+		intel_logical_ring_emit(ringbuf, value);
+
+		value = filler;
+	}
+
+	intel_logical_ring_emit(ringbuf, MI_NOOP);
+	intel_logical_ring_advance(ringbuf);
+
+	return 0;
+}
+
+/**
+ * intel_rcs_context_init_mocs() - program the MOCS register.
+ * @req:	Request to set up the MOCS tables for.
+ *
+ * This function will emit a batch buffer with the values required for
+ * programming the MOCS register values for all the currently supported
+ * rings.
+ *
+ * These registers are partially stored in the RCS context, so they are
+ * emitted at the same time so that when a context is created these registers
+ * are set up. These registers have to be emitted into the start of the
+ * context as setting the ELSP will re-init some of these registers back
+ * to the hw values.
+ *
+ * Return: 0 on success, otherwise the error status.
+ */
+int intel_rcs_context_init_mocs(struct drm_i915_gem_request *req)
+{
+	struct drm_i915_mocs_table t;
+	int ret;
+
+	if (get_mocs_settings(req->ring->dev, &t)) {
+		/* Program the control registers */
+		ret = emit_mocs_control_table(req, &t, GEN9_GFX_MOCS_0);
+		if (ret)
+			return ret;
+
+		ret = emit_mocs_control_table(req, &t, GEN9_MFX0_MOCS_0);
+		if (ret)
+			return ret;
+
+		ret = emit_mocs_control_table(req, &t, GEN9_MFX1_MOCS_0);
+		if (ret)
+			return ret;
+
+		ret = emit_mocs_control_table(req, &t, GEN9_VEBOX_MOCS_0);
+		if (ret)
+			return ret;
+
+		ret = emit_mocs_control_table(req, &t, GEN9_BLT_MOCS_0);
+		if (ret)
+			return ret;
+
+		/* Now program the l3cc registers */
+		ret = emit_mocs_l3cc_table(req, &t);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}

drivers/gpu/drm/i915/intel_mocs.h

+/*
+ * Copyright (c) 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef INTEL_MOCS_H
+#define INTEL_MOCS_H
+
+/**
+ * DOC: Memory Objects Control State (MOCS)
+ *
+ * Motivation:
+ * In previous Gens the MOCS settings was a value that was set by user land as
+ * part of the batch. In Gen9 this has changed to be a single table (per ring)
+ * that all batches now reference by index instead of programming the MOCS
+ * directly.
+ *
+ * The one wrinkle in this is that only PART of the MOCS tables are included
+ * in context (The GFX_MOCS_0 - GFX_MOCS_64 and the LNCFCMOCS0 - LNCFCMOCS32
+ * registers). The rest are not (the settings for the other rings).
+ *
+ * This table needs to be set at system start-up because the way the table
+ * interacts with the contexts and the GmmLib interface.
+ *
+ *
+ * Implementation:
+ *
+ * The tables (one per supported platform) are defined in intel_mocs.c
+ * and are programmed in the first batch after the context is loaded
+ * (with the hardware workarounds). This will then let the usual
+ * context handling keep the MOCS in step.
+ */
+
+#include <drm/drmP.h>
+#include "i915_drv.h"
+
+int intel_rcs_context_init_mocs(struct drm_i915_gem_request *req);
+
+#endif