drm/i915: Implement dynamic GuC WOPCM offset and size calculation

Hardware may have specific restrictions on GuC WOPCM offset and size. On
Gen9, the value of the GuC WOPCM size register needs to be larger than the
value of GuC WOPCM offset register + a Gen9 specific offset (144KB) for
reserved GuC WOPCM. Fail to enforce such a restriction on GuC WOPCM size
will lead to GuC firmware execution failures. On the other hand, with
current static GuC WOPCM offset and size values (512KB for both offset and
size), the GuC WOPCM size verification will fail on Gen9 even if it can be
fixed by lowering the GuC WOPCM offset by calculating its value based on
HuC firmware size (which is likely less than 200KB on Gen9), so that we can
have a GuC WOPCM size value which is large enough to pass the GuC WOPCM
size check.

This patch updates the reserved GuC WOPCM size for RC6 context on Gen9 to
24KB to strictly align with the Gen9 GuC WOPCM layout. It also adds support
to verify the GuC WOPCM size aganist the Gen9 hardware restrictions. To
meet all above requirements, let's provide dynamic partitioning of the
WOPCM that will be based on platform specific HuC/GuC firmware sizes.

v2:
 - Removed intel_wopcm_init (Ville/Sagar/Joonas)
 - Renamed and Moved the intel_wopcm_partition into intel_guc (Sagar)
 - Removed unnecessary function calls (Joonas)
 - Init GuC WOPCM partition as soon as firmware fetching is completed

v3:
 - Fixed indentation issues (Chris)
 - Removed layering violation code (Chris/Michal)
 - Created separat files for GuC wopcm code  (Michal)
 - Used inline function to avoid code duplication (Michal)

v4:
 - Preset the GuC WOPCM top during early GuC init (Chris)
 - Fail intel_uc_init_hw() as soon as GuC WOPCM partitioning failed

v5:
 - Moved GuC DMA WOPCM register updating code into intel_wopcm.c
 - Took care of the locking status before writing to GuC DMA
   Write-Once registers. (Joonas)

v6:
 - Made sure the GuC WOPCM size to be multiple of 4K (4K aligned)

v8:
 - Updated comments and fixed naming issues (Sagar/Joonas)
 - Updated commit message to include more description about the hardware
   restriction on GuC WOPCM size (Sagar)

v9:
 - Minor changes variable names and code comments (Sagar)
 - Added detailed GuC WOPCM layout drawing (Sagar/Michal)
 - Refined macro definitions to be reader friendly (Michal)
 - Removed redundent check to valid flag (Michal)
 - Unified first parameter for exported GuC WOPCM functions (Michal)
 - Refined the name and parameter list of hardware restriction checking
   functions (Michal)

v10:
 - Used shorter function name for internal functions (Joonas)
 - Moved init-ealry function into c file (Joonas)
 - Consolidated and removed redundant size checks (Joonas/Michal)
 - Removed unnecessary unlikely() from code which is only called once
   during boot (Joonas)
 - More fixes to kernel-doc format and content (Michal)
 - Avoided the use of PAGE_MASK for 4K pages (Michal)
 - Added error log messages to error paths (Michal)

v11:
 - Replaced intel_guc_wopcm with more generic intel_wopcm and attached
   intel_wopcm to drm_i915_private instead intel_guc (Michal)
 - dynamic calculation of GuC non-wopcm memory start (a.k.a WOPCM Top
   offset from GuC WOPCM base) (Michal)
 - Moved WOPCM marco definitions into .c source file (Michal)
 - Exported WOPCM layout diagram as kernel-doc (Michal)

v12:
 - Updated naming, function kernel-doc to align with new changes (Michal)

v13:
 - Updated the ordering of s-o-b/cc/r-b tags (Sagar)
 - Corrected one tense error in comment (Sagar)
 - Corrected typos and removed spurious comments (Joonas)

Bspec: 12690

Signed-off-by: Jackie Li <yaodong.li@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Sujaritha Sundaresan <sujaritha.sundaresan@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: John Spotswood <john.a.spotswood@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com> (v8)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v9)
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com> (v11)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v12)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1520987574-19351-2-git-send-email-yaodong.li@intel.com

1 files changed, 182 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_wopcm.c b/drivers/gpu/drm/i915/intel_wopcm.c
new file mode 100644
index 000000000000..7b150d580d4a
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_wopcm.c
@@ -0,0 +1,182 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2017-2018 Intel Corporation
+ */
+
+#include "intel_wopcm.h"
+#include "i915_drv.h"
+
+/**
+ * DOC: WOPCM Layout
+ *
+ * The layout of the WOPCM will be fixed after writing to GuC WOPCM size and
+ * offset registers whose are calculated are determined by size of HuC/GuC
+ * firmware size and set of hw requirements/restrictions as shown below:
+ *
+ *   +=========> +====================+ <== WOPCM Top
+ *   ^           |  HW contexts RSVD  |
+ *   |     +===> +====================+ <== GuC WOPCM Top
+ *   |     ^     |                    |
+ *   |     |     |                    |
+ *   |     |     |                    |
+ *   |    GuC    |                    |
+ *   |   WOPCM   |                    |
+ *   |    Size   +--------------------+
+ * WOPCM   |     |    GuC FW RSVD     |
+ *   |     |     +--------------------+
+ *   |     |     |   GuC Stack RSVD   |
+ *   |     |     +------------------- +
+ *   |     v     |   GuC WOPCM RSVD   |
+ *   |     +===> +====================+ <== GuC WOPCM base
+ *   |           |     WOPCM RSVD     |
+ *   |           +------------------- + <== HuC Firmware Top
+ *   v           |      HuC FW        |
+ *   +=========> +====================+ <== WOPCM Base
+ *
+ * GuC accessible WOPCM starts at GuC WOPCM base and ends at GuC WOPCM top.
+ * The top part of the WOPCM is reserved for hardware contexts (e.g. RC6
+ * context).
+ */
+
+/* Default WOPCM size 1MB. */
+#define GEN9_WOPCM_SIZE			(1024 * 1024)
+/* 16KB WOPCM (RSVD WOPCM) is reserved from HuC firmware top. */
+#define WOPCM_RESERVED_SIZE		(16 * 1024)
+
+/* 16KB reserved at the beginning of GuC WOPCM. */
+#define GUC_WOPCM_RESERVED		(16 * 1024)
+/* 8KB from GUC_WOPCM_RESERVED is reserved for GuC stack. */
+#define GUC_WOPCM_STACK_RESERVED	(8 * 1024)
+
+/* GuC WOPCM Offset value needs to be aligned to 16KB. */
+#define GUC_WOPCM_OFFSET_ALIGNMENT	(1UL << GUC_WOPCM_OFFSET_SHIFT)
+
+/* 24KB at the end of WOPCM is reserved for RC6 CTX on BXT. */
+#define BXT_WOPCM_RC6_CTX_RESERVED	(24 * 1024)
+
+/* 128KB from GUC_WOPCM_RESERVED is reserved for FW on Gen9. */
+#define GEN9_GUC_FW_RESERVED	(128 * 1024)
+#define GEN9_GUC_WOPCM_OFFSET	(GUC_WOPCM_RESERVED + GEN9_GUC_FW_RESERVED)
+
+/**
+ * intel_wopcm_init_early() - Early initialization of the WOPCM.
+ * @wopcm: pointer to intel_wopcm.
+ *
+ * Setup the size of WOPCM which will be used by later on WOPCM partitioning.
+ */
+void intel_wopcm_init_early(struct intel_wopcm *wopcm)
+{
+	wopcm->size = GEN9_WOPCM_SIZE;
+
+	DRM_DEBUG_DRIVER("WOPCM size: %uKiB\n", wopcm->size / 1024);
+}
+
+static inline u32 context_reserved_size(struct drm_i915_private *i915)
+{
+	if (IS_GEN9_LP(i915))
+		return BXT_WOPCM_RC6_CTX_RESERVED;
+	else
+		return 0;
+}
+
+static inline int gen9_check_dword_gap(u32 guc_wopcm_base, u32 guc_wopcm_size)
+{
+	u32 offset;
+
+	/*
+	 * GuC WOPCM size shall be at least a dword larger than the offset from
+	 * WOPCM base (GuC WOPCM offset from WOPCM base + GEN9_GUC_WOPCM_OFFSET)
+	 * due to hardware limitation on Gen9.
+	 */
+	offset = guc_wopcm_base + GEN9_GUC_WOPCM_OFFSET;
+	if (offset > guc_wopcm_size ||
+	    (guc_wopcm_size - offset) < sizeof(u32)) {
+		DRM_ERROR("GuC WOPCM size %uKiB is too small. %uKiB needed.\n",
+			  guc_wopcm_size / 1024,
+			  (u32)(offset + sizeof(u32)) / 1024);
+		return -E2BIG;
+	}
+
+	return 0;
+}
+
+static inline int check_hw_restriction(struct drm_i915_private *i915,
+				       u32 guc_wopcm_base, u32 guc_wopcm_size)
+{
+	int err = 0;
+
+	if (IS_GEN9(i915))
+		err = gen9_check_dword_gap(guc_wopcm_base, guc_wopcm_size);
+
+	return err;
+}
+
+/**
+ * intel_wopcm_init() - Initialize the WOPCM structure.
+ * @wopcm: pointer to intel_wopcm.
+ *
+ * This function will partition WOPCM space based on GuC and HuC firmware sizes
+ * and will allocate max remaining for use by GuC. This function will also
+ * enforce platform dependent hardware restrictions on GuC WOPCM offset and
+ * size. It will fail the WOPCM init if any of these checks were failed, so that
+ * the following GuC firmware uploading would be aborted.
+ *
+ * Return: 0 on success, non-zero error code on failure.
+ */
+int intel_wopcm_init(struct intel_wopcm *wopcm)
+{
+	struct drm_i915_private *i915 = wopcm_to_i915(wopcm);
+	u32 guc_fw_size = intel_uc_fw_get_upload_size(&i915->guc.fw);
+	u32 huc_fw_size = intel_uc_fw_get_upload_size(&i915->huc.fw);
+	u32 ctx_rsvd = context_reserved_size(i915);
+	u32 guc_wopcm_base;
+	u32 guc_wopcm_size;
+	u32 guc_wopcm_rsvd;
+	int err;
+
+	GEM_BUG_ON(!wopcm->size);
+
+	if (guc_fw_size >= wopcm->size) {
+		DRM_ERROR("GuC FW (%uKiB) is too big to fit in WOPCM.",
+			  guc_fw_size / 1024);
+		return -E2BIG;
+	}
+
+	if (huc_fw_size >= wopcm->size) {
+		DRM_ERROR("HuC FW (%uKiB) is too big to fit in WOPCM.",
+			  huc_fw_size / 1024);
+		return -E2BIG;
+	}
+
+	guc_wopcm_base = ALIGN(huc_fw_size + WOPCM_RESERVED_SIZE,
+			       GUC_WOPCM_OFFSET_ALIGNMENT);
+	if ((guc_wopcm_base + ctx_rsvd) >= wopcm->size) {
+		DRM_ERROR("GuC WOPCM base (%uKiB) is too big.\n",
+			  guc_wopcm_base / 1024);
+		return -E2BIG;
+	}
+
+	guc_wopcm_size = wopcm->size - guc_wopcm_base - ctx_rsvd;
+	guc_wopcm_size &= GUC_WOPCM_SIZE_MASK;
+
+	DRM_DEBUG_DRIVER("Calculated GuC WOPCM Region: [%uKiB, %uKiB)\n",
+			 guc_wopcm_base / 1024, guc_wopcm_size / 1024);
+
+	guc_wopcm_rsvd = GUC_WOPCM_RESERVED + GUC_WOPCM_STACK_RESERVED;
+	if ((guc_fw_size + guc_wopcm_rsvd) > guc_wopcm_size) {
+		DRM_ERROR("Need %uKiB WOPCM for GuC, %uKiB available.\n",
+			  (guc_fw_size + guc_wopcm_rsvd) / 1024,
+			  guc_wopcm_size / 1024);
+		return -E2BIG;
+	}
+
+	err = check_hw_restriction(i915, guc_wopcm_base, guc_wopcm_size);
+	if (err)
+		return err;
+
+	wopcm->guc.base = guc_wopcm_base;
+	wopcm->guc.size = guc_wopcm_size;
+
+	return 0;
+}