Merge tag 'drm-for-v4.11-less-shouty' of git://people.freedesktop.org/~airlied/linux

Pull drm updates from Dave Airlie:
 "This is the main drm pull request for v4.11.

  Nothing too major, the tinydrm and mmu-less support should make
  writing smaller drivers easier for some of the simpler platforms, and
  there are a bunch of documentation updates.

  Intel grew displayport MST audio support which is hopefully useful to
  people, and FBC is on by default for GEN9+ (so people know where to
  look for regressions). AMDGPU has a lot of fixes that would like new
  firmware files installed for some GPUs.

  Other than that it's pretty scattered all over.

  I may have a follow up pull request as I know BenH has a bunch of AST
  rework and fixes and I'd like to get those in once they've been tested
  by AST, and I've got at least one pull request I'm just trying to get
  the author to fix up.

  Core:
   - drm_mm reworked
   - Connector list locking and iterators
   - Documentation updates
   - Format handling rework
   - MMU-less support for fbdev helpers
   - drm_crtc_from_index helper
   - Core CRC API
   - Remove drm_framebuffer_unregister_private
   - Debugfs cleanup
   - EDID/Infoframe fixes
   - Release callback
   - Tinydrm support (smaller drivers for simple hw)

  panel:
   - Add support for some new simple panels

  i915:
   - FBC by default for gen9+
   - Shared dpll cleanups and docs
   - GEN8 powerdomain cleanup
   - DMC support on GLK
   - DP MST audio support
   - HuC loading support
   - GVT init ordering fixes
   - GVT IOMMU workaround fix

  amdgpu/radeon:
   - Power/clockgating improvements
   - Preliminary SR-IOV support
   - TTM buffer priority and eviction fixes
   - SI DPM quirks removed due to firmware fixes
   - Powerplay improvements
   - VCE/UVD powergating fixes
   - Cleanup SI GFX code to match CI/VI
   - Support for > 2 displays on 3/5 crtc asics
   - SI headless fixes

  nouveau:
   - Rework securre boot code in prep for GP10x secure boot
   - Channel recovery improvements
   - Initial power budget code
   - MMU rework preperation

  vmwgfx:
   - Bunch of fixes and cleanups

  exynos:
   - Runtime PM support for MIC driver
   - Cleanups to use atomic helpers
   - UHD Support for TM2/TM2E boards
   - Trigger mode fix for Rinato board

  etnaviv:
   - Shader performance fix
   - Command stream validator fixes
   - Command buffer suballocator

  rockchip:
   - CDN DisplayPort support
   - IOMMU support for arm64 platform

  imx-drm:
   - Fix i.MX5 TV encoder probing
   - Remove lower fb size limits

  msm:
   - Support for HW cursor on MDP5 devices
   - DSI encoder cleanup
   - GPU DT bindings cleanup

  sti:
   - stih410 cleanups
   - Create fbdev at binding
   - HQVDP fixes
   - Remove stih416 chip functionality
   - DVI/HDMI mode selection fixes
   - FPS statistic reporting

  omapdrm:
   - IRQ code cleanup

  dwi-hdmi bridge:
   - Cleanups and fixes

  adv-bridge:
   - Updates for nexus

  sii8520 bridge:
   - Add interlace mode support
   - Rework HDMI and lots of fixes

  qxl:
   - probing/teardown cleanups

  ZTE drm:
   - HDMI audio via SPDIF interface
   - Video Layer overlay plane support
   - Add TV encoder output device

  atmel-hlcdc:
   - Rework fbdev creation logic

  tegra:
   - OF node fix

  fsl-dcu:
   - Minor fixes

  mali-dp:
   - Assorted fixes

  sunxi:
   - Minor fix"

[ This was the "fixed" pull, that still had build warnings due to people
  not even having build tested the result. I'm not a happy camper

  I've fixed the things I noticed up in this merge.      - Linus ]

* tag 'drm-for-v4.11-less-shouty' of git://people.freedesktop.org/~airlied/linux: (1177 commits)
  lib/Kconfig: make PRIME_NUMBERS not user selectable
  drm/tinydrm: helpers: Properly fix backlight dependency
  drm/tinydrm: mipi-dbi: Fix field width specifier warning
  drm/tinydrm: mipi-dbi: Silence: ‘cmd’ may be used uninitialized
  drm/sti: fix build warnings in sti_drv.c and sti_vtg.c files
  drm/amd/powerplay: fix PSI feature on Polars12
  drm/amdgpu: refuse to reserve io mem for split VRAM buffers
  drm/ttm: fix use-after-free races in vm fault handling
  drm/tinydrm: Add support for Multi-Inno MI0283QT display
  dt-bindings: Add Multi-Inno MI0283QT binding
  dt-bindings: display/panel: Add common rotation property
  of: Add vendor prefix for Multi-Inno
  drm/tinydrm: Add MIPI DBI support
  drm/tinydrm: Add helper functions
  drm: Add DRM support for tiny LCD displays
  drm/amd/amdgpu: post card if there is real hw resetting performed
  drm/nouveau/tmr: provide backtrace when a timeout is hit
  drm/nouveau/pci/g92: Fix rearm
  drm/nouveau/drm/therm/fan: add a fallback if no fan control is specified in the vbios
  drm/nouveau/hwmon: expose power_max and power_crit
  ..

1 files changed, 658 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_guc_log.c b/drivers/gpu/drm/i915/intel_guc_log.c
new file mode 100644
index 000000000000..5c0f9a49da0e
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_guc_log.c
@@ -0,0 +1,658 @@
+/*
+ * Copyright © 2014-2017 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 <linux/debugfs.h>
+#include <linux/relay.h>
+#include "i915_drv.h"
+
+static void guc_log_capture_logs(struct intel_guc *guc);
+
+/**
+ * DOC: GuC firmware log
+ *
+ * Firmware log is enabled by setting i915.guc_log_level to non-negative level.
+ * Log data is printed out via reading debugfs i915_guc_log_dump. Reading from
+ * i915_guc_load_status will print out firmware loading status and scratch
+ * registers value.
+ *
+ */
+
+static int guc_log_flush_complete(struct intel_guc *guc)
+{
+	u32 action[] = {
+		INTEL_GUC_ACTION_LOG_BUFFER_FILE_FLUSH_COMPLETE
+	};
+
+	return intel_guc_send(guc, action, ARRAY_SIZE(action));
+}
+
+static int guc_log_flush(struct intel_guc *guc)
+{
+	u32 action[] = {
+		INTEL_GUC_ACTION_FORCE_LOG_BUFFER_FLUSH,
+		0
+	};
+
+	return intel_guc_send(guc, action, ARRAY_SIZE(action));
+}
+
+static int guc_log_control(struct intel_guc *guc, u32 control_val)
+{
+	u32 action[] = {
+		INTEL_GUC_ACTION_UK_LOG_ENABLE_LOGGING,
+		control_val
+	};
+
+	return intel_guc_send(guc, action, ARRAY_SIZE(action));
+}
+
+
+/*
+ * Sub buffer switch callback. Called whenever relay has to switch to a new
+ * sub buffer, relay stays on the same sub buffer if 0 is returned.
+ */
+static int subbuf_start_callback(struct rchan_buf *buf,
+				 void *subbuf,
+				 void *prev_subbuf,
+				 size_t prev_padding)
+{
+	/* Use no-overwrite mode by default, where relay will stop accepting
+	 * new data if there are no empty sub buffers left.
+	 * There is no strict synchronization enforced by relay between Consumer
+	 * and Producer. In overwrite mode, there is a possibility of getting
+	 * inconsistent/garbled data, the producer could be writing on to the
+	 * same sub buffer from which Consumer is reading. This can't be avoided
+	 * unless Consumer is fast enough and can always run in tandem with
+	 * Producer.
+	 */
+	if (relay_buf_full(buf))
+		return 0;
+
+	return 1;
+}
+
+/*
+ * file_create() callback. Creates relay file in debugfs.
+ */
+static struct dentry *create_buf_file_callback(const char *filename,
+					       struct dentry *parent,
+					       umode_t mode,
+					       struct rchan_buf *buf,
+					       int *is_global)
+{
+	struct dentry *buf_file;
+
+	/* This to enable the use of a single buffer for the relay channel and
+	 * correspondingly have a single file exposed to User, through which
+	 * it can collect the logs in order without any post-processing.
+	 * Need to set 'is_global' even if parent is NULL for early logging.
+	 */
+	*is_global = 1;
+
+	if (!parent)
+		return NULL;
+
+	/* Not using the channel filename passed as an argument, since for each
+	 * channel relay appends the corresponding CPU number to the filename
+	 * passed in relay_open(). This should be fine as relay just needs a
+	 * dentry of the file associated with the channel buffer and that file's
+	 * name need not be same as the filename passed as an argument.
+	 */
+	buf_file = debugfs_create_file("guc_log", mode,
+				       parent, buf, &relay_file_operations);
+	return buf_file;
+}
+
+/*
+ * file_remove() default callback. Removes relay file in debugfs.
+ */
+static int remove_buf_file_callback(struct dentry *dentry)
+{
+	debugfs_remove(dentry);
+	return 0;
+}
+
+/* relay channel callbacks */
+static struct rchan_callbacks relay_callbacks = {
+	.subbuf_start = subbuf_start_callback,
+	.create_buf_file = create_buf_file_callback,
+	.remove_buf_file = remove_buf_file_callback,
+};
+
+static void guc_log_remove_relay_file(struct intel_guc *guc)
+{
+	relay_close(guc->log.relay_chan);
+}
+
+static int guc_log_create_relay_channel(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+	struct rchan *guc_log_relay_chan;
+	size_t n_subbufs, subbuf_size;
+
+	/* Keep the size of sub buffers same as shared log buffer */
+	subbuf_size = guc->log.vma->obj->base.size;
+
+	/* Store up to 8 snapshots, which is large enough to buffer sufficient
+	 * boot time logs and provides enough leeway to User, in terms of
+	 * latency, for consuming the logs from relay. Also doesn't take
+	 * up too much memory.
+	 */
+	n_subbufs = 8;
+
+	guc_log_relay_chan = relay_open(NULL, NULL, subbuf_size,
+					n_subbufs, &relay_callbacks, dev_priv);
+	if (!guc_log_relay_chan) {
+		DRM_ERROR("Couldn't create relay chan for GuC logging\n");
+		return -ENOMEM;
+	}
+
+	GEM_BUG_ON(guc_log_relay_chan->subbuf_size < subbuf_size);
+	guc->log.relay_chan = guc_log_relay_chan;
+	return 0;
+}
+
+static int guc_log_create_relay_file(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+	struct dentry *log_dir;
+	int ret;
+
+	/* For now create the log file in /sys/kernel/debug/dri/0 dir */
+	log_dir = dev_priv->drm.primary->debugfs_root;
+
+	/* If /sys/kernel/debug/dri/0 location do not exist, then debugfs is
+	 * not mounted and so can't create the relay file.
+	 * The relay API seems to fit well with debugfs only, for availing relay
+	 * there are 3 requirements which can be met for debugfs file only in a
+	 * straightforward/clean manner :-
+	 * i)   Need the associated dentry pointer of the file, while opening the
+	 *      relay channel.
+	 * ii)  Should be able to use 'relay_file_operations' fops for the file.
+	 * iii) Set the 'i_private' field of file's inode to the pointer of
+	 *	relay channel buffer.
+	 */
+	if (!log_dir) {
+		DRM_ERROR("Debugfs dir not available yet for GuC log file\n");
+		return -ENODEV;
+	}
+
+	ret = relay_late_setup_files(guc->log.relay_chan, "guc_log", log_dir);
+	if (ret) {
+		DRM_ERROR("Couldn't associate relay chan with file %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void guc_move_to_next_buf(struct intel_guc *guc)
+{
+	/* Make sure the updates made in the sub buffer are visible when
+	 * Consumer sees the following update to offset inside the sub buffer.
+	 */
+	smp_wmb();
+
+	/* All data has been written, so now move the offset of sub buffer. */
+	relay_reserve(guc->log.relay_chan, guc->log.vma->obj->base.size);
+
+	/* Switch to the next sub buffer */
+	relay_flush(guc->log.relay_chan);
+}
+
+static void *guc_get_write_buffer(struct intel_guc *guc)
+{
+	if (!guc->log.relay_chan)
+		return NULL;
+
+	/* Just get the base address of a new sub buffer and copy data into it
+	 * ourselves. NULL will be returned in no-overwrite mode, if all sub
+	 * buffers are full. Could have used the relay_write() to indirectly
+	 * copy the data, but that would have been bit convoluted, as we need to
+	 * write to only certain locations inside a sub buffer which cannot be
+	 * done without using relay_reserve() along with relay_write(). So its
+	 * better to use relay_reserve() alone.
+	 */
+	return relay_reserve(guc->log.relay_chan, 0);
+}
+
+static bool guc_check_log_buf_overflow(struct intel_guc *guc,
+				       enum guc_log_buffer_type type,
+				       unsigned int full_cnt)
+{
+	unsigned int prev_full_cnt = guc->log.prev_overflow_count[type];
+	bool overflow = false;
+
+	if (full_cnt != prev_full_cnt) {
+		overflow = true;
+
+		guc->log.prev_overflow_count[type] = full_cnt;
+		guc->log.total_overflow_count[type] += full_cnt - prev_full_cnt;
+
+		if (full_cnt < prev_full_cnt) {
+			/* buffer_full_cnt is a 4 bit counter */
+			guc->log.total_overflow_count[type] += 16;
+		}
+		DRM_ERROR_RATELIMITED("GuC log buffer overflow\n");
+	}
+
+	return overflow;
+}
+
+static unsigned int guc_get_log_buffer_size(enum guc_log_buffer_type type)
+{
+	switch (type) {
+	case GUC_ISR_LOG_BUFFER:
+		return (GUC_LOG_ISR_PAGES + 1) * PAGE_SIZE;
+	case GUC_DPC_LOG_BUFFER:
+		return (GUC_LOG_DPC_PAGES + 1) * PAGE_SIZE;
+	case GUC_CRASH_DUMP_LOG_BUFFER:
+		return (GUC_LOG_CRASH_PAGES + 1) * PAGE_SIZE;
+	default:
+		MISSING_CASE(type);
+	}
+
+	return 0;
+}
+
+static void guc_read_update_log_buffer(struct intel_guc *guc)
+{
+	unsigned int buffer_size, read_offset, write_offset, bytes_to_copy, full_cnt;
+	struct guc_log_buffer_state *log_buf_state, *log_buf_snapshot_state;
+	struct guc_log_buffer_state log_buf_state_local;
+	enum guc_log_buffer_type type;
+	void *src_data, *dst_data;
+	bool new_overflow;
+
+	if (WARN_ON(!guc->log.buf_addr))
+		return;
+
+	/* Get the pointer to shared GuC log buffer */
+	log_buf_state = src_data = guc->log.buf_addr;
+
+	/* Get the pointer to local buffer to store the logs */
+	log_buf_snapshot_state = dst_data = guc_get_write_buffer(guc);
+
+	/* Actual logs are present from the 2nd page */
+	src_data += PAGE_SIZE;
+	dst_data += PAGE_SIZE;
+
+	for (type = GUC_ISR_LOG_BUFFER; type < GUC_MAX_LOG_BUFFER; type++) {
+		/* Make a copy of the state structure, inside GuC log buffer
+		 * (which is uncached mapped), on the stack to avoid reading
+		 * from it multiple times.
+		 */
+		memcpy(&log_buf_state_local, log_buf_state,
+		       sizeof(struct guc_log_buffer_state));
+		buffer_size = guc_get_log_buffer_size(type);
+		read_offset = log_buf_state_local.read_ptr;
+		write_offset = log_buf_state_local.sampled_write_ptr;
+		full_cnt = log_buf_state_local.buffer_full_cnt;
+
+		/* Bookkeeping stuff */
+		guc->log.flush_count[type] += log_buf_state_local.flush_to_file;
+		new_overflow = guc_check_log_buf_overflow(guc, type, full_cnt);
+
+		/* Update the state of shared log buffer */
+		log_buf_state->read_ptr = write_offset;
+		log_buf_state->flush_to_file = 0;
+		log_buf_state++;
+
+		if (unlikely(!log_buf_snapshot_state))
+			continue;
+
+		/* First copy the state structure in snapshot buffer */
+		memcpy(log_buf_snapshot_state, &log_buf_state_local,
+		       sizeof(struct guc_log_buffer_state));
+
+		/* The write pointer could have been updated by GuC firmware,
+		 * after sending the flush interrupt to Host, for consistency
+		 * set write pointer value to same value of sampled_write_ptr
+		 * in the snapshot buffer.
+		 */
+		log_buf_snapshot_state->write_ptr = write_offset;
+		log_buf_snapshot_state++;
+
+		/* Now copy the actual logs. */
+		if (unlikely(new_overflow)) {
+			/* copy the whole buffer in case of overflow */
+			read_offset = 0;
+			write_offset = buffer_size;
+		} else if (unlikely((read_offset > buffer_size) ||
+				    (write_offset > buffer_size))) {
+			DRM_ERROR("invalid log buffer state\n");
+			/* copy whole buffer as offsets are unreliable */
+			read_offset = 0;
+			write_offset = buffer_size;
+		}
+
+		/* Just copy the newly written data */
+		if (read_offset > write_offset) {
+			i915_memcpy_from_wc(dst_data, src_data, write_offset);
+			bytes_to_copy = buffer_size - read_offset;
+		} else {
+			bytes_to_copy = write_offset - read_offset;
+		}
+		i915_memcpy_from_wc(dst_data + read_offset,
+				    src_data + read_offset, bytes_to_copy);
+
+		src_data += buffer_size;
+		dst_data += buffer_size;
+	}
+
+	if (log_buf_snapshot_state)
+		guc_move_to_next_buf(guc);
+	else {
+		/* Used rate limited to avoid deluge of messages, logs might be
+		 * getting consumed by User at a slow rate.
+		 */
+		DRM_ERROR_RATELIMITED("no sub-buffer to capture logs\n");
+		guc->log.capture_miss_count++;
+	}
+}
+
+static void guc_log_cleanup(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+
+	lockdep_assert_held(&dev_priv->drm.struct_mutex);
+
+	/* First disable the flush interrupt */
+	gen9_disable_guc_interrupts(dev_priv);
+
+	if (guc->log.flush_wq)
+		destroy_workqueue(guc->log.flush_wq);
+
+	guc->log.flush_wq = NULL;
+
+	if (guc->log.relay_chan)
+		guc_log_remove_relay_file(guc);
+
+	guc->log.relay_chan = NULL;
+
+	if (guc->log.buf_addr)
+		i915_gem_object_unpin_map(guc->log.vma->obj);
+
+	guc->log.buf_addr = NULL;
+}
+
+static void capture_logs_work(struct work_struct *work)
+{
+	struct intel_guc *guc =
+		container_of(work, struct intel_guc, log.flush_work);
+
+	guc_log_capture_logs(guc);
+}
+
+static int guc_log_create_extras(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+	void *vaddr;
+	int ret;
+
+	lockdep_assert_held(&dev_priv->drm.struct_mutex);
+
+	/* Nothing to do */
+	if (i915.guc_log_level < 0)
+		return 0;
+
+	if (!guc->log.buf_addr) {
+		/* Create a WC (Uncached for read) vmalloc mapping of log
+		 * buffer pages, so that we can directly get the data
+		 * (up-to-date) from memory.
+		 */
+		vaddr = i915_gem_object_pin_map(guc->log.vma->obj, I915_MAP_WC);
+		if (IS_ERR(vaddr)) {
+			ret = PTR_ERR(vaddr);
+			DRM_ERROR("Couldn't map log buffer pages %d\n", ret);
+			return ret;
+		}
+
+		guc->log.buf_addr = vaddr;
+	}
+
+	if (!guc->log.relay_chan) {
+		/* Create a relay channel, so that we have buffers for storing
+		 * the GuC firmware logs, the channel will be linked with a file
+		 * later on when debugfs is registered.
+		 */
+		ret = guc_log_create_relay_channel(guc);
+		if (ret)
+			return ret;
+	}
+
+	if (!guc->log.flush_wq) {
+		INIT_WORK(&guc->log.flush_work, capture_logs_work);
+
+		 /*
+		 * GuC log buffer flush work item has to do register access to
+		 * send the ack to GuC and this work item, if not synced before
+		 * suspend, can potentially get executed after the GFX device is
+		 * suspended.
+		 * By marking the WQ as freezable, we don't have to bother about
+		 * flushing of this work item from the suspend hooks, the pending
+		 * work item if any will be either executed before the suspend
+		 * or scheduled later on resume. This way the handling of work
+		 * item can be kept same between system suspend & rpm suspend.
+		 */
+		guc->log.flush_wq = alloc_ordered_workqueue("i915-guc_log",
+							    WQ_HIGHPRI | WQ_FREEZABLE);
+		if (guc->log.flush_wq == NULL) {
+			DRM_ERROR("Couldn't allocate the wq for GuC logging\n");
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+void intel_guc_log_create(struct intel_guc *guc)
+{
+	struct i915_vma *vma;
+	unsigned long offset;
+	uint32_t size, flags;
+
+	if (i915.guc_log_level > GUC_LOG_VERBOSITY_MAX)
+		i915.guc_log_level = GUC_LOG_VERBOSITY_MAX;
+
+	/* The first page is to save log buffer state. Allocate one
+	 * extra page for others in case for overlap */
+	size = (1 + GUC_LOG_DPC_PAGES + 1 +
+		GUC_LOG_ISR_PAGES + 1 +
+		GUC_LOG_CRASH_PAGES + 1) << PAGE_SHIFT;
+
+	vma = guc->log.vma;
+	if (!vma) {
+		/* We require SSE 4.1 for fast reads from the GuC log buffer and
+		 * it should be present on the chipsets supporting GuC based
+		 * submisssions.
+		 */
+		if (WARN_ON(!i915_has_memcpy_from_wc())) {
+			/* logging will not be enabled */
+			i915.guc_log_level = -1;
+			return;
+		}
+
+		vma = intel_guc_allocate_vma(guc, size);
+		if (IS_ERR(vma)) {
+			/* logging will be off */
+			i915.guc_log_level = -1;
+			return;
+		}
+
+		guc->log.vma = vma;
+
+		if (guc_log_create_extras(guc)) {
+			guc_log_cleanup(guc);
+			i915_vma_unpin_and_release(&guc->log.vma);
+			i915.guc_log_level = -1;
+			return;
+		}
+	}
+
+	/* each allocated unit is a page */
+	flags = GUC_LOG_VALID | GUC_LOG_NOTIFY_ON_HALF_FULL |
+		(GUC_LOG_DPC_PAGES << GUC_LOG_DPC_SHIFT) |
+		(GUC_LOG_ISR_PAGES << GUC_LOG_ISR_SHIFT) |
+		(GUC_LOG_CRASH_PAGES << GUC_LOG_CRASH_SHIFT);
+
+	offset = guc_ggtt_offset(vma) >> PAGE_SHIFT; /* in pages */
+	guc->log.flags = (offset << GUC_LOG_BUF_ADDR_SHIFT) | flags;
+}
+
+static int guc_log_late_setup(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+	int ret;
+
+	lockdep_assert_held(&dev_priv->drm.struct_mutex);
+
+	if (i915.guc_log_level < 0)
+		return -EINVAL;
+
+	/* If log_level was set as -1 at boot time, then setup needed to
+	 * handle log buffer flush interrupts would not have been done yet,
+	 * so do that now.
+	 */
+	ret = guc_log_create_extras(guc);
+	if (ret)
+		goto err;
+
+	ret = guc_log_create_relay_file(guc);
+	if (ret)
+		goto err;
+
+	return 0;
+err:
+	guc_log_cleanup(guc);
+	/* logging will remain off */
+	i915.guc_log_level = -1;
+	return ret;
+}
+
+static void guc_log_capture_logs(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+
+	guc_read_update_log_buffer(guc);
+
+	/* Generally device is expected to be active only at this
+	 * time, so get/put should be really quick.
+	 */
+	intel_runtime_pm_get(dev_priv);
+	guc_log_flush_complete(guc);
+	intel_runtime_pm_put(dev_priv);
+}
+
+static void guc_flush_logs(struct intel_guc *guc)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+
+	if (!i915.enable_guc_submission || (i915.guc_log_level < 0))
+		return;
+
+	/* First disable the interrupts, will be renabled afterwards */
+	gen9_disable_guc_interrupts(dev_priv);
+
+	/* Before initiating the forceful flush, wait for any pending/ongoing
+	 * flush to complete otherwise forceful flush may not actually happen.
+	 */
+	flush_work(&guc->log.flush_work);
+
+	/* Ask GuC to update the log buffer state */
+	guc_log_flush(guc);
+
+	/* GuC would have updated log buffer by now, so capture it */
+	guc_log_capture_logs(guc);
+}
+
+int i915_guc_log_control(struct drm_i915_private *dev_priv, u64 control_val)
+{
+	struct intel_guc *guc = &dev_priv->guc;
+
+	union guc_log_control log_param;
+	int ret;
+
+	log_param.value = control_val;
+
+	if (log_param.verbosity < GUC_LOG_VERBOSITY_MIN ||
+	    log_param.verbosity > GUC_LOG_VERBOSITY_MAX)
+		return -EINVAL;
+
+	/* This combination doesn't make sense & won't have any effect */
+	if (!log_param.logging_enabled && (i915.guc_log_level < 0))
+		return 0;
+
+	ret = guc_log_control(guc, log_param.value);
+	if (ret < 0) {
+		DRM_DEBUG_DRIVER("guc_logging_control action failed %d\n", ret);
+		return ret;
+	}
+
+	i915.guc_log_level = log_param.verbosity;
+
+	/* If log_level was set as -1 at boot time, then the relay channel file
+	 * wouldn't have been created by now and interrupts also would not have
+	 * been enabled.
+	 */
+	if (!dev_priv->guc.log.relay_chan) {
+		ret = guc_log_late_setup(guc);
+		if (!ret)
+			gen9_enable_guc_interrupts(dev_priv);
+	} else if (!log_param.logging_enabled) {
+		/* Once logging is disabled, GuC won't generate logs & send an
+		 * interrupt. But there could be some data in the log buffer
+		 * which is yet to be captured. So request GuC to update the log
+		 * buffer state and then collect the left over logs.
+		 */
+		guc_flush_logs(guc);
+
+		/* As logging is disabled, update log level to reflect that */
+		i915.guc_log_level = -1;
+	} else {
+		/* In case interrupts were disabled, enable them now */
+		gen9_enable_guc_interrupts(dev_priv);
+	}
+
+	return ret;
+}
+
+void i915_guc_log_register(struct drm_i915_private *dev_priv)
+{
+	if (!i915.enable_guc_submission)
+		return;
+
+	mutex_lock(&dev_priv->drm.struct_mutex);
+	guc_log_late_setup(&dev_priv->guc);
+	mutex_unlock(&dev_priv->drm.struct_mutex);
+}
+
+void i915_guc_log_unregister(struct drm_i915_private *dev_priv)
+{
+	if (!i915.enable_guc_submission)
+		return;
+
+	mutex_lock(&dev_priv->drm.struct_mutex);
+	guc_log_cleanup(&dev_priv->guc);
+	mutex_unlock(&dev_priv->drm.struct_mutex);
+}