[PATCH v3 03/15] drm/i915: Unified firmware loading mechanism

[yu.dai@intel.com]

From: Dave Gordon <david.s.gordon@intel.com>

Factor out the common code of loading firmware into a new file,
leaving only the uC-specific parts in the GuC loaders.

Issue: VIZ-4884
Signed-off-by: Alex Dai <yu.dai@intel.com>
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
---
 drivers/gpu/drm/i915/Makefile          |   3 +
 drivers/gpu/drm/i915/intel_uc_loader.c | 244 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_uc_loader.h |  78 +++++++++++
 3 files changed, 325 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/intel_uc_loader.c
 create mode 100644 drivers/gpu/drm/i915/intel_uc_loader.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index a69002e..1b027c7 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -39,6 +39,9 @@ i915-y += i915_cmd_parser.o \
 	  intel_ringbuffer.o \
 	  intel_uncore.o
 
+# ancilliary microcontroller support
+i915-y += intel_uc_loader.o
+
 # autogenerated null render state
 i915-y += intel_renderstate_gen6.o \
 	  intel_renderstate_gen7.o \
diff --git a/drivers/gpu/drm/i915/intel_uc_loader.c b/drivers/gpu/drm/i915/intel_uc_loader.c
new file mode 100644
index 0000000..bc499f4
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_uc_loader.c
@@ -0,0 +1,244 @@
+/*
+ * Copyright © 2014 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/firmware.h>
+#include "i915_drv.h"
+#include "intel_uc_loader.h"
+
+/**
+ * DOC: Microcontroller (uC) firmware loading support
+ *
+ * Provide a more generic way to load firmware between the mainline driver (aka
+ * "main thread") and the loader (aka "async thread"). The firmware (aka "binary
+ * blob") loading process is split into two stages: fetch and load.
+ *
+ * For the first (fetch) stage, the mainline driver issues an firmware request
+ * call (request_firmware_nowait) to OS. The asynchronous thread will fetch the
+ * firmware blob from an external file into a GEM object, then notify mainline
+ * thread when it is done. The second (load) stage happens in main thread, which
+ * is to load the blob content into an onboard microcontroller. The load stage
+ * is implemented in mainline driver, but the intel_uc_fw_status provides the
+ * common code to track the phases of fetching or loading the firmware.
+ *
+ */
+
+/*
+ * Called once per uC, late in driver initialisation. GEM is now ready, and so
+ * we can now create a GEM object to hold the uC firmware. But first, we must
+ * synchronise with the firmware-fetching thread that was initiated during
+ * early driver load, in intel_uc_fw_init(), and see whether it successfully
+ * fetched the firmware blob.
+ */
+static void uc_fw_finish(struct drm_device *dev, struct intel_uc_fw *uc_fw)
+{
+	struct drm_i915_gem_object *obj = NULL;
+	const struct firmware *fw;
+
+	DRM_DEBUG_DRIVER("before waiting: %s fw fetch status %d, fw %p\n",
+		uc_fw->uc_name, uc_fw->uc_fw_fetch_status, uc_fw->uc_fw_blob);
+
+	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
+	WARN_ON(uc_fw->uc_fw_fetch_status != INTEL_UC_FIRMWARE_PENDING);
+
+	wait_for_completion(&uc_fw->uc_fw_fetched);
+
+	DRM_DEBUG_DRIVER("after waiting: %s fw fetch status %d, fw %p\n",
+		uc_fw->uc_name, uc_fw->uc_fw_fetch_status, uc_fw->uc_fw_blob);
+
+	fw = uc_fw->uc_fw_blob;
+	if (!fw) {
+		/* no firmware found; try again in case FS was not mounted */
+		DRM_DEBUG_DRIVER("retry fetching %s fw from <%s>\n",
+			uc_fw->uc_name, uc_fw->uc_fw_path);
+		if (request_firmware(&fw, uc_fw->uc_fw_path, &dev->pdev->dev))
+			goto fail;
+		DRM_DEBUG_DRIVER("fetch %s fw from <%s> succeeded, fw %p\n",
+			uc_fw->uc_name, uc_fw->uc_fw_path, fw);
+		uc_fw->uc_fw_blob = fw;
+	}
+
+	obj = i915_gem_alloc_object(dev, round_up(fw->size, PAGE_SIZE));
+	if (!obj)
+		goto fail;
+
+	if (i915_gem_object_write(obj, fw->data, fw->size))
+		goto fail;
+
+	DRM_DEBUG_DRIVER("%s fw fetch status SUCCESS\n", uc_fw->uc_name);
+	uc_fw->uc_fw_obj = obj;
+	uc_fw->uc_fw_size = fw->size;
+	uc_fw->uc_fw_fetch_status = INTEL_UC_FIRMWARE_SUCCESS;
+	return;
+
+fail:
+	DRM_DEBUG_DRIVER("%s fw fetch status FAIL; fw %p, obj %p\n",
+		uc_fw->uc_name, fw, obj);
+	DRM_ERROR("Failed to fetch %s firmware from <%s>\n",
+		  uc_fw->uc_name, uc_fw->uc_fw_path);
+
+	if (obj)
+		drm_gem_object_unreference(&obj->base);
+
+	uc_fw->uc_fw_fetch_status = INTEL_UC_FIRMWARE_FAIL;
+	uc_fw->uc_fw_blob = NULL;
+	release_firmware(fw);		/* OK even if fw is NULL */
+}
+
+/**
+ * intel_uc_fw_check() - check the status of the firmware fetching process
+ * @dev:	drm device
+ * @uc_fw:	intel_uc_fw structure
+
+ * If it's still PENDING, wait for completion first, then check and return the
+ * outcome.
+ *
+ * Return:	non-zero code on error
+ */
+int intel_uc_fw_check(struct drm_device *dev, struct intel_uc_fw *uc_fw)
+{
+	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
+
+	if (uc_fw->uc_fw_fetch_status == INTEL_UC_FIRMWARE_PENDING) {
+		/* We only come here once */
+		uc_fw_finish(dev, uc_fw);
+		/* state must now be FAIL or SUCCESS */
+	}
+
+	DRM_DEBUG_DRIVER("%s fw fetch status %d\n",
+		uc_fw->uc_name, uc_fw->uc_fw_fetch_status);
+
+	switch (uc_fw->uc_fw_fetch_status) {
+	case INTEL_UC_FIRMWARE_FAIL:
+		/* something went wrong :( */
+		return -EIO;
+
+	case INTEL_UC_FIRMWARE_NONE:
+		/* no firmware, nothing to do (not an error) */
+		return 0;
+
+	case INTEL_UC_FIRMWARE_PENDING:
+	default:
+		/* "can't happen" */
+		WARN_ONCE(1, "%s fw <%s> invalid uc_fw_fetch_status %d!\n",
+			uc_fw->uc_name, uc_fw->uc_fw_path,
+			uc_fw->uc_fw_fetch_status);
+		return -ENXIO;
+
+	case INTEL_UC_FIRMWARE_SUCCESS:
+		return 0;
+	}
+}
+
+/*
+ * Callback from the kernel's asynchronous firmware-fetching subsystem.
+ * All we have to do is stash the blob and signal completion.
+ * Error checking (e.g. no firmware) is left to mainline code.
+ * We don't have (and don't want or need to acquire) the struct_mutex here.
+ */
+static void uc_fw_fetch_callback(const struct firmware *fw, void *context)
+{
+	struct intel_uc_fw *uc_fw = context;
+
+	WARN_ON(uc_fw->uc_fw_fetch_status != INTEL_UC_FIRMWARE_PENDING);
+	DRM_DEBUG_DRIVER("%s firmware fetch from <%s> status %d, fw %p\n",
+			uc_fw->uc_name, uc_fw->uc_fw_path,
+			uc_fw->uc_fw_fetch_status, fw);
+
+	uc_fw->uc_fw_blob = fw;
+	complete(&uc_fw->uc_fw_fetched);
+}
+
+/**
+ * intel_uc_fw_init() - initiate the fetching of firmware
+ * @dev:	drm device
+ * @uc_fw:	intel_uc_fw structure
+ * @name:	firmware name
+ * @fw_path:	path prefix
+ *
+ * This is called just once per uC, during driver loading. It is therefore
+ * automatically single-threaded and does not need to acquire any mutexes
+ * or spinlocks. OTOH, GEM is not yet fully initialised, so we can't do
+ * very much here.
+ *
+ * The main task here is to initiate the fetching of the uC firmware into
+ * memory, using the standard kernel firmware fetching support.  The actual
+ * fetching will then proceed asynchronously and in parallel with the rest
+ * of driver initialisation; later in the loading process we will synchronise
+ * with the firmware-fetching thread before transferring the firmware image
+ * firstly into a GEM object and then into the uC's memory.
+ */
+void intel_uc_fw_init(struct drm_device *dev, struct intel_uc_fw *uc_fw,
+	const char *name, const char *fw_path)
+{
+	uc_fw->uc_name = name;
+	uc_fw->uc_fw_path = fw_path;
+	uc_fw->uc_fw_fetch_status = INTEL_UC_FIRMWARE_NONE;
+	init_completion(&uc_fw->uc_fw_fetched);
+
+	if (fw_path == NULL) {
+		DRM_ERROR("No known %s firmware on this platform\n", name);
+		uc_fw->uc_fw_fetch_status = INTEL_UC_FIRMWARE_FAIL;
+		return;
+	}
+
+	uc_fw->uc_fw_fetch_status = INTEL_UC_FIRMWARE_PENDING;
+
+	if (request_firmware_nowait(THIS_MODULE, true, fw_path,
+				    &dev->pdev->dev,
+				    GFP_KERNEL, uc_fw,
+				    uc_fw_fetch_callback)) {
+		DRM_ERROR("Failed to request %s firmware from <%s>\n",
+			  name, fw_path);
+		uc_fw->uc_fw_fetch_status = INTEL_UC_FIRMWARE_FAIL;
+		return;
+	}
+
+	/* firmware fetch initiated, callback will signal completion */
+	DRM_DEBUG_DRIVER("initiated fetching %s firmware from <%s>\n",
+		name, fw_path);
+}
+
+/**
+ * intel_uc_fw_fini() - clean up all uC firmware-related data
+ * @dev:	drm device
+ * @uc_fw:	intel_uc_fw structure
+ */
+void intel_uc_fw_fini(struct drm_device *dev, struct intel_uc_fw *uc_fw)
+{
+	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
+
+	/*
+	 * Generally, the blob should have been released earlier, but
+	 * if the driver load were aborted after the fetch had been
+	 * initiated but not completed it might still be around
+	 */
+	if (uc_fw->uc_fw_fetch_status == INTEL_UC_FIRMWARE_PENDING)
+		wait_for_completion(&uc_fw->uc_fw_fetched);
+	if (uc_fw->uc_fw_blob)
+		release_firmware(uc_fw->uc_fw_blob);
+	uc_fw->uc_fw_blob = NULL;
+
+	if (uc_fw->uc_fw_obj)
+		drm_gem_object_unreference(&uc_fw->uc_fw_obj->base);
+	uc_fw->uc_fw_obj = NULL;
+}
diff --git a/drivers/gpu/drm/i915/intel_uc_loader.h b/drivers/gpu/drm/i915/intel_uc_loader.h
new file mode 100644
index 0000000..0994f98
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_uc_loader.h
@@ -0,0 +1,78 @@
+/*
+ * Copyright © 2014 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_UC_LOADER_H
+#define _INTEL_UC_LOADER_H
+
+/*
+ * Microcontroller (uC) firmware loading support
+ */
+
+/*
+ * These values are used to track the stages of getting the required firmware
+ * into an onboard microcontroller. The common code tracks the phases of
+ * fetching the firmware (aka "binary blob") from an external file into a GEM
+ * object in the 'uc_fw_fetch_status' field below; the uC-specific DMA code
+ * uses the 'uc_fw_load_status' field to track the transfer from GEM object
+ * to uC memory.
+ *
+ * For the first (fetch) stage, the interpretation of the values is:
+ * NONE - no firmware is being fetched e.g. because there is no uC
+ * PENDING - firmware fetch initiated; callback will complete 'uc_fw_fetched'
+ * SUCCESS - uC firmware fetched into a GEM object and ready for use
+ * FAIL - something went wrong; uC firmware is not available
+ *
+ * The second (load) stage is simpler as there is no asynchronous handoff:
+ * NONE - no firmware is being loaded e.g. because there is no uC
+ * PENDING - firmware DMA load in progress
+ * SUCCESS - uC firmware loaded into uC memory and ready for use
+ * FAIL - something went wrong; uC firmware is not available
+ */
+enum intel_uc_fw_status {
+	INTEL_UC_FIRMWARE_FAIL = -1,
+	INTEL_UC_FIRMWARE_NONE = 0,
+	INTEL_UC_FIRMWARE_PENDING,
+	INTEL_UC_FIRMWARE_SUCCESS
+};
+
+/*
+ * This structure encapsulates all the data needed during the process of
+ * fetching, caching, and loading the firmware image into the uC.
+ */
+struct intel_uc_fw {
+	const char *			uc_name;
+	const char *			uc_fw_path;
+	const struct firmware *		uc_fw_blob;
+	struct completion		uc_fw_fetched;
+	size_t				uc_fw_size;
+	struct drm_i915_gem_object *	uc_fw_obj;
+	enum intel_uc_fw_status		uc_fw_fetch_status;
+	enum intel_uc_fw_status		uc_fw_load_status;
+};
+
+void intel_uc_fw_init(struct drm_device *dev, struct intel_uc_fw *uc_fw,
+	const char *uc_name, const char *fw_path);
+int intel_uc_fw_check(struct drm_device *dev, struct intel_uc_fw *uc_fw);
+void intel_uc_fw_fini(struct drm_device *dev, struct intel_uc_fw *uc_fw);
+
+#endif
-- 
1.9.1

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