[PATCH 02/15] drm/i915: Embedded microcontroller (uC) firmware loading support

Dave Gordon
2015-07-03T12:30:56Z

Current devices may contain one or more programmable microcontrollers
that need to have a firmware image (aka "binary blob") loaded from an
external medium and transferred to the device's memory.

This file provides common support functions for doing this; they can
then be used by each uC-specific loader, thus reducing code duplication
and testing effort.

v2:
Local functions should pass dev_priv rather than dev [Chris Wilson]
Various other improvements per Chris Wilson's review comments

v3:
Defeatured version without async prefetch [Daniel Vetter]

Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Alex Dai <yu.dai@intel.com>
---
drivers/gpu/drm/i915/Makefile | 3 +
drivers/gpu/drm/i915/intel_uc_loader.c | 310 +++++++++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_uc_loader.h | 92 ++++++++++
3 files changed, 405 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 de21965..f1f80fc 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

+# generic 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..a8fc1dd
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_uc_loader.c
@@ -0,0 +1,310 @@
+/*
+ * 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.
+ *
+ * Author:
+ * Dave Gordon <david.s.gordon@intel.com>
+ */
+#include <linux/firmware.h>
+#include "i915_drv.h"
+#include "intel_uc_loader.h"
+
+/**
+ * DOC: Common functions for embedded microcontroller (uC) firmware loading
+ *
+ * The functions in this file provide common support code for loading the
+ * firmware that may be required by an embedded microcontroller (uC).
+ *
+ * The function intel_uc_fw_init() should be called first; it requires no
+ * locking, and can be called even before GEM has been initialised. It just
+ * initialises the tracking data and stores its parameters for the subsequent
+ * call to intel_uc_fw_fetch().
+ *
+ * At some convenient point after GEM initialisation, the driver should call
+ * intel_uc_fw_fetch(). The first time, this will use the Linux kernel's
+ * request_firmware() call to open and read the firmware image into memory.
+ * (On subsequent calls, this is skipped, as either the firmware has already
+ * been fetched into memory, or it is already known that no valid firmware
+ * image could be found).
+ *
+ * The callback() function passed to intel_uc_fw_fetch() can further check
+ * the firmware image before it is saved. This function can reject the image
+ * by returning a negative error code (e.g. -ENOEXEC), or accept it. In the
+ * latter case, it can return INTEL_UC_FW_GOOD (which is also the default if
+ * no callback() is supplied), and the common code here will save the whole
+ * of the firmware image in a (pageable, shmfs-backed) GEM object.
+ *
+ * If saving the whole image unmodified is not appropriate (for example, if
+ * only a small part of the image is needed later, or the data needs to be
+ * reorganised before saving), the callback() function can instead make its
+ * own arrangements for saving the required data in a GEM object or otherwise
+ * and then return INTEL_UC_FW_SAVED.
+ *
+ * (If such a callback does stash (some of) the image data in a GEM object,
+ * it can use the uc_fw_obj and uc_fw_size fields; the common framework will
+ * then handle deallocating the object on failure or finalisation. Otherwise
+ * any allocated resources will have to be managed by the uC-specific code).
+ *
+ * After a successful call to intel_uc_fw_fetch(), the uC-specific code can
+ * transfer the data in the GEM object (or its own alternative) to the uC's
+ * memory (in some uC-specific way, not handled here).
+ *
+ * During driver shutdown, or if driver load is aborted, intel_uc_fw_fini()
+ * should be called to release any remaining resources.
+ */
+
+/* User-friendly representation of an enum */
+const char *intel_uc_fw_status_repr(enum intel_uc_fw_status status)
+{
+ switch (status) {
+ case INTEL_UC_FIRMWARE_FAIL:
+ return "FAIL";
+ case INTEL_UC_FIRMWARE_NONE:
+ return "NONE";
+ case INTEL_UC_FIRMWARE_PENDING:
+ return "PENDING";
+ case INTEL_UC_FIRMWARE_SUCCESS:
+ return "SUCCESS";
+ default:
+ return "UNKNOWN!";
+ }
+};
+
+/*
+ * Called once per uC, late in driver initialisation, after GEM is set up.
+ * First, we fetch the firmware image using request_firmware(), then allow
+ * the optional callback() function to check it. If it's good, and callback()
+ * doesn't say it's already saved the image, we will save it here by copying
+ * the whole thing into a (pageable, shmfs-backed) GEM object,
+ */
+static void
+uc_fw_fetch(struct intel_uc_fw *uc_fw,
+ int callback(struct intel_uc_fw *))
+{
+ struct drm_device *dev = uc_fw->uc_dev;
+ struct drm_i915_gem_object *obj;
+ const struct firmware *fw;
+ int cb_status = INTEL_UC_FW_GOOD;
+
+ DRM_DEBUG_DRIVER("before waiting: %s fw fetch status %s, fw %p\n",
+ uc_fw->uc_name,
+ intel_uc_fw_status_repr(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);
+
+ if (request_firmware(&fw, uc_fw->uc_fw_path, &dev->pdev->dev))
+ goto fail;
+ if (!fw)
+ 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;
+
+ /* Callback to the optional uC-specific function, if supplied */
+ if (callback)
+ cb_status = callback(uc_fw);
+ if (cb_status < 0)
+ goto fail;
+ switch (cb_status) {
+ default:
+ WARN(1, "Invalid status %d from fw checking callback %pf\n",
+ cb_status, callback);
+ goto fail;
+
+ case INTEL_UC_FW_SAVED:
+ // Good, already saved, nothing to do
+ break;
+
+ case INTEL_UC_FW_GOOD:
+ // Good, save in GEM object
+ obj = i915_gem_object_create_from_data(dev, fw->data, fw->size);
+ if (!obj)
+ goto fail;
+
+ uc_fw->uc_fw_obj = obj;
+ uc_fw->uc_fw_size = fw->size;
+ }
+
+ DRM_DEBUG_DRIVER("%s fw fetch status SUCCESS, cb %d, obj %p\n",
+ uc_fw->uc_name, cb_status, uc_fw->uc_fw_obj);
+
+ release_firmware(fw);
+ uc_fw->uc_fw_blob = NULL;
+ 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, uc_fw->uc_fw_obj);
+ DRM_ERROR("Failed to fetch %s firmware from %s\n",
+ uc_fw->uc_name, uc_fw->uc_fw_path);
+
+ obj = uc_fw->uc_fw_obj;
+ if (obj)
+ drm_gem_object_unreference(&obj->base);
+ uc_fw->uc_fw_obj = NULL;
+
+ release_firmware(fw); /* OK even if fw is NULL */
+ uc_fw->uc_fw_blob = NULL;
+ uc_fw->uc_fw_fetch_status = INTEL_UC_FIRMWARE_FAIL;
+}
+
+/**
+ * intel_uc_fw_fetch() - fetch the firmware image
+ * @uc_fw: intel_uc_fw structure
+ * @callback: optional callback function to validate and/or save the image
+ *
+ * If the fetch is not PENDING (i.e. on the second and subsequent calls), this
+ * function will just return an approriate errno, based on the previously-set
+ * status.
+ *
+ * On the first call only, it will try to retrieve the firmaware image using
+ * the parameters set earlier. If an image is found, the optional @callback()
+ * will be called to further validate it.
+ *
+ * When it is called, @uc_fw->uc_fw_blob refers to the fetched firmware image,
+ * and @uc_fw->uc_fw_obj is NULL. The @callback() function can return an error
+ * code (any negative value), in which case the image will be rejected. The
+ * fetch status will be set to FAIL, and this function will return -EIO.
+ *
+ * Or, @callback() can return INTEL_UC_FW_GOOD. The image is considered good,
+ * and it will be saved in a GEM object as described above. In this case,
+ * @uc_fw->uc_fw_obj will be set to point to the GEM object, and the size of
+ * the image will be in @uc_fw->uc_fw_size. This is also the default if no
+ * @callback() is supplied.
+ *
+ * Finally, @callback() can return INTEL_UC_FW_SAVED. The image is considered
+ * good, but @callback() has already deal with saving the content, so this
+ * common code will not allocate and fill a GEM object. @callback() may use
+ * @uc_fw->uc_fw_obj to hold a reference to its own GEM object, if it has
+ * allocated one, and in this case the common code will deal with disposing
+ * of it on error or finalisation; otherwise it can make its own arragements.
+ *
+ * After this call, @uc_fw->uc_fw_fetch_status will show whether the firmware
+ * image was successfully fetched and saved.
+ *
+ * In all cases the firmware blob is released before this function returns.
+ *
+ * Return: non-zero code on error
+ */
+int
+intel_uc_fw_fetch(struct intel_uc_fw *uc_fw,
+ int callback(struct intel_uc_fw *))
+{
+ WARN_ON(!mutex_is_locked(&uc_fw->uc_dev->struct_mutex));
+
+ if (uc_fw->uc_fw_fetch_status == INTEL_UC_FIRMWARE_PENDING) {
+ /* We only come here once */
+ uc_fw_fetch(uc_fw, callback);
+ /* status must now be FAIL or SUCCESS */
+ }
+
+ DRM_DEBUG_DRIVER("%s fw fetch status %s\n", uc_fw->uc_name,
+ intel_uc_fw_status_repr(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 %s [%d]\n",
+ uc_fw->uc_name, uc_fw->uc_fw_path,
+ intel_uc_fw_status_repr(uc_fw->uc_fw_fetch_status),
+ uc_fw->uc_fw_fetch_status);
+ return -ENXIO;
+
+ case INTEL_UC_FIRMWARE_SUCCESS:
+ return 0;
+ }
+}
+
+/**
+ * intel_uc_fw_init() - define parameters for fetching firmware
+ * @dev: drm device
+ * @uc_fw: intel_uc_fw structure
+ * @name: human-readable device name (e.g. "GuC") for messages
+ * @fw_path: (trailing parts of) path to firmware (e.g. "i915/guc_fw.bin")
+ * @fw_path == NULL means "no firmware expected" (not an error),
+ * @fw_path == "" (empty string) means "firmware unknown" i.e.
+ * the uC requires firmware, but the driver doesn't know where
+ * to find the proper version. This will be logged as an error.
+ *
+ * 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 save the parameters for later. The actual fetching
+ * will happen when intel_uc_fw_init() is called, after GEM initialisation is
+ * complete.
+ */
+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_dev = dev;
+ uc_fw->uc_name = name;
+ uc_fw->uc_fw_path = fw_path;
+ uc_fw->uc_fw_fetch_status = INTEL_UC_FIRMWARE_NONE;
+ uc_fw->uc_fw_load_status = INTEL_UC_FIRMWARE_NONE;
+
+ if (fw_path == NULL)
+ return;
+
+ if (*fw_path == '\0') {
+ DRM_ERROR("No %s firmware known for 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;
+ DRM_DEBUG_DRIVER("%s firmware pending, path %s\n",
+ name, fw_path);
+}
+
+/**
+ * intel_uc_fw_fini() - clean up all uC firmware-related data
+ * @uc_fw: intel_uc_fw structure
+ */
+void
+intel_uc_fw_fini(struct intel_uc_fw *uc_fw)
+{
+ WARN_ON(!mutex_is_locked(&uc_fw->uc_dev->struct_mutex));
+
+ if (uc_fw->uc_fw_obj)
+ drm_gem_object_unreference(&uc_fw->uc_fw_obj->base);
+ uc_fw->uc_fw_obj = NULL;
+
+ release_firmware(uc_fw->uc_fw_blob); /* OK even if NULL */
+ uc_fw->uc_fw_blob = NULL;
+
+ uc_fw->uc_fw_fetch_status = INTEL_UC_FIRMWARE_NONE;
+}
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..b710406
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_uc_loader.h
@@ -0,0 +1,92 @@
+/*
+ * 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.
+ *
+ * Author:
+ * Dave Gordon <david.s.gordon@intel.com>
+ */
+#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 - parameters initialised, pending call to intel_uc_fw_fetch()
+ * 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 similar:
+ * 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
+ *
+ * The function intel_uc_fw_status_repr() will convert this enum to a
+ * string representation suitable for use in log messages.
+ */
+enum intel_uc_fw_status {
+ INTEL_UC_FIRMWARE_FAIL = -1,
+ INTEL_UC_FIRMWARE_NONE = 0,
+ INTEL_UC_FIRMWARE_PENDING,
+ INTEL_UC_FIRMWARE_SUCCESS
+};
+const char *intel_uc_fw_status_repr(enum intel_uc_fw_status status);
+
+/*
+ * 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 {
+ struct drm_device * uc_dev;
+ const char * uc_name;
+ const char * uc_fw_path;
+ const struct firmware * uc_fw_blob;
+ 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_fetch(struct intel_uc_fw *uc_fw,
+ int callback(struct intel_uc_fw *));
+void intel_uc_fw_fini(struct intel_uc_fw *uc_fw);
+
+/*
+ * The callback() function passed to intel_uc_fw_fetch() above can return
+ * a negative number (a standard error code), or one of the values below:
+ */
+#define INTEL_UC_FW_GOOD 1 /* f/w good, save in GEM object */
+#define INTEL_UC_FW_SAVED 2 /* f/w good, already saved */
+
+#endif
--
1.9.1