Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

3 files changed, 484 insertions, 0 deletions

diff --git a/drivers/firmware/microchip/Kconfig b/drivers/firmware/microchip/Kconfig
new file mode 100644
index 000000000..434b923e0
--- /dev/null
+++ b/drivers/firmware/microchip/Kconfig
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config POLARFIRE_SOC_AUTO_UPDATE
+	tristate "Microchip PolarFire SoC AUTO UPDATE"
+	depends on POLARFIRE_SOC_SYS_CTRL
+	select FW_LOADER
+	select FW_UPLOAD
+	help
+	  Support for reprogramming PolarFire SoC from within Linux, using the
+	  Auto Upgrade feature of the system controller.
+
+	  If built as a module, it will be called mpfs-auto-update.
diff --git a/drivers/firmware/microchip/Makefile b/drivers/firmware/microchip/Makefile
new file mode 100644
index 000000000..38796fd82
--- /dev/null
+++ b/drivers/firmware/microchip/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_POLARFIRE_SOC_AUTO_UPDATE) += mpfs-auto-update.o
diff --git a/drivers/firmware/microchip/mpfs-auto-update.c b/drivers/firmware/microchip/mpfs-auto-update.c
new file mode 100644
index 000000000..1211fd8d0
--- /dev/null
+++ b/drivers/firmware/microchip/mpfs-auto-update.c
@@ -0,0 +1,469 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Microchip Polarfire SoC "Auto Update" FPGA reprogramming.
+ *
+ * Documentation of this functionality is available in the "PolarFire® FPGA and
+ * PolarFire SoC FPGA Programming" User Guide.
+ *
+ * Copyright (c) 2022-2023 Microchip Corporation. All rights reserved.
+ *
+ * Author: Conor Dooley <conor.dooley@microchip.com>
+ */
+#include <linux/cleanup.h>
+#include <linux/debugfs.h>
+#include <linux/firmware.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/platform_device.h>
+#include <linux/sizes.h>
+
+#include <soc/microchip/mpfs.h>
+
+#define AUTO_UPDATE_DEFAULT_MBOX_OFFSET		0u
+#define AUTO_UPDATE_DEFAULT_RESP_OFFSET		0u
+
+#define AUTO_UPDATE_FEATURE_CMD_OPCODE		0x05u
+#define AUTO_UPDATE_FEATURE_CMD_DATA_SIZE	0u
+#define AUTO_UPDATE_FEATURE_RESP_SIZE		33u
+#define AUTO_UPDATE_FEATURE_CMD_DATA		NULL
+#define AUTO_UPDATE_FEATURE_ENABLED		BIT(5)
+
+#define AUTO_UPDATE_AUTHENTICATE_CMD_OPCODE	0x22u
+#define AUTO_UPDATE_AUTHENTICATE_CMD_DATA_SIZE	0u
+#define AUTO_UPDATE_AUTHENTICATE_RESP_SIZE	1u
+#define AUTO_UPDATE_AUTHENTICATE_CMD_DATA	NULL
+
+#define AUTO_UPDATE_PROGRAM_CMD_OPCODE		0x46u
+#define AUTO_UPDATE_PROGRAM_CMD_DATA_SIZE	0u
+#define AUTO_UPDATE_PROGRAM_RESP_SIZE		1u
+#define AUTO_UPDATE_PROGRAM_CMD_DATA		NULL
+
+/*
+ * SPI Flash layout example:
+ * |------------------------------| 0x0000000
+ * | 1 KiB                        |
+ * | SPI "directories"            |
+ * |------------------------------| 0x0000400
+ * | 1 MiB                        |
+ * | Reserved area                |
+ * | Used for bitstream info      |
+ * |------------------------------| 0x0100400
+ * | 20 MiB                       |
+ * | Golden Image                 |
+ * |------------------------------| 0x1500400
+ * | 20 MiB                       |
+ * | Auto Upgrade Image           |
+ * |------------------------------| 0x2900400
+ * | 20 MiB                       |
+ * | Reserved for multi-image IAP |
+ * | Unused for Auto Upgrade      |
+ * |------------------------------| 0x3D00400
+ * | ? B                          |
+ * | Unused                       |
+ * |------------------------------| 0x?
+ */
+#define AUTO_UPDATE_DIRECTORY_BASE	0u
+#define AUTO_UPDATE_DIRECTORY_WIDTH	4u
+#define AUTO_UPDATE_GOLDEN_INDEX	0u
+#define AUTO_UPDATE_UPGRADE_INDEX	1u
+#define AUTO_UPDATE_BLANK_INDEX		2u
+#define AUTO_UPDATE_GOLDEN_DIRECTORY	(AUTO_UPDATE_DIRECTORY_WIDTH * AUTO_UPDATE_GOLDEN_INDEX)
+#define AUTO_UPDATE_UPGRADE_DIRECTORY	(AUTO_UPDATE_DIRECTORY_WIDTH * AUTO_UPDATE_UPGRADE_INDEX)
+#define AUTO_UPDATE_BLANK_DIRECTORY	(AUTO_UPDATE_DIRECTORY_WIDTH * AUTO_UPDATE_BLANK_INDEX)
+#define AUTO_UPDATE_DIRECTORY_SIZE	SZ_1K
+#define AUTO_UPDATE_INFO_BASE		AUTO_UPDATE_DIRECTORY_SIZE
+#define AUTO_UPDATE_INFO_SIZE		SZ_1M
+#define AUTO_UPDATE_BITSTREAM_BASE	(AUTO_UPDATE_DIRECTORY_SIZE + AUTO_UPDATE_INFO_SIZE)
+
+struct mpfs_auto_update_priv {
+	struct mpfs_sys_controller *sys_controller;
+	struct device *dev;
+	struct mtd_info *flash;
+	struct fw_upload *fw_uploader;
+	size_t size_per_bitstream;
+	bool cancel_request;
+};
+
+static bool mpfs_auto_update_is_bitstream_info(const u8 *data, u32 size)
+{
+	if (size < 4)
+		return false;
+
+	if (data[0] == 0x4d && data[1] == 0x43 && data[2] == 0x48 && data[3] == 0x50)
+		return true;
+
+	return false;
+}
+
+static enum fw_upload_err mpfs_auto_update_prepare(struct fw_upload *fw_uploader, const u8 *data,
+						   u32 size)
+{
+	struct mpfs_auto_update_priv *priv = fw_uploader->dd_handle;
+	size_t erase_size = AUTO_UPDATE_DIRECTORY_SIZE;
+
+	/*
+	 * Verifying the Golden Image is idealistic. It will be evaluated
+	 * against the currently programmed image and thus may fail - due to
+	 * either rollback protection (if its an older version than that in use)
+	 * or if the version is the same as that of the in-use image.
+	 * Extracting the information as to why a failure occurred is not
+	 * currently possible due to limitations of the system controller
+	 * driver. If those are fixed, verification of the Golden Image should
+	 * be added here.
+	 */
+
+	erase_size = round_up(erase_size, (u64)priv->flash->erasesize);
+
+	/*
+	 * We need to calculate if we have enough space in the flash for the
+	 * new image.
+	 * First, chop off the first 1 KiB as it's reserved for the directory.
+	 * The 1 MiB reserved for design info needs to be ignored also.
+	 * All that remains is carved into 3 & rounded down to the erasesize.
+	 * If this is smaller than the image size, we abort.
+	 * There's also no need to consume more than 20 MiB per image.
+	 */
+	priv->size_per_bitstream = priv->flash->size - SZ_1K - SZ_1M;
+	priv->size_per_bitstream = round_down(priv->size_per_bitstream / 3, erase_size);
+	if (priv->size_per_bitstream > 20 * SZ_1M)
+		priv->size_per_bitstream = 20 * SZ_1M;
+
+	if (priv->size_per_bitstream < size) {
+		dev_err(priv->dev,
+			"flash device has insufficient capacity to store this bitstream\n");
+		return FW_UPLOAD_ERR_INVALID_SIZE;
+	}
+
+	priv->cancel_request = false;
+
+	return FW_UPLOAD_ERR_NONE;
+}
+
+static void mpfs_auto_update_cancel(struct fw_upload *fw_uploader)
+{
+	struct mpfs_auto_update_priv *priv = fw_uploader->dd_handle;
+
+	priv->cancel_request = true;
+}
+
+static enum fw_upload_err mpfs_auto_update_poll_complete(struct fw_upload *fw_uploader)
+{
+	return FW_UPLOAD_ERR_NONE;
+}
+
+static int mpfs_auto_update_verify_image(struct fw_upload *fw_uploader)
+{
+	struct mpfs_auto_update_priv *priv = fw_uploader->dd_handle;
+	u32 *response_msg __free(kfree) =
+		kzalloc(AUTO_UPDATE_FEATURE_RESP_SIZE * sizeof(*response_msg), GFP_KERNEL);
+	struct mpfs_mss_response *response __free(kfree) =
+		kzalloc_obj(struct mpfs_mss_response);
+	struct mpfs_mss_msg *message __free(kfree) =
+		kzalloc_obj(struct mpfs_mss_msg);
+	int ret;
+
+	if (!response_msg || !response || !message)
+		return -ENOMEM;
+
+	/*
+	 * The system controller can verify that an image in the flash is valid.
+	 * Rather than duplicate the check in this driver, call the relevant
+	 * service from the system controller instead.
+	 * This service has no command data and no response data. It overloads
+	 * mbox_offset with the image index in the flash's SPI directory where
+	 * the bitstream is located.
+	 */
+	response->resp_msg = response_msg;
+	response->resp_size = AUTO_UPDATE_AUTHENTICATE_RESP_SIZE;
+	message->cmd_opcode = AUTO_UPDATE_AUTHENTICATE_CMD_OPCODE;
+	message->cmd_data_size = AUTO_UPDATE_AUTHENTICATE_CMD_DATA_SIZE;
+	message->response = response;
+	message->cmd_data = AUTO_UPDATE_AUTHENTICATE_CMD_DATA;
+	message->mbox_offset = AUTO_UPDATE_UPGRADE_INDEX;
+	message->resp_offset = AUTO_UPDATE_DEFAULT_RESP_OFFSET;
+
+	dev_info(priv->dev, "Running verification of Upgrade Image\n");
+	ret = mpfs_blocking_transaction(priv->sys_controller, message);
+	if (ret | response->resp_status) {
+		dev_warn(priv->dev, "Verification of Upgrade Image failed!\n");
+		return ret ? ret : -EBADMSG;
+	}
+
+	dev_info(priv->dev, "Verification of Upgrade Image passed!\n");
+
+	return 0;
+}
+
+static int mpfs_auto_update_set_image_address(struct mpfs_auto_update_priv *priv,
+					      u32 image_address, loff_t directory_address)
+{
+	struct erase_info erase;
+	size_t erase_size = round_up(AUTO_UPDATE_DIRECTORY_SIZE, (u64)priv->flash->erasesize);
+	size_t bytes_written = 0, bytes_read = 0;
+	char *buffer __free(kfree) = kzalloc(erase_size, GFP_KERNEL);
+	int ret;
+
+	if (!buffer)
+		return -ENOMEM;
+
+	erase.addr = AUTO_UPDATE_DIRECTORY_BASE;
+	erase.len = erase_size;
+
+	/*
+	 * We need to write the "SPI DIRECTORY" to the first 1 KiB, telling
+	 * the system controller where to find the actual bitstream. Since
+	 * this is spi-nor, we have to read the first eraseblock, erase that
+	 * portion of the flash, modify the data and then write it back.
+	 * There's no need to do this though if things are already the way they
+	 * should be, so check and save the write in that case.
+	 */
+	ret = mtd_read(priv->flash, AUTO_UPDATE_DIRECTORY_BASE, erase_size, &bytes_read,
+		       (u_char *)buffer);
+	if (ret)
+		return ret;
+
+	if (bytes_read != erase_size)
+		return -EIO;
+
+	if ((*(u32 *)(buffer + AUTO_UPDATE_UPGRADE_DIRECTORY) == image_address) &&
+	    !(*(u32 *)(buffer + AUTO_UPDATE_BLANK_DIRECTORY)))
+		return 0;
+
+	ret = mtd_erase(priv->flash, &erase);
+	if (ret)
+		return ret;
+
+	/*
+	 * Populate the image address and then zero out the next directory so
+	 * that the system controller doesn't complain if in "Single Image"
+	 * mode.
+	 */
+	memcpy(buffer + AUTO_UPDATE_UPGRADE_DIRECTORY, &image_address,
+	       AUTO_UPDATE_DIRECTORY_WIDTH);
+	memset(buffer + AUTO_UPDATE_BLANK_DIRECTORY, 0x0, AUTO_UPDATE_DIRECTORY_WIDTH);
+
+	dev_info(priv->dev, "Writing the image address (0x%x) to the flash directory (0x%llx)\n",
+		 image_address, directory_address);
+
+	ret = mtd_write(priv->flash, 0x0, erase_size, &bytes_written, (u_char *)buffer);
+	if (ret)
+		return ret;
+
+	if (bytes_written != erase_size)
+		return -EIO;
+
+	return 0;
+}
+
+static int mpfs_auto_update_write_bitstream(struct fw_upload *fw_uploader, const u8 *data,
+					    u32 offset, u32 size, u32 *written)
+{
+	struct mpfs_auto_update_priv *priv = fw_uploader->dd_handle;
+	struct erase_info erase;
+	loff_t directory_address = AUTO_UPDATE_UPGRADE_DIRECTORY;
+	size_t erase_size = AUTO_UPDATE_DIRECTORY_SIZE;
+	size_t bytes_written = 0;
+	bool is_info = mpfs_auto_update_is_bitstream_info(data, size);
+	u32 image_address;
+	int ret;
+
+	erase_size = round_up(erase_size, (u64)priv->flash->erasesize);
+
+	if (is_info)
+		image_address = AUTO_UPDATE_INFO_BASE;
+	else
+		image_address = AUTO_UPDATE_BITSTREAM_BASE +
+				AUTO_UPDATE_UPGRADE_INDEX * priv->size_per_bitstream;
+
+	/*
+	 * For bitstream info, the descriptor is written to a fixed offset,
+	 * so there is no need to set the image address.
+	 */
+	if (!is_info) {
+		ret = mpfs_auto_update_set_image_address(priv, image_address, directory_address);
+		if (ret) {
+			dev_err(priv->dev, "failed to set image address in the SPI directory: %d\n", ret);
+			return ret;
+		}
+	} else {
+		if (size > AUTO_UPDATE_INFO_SIZE) {
+			dev_err(priv->dev, "bitstream info exceeds permitted size\n");
+			return -ENOSPC;
+		}
+	}
+
+	/*
+	 * Now the .spi image itself can be written to the flash. Preservation
+	 * of contents here is not important here, unlike the spi "directory"
+	 * which must be RMWed.
+	 */
+	erase.len = round_up(size, (size_t)priv->flash->erasesize);
+	erase.addr = image_address;
+
+	dev_info(priv->dev, "Erasing the flash at address (0x%x)\n", image_address);
+	ret = mtd_erase(priv->flash, &erase);
+	if (ret)
+		return ret;
+
+	/*
+	 * No parsing etc of the bitstream is required. The system controller
+	 * will do all of that itself - including verifying that the bitstream
+	 * is valid.
+	 */
+	dev_info(priv->dev, "Writing the image to the flash at address (0x%x)\n", image_address);
+	ret = mtd_write(priv->flash, (loff_t)image_address, size, &bytes_written, data);
+	if (ret)
+		return ret;
+
+	if (bytes_written != size)
+		return -EIO;
+
+	*written = bytes_written;
+	dev_info(priv->dev, "Wrote 0x%zx bytes to the flash\n", bytes_written);
+
+	return 0;
+}
+
+static enum fw_upload_err mpfs_auto_update_write(struct fw_upload *fw_uploader, const u8 *data,
+						 u32 offset, u32 size, u32 *written)
+{
+	struct mpfs_auto_update_priv *priv = fw_uploader->dd_handle;
+	int ret;
+
+	ret = mpfs_auto_update_write_bitstream(fw_uploader, data, offset, size, written);
+	if (ret)
+		return FW_UPLOAD_ERR_RW_ERROR;
+
+	if (priv->cancel_request)
+		return FW_UPLOAD_ERR_CANCELED;
+
+	if (mpfs_auto_update_is_bitstream_info(data, size))
+		return FW_UPLOAD_ERR_NONE;
+
+	ret = mpfs_auto_update_verify_image(fw_uploader);
+	if (ret)
+		return FW_UPLOAD_ERR_FW_INVALID;
+
+	return FW_UPLOAD_ERR_NONE;
+}
+
+static const struct fw_upload_ops mpfs_auto_update_ops = {
+	.prepare = mpfs_auto_update_prepare,
+	.write = mpfs_auto_update_write,
+	.poll_complete = mpfs_auto_update_poll_complete,
+	.cancel = mpfs_auto_update_cancel,
+};
+
+static int mpfs_auto_update_available(struct mpfs_auto_update_priv *priv)
+{
+	u32 *response_msg __free(kfree) =
+		kzalloc(AUTO_UPDATE_FEATURE_RESP_SIZE * sizeof(*response_msg), GFP_KERNEL);
+	struct mpfs_mss_response *response __free(kfree) =
+		kzalloc_obj(struct mpfs_mss_response);
+	struct mpfs_mss_msg *message __free(kfree) =
+		kzalloc_obj(struct mpfs_mss_msg);
+	int ret;
+
+	if (!response_msg || !response || !message)
+		return -ENOMEM;
+
+	/*
+	 * To verify that Auto Update is possible, the "Query Security Service
+	 * Request" is performed.
+	 * This service has no command data & does not overload mbox_offset.
+	 */
+	response->resp_msg = response_msg;
+	response->resp_size = AUTO_UPDATE_FEATURE_RESP_SIZE;
+	message->cmd_opcode = AUTO_UPDATE_FEATURE_CMD_OPCODE;
+	message->cmd_data_size = AUTO_UPDATE_FEATURE_CMD_DATA_SIZE;
+	message->response = response;
+	message->cmd_data = AUTO_UPDATE_FEATURE_CMD_DATA;
+	message->mbox_offset = AUTO_UPDATE_DEFAULT_MBOX_OFFSET;
+	message->resp_offset = AUTO_UPDATE_DEFAULT_RESP_OFFSET;
+
+	ret = mpfs_blocking_transaction(priv->sys_controller, message);
+	if (ret)
+		return ret;
+
+	/*
+	 * Currently, the system controller's firmware does not generate any
+	 * interrupts for failed services, so mpfs_blocking_transaction() should
+	 * time out & therefore return an error.
+	 * Hitting this check is highly unlikely at present, but if the system
+	 * controller's behaviour changes so that it does generate interrupts
+	 * for failed services, it will be required.
+	 */
+	if (response->resp_status)
+		return -EIO;
+
+	/*
+	 * Bit 5 of byte 1 is "UL_IAP" & if it is set, Auto Update is
+	 * not possible.
+	 */
+	if ((((u8 *)response_msg)[1] & AUTO_UPDATE_FEATURE_ENABLED))
+		return -EPERM;
+
+	return 0;
+}
+
+static int mpfs_auto_update_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mpfs_auto_update_priv *priv;
+	struct fw_upload *fw_uploader;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->sys_controller = mpfs_sys_controller_get(dev);
+	if (IS_ERR(priv->sys_controller))
+		return dev_err_probe(dev, PTR_ERR(priv->sys_controller),
+				     "Could not register as a sub device of the system controller\n");
+
+	priv->flash = mpfs_sys_controller_get_flash(priv->sys_controller);
+	if (IS_ERR_OR_NULL(priv->flash)) {
+		dev_dbg(dev, "No flash connected to the system controller, auto-update not supported\n");
+		return -ENODEV;
+	}
+
+	priv->dev = dev;
+	platform_set_drvdata(pdev, priv);
+
+	ret = mpfs_auto_update_available(priv);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "The current bitstream does not support auto-update\n");
+
+	fw_uploader = firmware_upload_register(THIS_MODULE, dev, "mpfs-auto-update",
+					       &mpfs_auto_update_ops, priv);
+	if (IS_ERR(fw_uploader))
+		return dev_err_probe(dev, PTR_ERR(fw_uploader),
+				     "Failed to register the bitstream uploader\n");
+
+	priv->fw_uploader = fw_uploader;
+
+	return 0;
+}
+
+static void mpfs_auto_update_remove(struct platform_device *pdev)
+{
+	struct mpfs_auto_update_priv *priv = platform_get_drvdata(pdev);
+
+	firmware_upload_unregister(priv->fw_uploader);
+}
+
+static struct platform_driver mpfs_auto_update_driver = {
+	.driver = {
+		.name = "mpfs-auto-update",
+	},
+	.probe = mpfs_auto_update_probe,
+	.remove = mpfs_auto_update_remove,
+};
+module_platform_driver(mpfs_auto_update_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
+MODULE_DESCRIPTION("PolarFire SoC Auto Update FPGA reprogramming");