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
  ...

6 files changed, 586 insertions, 0 deletions

diff --git a/drivers/soc/microchip/Kconfig b/drivers/soc/microchip/Kconfig
new file mode 100644
index 000000000..af7946741
--- /dev/null
+++ b/drivers/soc/microchip/Kconfig
@@ -0,0 +1,34 @@
+config POLARFIRE_SOC_IRQ_MUX
+	bool "Microchip PolarFire SoC's GPIO IRQ Mux"
+	depends on ARCH_MICROCHIP
+	select REGMAP
+	select REGMAP_MMIO
+	default y
+	help
+	  Support for the interrupt mux on Polarfire SoC. It sits between
+	  the GPIO controllers and the PLIC, as only 41 interrupts are shared
+	  between 3 GPIO controllers with a total of 70 interrupts.
+
+config POLARFIRE_SOC_SYS_CTRL
+	tristate "Microchip PolarFire SoC (MPFS) system controller support"
+	depends on POLARFIRE_SOC_MAILBOX
+	depends on MTD
+	help
+	  This driver adds support for the PolarFire SoC (MPFS) system controller.
+
+	  To compile this driver as a module, choose M here. the
+	  module will be called mpfs_system_controller.
+
+	  If unsure, say N.
+
+config POLARFIRE_SOC_SYSCONS
+	bool "PolarFire SoC (MPFS) syscon drivers"
+	default y
+	depends on ARCH_MICROCHIP
+	select MFD_CORE
+	help
+	  These drivers add support for the syscons on PolarFire SoC (MPFS).
+	  Without these drivers core parts of the kernel such as clocks
+	  and resets will not function correctly.
+
+	  If unsure, and on a PolarFire SoC, say y.
diff --git a/drivers/soc/microchip/Makefile b/drivers/soc/microchip/Makefile
new file mode 100644
index 000000000..55775db45
--- /dev/null
+++ b/drivers/soc/microchip/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_POLARFIRE_SOC_IRQ_MUX)	+= mpfs-irqmux.o
+obj-$(CONFIG_POLARFIRE_SOC_SYS_CTRL)	+= mpfs-sys-controller.o
+obj-$(CONFIG_POLARFIRE_SOC_SYSCONS)	+= mpfs-control-scb.o mpfs-mss-top-sysreg.o
diff --git a/drivers/soc/microchip/mpfs-control-scb.c b/drivers/soc/microchip/mpfs-control-scb.c
new file mode 100644
index 000000000..8dda5704a
--- /dev/null
+++ b/drivers/soc/microchip/mpfs-control-scb.c
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/array_size.h>
+#include <linux/of.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/syscon.h>
+#include <linux/platform_device.h>
+
+static const struct mfd_cell mpfs_control_scb_devs[] = {
+	MFD_CELL_NAME("mpfs-tvs"),
+};
+
+static int mpfs_control_scb_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	return devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				    mpfs_control_scb_devs,
+				    ARRAY_SIZE(mpfs_control_scb_devs), NULL, 0,
+				    NULL);
+}
+
+static const struct of_device_id mpfs_control_scb_of_match[] = {
+	{ .compatible = "microchip,mpfs-control-scb", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mpfs_control_scb_of_match);
+
+static struct platform_driver mpfs_control_scb_driver = {
+	.driver = {
+		.name = "mpfs-control-scb",
+		.of_match_table = mpfs_control_scb_of_match,
+	},
+	.probe = mpfs_control_scb_probe,
+};
+module_platform_driver(mpfs_control_scb_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
+MODULE_DESCRIPTION("PolarFire SoC control scb driver");
diff --git a/drivers/soc/microchip/mpfs-irqmux.c b/drivers/soc/microchip/mpfs-irqmux.c
new file mode 100644
index 000000000..ae15e913e
--- /dev/null
+++ b/drivers/soc/microchip/mpfs-irqmux.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Largely copied from rzn1_irqmux.c
+ */
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define MPFS_IRQMUX_CR			0x54
+#define MPFS_IRQMUX_NUM_CHILDREN	96
+#define MPFS_IRQMUX_NUM_DIRECT		38
+#define MPFS_IRQMUX_DIRECT_START	13
+#define MPFS_IRQMUX_DIRECT_END		50
+#define MPFS_IRQMUX_NONDIRECT_END	53
+
+static int mpfs_irqmux_is_direct_mode(struct device *dev,
+				      const struct of_phandle_args *parent_args)
+{
+	if (parent_args->args_count != 1) {
+		dev_err(dev, "Invalid interrupt-map item\n");
+		return -EINVAL;
+	}
+
+	if (parent_args->args[0] < MPFS_IRQMUX_DIRECT_START ||
+			parent_args->args[0] > MPFS_IRQMUX_NONDIRECT_END) {
+		dev_err(dev, "Invalid interrupt %u\n", parent_args->args[0]);
+		return -EINVAL;
+	}
+
+	if (parent_args->args[0] > MPFS_IRQMUX_DIRECT_END)
+		return 0;
+
+	return 1;
+}
+
+static int mpfs_irqmux_probe(struct platform_device *pdev)
+{
+	DECLARE_BITMAP(child_done, MPFS_IRQMUX_NUM_CHILDREN) = {};
+	DECLARE_BITMAP(parent_done, MPFS_IRQMUX_NUM_DIRECT) = {};
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct of_imap_parser imap_parser;
+	struct of_imap_item imap_item;
+	struct regmap *regmap;
+	int ret, direct_mode, line, controller, gpio, parent_line;
+	u32 tmp, val = 0, old;
+
+	regmap = device_node_to_regmap(pdev->dev.parent->of_node);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap), "Failed to find syscon regmap\n");
+
+	/* We support only #interrupt-cells = <1> and #address-cells = <0> */
+	ret = of_property_read_u32(np, "#interrupt-cells", &tmp);
+	if (ret)
+		return ret;
+	if (tmp != 1)
+		return -EINVAL;
+
+	ret = of_property_read_u32(np, "#address-cells", &tmp);
+	if (ret)
+		return ret;
+	if (tmp != 0)
+		return -EINVAL;
+
+	ret = of_imap_parser_init(&imap_parser, np, &imap_item);
+	if (ret)
+		return ret;
+
+	for_each_of_imap_item(&imap_parser, &imap_item) {
+
+		direct_mode = mpfs_irqmux_is_direct_mode(dev, &imap_item.parent_args);
+		if (direct_mode < 0) {
+			of_node_put(imap_item.parent_args.np);
+			return direct_mode;
+		}
+
+		line = imap_item.child_imap[0];
+		gpio = line % 32;
+		controller = line / 32;
+
+		if (controller > 2) {
+			of_node_put(imap_item.parent_args.np);
+			dev_err(dev, "child interrupt number too large: %d\n", line);
+			return -EINVAL;
+		}
+
+		if (test_and_set_bit(line, child_done)) {
+			of_node_put(imap_item.parent_args.np);
+			dev_err(dev, "mux child line %d already defined in interrupt-map\n",
+				line);
+			return -EINVAL;
+		}
+
+		parent_line = imap_item.parent_args.args[0] - MPFS_IRQMUX_DIRECT_START;
+		if (direct_mode && test_and_set_bit(parent_line, parent_done)) {
+			of_node_put(imap_item.parent_args.np);
+			dev_err(dev, "mux parent line %d already defined in interrupt-map\n",
+				line);
+			return -EINVAL;
+		}
+
+		/*
+		 * There are 41 interrupts assigned to GPIOs, of which 38 are "direct". Since the
+		 * mux has 32 bits only, 6 of these exclusive/"direct" interrupts remain. These
+		 * are used by GPIO controller 1's lines 18 to 23. Nothing needs to be done
+		 * for these interrupts.
+		 */
+		if (controller == 1 && gpio >= 18)
+			continue;
+
+		/*
+		 * The mux has a single register, where bits 0 to 13 mux between GPIO controller
+		 * 1's 14 GPIOs and GPIO controller 2's first 14 GPIOs. The remaining bits mux
+		 * between the first 18 GPIOs of controller 1 and the last 18 GPIOS of
+		 * controller 2. If a bit in the mux's control register is set, the
+		 * corresponding interrupt line for GPIO controller 0 or 1 will be put in
+		 * "non-direct" mode. If cleared, the "fabric" controller's will.
+		 *
+		 * Register layout:
+		 *    GPIO 1 interrupt line 17 | mux bit 31 | GPIO 2 interrupt line 31
+		 *    ...                      | ...        | ...
+		 *    ...                      | ...        | ...
+		 *    GPIO 1 interrupt line  0 | mux bit 14 | GPIO 2 interrupt line 14
+		 *    GPIO 0 interrupt line 13 | mux bit 13 | GPIO 2 interrupt line 13
+		 *    ...                      | ...        | ...
+		 *    ...                      | ...        | ...
+		 *    GPIO 0 interrupt line  0 | mux bit  0 | GPIO 2 interrupt line  0
+		 *
+		 * As the binding mandates 70 items, one for each GPIO line, there's no need to
+		 * handle anything for GPIO controller 2, since the bit will be set for the
+		 * corresponding line in GPIO controller 0 or 1.
+		 */
+		if (controller == 2)
+			continue;
+
+		/*
+		 * If in direct mode, the bit is cleared, nothing needs to be done as val is zero
+		 * initialised and that's the direct mode setting for GPIO controller 0 and 1.
+		 */
+		if (direct_mode)
+			continue;
+
+		if (controller == 0)
+			val |= 1U << gpio;
+		else
+			val |= 1U << (gpio + 14);
+	}
+
+	regmap_read(regmap, MPFS_IRQMUX_CR, &old);
+	regmap_write(regmap, MPFS_IRQMUX_CR, val);
+
+	if (val != old)
+		dev_info(dev, "firmware mux setting of 0x%x overwritten to 0x%x\n", old, val);
+
+	return 0;
+}
+
+static const struct of_device_id mpfs_irqmux_of_match[] = {
+	{ .compatible = "microchip,mpfs-irqmux", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mpfs_irqmux_of_match);
+
+static struct platform_driver mpfs_irqmux_driver = {
+	.probe = mpfs_irqmux_probe,
+	.driver = {
+		.name = "mpfs_irqmux",
+		.of_match_table = mpfs_irqmux_of_match,
+	},
+};
+module_platform_driver(mpfs_irqmux_driver);
+
+MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
+MODULE_DESCRIPTION("Polarfire SoC interrupt mux driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/soc/microchip/mpfs-mss-top-sysreg.c b/drivers/soc/microchip/mpfs-mss-top-sysreg.c
new file mode 100644
index 000000000..b0f42b8dd
--- /dev/null
+++ b/drivers/soc/microchip/mpfs-mss-top-sysreg.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/array_size.h>
+#include <linux/of.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+static const struct mfd_cell mpfs_mss_top_sysreg_devs[] = {
+	MFD_CELL_NAME("mpfs-reset"),
+};
+
+static int mpfs_mss_top_sysreg_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				   mpfs_mss_top_sysreg_devs,
+				   ARRAY_SIZE(mpfs_mss_top_sysreg_devs), NULL,
+				   0, NULL);
+	if (ret)
+		return ret;
+
+	return devm_of_platform_populate(dev);
+}
+
+static const struct of_device_id mpfs_mss_top_sysreg_of_match[] = {
+	{ .compatible = "microchip,mpfs-mss-top-sysreg", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mpfs_mss_top_sysreg_of_match);
+
+static struct platform_driver mpfs_mss_top_sysreg_driver = {
+	.driver = {
+		.name = "mpfs-mss-top-sysreg",
+		.of_match_table = mpfs_mss_top_sysreg_of_match,
+	},
+	.probe = mpfs_mss_top_sysreg_probe,
+};
+module_platform_driver(mpfs_mss_top_sysreg_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
+MODULE_DESCRIPTION("PolarFire SoC mss top sysreg driver");
diff --git a/drivers/soc/microchip/mpfs-sys-controller.c b/drivers/soc/microchip/mpfs-sys-controller.c
new file mode 100644
index 000000000..0400a01b2
--- /dev/null
+++ b/drivers/soc/microchip/mpfs-sys-controller.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Microchip PolarFire SoC (MPFS) system controller driver
+ *
+ * Copyright (c) 2020-2021 Microchip Corporation. All rights reserved.
+ *
+ * Author: Conor Dooley <conor.dooley@microchip.com>
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/kref.h>
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/mtd/mtd.h>
+#include <linux/spi/spi.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/mailbox_client.h>
+#include <linux/platform_device.h>
+#include <soc/microchip/mpfs.h>
+
+/*
+ * This timeout must be long, as some services (example: image authentication)
+ * take significant time to complete
+ */
+#define MPFS_SYS_CTRL_TIMEOUT_MS 30000
+
+static DEFINE_MUTEX(transaction_lock);
+
+struct mpfs_sys_controller {
+	struct mbox_client client;
+	struct mbox_chan *chan;
+	struct completion c;
+	struct mtd_info *flash;
+	struct kref consumers;
+};
+
+struct mpfs_syscon_config {
+	unsigned int nb_subdevs;
+	struct platform_device *subdevs;
+};
+
+int mpfs_blocking_transaction(struct mpfs_sys_controller *sys_controller, struct mpfs_mss_msg *msg)
+{
+	unsigned long timeout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
+	int ret;
+
+	ret = mutex_lock_interruptible(&transaction_lock);
+	if (ret)
+		return ret;
+
+	reinit_completion(&sys_controller->c);
+
+	ret = mbox_send_message(sys_controller->chan, msg);
+	if (ret < 0) {
+		dev_warn(sys_controller->client.dev, "MPFS sys controller service timeout\n");
+		goto out;
+	}
+
+	/*
+	 * Unfortunately, the system controller will only deliver an interrupt
+	 * if a service succeeds. mbox_send_message() will block until the busy
+	 * flag is gone. If the busy flag is gone but no interrupt has arrived
+	 * to trigger the rx callback then the service can be deemed to have
+	 * failed.
+	 * The caller can then interrogate msg::response::resp_status to
+	 * determine the cause of the failure.
+	 * mbox_send_message() returns positive integers in the success path, so
+	 * ret needs to be cleared if we do get an interrupt.
+	 */
+	if (!wait_for_completion_timeout(&sys_controller->c, timeout)) {
+		ret = -EBADMSG;
+		dev_warn(sys_controller->client.dev,
+			 "MPFS sys controller service failed with status: %d\n",
+			 msg->response->resp_status);
+	} else {
+		ret = 0;
+	}
+
+out:
+	mutex_unlock(&transaction_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(mpfs_blocking_transaction);
+
+static void mpfs_sys_controller_rx_callback(struct mbox_client *client, void *msg)
+{
+	struct mpfs_sys_controller *sys_controller =
+		container_of(client, struct mpfs_sys_controller, client);
+
+	complete(&sys_controller->c);
+}
+
+static void mpfs_sys_controller_delete(struct kref *kref)
+{
+	struct mpfs_sys_controller *sys_controller =
+		container_of(kref, struct mpfs_sys_controller, consumers);
+
+	mbox_free_channel(sys_controller->chan);
+	kfree(sys_controller);
+}
+
+static void mpfs_sys_controller_put(void *data)
+{
+	struct mpfs_sys_controller *sys_controller = data;
+
+	kref_put(&sys_controller->consumers, mpfs_sys_controller_delete);
+}
+
+struct mtd_info *mpfs_sys_controller_get_flash(struct mpfs_sys_controller *mpfs_client)
+{
+	return mpfs_client->flash;
+}
+EXPORT_SYMBOL(mpfs_sys_controller_get_flash);
+
+static int mpfs_sys_controller_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mpfs_sys_controller *sys_controller;
+	struct mpfs_syscon_config *of_data;
+	struct device_node *np;
+	int i, ret;
+
+	sys_controller = kzalloc_obj(*sys_controller);
+	if (!sys_controller)
+		return -ENOMEM;
+
+	np = of_parse_phandle(dev->of_node, "microchip,bitstream-flash", 0);
+	if (!np)
+		goto no_flash;
+
+	sys_controller->flash = of_get_mtd_device_by_node(np);
+	of_node_put(np);
+	if (IS_ERR(sys_controller->flash)) {
+		ret = dev_err_probe(dev, PTR_ERR(sys_controller->flash), "Failed to get flash\n");
+		goto out_free;
+	}
+
+no_flash:
+	sys_controller->client.dev = dev;
+	sys_controller->client.rx_callback = mpfs_sys_controller_rx_callback;
+	sys_controller->client.tx_block = 1U;
+	sys_controller->client.tx_tout = msecs_to_jiffies(MPFS_SYS_CTRL_TIMEOUT_MS);
+
+	sys_controller->chan = mbox_request_channel(&sys_controller->client, 0);
+	if (IS_ERR(sys_controller->chan)) {
+		ret = dev_err_probe(dev, PTR_ERR(sys_controller->chan),
+				    "Failed to get mbox channel\n");
+		goto out_free;
+	}
+
+	init_completion(&sys_controller->c);
+	kref_init(&sys_controller->consumers);
+
+	platform_set_drvdata(pdev, sys_controller);
+
+	of_data = (struct mpfs_syscon_config *) device_get_match_data(dev);
+	if (!of_data) {
+		ret = dev_err_probe(dev, -EINVAL, "Error getting match data\n");
+		goto out_free_channel;
+	}
+
+	for (i = 0; i < of_data->nb_subdevs; i++) {
+		of_data->subdevs[i].dev.parent = dev;
+		if (platform_device_register(&of_data->subdevs[i]))
+			dev_warn(dev, "Error registering sub device %s\n",
+				 of_data->subdevs[i].name);
+	}
+
+	dev_info(&pdev->dev, "Registered MPFS system controller\n");
+
+	return 0;
+
+out_free_channel:
+	mbox_free_channel(sys_controller->chan);
+out_free:
+	kfree(sys_controller);
+	return ret;
+}
+
+static void mpfs_sys_controller_remove(struct platform_device *pdev)
+{
+	struct mpfs_sys_controller *sys_controller = platform_get_drvdata(pdev);
+
+	mpfs_sys_controller_put(sys_controller);
+}
+
+static struct platform_device mpfs_subdevs[] = {
+	{
+		.name		= "mpfs-rng",
+		.id		= -1,
+	},
+	{
+		.name		= "mpfs-generic-service",
+		.id		= -1,
+	},
+	{
+		.name		= "mpfs-auto-update",
+		.id		= -1,
+	},
+};
+
+static struct platform_device pic64gx_subdevs[] = {
+	{
+		.name		= "mpfs-rng",
+		.id		= -1,
+	},
+	{
+		.name		= "mpfs-generic-service",
+		.id		= -1,
+	},
+};
+
+static const struct mpfs_syscon_config mpfs_config = {
+	.nb_subdevs = ARRAY_SIZE(mpfs_subdevs),
+	.subdevs = mpfs_subdevs,
+};
+
+static const struct mpfs_syscon_config pic64gx_config = {
+	.nb_subdevs = ARRAY_SIZE(pic64gx_subdevs),
+	.subdevs = pic64gx_subdevs,
+};
+
+static const struct of_device_id mpfs_sys_controller_of_match[] = {
+	{.compatible = "microchip,mpfs-sys-controller", .data = &mpfs_config},
+	{.compatible = "microchip,pic64gx-sys-controller", .data = &pic64gx_config},
+	{},
+};
+MODULE_DEVICE_TABLE(of, mpfs_sys_controller_of_match);
+
+struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev)
+{
+	const struct of_device_id *match;
+	struct mpfs_sys_controller *sys_controller;
+	int ret;
+
+	if (!dev->parent)
+		goto err_no_device;
+
+	match = of_match_node(mpfs_sys_controller_of_match,  dev->parent->of_node);
+	of_node_put(dev->parent->of_node);
+	if (!match)
+		goto err_no_device;
+
+	sys_controller = dev_get_drvdata(dev->parent);
+	if (!sys_controller)
+		goto err_bad_device;
+
+	if (!kref_get_unless_zero(&sys_controller->consumers))
+		goto err_bad_device;
+
+	ret = devm_add_action_or_reset(dev, mpfs_sys_controller_put, sys_controller);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return sys_controller;
+
+err_no_device:
+	dev_dbg(dev, "Parent device was not an MPFS system controller\n");
+	return ERR_PTR(-ENODEV);
+
+err_bad_device:
+	dev_dbg(dev, "MPFS system controller found but could not register as a sub device\n");
+	return ERR_PTR(-EPROBE_DEFER);
+}
+EXPORT_SYMBOL(mpfs_sys_controller_get);
+
+static struct platform_driver mpfs_sys_controller_driver = {
+	.driver = {
+		.name = "mpfs-sys-controller",
+		.of_match_table = mpfs_sys_controller_of_match,
+	},
+	.probe = mpfs_sys_controller_probe,
+	.remove = mpfs_sys_controller_remove,
+};
+module_platform_driver(mpfs_sys_controller_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
+MODULE_DESCRIPTION("MPFS system controller driver");