Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 585 insertions, 0 deletions

diff --git a/drivers/clk/bcm/clk-raspberrypi.c b/drivers/clk/bcm/clk-raspberrypi.c
new file mode 100644
index 000000000..f1a99de6d
--- /dev/null
+++ b/drivers/clk/bcm/clk-raspberrypi.c
@@ -0,0 +1,585 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Raspberry Pi driver for firmware controlled clocks
+ *
+ * Even though clk-bcm2835 provides an interface to the hardware registers for
+ * the system clocks we've had to factor out 'pllb' as the firmware 'owns' it.
+ * We're not allowed to change it directly as we might race with the
+ * over-temperature and under-voltage protections provided by the firmware.
+ *
+ * Copyright (C) 2019 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
+ */
+
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+static char *rpi_firmware_clk_names[] = {
+	[RPI_FIRMWARE_EMMC_CLK_ID]	= "emmc",
+	[RPI_FIRMWARE_UART_CLK_ID]	= "uart",
+	[RPI_FIRMWARE_ARM_CLK_ID]	= "arm",
+	[RPI_FIRMWARE_CORE_CLK_ID]	= "core",
+	[RPI_FIRMWARE_V3D_CLK_ID]	= "v3d",
+	[RPI_FIRMWARE_H264_CLK_ID]	= "h264",
+	[RPI_FIRMWARE_ISP_CLK_ID]	= "isp",
+	[RPI_FIRMWARE_SDRAM_CLK_ID]	= "sdram",
+	[RPI_FIRMWARE_PIXEL_CLK_ID]	= "pixel",
+	[RPI_FIRMWARE_PWM_CLK_ID]	= "pwm",
+	[RPI_FIRMWARE_HEVC_CLK_ID]	= "hevc",
+	[RPI_FIRMWARE_EMMC2_CLK_ID]	= "emmc2",
+	[RPI_FIRMWARE_M2MC_CLK_ID]	= "m2mc",
+	[RPI_FIRMWARE_PIXEL_BVB_CLK_ID]	= "pixel-bvb",
+	[RPI_FIRMWARE_VEC_CLK_ID]	= "vec",
+	[RPI_FIRMWARE_DISP_CLK_ID]	= "disp",
+};
+
+#define RPI_FIRMWARE_STATE_ENABLE_BIT	BIT(0)
+#define RPI_FIRMWARE_STATE_WAIT_BIT	BIT(1)
+
+struct raspberrypi_clk_variant;
+
+struct raspberrypi_clk {
+	struct device *dev;
+	struct rpi_firmware *firmware;
+	struct platform_device *cpufreq;
+};
+
+struct raspberrypi_clk_data {
+	struct clk_hw hw;
+
+	unsigned int id;
+	struct raspberrypi_clk_variant *variant;
+
+	struct raspberrypi_clk *rpi;
+};
+
+static inline
+const struct raspberrypi_clk_data *clk_hw_to_data(const struct clk_hw *hw)
+{
+	return container_of(hw, struct raspberrypi_clk_data, hw);
+}
+
+struct raspberrypi_clk_variant {
+	bool		export;
+	char		*clkdev;
+	unsigned long	min_rate;
+	bool		minimize;
+	bool		maximize;
+	u32		flags;
+};
+
+static struct raspberrypi_clk_variant
+raspberrypi_clk_variants[RPI_FIRMWARE_NUM_CLK_ID] = {
+	[RPI_FIRMWARE_ARM_CLK_ID] = {
+		.export = true,
+		.clkdev = "cpu0",
+		.flags = CLK_IS_CRITICAL,
+	},
+	[RPI_FIRMWARE_CORE_CLK_ID] = {
+		.export = true,
+
+		/*
+		 * The clock is shared between the HVS and the CSI
+		 * controllers, on the BCM2711 and will change depending
+		 * on the pixels composited on the HVS and the capture
+		 * resolution on Unicam.
+		 *
+		 * Since the rate can get quite large, and we need to
+		 * coordinate between both driver instances, let's
+		 * always use the minimum the drivers will let us.
+		 */
+		.minimize = true,
+
+		/*
+		 * It should never be disabled as it drives the bus for
+		 * everything else.
+		 */
+		.flags = CLK_IS_CRITICAL,
+	},
+	[RPI_FIRMWARE_M2MC_CLK_ID] = {
+		.export = true,
+
+		/*
+		 * If we boot without any cable connected to any of the
+		 * HDMI connector, the firmware will skip the HSM
+		 * initialization and leave it with a rate of 0,
+		 * resulting in a bus lockup when we're accessing the
+		 * registers even if it's enabled.
+		 *
+		 * Let's put a sensible default so that we don't end up
+		 * in this situation.
+		 */
+		.min_rate = 120000000,
+
+		/*
+		 * The clock is shared between the two HDMI controllers
+		 * on the BCM2711 and will change depending on the
+		 * resolution output on each. Since the rate can get
+		 * quite large, and we need to coordinate between both
+		 * driver instances, let's always use the minimum the
+		 * drivers will let us.
+		 */
+		.minimize = true,
+
+		/*
+		 * As mentioned above, this clock is disabled during boot,
+		 * the firmware will skip the HSM initialization, resulting
+		 * in a bus lockup. Therefore, make sure it's enabled
+		 * during boot, but after it, it can be enabled/disabled
+		 * by the driver.
+		 */
+		.flags = CLK_IGNORE_UNUSED,
+	},
+	[RPI_FIRMWARE_V3D_CLK_ID] = {
+		.export = true,
+		.maximize = true,
+	},
+	[RPI_FIRMWARE_PIXEL_CLK_ID] = {
+		.export = true,
+		.minimize = true,
+		.flags = CLK_IS_CRITICAL,
+	},
+	[RPI_FIRMWARE_HEVC_CLK_ID] = {
+		.export = true,
+		.minimize = true,
+		.flags = CLK_IS_CRITICAL,
+	},
+	[RPI_FIRMWARE_ISP_CLK_ID] = {
+		.export = true,
+		.minimize = true,
+	},
+	[RPI_FIRMWARE_PIXEL_BVB_CLK_ID] = {
+		.export = true,
+		.minimize = true,
+		.flags = CLK_IS_CRITICAL,
+	},
+	[RPI_FIRMWARE_VEC_CLK_ID] = {
+		.export = true,
+		.minimize = true,
+
+		/*
+		 * If this clock is disabled during boot, it causes a bus
+		 * lockup in RPi 3B. Therefore, make sure it's left enabled
+		 * during boot.
+		 */
+		.flags = CLK_IGNORE_UNUSED,
+	},
+	[RPI_FIRMWARE_DISP_CLK_ID] = {
+		.export = true,
+		.minimize = true,
+	},
+};
+
+/*
+ * Structure of the message passed to Raspberry Pi's firmware in order to
+ * change clock rates. The 'disable_turbo' option is only available to the ARM
+ * clock (pllb) which we enable by default as turbo mode will alter multiple
+ * clocks at once.
+ *
+ * Even though we're able to access the clock registers directly we're bound to
+ * use the firmware interface as the firmware ultimately takes care of
+ * mitigating overheating/undervoltage situations and we would be changing
+ * frequencies behind his back.
+ *
+ * For more information on the firmware interface check:
+ * https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface
+ */
+struct raspberrypi_firmware_prop {
+	__le32 id;
+	__le32 val;
+	__le32 disable_turbo;
+} __packed;
+
+static int raspberrypi_clock_property(struct rpi_firmware *firmware,
+				      const struct raspberrypi_clk_data *data,
+				      u32 tag, u32 *val)
+{
+	struct raspberrypi_firmware_prop msg = {
+		.id = cpu_to_le32(data->id),
+		.val = cpu_to_le32(*val),
+	};
+	int ret;
+
+	ret = rpi_firmware_property(firmware, tag, &msg, sizeof(msg));
+	if (ret)
+		return ret;
+
+	*val = le32_to_cpu(msg.val);
+
+	return 0;
+}
+
+static int raspberrypi_fw_is_prepared(struct clk_hw *hw)
+{
+	const struct raspberrypi_clk_data *data = clk_hw_to_data(hw);
+	struct raspberrypi_clk *rpi = data->rpi;
+	u32 val = 0;
+	int ret;
+
+	ret = raspberrypi_clock_property(rpi->firmware, data,
+					 RPI_FIRMWARE_GET_CLOCK_STATE, &val);
+	if (ret) {
+		dev_err_ratelimited(rpi->dev, "Failed to get %s state: %d\n",
+				    clk_hw_get_name(hw), ret);
+		return 0;
+	}
+
+	return !!(val & RPI_FIRMWARE_STATE_ENABLE_BIT);
+}
+
+
+static unsigned long raspberrypi_fw_get_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	const struct raspberrypi_clk_data *data = clk_hw_to_data(hw);
+	struct raspberrypi_clk *rpi = data->rpi;
+	u32 val = 0;
+	int ret;
+
+	ret = raspberrypi_clock_property(rpi->firmware, data,
+					 RPI_FIRMWARE_GET_CLOCK_RATE, &val);
+	if (ret) {
+		dev_err_ratelimited(rpi->dev, "Failed to get %s frequency: %d\n",
+				    clk_hw_get_name(hw), ret);
+		return 0;
+	}
+
+	return val;
+}
+
+static int raspberrypi_fw_set_rate(struct clk_hw *hw, unsigned long rate,
+				   unsigned long parent_rate)
+{
+	const struct raspberrypi_clk_data *data = clk_hw_to_data(hw);
+	struct raspberrypi_clk *rpi = data->rpi;
+	u32 _rate = rate;
+	int ret;
+
+	ret = raspberrypi_clock_property(rpi->firmware, data,
+					 RPI_FIRMWARE_SET_CLOCK_RATE, &_rate);
+	if (ret)
+		dev_err_ratelimited(rpi->dev, "Failed to change %s frequency: %d\n",
+				    clk_hw_get_name(hw), ret);
+
+	return ret;
+}
+
+static int raspberrypi_fw_dumb_determine_rate(struct clk_hw *hw,
+					      struct clk_rate_request *req)
+{
+	const struct raspberrypi_clk_data *data = clk_hw_to_data(hw);
+	struct raspberrypi_clk_variant *variant = data->variant;
+
+	/*
+	 * The firmware will do the rounding but that isn't part of
+	 * the interface with the firmware, so we just do our best
+	 * here.
+	 */
+
+	req->rate = clamp(req->rate, req->min_rate, req->max_rate);
+
+	/*
+	 * We want to aggressively reduce the clock rate here, so let's
+	 * just ignore the requested rate and return the bare minimum
+	 * rate we can get away with.
+	 */
+	if (variant->minimize && req->min_rate > 0)
+		req->rate = req->min_rate;
+
+	return 0;
+}
+
+static int raspberrypi_fw_prepare(struct clk_hw *hw)
+{
+	const struct raspberrypi_clk_data *data = clk_hw_to_data(hw);
+	struct raspberrypi_clk_variant *variant = data->variant;
+	struct raspberrypi_clk *rpi = data->rpi;
+	u32 state = RPI_FIRMWARE_STATE_ENABLE_BIT;
+	int ret;
+
+	ret = raspberrypi_clock_property(rpi->firmware, data,
+					 RPI_FIRMWARE_SET_CLOCK_STATE, &state);
+	if (ret) {
+		dev_err_ratelimited(rpi->dev,
+				    "Failed to set clock %s state to on: %d\n",
+				    clk_hw_get_name(hw), ret);
+		return ret;
+	}
+
+	/*
+	 * For clocks marked with 'maximize', restore the rate to the
+	 * maximum after enabling. This compensates for the rate being
+	 * set to minimum during unprepare (see raspberrypi_fw_unprepare).
+	 */
+	if (variant->maximize) {
+		unsigned long min_rate, max_rate;
+
+		clk_hw_get_rate_range(hw, &min_rate, &max_rate);
+		ret = raspberrypi_fw_set_rate(hw, max_rate, 0);
+	}
+
+	return ret;
+}
+
+static void raspberrypi_fw_unprepare(struct clk_hw *hw)
+{
+	const struct raspberrypi_clk_data *data = clk_hw_to_data(hw);
+	struct raspberrypi_clk *rpi = data->rpi;
+	unsigned long min_rate, max_rate;
+	u32 state = 0;
+	int ret;
+
+	clk_hw_get_rate_range(hw, &min_rate, &max_rate);
+
+	/*
+	 * Setting the rate in unprepare is a deviation from the usual CCF
+	 * behavior, where unprepare only gates the clock. However, this is
+	 * needed, as RPI_FIRMWARE_SET_CLOCK_STATE doesn't actually power off
+	 * the clock on current firmware versions. Setting the rate to minimum
+	 * before disabling the clock is the only way to achieve meaningful
+	 * power savings.
+	 *
+	 * This is safe because no consumer should rely on the rate of an
+	 * unprepared clock. Any consumer must call clk_prepare() before use,
+	 * at which point the rate is either restored to maximum (for clocks
+	 * with the 'maximize' flag) or re-established by the consumer.
+	 */
+	raspberrypi_fw_set_rate(hw, min_rate, 0);
+
+	ret = raspberrypi_clock_property(rpi->firmware, data,
+					 RPI_FIRMWARE_SET_CLOCK_STATE, &state);
+	if (ret)
+		dev_err_ratelimited(rpi->dev,
+				    "Failed to set clock %s state to off: %d\n",
+				    clk_hw_get_name(hw), ret);
+}
+
+static const struct clk_ops raspberrypi_firmware_clk_ops = {
+	.prepare        = raspberrypi_fw_prepare,
+	.unprepare      = raspberrypi_fw_unprepare,
+	.is_prepared	= raspberrypi_fw_is_prepared,
+	.recalc_rate	= raspberrypi_fw_get_rate,
+	.determine_rate	= raspberrypi_fw_dumb_determine_rate,
+	.set_rate	= raspberrypi_fw_set_rate,
+};
+
+static struct clk_hw *raspberrypi_clk_register(struct raspberrypi_clk *rpi,
+					       unsigned int parent,
+					       unsigned int id,
+					       struct raspberrypi_clk_variant *variant)
+{
+	struct raspberrypi_clk_data *data;
+	struct clk_init_data init = {};
+	u32 min_rate, max_rate;
+	int ret;
+
+	data = devm_kzalloc(rpi->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+	data->rpi = rpi;
+	data->id = id;
+	data->variant = variant;
+
+	init.name = devm_kasprintf(rpi->dev, GFP_KERNEL,
+				   "fw-clk-%s",
+				   rpi_firmware_clk_names[id]);
+	if (!init.name)
+		return ERR_PTR(-ENOMEM);
+	init.ops = &raspberrypi_firmware_clk_ops;
+	init.flags = variant->flags | CLK_GET_RATE_NOCACHE;
+
+	data->hw.init = &init;
+
+	ret = raspberrypi_clock_property(rpi->firmware, data,
+					 RPI_FIRMWARE_GET_MIN_CLOCK_RATE,
+					 &min_rate);
+	if (ret) {
+		dev_err(rpi->dev, "Failed to get clock %d min freq: %d\n",
+			id, ret);
+		return ERR_PTR(ret);
+	}
+
+	ret = raspberrypi_clock_property(rpi->firmware, data,
+					 RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
+					 &max_rate);
+	if (ret) {
+		dev_err(rpi->dev, "Failed to get clock %d max freq: %d\n",
+			id, ret);
+		return ERR_PTR(ret);
+	}
+
+	ret = devm_clk_hw_register(rpi->dev, &data->hw);
+	if (ret)
+		return ERR_PTR(ret);
+
+	clk_hw_set_rate_range(&data->hw, min_rate, max_rate);
+
+	if (variant->clkdev) {
+		ret = devm_clk_hw_register_clkdev(rpi->dev, &data->hw,
+						  NULL, variant->clkdev);
+		if (ret) {
+			dev_err(rpi->dev, "Failed to initialize clkdev\n");
+			return ERR_PTR(ret);
+		}
+	}
+
+	if (variant->min_rate) {
+		unsigned long rate;
+
+		clk_hw_set_rate_range(&data->hw, variant->min_rate, max_rate);
+
+		rate = raspberrypi_fw_get_rate(&data->hw, 0);
+		if (rate < variant->min_rate) {
+			ret = raspberrypi_fw_set_rate(&data->hw, variant->min_rate, 0);
+			if (ret)
+				return ERR_PTR(ret);
+		}
+	}
+
+	return &data->hw;
+}
+
+struct rpi_firmware_get_clocks_response {
+	u32 parent;
+	u32 id;
+};
+
+static int raspberrypi_discover_clocks(struct raspberrypi_clk *rpi,
+				       struct clk_hw_onecell_data *data)
+{
+	struct rpi_firmware_get_clocks_response *clks;
+	int ret;
+
+	/*
+	 * The firmware doesn't guarantee that the last element of
+	 * RPI_FIRMWARE_GET_CLOCKS is zeroed. So allocate an additional
+	 * zero element as sentinel.
+	 */
+	clks = devm_kcalloc(rpi->dev,
+			    RPI_FIRMWARE_NUM_CLK_ID + 1, sizeof(*clks),
+			    GFP_KERNEL);
+	if (!clks)
+		return -ENOMEM;
+
+	ret = rpi_firmware_property(rpi->firmware, RPI_FIRMWARE_GET_CLOCKS,
+				    clks,
+				    sizeof(*clks) * RPI_FIRMWARE_NUM_CLK_ID);
+	if (ret)
+		return ret;
+
+	while (clks->id) {
+		struct raspberrypi_clk_variant *variant;
+
+		if (clks->id >= RPI_FIRMWARE_NUM_CLK_ID) {
+			dev_err(rpi->dev, "Unknown clock id: %u (max: %u)\n",
+					   clks->id, RPI_FIRMWARE_NUM_CLK_ID - 1);
+			return -EINVAL;
+		}
+
+		variant = &raspberrypi_clk_variants[clks->id];
+		if (variant->export) {
+			struct clk_hw *hw;
+
+			hw = raspberrypi_clk_register(rpi, clks->parent,
+						      clks->id, variant);
+			if (IS_ERR(hw))
+				return PTR_ERR(hw);
+
+			data->num = clks->id + 1;
+			data->hws[clks->id] = hw;
+		}
+
+		clks++;
+	}
+
+	return 0;
+}
+
+static int raspberrypi_clk_probe(struct platform_device *pdev)
+{
+	struct clk_hw_onecell_data *clk_data;
+	struct device_node *firmware_node;
+	struct device *dev = &pdev->dev;
+	struct rpi_firmware *firmware;
+	struct raspberrypi_clk *rpi;
+	int ret;
+
+	/*
+	 * We can be probed either through the an old-fashioned
+	 * platform device registration or through a DT node that is a
+	 * child of the firmware node. Handle both cases.
+	 */
+	if (dev->of_node)
+		firmware_node = of_get_parent(dev->of_node);
+	else
+		firmware_node = of_find_compatible_node(NULL, NULL,
+							"raspberrypi,bcm2835-firmware");
+	if (!firmware_node) {
+		dev_err(dev, "Missing firmware node\n");
+		return -ENOENT;
+	}
+
+	firmware = devm_rpi_firmware_get(&pdev->dev, firmware_node);
+	of_node_put(firmware_node);
+	if (!firmware)
+		return -EPROBE_DEFER;
+
+	rpi = devm_kzalloc(dev, sizeof(*rpi), GFP_KERNEL);
+	if (!rpi)
+		return -ENOMEM;
+
+	rpi->dev = dev;
+	rpi->firmware = firmware;
+	platform_set_drvdata(pdev, rpi);
+
+	clk_data = devm_kzalloc(dev, struct_size(clk_data, hws,
+						 RPI_FIRMWARE_NUM_CLK_ID),
+				GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+
+	ret = raspberrypi_discover_clocks(rpi, clk_data);
+	if (ret)
+		return ret;
+
+	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
+					  clk_data);
+	if (ret)
+		return ret;
+
+	rpi->cpufreq = platform_device_register_data(dev, "raspberrypi-cpufreq",
+						     -1, NULL, 0);
+
+	return 0;
+}
+
+static void raspberrypi_clk_remove(struct platform_device *pdev)
+{
+	struct raspberrypi_clk *rpi = platform_get_drvdata(pdev);
+
+	platform_device_unregister(rpi->cpufreq);
+}
+
+static const struct of_device_id raspberrypi_clk_match[] = {
+	{ .compatible = "raspberrypi,firmware-clocks" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, raspberrypi_clk_match);
+
+static struct platform_driver raspberrypi_clk_driver = {
+	.driver = {
+		.name = "raspberrypi-clk",
+		.of_match_table = raspberrypi_clk_match,
+	},
+	.probe          = raspberrypi_clk_probe,
+	.remove		= raspberrypi_clk_remove,
+};
+module_platform_driver(raspberrypi_clk_driver);
+
+MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
+MODULE_DESCRIPTION("Raspberry Pi firmware clock driver");
+MODULE_LICENSE("GPL");