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, 883 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
new file mode 100644
index 000000000..7fc60880e
--- /dev/null
+++ b/drivers/rtc/rtc-sun6i.c
@@ -0,0 +1,883 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * An RTC driver for Allwinner A31/A23
+ *
+ * Copyright (c) 2014, Chen-Yu Tsai <wens@csie.org>
+ *
+ * based on rtc-sunxi.c
+ *
+ * An RTC driver for Allwinner A10/A20
+ *
+ * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/clk/sunxi-ng.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+/* Control register */
+#define SUN6I_LOSC_CTRL				0x0000
+#define SUN6I_LOSC_CTRL_KEY			(0x16aa << 16)
+#define SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS		BIT(15)
+#define SUN6I_LOSC_CTRL_ALM_DHMS_ACC		BIT(9)
+#define SUN6I_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
+#define SUN6I_LOSC_CTRL_RTC_YMD_ACC		BIT(7)
+#define SUN6I_LOSC_CTRL_EXT_LOSC_EN		BIT(4)
+#define SUN6I_LOSC_CTRL_EXT_OSC			BIT(0)
+#define SUN6I_LOSC_CTRL_ACC_MASK		GENMASK(9, 7)
+
+#define SUN6I_LOSC_CLK_PRESCAL			0x0008
+
+/* RTC */
+#define SUN6I_RTC_YMD				0x0010
+#define SUN6I_RTC_HMS				0x0014
+
+/* Alarm 0 (counter) */
+#define SUN6I_ALRM_COUNTER			0x0020
+/* This holds the remaining alarm seconds on older SoCs (current value) */
+#define SUN6I_ALRM_COUNTER_HMS			0x0024
+#define SUN6I_ALRM_EN				0x0028
+#define SUN6I_ALRM_EN_CNT_EN			BIT(0)
+#define SUN6I_ALRM_IRQ_EN			0x002c
+#define SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN		BIT(0)
+#define SUN6I_ALRM_IRQ_STA			0x0030
+#define SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND		BIT(0)
+
+/* Alarm 1 (wall clock) */
+#define SUN6I_ALRM1_EN				0x0044
+#define SUN6I_ALRM1_IRQ_EN			0x0048
+#define SUN6I_ALRM1_IRQ_STA			0x004c
+#define SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND	BIT(0)
+
+/* Alarm config */
+#define SUN6I_ALARM_CONFIG			0x0050
+#define SUN6I_ALARM_CONFIG_WAKEUP		BIT(0)
+
+#define SUN6I_LOSC_OUT_GATING			0x0060
+#define SUN6I_LOSC_OUT_GATING_EN_OFFSET		0
+
+/* General-purpose data */
+#define SUN6I_GP_DATA				0x0100
+#define SUN6I_GP_DATA_SIZE			0x20
+
+/*
+ * Get date values
+ */
+#define SUN6I_DATE_GET_DAY_VALUE(x)		((x)  & 0x0000001f)
+#define SUN6I_DATE_GET_MON_VALUE(x)		(((x) & 0x00000f00) >> 8)
+#define SUN6I_DATE_GET_YEAR_VALUE(x)		(((x) & 0x003f0000) >> 16)
+#define SUN6I_LEAP_GET_VALUE(x)			(((x) & 0x00400000) >> 22)
+
+/*
+ * Get time values
+ */
+#define SUN6I_TIME_GET_SEC_VALUE(x)		((x)  & 0x0000003f)
+#define SUN6I_TIME_GET_MIN_VALUE(x)		(((x) & 0x00003f00) >> 8)
+#define SUN6I_TIME_GET_HOUR_VALUE(x)		(((x) & 0x001f0000) >> 16)
+
+/*
+ * Set date values
+ */
+#define SUN6I_DATE_SET_DAY_VALUE(x)		((x)       & 0x0000001f)
+#define SUN6I_DATE_SET_MON_VALUE(x)		((x) <<  8 & 0x00000f00)
+#define SUN6I_DATE_SET_YEAR_VALUE(x)		((x) << 16 & 0x003f0000)
+#define SUN6I_LEAP_SET_VALUE(x)			((x) << 22 & 0x00400000)
+
+/*
+ * Set time values
+ */
+#define SUN6I_TIME_SET_SEC_VALUE(x)		((x)       & 0x0000003f)
+#define SUN6I_TIME_SET_MIN_VALUE(x)		((x) <<  8 & 0x00003f00)
+#define SUN6I_TIME_SET_HOUR_VALUE(x)		((x) << 16 & 0x001f0000)
+
+/*
+ * The year parameter passed to the driver is usually an offset relative to
+ * the year 1900. This macro is used to convert this offset to another one
+ * relative to the minimum year allowed by the hardware.
+ *
+ * The year range is 1970 - 2033. This range is selected to match Allwinner's
+ * driver, even though it is somewhat limited.
+ */
+#define SUN6I_YEAR_MIN				1970
+#define SUN6I_YEAR_OFF				(SUN6I_YEAR_MIN - 1900)
+
+#define SECS_PER_DAY				(24 * 3600ULL)
+
+/*
+ * There are other differences between models, including:
+ *
+ *   - number of GPIO pins that can be configured to hold a certain level
+ *   - crypto-key related registers (H5, H6)
+ *   - boot process related (super standby, secondary processor entry address)
+ *     registers (R40, H6)
+ *   - SYS power domain controls (R40)
+ *   - DCXO controls (H6)
+ *   - RC oscillator calibration (H6)
+ *
+ * These functions are not covered by this driver.
+ */
+struct sun6i_rtc_clk_data {
+	unsigned long rc_osc_rate;
+	unsigned int fixed_prescaler : 16;
+	unsigned int has_prescaler : 1;
+	unsigned int has_out_clk : 1;
+	unsigned int has_losc_en : 1;
+	unsigned int has_auto_swt : 1;
+};
+
+#define RTC_LINEAR_DAY	BIT(0)
+
+struct sun6i_rtc_dev {
+	struct rtc_device *rtc;
+	const struct sun6i_rtc_clk_data *data;
+	void __iomem *base;
+	int irq;
+	time64_t alarm;
+	unsigned long flags;
+
+	struct clk_hw hw;
+	struct clk_hw *int_osc;
+	struct clk *losc;
+	struct clk *ext_losc;
+
+	spinlock_t lock;
+};
+
+static struct sun6i_rtc_dev *sun6i_rtc;
+
+static unsigned long sun6i_rtc_osc_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
+	u32 val = 0;
+
+	val = readl(rtc->base + SUN6I_LOSC_CTRL);
+	if (val & SUN6I_LOSC_CTRL_EXT_OSC)
+		return parent_rate;
+
+	if (rtc->data->fixed_prescaler)
+		parent_rate /= rtc->data->fixed_prescaler;
+
+	if (rtc->data->has_prescaler) {
+		val = readl(rtc->base + SUN6I_LOSC_CLK_PRESCAL);
+		val &= GENMASK(4, 0);
+	}
+
+	return parent_rate / (val + 1);
+}
+
+static u8 sun6i_rtc_osc_get_parent(struct clk_hw *hw)
+{
+	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
+
+	return readl(rtc->base + SUN6I_LOSC_CTRL) & SUN6I_LOSC_CTRL_EXT_OSC;
+}
+
+static int sun6i_rtc_osc_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct sun6i_rtc_dev *rtc = container_of(hw, struct sun6i_rtc_dev, hw);
+	unsigned long flags;
+	u32 val;
+
+	if (index > 1)
+		return -EINVAL;
+
+	spin_lock_irqsave(&rtc->lock, flags);
+	val = readl(rtc->base + SUN6I_LOSC_CTRL);
+	val &= ~SUN6I_LOSC_CTRL_EXT_OSC;
+	val |= SUN6I_LOSC_CTRL_KEY;
+	val |= index ? SUN6I_LOSC_CTRL_EXT_OSC : 0;
+	if (rtc->data->has_losc_en) {
+		val &= ~SUN6I_LOSC_CTRL_EXT_LOSC_EN;
+		val |= index ? SUN6I_LOSC_CTRL_EXT_LOSC_EN : 0;
+	}
+	writel(val, rtc->base + SUN6I_LOSC_CTRL);
+	spin_unlock_irqrestore(&rtc->lock, flags);
+
+	return 0;
+}
+
+static const struct clk_ops sun6i_rtc_osc_ops = {
+	.recalc_rate	= sun6i_rtc_osc_recalc_rate,
+	.determine_rate	= clk_hw_determine_rate_no_reparent,
+
+	.get_parent	= sun6i_rtc_osc_get_parent,
+	.set_parent	= sun6i_rtc_osc_set_parent,
+};
+
+static void __init sun6i_rtc_clk_init(struct device_node *node,
+				      const struct sun6i_rtc_clk_data *data)
+{
+	struct clk_hw_onecell_data *clk_data;
+	struct sun6i_rtc_dev *rtc;
+	struct clk_init_data init = {
+		.ops		= &sun6i_rtc_osc_ops,
+		.name		= "losc",
+	};
+	const char *iosc_name = "rtc-int-osc";
+	const char *clkout_name = "osc32k-out";
+	const char *parents[2];
+	u32 reg;
+
+	rtc = kzalloc_obj(*rtc);
+	if (!rtc)
+		return;
+
+	rtc->data = data;
+	clk_data = kzalloc_flex(*clk_data, hws, 3);
+	if (!clk_data) {
+		kfree(rtc);
+		return;
+	}
+
+	spin_lock_init(&rtc->lock);
+
+	rtc->base = of_io_request_and_map(node, 0, of_node_full_name(node));
+	if (IS_ERR(rtc->base)) {
+		pr_crit("Can't map RTC registers");
+		goto err;
+	}
+
+	reg = SUN6I_LOSC_CTRL_KEY;
+	if (rtc->data->has_auto_swt) {
+		/* Bypass auto-switch to int osc, on ext losc failure */
+		reg |= SUN6I_LOSC_CTRL_AUTO_SWT_BYPASS;
+		writel(reg, rtc->base + SUN6I_LOSC_CTRL);
+	}
+
+	/* Switch to the external, more precise, oscillator, if present */
+	if (of_property_present(node, "clocks")) {
+		reg |= SUN6I_LOSC_CTRL_EXT_OSC;
+		if (rtc->data->has_losc_en)
+			reg |= SUN6I_LOSC_CTRL_EXT_LOSC_EN;
+	}
+	writel(reg, rtc->base + SUN6I_LOSC_CTRL);
+
+	/* Yes, I know, this is ugly. */
+	sun6i_rtc = rtc;
+
+	of_property_read_string_index(node, "clock-output-names", 2,
+				      &iosc_name);
+
+	rtc->int_osc = clk_hw_register_fixed_rate_with_accuracy(NULL,
+								iosc_name,
+								NULL, 0,
+								rtc->data->rc_osc_rate,
+								300000000);
+	if (IS_ERR(rtc->int_osc)) {
+		pr_crit("Couldn't register the internal oscillator\n");
+		goto err;
+	}
+
+	parents[0] = clk_hw_get_name(rtc->int_osc);
+	/* If there is no external oscillator, this will be NULL and ... */
+	parents[1] = of_clk_get_parent_name(node, 0);
+
+	rtc->hw.init = &init;
+
+	init.parent_names = parents;
+	/* ... number of clock parents will be 1. */
+	init.num_parents = of_clk_get_parent_count(node) + 1;
+	of_property_read_string_index(node, "clock-output-names", 0,
+				      &init.name);
+
+	rtc->losc = clk_register(NULL, &rtc->hw);
+	if (IS_ERR(rtc->losc)) {
+		pr_crit("Couldn't register the LOSC clock\n");
+		goto err_register;
+	}
+
+	of_property_read_string_index(node, "clock-output-names", 1,
+				      &clkout_name);
+	rtc->ext_losc = clk_register_gate(NULL, clkout_name, init.name,
+					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
+					  SUN6I_LOSC_OUT_GATING_EN_OFFSET, 0,
+					  &rtc->lock);
+	if (IS_ERR(rtc->ext_losc)) {
+		pr_crit("Couldn't register the LOSC external gate\n");
+		goto err_register;
+	}
+
+	clk_data->num = 3;
+	clk_data->hws[0] = &rtc->hw;
+	clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
+	clk_data->hws[2] = rtc->int_osc;
+	of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
+	return;
+
+err_register:
+	clk_hw_unregister_fixed_rate(rtc->int_osc);
+err:
+	kfree(clk_data);
+}
+
+static const struct sun6i_rtc_clk_data sun6i_a31_rtc_data = {
+	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
+	.has_prescaler = 1,
+};
+
+static void __init sun6i_a31_rtc_clk_init(struct device_node *node)
+{
+	sun6i_rtc_clk_init(node, &sun6i_a31_rtc_data);
+}
+CLK_OF_DECLARE_DRIVER(sun6i_a31_rtc_clk, "allwinner,sun6i-a31-rtc",
+		      sun6i_a31_rtc_clk_init);
+
+static const struct sun6i_rtc_clk_data sun8i_a23_rtc_data = {
+	.rc_osc_rate = 667000, /* datasheet says 600 ~ 700 KHz */
+	.has_prescaler = 1,
+	.has_out_clk = 1,
+};
+
+static void __init sun8i_a23_rtc_clk_init(struct device_node *node)
+{
+	sun6i_rtc_clk_init(node, &sun8i_a23_rtc_data);
+}
+CLK_OF_DECLARE_DRIVER(sun8i_a23_rtc_clk, "allwinner,sun8i-a23-rtc",
+		      sun8i_a23_rtc_clk_init);
+
+static const struct sun6i_rtc_clk_data sun8i_h3_rtc_data = {
+	.rc_osc_rate = 16000000,
+	.fixed_prescaler = 32,
+	.has_prescaler = 1,
+	.has_out_clk = 1,
+};
+
+static void __init sun8i_h3_rtc_clk_init(struct device_node *node)
+{
+	sun6i_rtc_clk_init(node, &sun8i_h3_rtc_data);
+}
+CLK_OF_DECLARE_DRIVER(sun8i_h3_rtc_clk, "allwinner,sun8i-h3-rtc",
+		      sun8i_h3_rtc_clk_init);
+/* As far as we are concerned, clocks for H5 are the same as H3 */
+CLK_OF_DECLARE_DRIVER(sun50i_h5_rtc_clk, "allwinner,sun50i-h5-rtc",
+		      sun8i_h3_rtc_clk_init);
+
+static const struct sun6i_rtc_clk_data sun50i_h6_rtc_data = {
+	.rc_osc_rate = 16000000,
+	.fixed_prescaler = 32,
+	.has_prescaler = 1,
+	.has_out_clk = 1,
+	.has_losc_en = 1,
+	.has_auto_swt = 1,
+};
+
+static void __init sun50i_h6_rtc_clk_init(struct device_node *node)
+{
+	sun6i_rtc_clk_init(node, &sun50i_h6_rtc_data);
+}
+CLK_OF_DECLARE_DRIVER(sun50i_h6_rtc_clk, "allwinner,sun50i-h6-rtc",
+		      sun50i_h6_rtc_clk_init);
+
+/*
+ * The R40 user manual is self-conflicting on whether the prescaler is
+ * fixed or configurable. The clock diagram shows it as fixed, but there
+ * is also a configurable divider in the RTC block.
+ */
+static const struct sun6i_rtc_clk_data sun8i_r40_rtc_data = {
+	.rc_osc_rate = 16000000,
+	.fixed_prescaler = 512,
+};
+static void __init sun8i_r40_rtc_clk_init(struct device_node *node)
+{
+	sun6i_rtc_clk_init(node, &sun8i_r40_rtc_data);
+}
+CLK_OF_DECLARE_DRIVER(sun8i_r40_rtc_clk, "allwinner,sun8i-r40-rtc",
+		      sun8i_r40_rtc_clk_init);
+
+static const struct sun6i_rtc_clk_data sun8i_v3_rtc_data = {
+	.rc_osc_rate = 32000,
+	.has_out_clk = 1,
+	.has_auto_swt = 1,
+};
+
+static void __init sun8i_v3_rtc_clk_init(struct device_node *node)
+{
+	sun6i_rtc_clk_init(node, &sun8i_v3_rtc_data);
+}
+CLK_OF_DECLARE_DRIVER(sun8i_v3_rtc_clk, "allwinner,sun8i-v3-rtc",
+		      sun8i_v3_rtc_clk_init);
+
+static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)
+{
+	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;
+	irqreturn_t ret = IRQ_NONE;
+	u32 val;
+
+	spin_lock(&chip->lock);
+	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);
+
+	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
+		val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND;
+		writel(val, chip->base + SUN6I_ALRM_IRQ_STA);
+
+		rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
+
+		ret = IRQ_HANDLED;
+	}
+	spin_unlock(&chip->lock);
+
+	return ret;
+}
+
+static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
+{
+	u32 alrm_val = 0;
+	u32 alrm_irq_val = 0;
+	u32 alrm_wake_val = 0;
+	unsigned long flags;
+
+	if (to) {
+		alrm_val = SUN6I_ALRM_EN_CNT_EN;
+		alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN;
+		alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP;
+	} else {
+		writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
+		       chip->base + SUN6I_ALRM_IRQ_STA);
+	}
+
+	spin_lock_irqsave(&chip->lock, flags);
+	writel(alrm_val, chip->base + SUN6I_ALRM_EN);
+	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);
+	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);
+	spin_unlock_irqrestore(&chip->lock, flags);
+}
+
+static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
+{
+	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+	u32 date, time;
+
+	/*
+	 * read again in case it changes
+	 */
+	do {
+		date = readl(chip->base + SUN6I_RTC_YMD);
+		time = readl(chip->base + SUN6I_RTC_HMS);
+	} while ((date != readl(chip->base + SUN6I_RTC_YMD)) ||
+		 (time != readl(chip->base + SUN6I_RTC_HMS)));
+
+	if (chip->flags & RTC_LINEAR_DAY) {
+		/*
+		 * Newer chips store a linear day number, the manual
+		 * does not mandate any epoch base. The BSP driver uses
+		 * the UNIX epoch, let's just copy that, as it's the
+		 * easiest anyway.
+		 */
+		rtc_time64_to_tm((date & 0xffff) * SECS_PER_DAY, rtc_tm);
+	} else {
+		rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date);
+		rtc_tm->tm_mon  = SUN6I_DATE_GET_MON_VALUE(date) - 1;
+		rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date);
+
+		/*
+		 * switch from (data_year->min)-relative offset to
+		 * a (1900)-relative one
+		 */
+		rtc_tm->tm_year += SUN6I_YEAR_OFF;
+	}
+
+	rtc_tm->tm_sec  = SUN6I_TIME_GET_SEC_VALUE(time);
+	rtc_tm->tm_min  = SUN6I_TIME_GET_MIN_VALUE(time);
+	rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time);
+
+	return 0;
+}
+
+static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+	unsigned long flags;
+	u32 alrm_st;
+	u32 alrm_en;
+
+	spin_lock_irqsave(&chip->lock, flags);
+	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);
+	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);
+	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);
+	rtc_time64_to_tm(chip->alarm, &wkalrm->time);
+
+	return 0;
+}
+
+static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
+{
+	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+	struct rtc_time *alrm_tm = &wkalrm->time;
+	struct rtc_time tm_now;
+	time64_t time_set;
+	u32 counter_val, counter_val_hms;
+	int ret;
+
+	time_set = rtc_tm_to_time64(alrm_tm);
+
+	if (chip->flags & RTC_LINEAR_DAY) {
+		/*
+		 * The alarm registers hold the actual alarm time, encoded
+		 * in the same way (linear day + HMS) as the current time.
+		 */
+		counter_val_hms = SUN6I_TIME_SET_SEC_VALUE(alrm_tm->tm_sec)  |
+				  SUN6I_TIME_SET_MIN_VALUE(alrm_tm->tm_min)  |
+				  SUN6I_TIME_SET_HOUR_VALUE(alrm_tm->tm_hour);
+		/* The division will cut off the H:M:S part of alrm_tm. */
+		counter_val = div_u64(rtc_tm_to_time64(alrm_tm), SECS_PER_DAY);
+	} else {
+		/* The alarm register holds the number of seconds left. */
+		time64_t time_now;
+
+		ret = sun6i_rtc_gettime(dev, &tm_now);
+		if (ret < 0) {
+			dev_err(dev, "Error in getting time\n");
+			return -EINVAL;
+		}
+
+		time_now = rtc_tm_to_time64(&tm_now);
+		if (time_set <= time_now) {
+			dev_err(dev, "Date to set in the past\n");
+			return -EINVAL;
+		}
+		if ((time_set - time_now) > U32_MAX) {
+			dev_err(dev, "Date too far in the future\n");
+			return -EINVAL;
+		}
+
+		counter_val = time_set - time_now;
+	}
+
+	sun6i_rtc_setaie(0, chip);
+	writel(0, chip->base + SUN6I_ALRM_COUNTER);
+	if (chip->flags & RTC_LINEAR_DAY)
+		writel(0, chip->base + SUN6I_ALRM_COUNTER_HMS);
+	usleep_range(100, 300);
+
+	writel(counter_val, chip->base + SUN6I_ALRM_COUNTER);
+	if (chip->flags & RTC_LINEAR_DAY)
+		writel(counter_val_hms, chip->base + SUN6I_ALRM_COUNTER_HMS);
+	chip->alarm = time_set;
+
+	sun6i_rtc_setaie(wkalrm->enabled, chip);
+
+	return 0;
+}
+
+static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset,
+			  unsigned int mask, unsigned int ms_timeout)
+{
+	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
+	u32 reg;
+
+	do {
+		reg = readl(chip->base + offset);
+		reg &= mask;
+
+		if (!reg)
+			return 0;
+
+	} while (time_before(jiffies, timeout));
+
+	return -ETIMEDOUT;
+}
+
+static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
+{
+	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+	u32 date = 0;
+	u32 time = 0;
+
+	time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec)  |
+		SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min)  |
+		SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour);
+
+	if (chip->flags & RTC_LINEAR_DAY) {
+		/* The division will cut off the H:M:S part of rtc_tm. */
+		date = div_u64(rtc_tm_to_time64(rtc_tm), SECS_PER_DAY);
+	} else {
+		rtc_tm->tm_year -= SUN6I_YEAR_OFF;
+		rtc_tm->tm_mon += 1;
+
+		date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) |
+			SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon)  |
+			SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year);
+
+		if (is_leap_year(rtc_tm->tm_year + SUN6I_YEAR_MIN))
+			date |= SUN6I_LEAP_SET_VALUE(1);
+	}
+
+	/* Check whether registers are writable */
+	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
+			   SUN6I_LOSC_CTRL_ACC_MASK, 50)) {
+		dev_err(dev, "rtc is still busy.\n");
+		return -EBUSY;
+	}
+
+	writel(time, chip->base + SUN6I_RTC_HMS);
+
+	/*
+	 * After writing the RTC HH-MM-SS register, the
+	 * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not
+	 * be cleared until the real writing operation is finished
+	 */
+
+	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
+			   SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) {
+		dev_err(dev, "Failed to set rtc time.\n");
+		return -ETIMEDOUT;
+	}
+
+	writel(date, chip->base + SUN6I_RTC_YMD);
+
+	/*
+	 * After writing the RTC YY-MM-DD register, the
+	 * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not
+	 * be cleared until the real writing operation is finished
+	 */
+
+	if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL,
+			   SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) {
+		dev_err(dev, "Failed to set rtc time.\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+
+	if (!enabled)
+		sun6i_rtc_setaie(enabled, chip);
+
+	return 0;
+}
+
+static const struct rtc_class_ops sun6i_rtc_ops = {
+	.read_time		= sun6i_rtc_gettime,
+	.set_time		= sun6i_rtc_settime,
+	.read_alarm		= sun6i_rtc_getalarm,
+	.set_alarm		= sun6i_rtc_setalarm,
+	.alarm_irq_enable	= sun6i_rtc_alarm_irq_enable
+};
+
+static int sun6i_rtc_nvmem_read(void *priv, unsigned int offset, void *_val, size_t bytes)
+{
+	struct sun6i_rtc_dev *chip = priv;
+	u32 *val = _val;
+	int i;
+
+	for (i = 0; i < bytes / 4; ++i)
+		val[i] = readl(chip->base + SUN6I_GP_DATA + offset + 4 * i);
+
+	return 0;
+}
+
+static int sun6i_rtc_nvmem_write(void *priv, unsigned int offset, void *_val, size_t bytes)
+{
+	struct sun6i_rtc_dev *chip = priv;
+	u32 *val = _val;
+	int i;
+
+	for (i = 0; i < bytes / 4; ++i)
+		writel(val[i], chip->base + SUN6I_GP_DATA + offset + 4 * i);
+
+	return 0;
+}
+
+static struct nvmem_config sun6i_rtc_nvmem_cfg = {
+	.type		= NVMEM_TYPE_BATTERY_BACKED,
+	.reg_read	= sun6i_rtc_nvmem_read,
+	.reg_write	= sun6i_rtc_nvmem_write,
+	.size		= SUN6I_GP_DATA_SIZE,
+	.word_size	= 4,
+	.stride		= 4,
+};
+
+#ifdef CONFIG_PM_SLEEP
+/* Enable IRQ wake on suspend, to wake up from RTC. */
+static int sun6i_rtc_suspend(struct device *dev)
+{
+	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(chip->irq);
+
+	return 0;
+}
+
+/* Disable IRQ wake on resume. */
+static int sun6i_rtc_resume(struct device *dev)
+{
+	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(chip->irq);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(sun6i_rtc_pm_ops,
+	sun6i_rtc_suspend, sun6i_rtc_resume);
+
+static void sun6i_rtc_bus_clk_cleanup(void *data)
+{
+	struct clk *bus_clk = data;
+
+	clk_disable_unprepare(bus_clk);
+}
+
+static int sun6i_rtc_probe(struct platform_device *pdev)
+{
+	struct sun6i_rtc_dev *chip = sun6i_rtc;
+	struct device *dev = &pdev->dev;
+	struct clk *bus_clk;
+	int ret;
+
+	bus_clk = devm_clk_get_optional(dev, "bus");
+	if (IS_ERR(bus_clk))
+		return PTR_ERR(bus_clk);
+
+	if (bus_clk) {
+		ret = clk_prepare_enable(bus_clk);
+		if (ret)
+			return ret;
+
+		ret = devm_add_action_or_reset(dev, sun6i_rtc_bus_clk_cleanup,
+					       bus_clk);
+		if (ret)
+			return ret;
+	}
+
+	if (!chip) {
+		chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+		if (!chip)
+			return -ENOMEM;
+
+		spin_lock_init(&chip->lock);
+
+		chip->base = devm_platform_ioremap_resource(pdev, 0);
+		if (IS_ERR(chip->base))
+			return PTR_ERR(chip->base);
+
+		if (IS_REACHABLE(CONFIG_SUN6I_RTC_CCU)) {
+			ret = sun6i_rtc_ccu_probe(dev, chip->base);
+			if (ret)
+				return ret;
+		}
+	}
+
+	platform_set_drvdata(pdev, chip);
+
+	chip->flags = (unsigned long)of_device_get_match_data(&pdev->dev);
+
+	chip->irq = platform_get_irq(pdev, 0);
+	if (chip->irq < 0)
+		return chip->irq;
+
+	ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq,
+			       0, dev_name(&pdev->dev), chip);
+	if (ret) {
+		dev_err(&pdev->dev, "Could not request IRQ\n");
+		return ret;
+	}
+
+	/* clear the alarm counter value */
+	writel(0, chip->base + SUN6I_ALRM_COUNTER);
+
+	/* disable counter alarm */
+	writel(0, chip->base + SUN6I_ALRM_EN);
+
+	/* disable counter alarm interrupt */
+	writel(0, chip->base + SUN6I_ALRM_IRQ_EN);
+
+	/* disable week alarm */
+	writel(0, chip->base + SUN6I_ALRM1_EN);
+
+	/* disable week alarm interrupt */
+	writel(0, chip->base + SUN6I_ALRM1_IRQ_EN);
+
+	/* clear counter alarm pending interrupts */
+	writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND,
+	       chip->base + SUN6I_ALRM_IRQ_STA);
+
+	/* clear week alarm pending interrupts */
+	writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND,
+	       chip->base + SUN6I_ALRM1_IRQ_STA);
+
+	/* disable alarm wakeup */
+	writel(0, chip->base + SUN6I_ALARM_CONFIG);
+
+	clk_prepare_enable(chip->losc);
+
+	device_init_wakeup(&pdev->dev, true);
+
+	chip->rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(chip->rtc))
+		return PTR_ERR(chip->rtc);
+
+	chip->rtc->ops = &sun6i_rtc_ops;
+	if (chip->flags & RTC_LINEAR_DAY)
+		chip->rtc->range_max = (65536 * SECS_PER_DAY) - 1;
+	else
+		chip->rtc->range_max = 2019686399LL; /* 2033-12-31 23:59:59 */
+
+	ret = devm_rtc_register_device(chip->rtc);
+	if (ret)
+		return ret;
+
+	sun6i_rtc_nvmem_cfg.priv = chip;
+	ret = devm_rtc_nvmem_register(chip->rtc, &sun6i_rtc_nvmem_cfg);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/*
+ * As far as RTC functionality goes, all models are the same. The
+ * datasheets claim that different models have different number of
+ * registers available for non-volatile storage, but experiments show
+ * that all SoCs have 16 registers available for this purpose.
+ */
+static const struct of_device_id sun6i_rtc_dt_ids[] = {
+	{ .compatible = "allwinner,sun6i-a31-rtc" },
+	{ .compatible = "allwinner,sun8i-a23-rtc" },
+	{ .compatible = "allwinner,sun8i-h3-rtc" },
+	{ .compatible = "allwinner,sun8i-r40-rtc" },
+	{ .compatible = "allwinner,sun8i-v3-rtc" },
+	{ .compatible = "allwinner,sun50i-h5-rtc" },
+	{ .compatible = "allwinner,sun50i-h6-rtc" },
+	{ .compatible = "allwinner,sun50i-h616-rtc",
+		.data = (void *)RTC_LINEAR_DAY },
+	{ .compatible = "allwinner,sun50i-r329-rtc",
+		.data = (void *)RTC_LINEAR_DAY },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids);
+
+static struct platform_driver sun6i_rtc_driver = {
+	.probe		= sun6i_rtc_probe,
+	.driver		= {
+		.name		= "sun6i-rtc",
+		.of_match_table = sun6i_rtc_dt_ids,
+		.pm = &sun6i_rtc_pm_ops,
+	},
+};
+builtin_platform_driver(sun6i_rtc_driver);