Merge tag 'timers-core-2020-01-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "The timekeeping and timers departement provides:

   - Time namespace support:

     If a container migrates from one host to another then it expects
     that clocks based on MONOTONIC and BOOTTIME are not subject to
     disruption. Due to different boot time and non-suspended runtime
     these clocks can differ significantly on two hosts, in the worst
     case time goes backwards which is a violation of the POSIX
     requirements.

     The time namespace addresses this problem. It allows to set offsets
     for clock MONOTONIC and BOOTTIME once after creation and before
     tasks are associated with the namespace. These offsets are taken
     into account by timers and timekeeping including the VDSO.

     Offsets for wall clock based clocks (REALTIME/TAI) are not provided
     by this mechanism. While in theory possible, the overhead and code
     complexity would be immense and not justified by the esoteric
     potential use cases which were discussed at Plumbers '18.

     The overhead for tasks in the root namespace (ie where host time
     offsets = 0) is in the noise and great effort was made to ensure
     that especially in the VDSO. If time namespace is disabled in the
     kernel configuration the code is compiled out.

     Kudos to Andrei Vagin and Dmitry Sofanov who implemented this
     feature and kept on for more than a year addressing review
     comments, finding better solutions. A pleasant experience.

   - Overhaul of the alarmtimer device dependency handling to ensure
     that the init/suspend/resume ordering is correct.

   - A new clocksource/event driver for Microchip PIT64

   - Suspend/resume support for the Hyper-V clocksource

   - The usual pile of fixes, updates and improvements mostly in the
     driver code"

* tag 'timers-core-2020-01-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits)
  alarmtimer: Make alarmtimer_get_rtcdev() a stub when CONFIG_RTC_CLASS=n
  alarmtimer: Use wakeup source from alarmtimer platform device
  alarmtimer: Make alarmtimer platform device child of RTC device
  alarmtimer: Update alarmtimer_get_rtcdev() docs to reflect reality
  hrtimer: Add missing sparse annotation for __run_timer()
  lib/vdso: Only read hrtimer_res when needed in __cvdso_clock_getres()
  MIPS: vdso: Define BUILD_VDSO32 when building a 32bit kernel
  clocksource/drivers/hyper-v: Set TSC clocksource as default w/ InvariantTSC
  clocksource/drivers/hyper-v: Untangle stimers and timesync from clocksources
  clocksource/drivers/timer-microchip-pit64b: Fix sparse warning
  clocksource/drivers/exynos_mct: Rename Exynos to lowercase
  clocksource/drivers/timer-ti-dm: Fix uninitialized pointer access
  clocksource/drivers/timer-ti-dm: Switch to platform_get_irq
  clocksource/drivers/timer-ti-dm: Convert to devm_platform_ioremap_resource
  clocksource/drivers/em_sti: Fix variable declaration in em_sti_probe
  clocksource/drivers/em_sti: Convert to devm_platform_ioremap_resource
  clocksource/drivers/bcm2835_timer: Fix memory leak of timer
  clocksource/drivers/cadence-ttc: Use ttc driver as platform driver
  clocksource/drivers/timer-microchip-pit64b: Add Microchip PIT64B support
  clocksource/drivers/hyper-v: Reserve PAGE_SIZE space for tsc page
  ...

1 files changed, 451 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-microchip-pit64b.c b/drivers/clocksource/timer-microchip-pit64b.c
new file mode 100644
index 000000000000..bd63d3484838
--- /dev/null
+++ b/drivers/clocksource/timer-microchip-pit64b.c
@@ -0,0 +1,451 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 64-bit Periodic Interval Timer driver
+ *
+ * Copyright (C) 2019 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Claudiu Beznea <claudiu.beznea@microchip.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+#include <linux/slab.h>
+
+#define MCHP_PIT64B_CR			0x00	/* Control Register */
+#define MCHP_PIT64B_CR_START		BIT(0)
+#define MCHP_PIT64B_CR_SWRST		BIT(8)
+
+#define MCHP_PIT64B_MR			0x04	/* Mode Register */
+#define MCHP_PIT64B_MR_CONT		BIT(0)
+#define MCHP_PIT64B_MR_ONE_SHOT		(0)
+#define MCHP_PIT64B_MR_SGCLK		BIT(3)
+#define MCHP_PIT64B_MR_PRES		GENMASK(11, 8)
+
+#define MCHP_PIT64B_LSB_PR		0x08	/* LSB Period Register */
+
+#define MCHP_PIT64B_MSB_PR		0x0C	/* MSB Period Register */
+
+#define MCHP_PIT64B_IER			0x10	/* Interrupt Enable Register */
+#define MCHP_PIT64B_IER_PERIOD		BIT(0)
+
+#define MCHP_PIT64B_ISR			0x1C	/* Interrupt Status Register */
+
+#define MCHP_PIT64B_TLSBR		0x20	/* Timer LSB Register */
+
+#define MCHP_PIT64B_TMSBR		0x24	/* Timer MSB Register */
+
+#define MCHP_PIT64B_PRES_MAX		0x10
+#define MCHP_PIT64B_LSBMASK		GENMASK_ULL(31, 0)
+#define MCHP_PIT64B_PRES_TO_MODE(p)	(MCHP_PIT64B_MR_PRES & ((p) << 8))
+#define MCHP_PIT64B_MODE_TO_PRES(m)	((MCHP_PIT64B_MR_PRES & (m)) >> 8)
+#define MCHP_PIT64B_DEF_CS_FREQ		5000000UL	/* 5 MHz */
+#define MCHP_PIT64B_DEF_CE_FREQ		32768		/* 32 KHz */
+
+#define MCHP_PIT64B_NAME		"pit64b"
+
+/**
+ * struct mchp_pit64b_timer - PIT64B timer data structure
+ * @base: base address of PIT64B hardware block
+ * @pclk: PIT64B's peripheral clock
+ * @gclk: PIT64B's generic clock
+ * @mode: precomputed value for mode register
+ */
+struct mchp_pit64b_timer {
+	void __iomem	*base;
+	struct clk	*pclk;
+	struct clk	*gclk;
+	u32		mode;
+};
+
+/**
+ * mchp_pit64b_clkevt - PIT64B clockevent data structure
+ * @timer: PIT64B timer
+ * @clkevt: clockevent
+ */
+struct mchp_pit64b_clkevt {
+	struct mchp_pit64b_timer	timer;
+	struct clock_event_device	clkevt;
+};
+
+#define to_mchp_pit64b_timer(x) \
+	((struct mchp_pit64b_timer *)container_of(x,\
+		struct mchp_pit64b_clkevt, clkevt))
+
+/* Base address for clocksource timer. */
+static void __iomem *mchp_pit64b_cs_base;
+/* Default cycles for clockevent timer. */
+static u64 mchp_pit64b_ce_cycles;
+
+static inline u64 mchp_pit64b_cnt_read(void __iomem *base)
+{
+	unsigned long	flags;
+	u32		low, high;
+
+	raw_local_irq_save(flags);
+
+	/*
+	 * When using a 64 bit period TLSB must be read first, followed by the
+	 * read of TMSB. This sequence generates an atomic read of the 64 bit
+	 * timer value whatever the lapse of time between the accesses.
+	 */
+	low = readl_relaxed(base + MCHP_PIT64B_TLSBR);
+	high = readl_relaxed(base + MCHP_PIT64B_TMSBR);
+
+	raw_local_irq_restore(flags);
+
+	return (((u64)high << 32) | low);
+}
+
+static inline void mchp_pit64b_reset(struct mchp_pit64b_timer *timer,
+				     u64 cycles, u32 mode, u32 irqs)
+{
+	u32 low, high;
+
+	low = cycles & MCHP_PIT64B_LSBMASK;
+	high = cycles >> 32;
+
+	writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR);
+	writel_relaxed(mode | timer->mode, timer->base + MCHP_PIT64B_MR);
+	writel_relaxed(high, timer->base + MCHP_PIT64B_MSB_PR);
+	writel_relaxed(low, timer->base + MCHP_PIT64B_LSB_PR);
+	writel_relaxed(irqs, timer->base + MCHP_PIT64B_IER);
+	writel_relaxed(MCHP_PIT64B_CR_START, timer->base + MCHP_PIT64B_CR);
+}
+
+static u64 mchp_pit64b_clksrc_read(struct clocksource *cs)
+{
+	return mchp_pit64b_cnt_read(mchp_pit64b_cs_base);
+}
+
+static u64 mchp_pit64b_sched_read_clk(void)
+{
+	return mchp_pit64b_cnt_read(mchp_pit64b_cs_base);
+}
+
+static int mchp_pit64b_clkevt_shutdown(struct clock_event_device *cedev)
+{
+	struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev);
+
+	writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR);
+
+	return 0;
+}
+
+static int mchp_pit64b_clkevt_set_periodic(struct clock_event_device *cedev)
+{
+	struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev);
+
+	mchp_pit64b_reset(timer, mchp_pit64b_ce_cycles, MCHP_PIT64B_MR_CONT,
+			  MCHP_PIT64B_IER_PERIOD);
+
+	return 0;
+}
+
+static int mchp_pit64b_clkevt_set_next_event(unsigned long evt,
+					     struct clock_event_device *cedev)
+{
+	struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev);
+
+	mchp_pit64b_reset(timer, evt, MCHP_PIT64B_MR_ONE_SHOT,
+			  MCHP_PIT64B_IER_PERIOD);
+
+	return 0;
+}
+
+static void mchp_pit64b_clkevt_suspend(struct clock_event_device *cedev)
+{
+	struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev);
+
+	writel_relaxed(MCHP_PIT64B_CR_SWRST, timer->base + MCHP_PIT64B_CR);
+	if (timer->mode & MCHP_PIT64B_MR_SGCLK)
+		clk_disable_unprepare(timer->gclk);
+	clk_disable_unprepare(timer->pclk);
+}
+
+static void mchp_pit64b_clkevt_resume(struct clock_event_device *cedev)
+{
+	struct mchp_pit64b_timer *timer = to_mchp_pit64b_timer(cedev);
+
+	clk_prepare_enable(timer->pclk);
+	if (timer->mode & MCHP_PIT64B_MR_SGCLK)
+		clk_prepare_enable(timer->gclk);
+}
+
+static irqreturn_t mchp_pit64b_interrupt(int irq, void *dev_id)
+{
+	struct mchp_pit64b_clkevt *irq_data = dev_id;
+
+	/* Need to clear the interrupt. */
+	readl_relaxed(irq_data->timer.base + MCHP_PIT64B_ISR);
+
+	irq_data->clkevt.event_handler(&irq_data->clkevt);
+
+	return IRQ_HANDLED;
+}
+
+static void __init mchp_pit64b_pres_compute(u32 *pres, u32 clk_rate,
+					    u32 max_rate)
+{
+	u32 tmp;
+
+	for (*pres = 0; *pres < MCHP_PIT64B_PRES_MAX; (*pres)++) {
+		tmp = clk_rate / (*pres + 1);
+		if (tmp <= max_rate)
+			break;
+	}
+
+	/* Use the bigest prescaler if we didn't match one. */
+	if (*pres == MCHP_PIT64B_PRES_MAX)
+		*pres = MCHP_PIT64B_PRES_MAX - 1;
+}
+
+/**
+ * mchp_pit64b_init_mode - prepare PIT64B mode register value to be used at
+ *			   runtime; this includes prescaler and SGCLK bit
+ *
+ * PIT64B timer may be fed by gclk or pclk. When gclk is used its rate has to
+ * be at least 3 times lower that pclk's rate. pclk rate is fixed, gclk rate
+ * could be changed via clock APIs. The chosen clock (pclk or gclk) could be
+ * divided by the internal PIT64B's divider.
+ *
+ * This function, first tries to use GCLK by requesting the desired rate from
+ * PMC and then using the internal PIT64B prescaler, if any, to reach the
+ * requested rate. If PCLK/GCLK < 3 (condition requested by PIT64B hardware)
+ * then the function falls back on using PCLK as clock source for PIT64B timer
+ * choosing the highest prescaler in case it doesn't locate one to match the
+ * requested frequency.
+ *
+ * Below is presented the PIT64B block in relation with PMC:
+ *
+ *                                PIT64B
+ *  PMC             +------------------------------------+
+ * +----+           |   +-----+                          |
+ * |    |-->gclk -->|-->|     |    +---------+  +-----+  |
+ * |    |           |   | MUX |--->| Divider |->|timer|  |
+ * |    |-->pclk -->|-->|     |    +---------+  +-----+  |
+ * +----+           |   +-----+                          |
+ *                  |      ^                             |
+ *                  |     sel                            |
+ *                  +------------------------------------+
+ *
+ * Where:
+ *	- gclk rate <= pclk rate/3
+ *	- gclk rate could be requested from PMC
+ *	- pclk rate is fixed (cannot be requested from PMC)
+ */
+static int __init mchp_pit64b_init_mode(struct mchp_pit64b_timer *timer,
+					unsigned long max_rate)
+{
+	unsigned long pclk_rate, diff = 0, best_diff = ULONG_MAX;
+	long gclk_round = 0;
+	u32 pres, best_pres = 0;
+
+	pclk_rate = clk_get_rate(timer->pclk);
+	if (!pclk_rate)
+		return -EINVAL;
+
+	timer->mode = 0;
+
+	/* Try using GCLK. */
+	gclk_round = clk_round_rate(timer->gclk, max_rate);
+	if (gclk_round < 0)
+		goto pclk;
+
+	if (pclk_rate / gclk_round < 3)
+		goto pclk;
+
+	mchp_pit64b_pres_compute(&pres, gclk_round, max_rate);
+	best_diff = abs(gclk_round / (pres + 1) - max_rate);
+	best_pres = pres;
+
+	if (!best_diff) {
+		timer->mode |= MCHP_PIT64B_MR_SGCLK;
+		goto done;
+	}
+
+pclk:
+	/* Check if requested rate could be obtained using PCLK. */
+	mchp_pit64b_pres_compute(&pres, pclk_rate, max_rate);
+	diff = abs(pclk_rate / (pres + 1) - max_rate);
+
+	if (best_diff > diff) {
+		/* Use PCLK. */
+		best_pres = pres;
+	} else {
+		/* Use GCLK. */
+		timer->mode |= MCHP_PIT64B_MR_SGCLK;
+		clk_set_rate(timer->gclk, gclk_round);
+	}
+
+done:
+	timer->mode |= MCHP_PIT64B_PRES_TO_MODE(best_pres);
+
+	pr_info("PIT64B: using clk=%s with prescaler %u, freq=%lu [Hz]\n",
+		timer->mode & MCHP_PIT64B_MR_SGCLK ? "gclk" : "pclk", best_pres,
+		timer->mode & MCHP_PIT64B_MR_SGCLK ?
+		gclk_round / (best_pres + 1) : pclk_rate / (best_pres + 1));
+
+	return 0;
+}
+
+static int __init mchp_pit64b_init_clksrc(struct mchp_pit64b_timer *timer,
+					  u32 clk_rate)
+{
+	int ret;
+
+	mchp_pit64b_reset(timer, ULLONG_MAX, MCHP_PIT64B_MR_CONT, 0);
+
+	mchp_pit64b_cs_base = timer->base;
+
+	ret = clocksource_mmio_init(timer->base, MCHP_PIT64B_NAME, clk_rate,
+				    210, 64, mchp_pit64b_clksrc_read);
+	if (ret) {
+		pr_debug("clksrc: Failed to register PIT64B clocksource!\n");
+
+		/* Stop timer. */
+		writel_relaxed(MCHP_PIT64B_CR_SWRST,
+			       timer->base + MCHP_PIT64B_CR);
+
+		return ret;
+	}
+
+	sched_clock_register(mchp_pit64b_sched_read_clk, 64, clk_rate);
+
+	return 0;
+}
+
+static int __init mchp_pit64b_init_clkevt(struct mchp_pit64b_timer *timer,
+					  u32 clk_rate, u32 irq)
+{
+	struct mchp_pit64b_clkevt *ce;
+	int ret;
+
+	ce = kzalloc(sizeof(*ce), GFP_KERNEL);
+	if (!ce)
+		return -ENOMEM;
+
+	mchp_pit64b_ce_cycles = DIV_ROUND_CLOSEST(clk_rate, HZ);
+
+	ce->timer.base = timer->base;
+	ce->timer.pclk = timer->pclk;
+	ce->timer.gclk = timer->gclk;
+	ce->timer.mode = timer->mode;
+	ce->clkevt.name = MCHP_PIT64B_NAME;
+	ce->clkevt.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC;
+	ce->clkevt.rating = 150;
+	ce->clkevt.set_state_shutdown = mchp_pit64b_clkevt_shutdown;
+	ce->clkevt.set_state_periodic = mchp_pit64b_clkevt_set_periodic;
+	ce->clkevt.set_next_event = mchp_pit64b_clkevt_set_next_event;
+	ce->clkevt.suspend = mchp_pit64b_clkevt_suspend;
+	ce->clkevt.resume = mchp_pit64b_clkevt_resume;
+	ce->clkevt.cpumask = cpumask_of(0);
+	ce->clkevt.irq = irq;
+
+	ret = request_irq(irq, mchp_pit64b_interrupt, IRQF_TIMER,
+			  "pit64b_tick", ce);
+	if (ret) {
+		pr_debug("clkevt: Failed to setup PIT64B IRQ\n");
+		kfree(ce);
+		return ret;
+	}
+
+	clockevents_config_and_register(&ce->clkevt, clk_rate, 1, ULONG_MAX);
+
+	return 0;
+}
+
+static int __init mchp_pit64b_dt_init_timer(struct device_node *node,
+					    bool clkevt)
+{
+	u32 freq = clkevt ? MCHP_PIT64B_DEF_CE_FREQ : MCHP_PIT64B_DEF_CS_FREQ;
+	struct mchp_pit64b_timer timer;
+	unsigned long clk_rate;
+	u32 irq = 0;
+	int ret;
+
+	/* Parse DT node. */
+	timer.pclk = of_clk_get_by_name(node, "pclk");
+	if (IS_ERR(timer.pclk))
+		return PTR_ERR(timer.pclk);
+
+	timer.gclk = of_clk_get_by_name(node, "gclk");
+	if (IS_ERR(timer.gclk))
+		return PTR_ERR(timer.gclk);
+
+	timer.base = of_iomap(node, 0);
+	if (!timer.base)
+		return -ENXIO;
+
+	if (clkevt) {
+		irq = irq_of_parse_and_map(node, 0);
+		if (!irq) {
+			ret = -ENODEV;
+			goto io_unmap;
+		}
+	}
+
+	/* Initialize mode (prescaler + SGCK bit). To be used at runtime. */
+	ret = mchp_pit64b_init_mode(&timer, freq);
+	if (ret)
+		goto irq_unmap;
+
+	ret = clk_prepare_enable(timer.pclk);
+	if (ret)
+		goto irq_unmap;
+
+	if (timer.mode & MCHP_PIT64B_MR_SGCLK) {
+		ret = clk_prepare_enable(timer.gclk);
+		if (ret)
+			goto pclk_unprepare;
+
+		clk_rate = clk_get_rate(timer.gclk);
+	} else {
+		clk_rate = clk_get_rate(timer.pclk);
+	}
+	clk_rate = clk_rate / (MCHP_PIT64B_MODE_TO_PRES(timer.mode) + 1);
+
+	if (clkevt)
+		ret = mchp_pit64b_init_clkevt(&timer, clk_rate, irq);
+	else
+		ret = mchp_pit64b_init_clksrc(&timer, clk_rate);
+
+	if (ret)
+		goto gclk_unprepare;
+
+	return 0;
+
+gclk_unprepare:
+	if (timer.mode & MCHP_PIT64B_MR_SGCLK)
+		clk_disable_unprepare(timer.gclk);
+pclk_unprepare:
+	clk_disable_unprepare(timer.pclk);
+irq_unmap:
+	irq_dispose_mapping(irq);
+io_unmap:
+	iounmap(timer.base);
+
+	return ret;
+}
+
+static int __init mchp_pit64b_dt_init(struct device_node *node)
+{
+	static int inits;
+
+	switch (inits++) {
+	case 0:
+		/* 1st request, register clockevent. */
+		return mchp_pit64b_dt_init_timer(node, true);
+	case 1:
+		/* 2nd request, register clocksource. */
+		return mchp_pit64b_dt_init_timer(node, false);
+	}
+
+	/* The rest, don't care. */
+	return -EINVAL;
+}
+
+TIMER_OF_DECLARE(mchp_pit64b, "microchip,sam9x60-pit64b", mchp_pit64b_dt_init);