Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "This update provides the following changes:

   - The rework of the timer wheel which addresses the shortcomings of
     the current wheel (cascading, slow search for next expiring timer,
     etc).  That's the first major change of the wheel in almost 20
     years since Finn implemted it.

   - A large overhaul of the clocksource drivers init functions to
     consolidate the Device Tree initialization

   - Some more Y2038 updates

   - A capability fix for timerfd

   - Yet another clock chip driver

   - The usual pile of updates, comment improvements all over the place"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (130 commits)
  tick/nohz: Optimize nohz idle enter
  clockevents: Make clockevents_subsys static
  clocksource/drivers/time-armada-370-xp: Fix return value check
  timers: Implement optimization for same expiry time in mod_timer()
  timers: Split out index calculation
  timers: Only wake softirq if necessary
  timers: Forward the wheel clock whenever possible
  timers/nohz: Remove pointless tick_nohz_kick_tick() function
  timers: Optimize collect_expired_timers() for NOHZ
  timers: Move __run_timers() function
  timers: Remove set_timer_slack() leftovers
  timers: Switch to a non-cascading wheel
  timers: Reduce the CPU index space to 256k
  timers: Give a few structs and members proper names
  hlist: Add hlist_is_singular_node() helper
  signals: Use hrtimer for sigtimedwait()
  timers: Remove the deprecated mod_timer_pinned() API
  timers, net/ipv4/inet: Initialize connection request timers as pinned
  timers, drivers/tty/mips_ejtag: Initialize the poll timer as pinned
  timers, drivers/tty/metag_da: Initialize the poll timer as pinned
  ...

1 files changed, 297 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-oxnas-rps.c b/drivers/clocksource/timer-oxnas-rps.c
new file mode 100644
index 000000000000..bd887e2a8cf8
--- /dev/null
+++ b/drivers/clocksource/timer-oxnas-rps.c
@@ -0,0 +1,297 @@
+/*
+ * drivers/clocksource/timer-oxnas-rps.c
+ *
+ * Copyright (C) 2009 Oxford Semiconductor Ltd
+ * Copyright (C) 2013 Ma Haijun <mahaijuns@gmail.com>
+ * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/clockchips.h>
+#include <linux/sched_clock.h>
+
+/* TIMER1 used as tick
+ * TIMER2 used as clocksource
+ */
+
+/* Registers definitions */
+
+#define TIMER_LOAD_REG		0x0
+#define TIMER_CURR_REG		0x4
+#define TIMER_CTRL_REG		0x8
+#define TIMER_CLRINT_REG	0xC
+
+#define TIMER_BITS		24
+
+#define TIMER_MAX_VAL		(BIT(TIMER_BITS) - 1)
+
+#define TIMER_PERIODIC		BIT(6)
+#define TIMER_ENABLE		BIT(7)
+
+#define TIMER_DIV1		(0)
+#define TIMER_DIV16		(1 << 2)
+#define TIMER_DIV256		(2 << 2)
+
+#define TIMER1_REG_OFFSET	0
+#define TIMER2_REG_OFFSET	0x20
+
+/* Clockevent & Clocksource data */
+
+struct oxnas_rps_timer {
+	struct clock_event_device clkevent;
+	void __iomem *clksrc_base;
+	void __iomem *clkevt_base;
+	unsigned long timer_period;
+	unsigned int timer_prescaler;
+	struct clk *clk;
+	int irq;
+};
+
+static irqreturn_t oxnas_rps_timer_irq(int irq, void *dev_id)
+{
+	struct oxnas_rps_timer *rps = dev_id;
+
+	writel_relaxed(0, rps->clkevt_base + TIMER_CLRINT_REG);
+
+	rps->clkevent.event_handler(&rps->clkevent);
+
+	return IRQ_HANDLED;
+}
+
+static void oxnas_rps_timer_config(struct oxnas_rps_timer *rps,
+				   unsigned long period,
+				   unsigned int periodic)
+{
+	uint32_t cfg = rps->timer_prescaler;
+
+	if (period)
+		cfg |= TIMER_ENABLE;
+
+	if (periodic)
+		cfg |= TIMER_PERIODIC;
+
+	writel_relaxed(period, rps->clkevt_base + TIMER_LOAD_REG);
+	writel_relaxed(cfg, rps->clkevt_base + TIMER_CTRL_REG);
+}
+
+static int oxnas_rps_timer_shutdown(struct clock_event_device *evt)
+{
+	struct oxnas_rps_timer *rps =
+		container_of(evt, struct oxnas_rps_timer, clkevent);
+
+	oxnas_rps_timer_config(rps, 0, 0);
+
+	return 0;
+}
+
+static int oxnas_rps_timer_set_periodic(struct clock_event_device *evt)
+{
+	struct oxnas_rps_timer *rps =
+		container_of(evt, struct oxnas_rps_timer, clkevent);
+
+	oxnas_rps_timer_config(rps, rps->timer_period, 1);
+
+	return 0;
+}
+
+static int oxnas_rps_timer_set_oneshot(struct clock_event_device *evt)
+{
+	struct oxnas_rps_timer *rps =
+		container_of(evt, struct oxnas_rps_timer, clkevent);
+
+	oxnas_rps_timer_config(rps, rps->timer_period, 0);
+
+	return 0;
+}
+
+static int oxnas_rps_timer_next_event(unsigned long delta,
+				struct clock_event_device *evt)
+{
+	struct oxnas_rps_timer *rps =
+		container_of(evt, struct oxnas_rps_timer, clkevent);
+
+	oxnas_rps_timer_config(rps, delta, 0);
+
+	return 0;
+}
+
+static int __init oxnas_rps_clockevent_init(struct oxnas_rps_timer *rps)
+{
+	ulong clk_rate = clk_get_rate(rps->clk);
+	ulong timer_rate;
+
+	/* Start with prescaler 1 */
+	rps->timer_prescaler = TIMER_DIV1;
+	rps->timer_period = DIV_ROUND_UP(clk_rate, HZ);
+	timer_rate = clk_rate;
+
+	if (rps->timer_period > TIMER_MAX_VAL) {
+		rps->timer_prescaler = TIMER_DIV16;
+		timer_rate = clk_rate / 16;
+		rps->timer_period = DIV_ROUND_UP(timer_rate, HZ);
+	}
+	if (rps->timer_period > TIMER_MAX_VAL) {
+		rps->timer_prescaler = TIMER_DIV256;
+		timer_rate = clk_rate / 256;
+		rps->timer_period = DIV_ROUND_UP(timer_rate, HZ);
+	}
+
+	rps->clkevent.name = "oxnas-rps";
+	rps->clkevent.features = CLOCK_EVT_FEAT_PERIODIC |
+				 CLOCK_EVT_FEAT_ONESHOT |
+				 CLOCK_EVT_FEAT_DYNIRQ;
+	rps->clkevent.tick_resume = oxnas_rps_timer_shutdown;
+	rps->clkevent.set_state_shutdown = oxnas_rps_timer_shutdown;
+	rps->clkevent.set_state_periodic = oxnas_rps_timer_set_periodic;
+	rps->clkevent.set_state_oneshot = oxnas_rps_timer_set_oneshot;
+	rps->clkevent.set_next_event = oxnas_rps_timer_next_event;
+	rps->clkevent.rating = 200;
+	rps->clkevent.cpumask = cpu_possible_mask;
+	rps->clkevent.irq = rps->irq;
+	clockevents_config_and_register(&rps->clkevent,
+					timer_rate,
+					1,
+					TIMER_MAX_VAL);
+
+	pr_info("Registered clock event rate %luHz prescaler %x period %lu\n",
+			clk_rate,
+			rps->timer_prescaler,
+			rps->timer_period);
+
+	return 0;
+}
+
+/* Clocksource */
+
+static void __iomem *timer_sched_base;
+
+static u64 notrace oxnas_rps_read_sched_clock(void)
+{
+	return ~readl_relaxed(timer_sched_base);
+}
+
+static int __init oxnas_rps_clocksource_init(struct oxnas_rps_timer *rps)
+{
+	ulong clk_rate = clk_get_rate(rps->clk);
+	int ret;
+
+	/* use prescale 16 */
+	clk_rate = clk_rate / 16;
+
+	writel_relaxed(TIMER_MAX_VAL, rps->clksrc_base + TIMER_LOAD_REG);
+	writel_relaxed(TIMER_PERIODIC | TIMER_ENABLE | TIMER_DIV16,
+			rps->clksrc_base + TIMER_CTRL_REG);
+
+	timer_sched_base = rps->clksrc_base + TIMER_CURR_REG;
+	sched_clock_register(oxnas_rps_read_sched_clock,
+			     TIMER_BITS, clk_rate);
+	ret = clocksource_mmio_init(timer_sched_base,
+				    "oxnas_rps_clocksource_timer",
+				    clk_rate, 250, TIMER_BITS,
+				    clocksource_mmio_readl_down);
+	if (WARN_ON(ret)) {
+		pr_err("can't register clocksource\n");
+		return ret;
+	}
+
+	pr_info("Registered clocksource rate %luHz\n", clk_rate);
+
+	return 0;
+}
+
+static int __init oxnas_rps_timer_init(struct device_node *np)
+{
+	struct oxnas_rps_timer *rps;
+	void __iomem *base;
+	int ret;
+
+	rps = kzalloc(sizeof(*rps), GFP_KERNEL);
+	if (!rps)
+		return -ENOMEM;
+
+	rps->clk = of_clk_get(np, 0);
+	if (IS_ERR(rps->clk)) {
+		ret = PTR_ERR(rps->clk);
+		goto err_alloc;
+	}
+
+	ret = clk_prepare_enable(rps->clk);
+	if (ret)
+		goto err_clk;
+
+	base = of_iomap(np, 0);
+	if (!base) {
+		ret = -ENXIO;
+		goto err_clk_prepare;
+	}
+
+	rps->irq = irq_of_parse_and_map(np, 0);
+	if (rps->irq < 0) {
+		ret = -EINVAL;
+		goto err_iomap;
+	}
+
+	rps->clkevt_base = base + TIMER1_REG_OFFSET;
+	rps->clksrc_base = base + TIMER2_REG_OFFSET;
+
+	/* Disable timers */
+	writel_relaxed(0, rps->clkevt_base + TIMER_CTRL_REG);
+	writel_relaxed(0, rps->clksrc_base + TIMER_CTRL_REG);
+	writel_relaxed(0, rps->clkevt_base + TIMER_LOAD_REG);
+	writel_relaxed(0, rps->clksrc_base + TIMER_LOAD_REG);
+	writel_relaxed(0, rps->clkevt_base + TIMER_CLRINT_REG);
+	writel_relaxed(0, rps->clksrc_base + TIMER_CLRINT_REG);
+
+	ret = request_irq(rps->irq, oxnas_rps_timer_irq,
+			  IRQF_TIMER | IRQF_IRQPOLL,
+			  "rps-timer", rps);
+	if (ret)
+		goto err_iomap;
+
+	ret = oxnas_rps_clocksource_init(rps);
+	if (ret)
+		goto err_irqreq;
+
+	ret = oxnas_rps_clockevent_init(rps);
+	if (ret)
+		goto err_irqreq;
+
+	return 0;
+
+err_irqreq:
+	free_irq(rps->irq, rps);
+err_iomap:
+	iounmap(base);
+err_clk_prepare:
+	clk_disable_unprepare(rps->clk);
+err_clk:
+	clk_put(rps->clk);
+err_alloc:
+	kfree(rps);
+
+	return ret;
+}
+
+CLOCKSOURCE_OF_DECLARE(ox810se_rps,
+		       "oxsemi,ox810se-rps-timer", oxnas_rps_timer_init);