File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/clocksource/cadence_ttc_timer.c b/drivers/clocksource/cadence_ttc_timer.c
new file mode 100644
index 0000000..9be6018
--- /dev/null
+++ b/drivers/clocksource/cadence_ttc_timer.c
@@ -0,0 +1,524 @@
+/*
+ * This file contains driver for the Cadence Triple Timer Counter Rev 06
+ *
+ * Copyright (C) 2011-2013 Xilinx
+ *
+ * based on arch/mips/kernel/time.c timer driver
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/clockchips.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+#include <linux/sched_clock.h>
+
+/*
+ * This driver configures the 2 16/32-bit count-up timers as follows:
+ *
+ * T1: Timer 1, clocksource for generic timekeeping
+ * T2: Timer 2, clockevent source for hrtimers
+ * T3: Timer 3, <unused>
+ *
+ * The input frequency to the timer module for emulation is 2.5MHz which is
+ * common to all the timer channels (T1, T2, and T3). With a pre-scaler of 32,
+ * the timers are clocked at 78.125KHz (12.8 us resolution).
+
+ * The input frequency to the timer module in silicon is configurable and
+ * obtained from device tree. The pre-scaler of 32 is used.
+ */
+
+/*
+ * Timer Register Offset Definitions of Timer 1, Increment base address by 4
+ * and use same offsets for Timer 2
+ */
+#define TTC_CLK_CNTRL_OFFSET 0x00 /* Clock Control Reg, RW */
+#define TTC_CNT_CNTRL_OFFSET 0x0C /* Counter Control Reg, RW */
+#define TTC_COUNT_VAL_OFFSET 0x18 /* Counter Value Reg, RO */
+#define TTC_INTR_VAL_OFFSET 0x24 /* Interval Count Reg, RW */
+#define TTC_ISR_OFFSET 0x54 /* Interrupt Status Reg, RO */
+#define TTC_IER_OFFSET 0x60 /* Interrupt Enable Reg, RW */
+
+#define TTC_CNT_CNTRL_DISABLE_MASK 0x1
+
+#define TTC_CLK_CNTRL_CSRC_MASK (1 << 5) /* clock source */
+#define TTC_CLK_CNTRL_PSV_MASK 0x1e
+#define TTC_CLK_CNTRL_PSV_SHIFT 1
+
+/*
+ * Setup the timers to use pre-scaling, using a fixed value for now that will
+ * work across most input frequency, but it may need to be more dynamic
+ */
+#define PRESCALE_EXPONENT 11 /* 2 ^ PRESCALE_EXPONENT = PRESCALE */
+#define PRESCALE 2048 /* The exponent must match this */
+#define CLK_CNTRL_PRESCALE ((PRESCALE_EXPONENT - 1) << 1)
+#define CLK_CNTRL_PRESCALE_EN 1
+#define CNT_CNTRL_RESET (1 << 4)
+
+#define MAX_F_ERR 50
+
+/**
+ * struct ttc_timer - This definition defines local timer structure
+ *
+ * @base_addr: Base address of timer
+ * @freq: Timer input clock frequency
+ * @clk: Associated clock source
+ * @clk_rate_change_nb Notifier block for clock rate changes
+ */
+struct ttc_timer {
+ void __iomem *base_addr;
+ unsigned long freq;
+ struct clk *clk;
+ struct notifier_block clk_rate_change_nb;
+};
+
+#define to_ttc_timer(x) \
+ container_of(x, struct ttc_timer, clk_rate_change_nb)
+
+struct ttc_timer_clocksource {
+ u32 scale_clk_ctrl_reg_old;
+ u32 scale_clk_ctrl_reg_new;
+ struct ttc_timer ttc;
+ struct clocksource cs;
+};
+
+#define to_ttc_timer_clksrc(x) \
+ container_of(x, struct ttc_timer_clocksource, cs)
+
+struct ttc_timer_clockevent {
+ struct ttc_timer ttc;
+ struct clock_event_device ce;
+};
+
+#define to_ttc_timer_clkevent(x) \
+ container_of(x, struct ttc_timer_clockevent, ce)
+
+static void __iomem *ttc_sched_clock_val_reg;
+
+/**
+ * ttc_set_interval - Set the timer interval value
+ *
+ * @timer: Pointer to the timer instance
+ * @cycles: Timer interval ticks
+ **/
+static void ttc_set_interval(struct ttc_timer *timer,
+ unsigned long cycles)
+{
+ u32 ctrl_reg;
+
+ /* Disable the counter, set the counter value and re-enable counter */
+ ctrl_reg = readl_relaxed(timer->base_addr + TTC_CNT_CNTRL_OFFSET);
+ ctrl_reg |= TTC_CNT_CNTRL_DISABLE_MASK;
+ writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET);
+
+ writel_relaxed(cycles, timer->base_addr + TTC_INTR_VAL_OFFSET);
+
+ /*
+ * Reset the counter (0x10) so that it starts from 0, one-shot
+ * mode makes this needed for timing to be right.
+ */
+ ctrl_reg |= CNT_CNTRL_RESET;
+ ctrl_reg &= ~TTC_CNT_CNTRL_DISABLE_MASK;
+ writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET);
+}
+
+/**
+ * ttc_clock_event_interrupt - Clock event timer interrupt handler
+ *
+ * @irq: IRQ number of the Timer
+ * @dev_id: void pointer to the ttc_timer instance
+ *
+ * returns: Always IRQ_HANDLED - success
+ **/
+static irqreturn_t ttc_clock_event_interrupt(int irq, void *dev_id)
+{
+ struct ttc_timer_clockevent *ttce = dev_id;
+ struct ttc_timer *timer = &ttce->ttc;
+
+ /* Acknowledge the interrupt and call event handler */
+ readl_relaxed(timer->base_addr + TTC_ISR_OFFSET);
+
+ ttce->ce.event_handler(&ttce->ce);
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * __ttc_clocksource_read - Reads the timer counter register
+ *
+ * returns: Current timer counter register value
+ **/
+static cycle_t __ttc_clocksource_read(struct clocksource *cs)
+{
+ struct ttc_timer *timer = &to_ttc_timer_clksrc(cs)->ttc;
+
+ return (cycle_t)readl_relaxed(timer->base_addr +
+ TTC_COUNT_VAL_OFFSET);
+}
+
+static u64 notrace ttc_sched_clock_read(void)
+{
+ return readl_relaxed(ttc_sched_clock_val_reg);
+}
+
+/**
+ * ttc_set_next_event - Sets the time interval for next event
+ *
+ * @cycles: Timer interval ticks
+ * @evt: Address of clock event instance
+ *
+ * returns: Always 0 - success
+ **/
+static int ttc_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt);
+ struct ttc_timer *timer = &ttce->ttc;
+
+ ttc_set_interval(timer, cycles);
+ return 0;
+}
+
+/**
+ * ttc_set_{shutdown|oneshot|periodic} - Sets the state of timer
+ *
+ * @evt: Address of clock event instance
+ **/
+static int ttc_shutdown(struct clock_event_device *evt)
+{
+ struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt);
+ struct ttc_timer *timer = &ttce->ttc;
+ u32 ctrl_reg;
+
+ ctrl_reg = readl_relaxed(timer->base_addr + TTC_CNT_CNTRL_OFFSET);
+ ctrl_reg |= TTC_CNT_CNTRL_DISABLE_MASK;
+ writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET);
+ return 0;
+}
+
+static int ttc_set_periodic(struct clock_event_device *evt)
+{
+ struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt);
+ struct ttc_timer *timer = &ttce->ttc;
+
+ ttc_set_interval(timer,
+ DIV_ROUND_CLOSEST(ttce->ttc.freq, PRESCALE * HZ));
+ return 0;
+}
+
+static int ttc_resume(struct clock_event_device *evt)
+{
+ struct ttc_timer_clockevent *ttce = to_ttc_timer_clkevent(evt);
+ struct ttc_timer *timer = &ttce->ttc;
+ u32 ctrl_reg;
+
+ ctrl_reg = readl_relaxed(timer->base_addr + TTC_CNT_CNTRL_OFFSET);
+ ctrl_reg &= ~TTC_CNT_CNTRL_DISABLE_MASK;
+ writel_relaxed(ctrl_reg, timer->base_addr + TTC_CNT_CNTRL_OFFSET);
+ return 0;
+}
+
+static int ttc_rate_change_clocksource_cb(struct notifier_block *nb,
+ unsigned long event, void *data)
+{
+ struct clk_notifier_data *ndata = data;
+ struct ttc_timer *ttc = to_ttc_timer(nb);
+ struct ttc_timer_clocksource *ttccs = container_of(ttc,
+ struct ttc_timer_clocksource, ttc);
+
+ switch (event) {
+ case PRE_RATE_CHANGE:
+ {
+ u32 psv;
+ unsigned long factor, rate_low, rate_high;
+
+ if (ndata->new_rate > ndata->old_rate) {
+ factor = DIV_ROUND_CLOSEST(ndata->new_rate,
+ ndata->old_rate);
+ rate_low = ndata->old_rate;
+ rate_high = ndata->new_rate;
+ } else {
+ factor = DIV_ROUND_CLOSEST(ndata->old_rate,
+ ndata->new_rate);
+ rate_low = ndata->new_rate;
+ rate_high = ndata->old_rate;
+ }
+
+ if (!is_power_of_2(factor))
+ return NOTIFY_BAD;
+
+ if (abs(rate_high - (factor * rate_low)) > MAX_F_ERR)
+ return NOTIFY_BAD;
+
+ factor = __ilog2_u32(factor);
+
+ /*
+ * store timer clock ctrl register so we can restore it in case
+ * of an abort.
+ */
+ ttccs->scale_clk_ctrl_reg_old =
+ readl_relaxed(ttccs->ttc.base_addr +
+ TTC_CLK_CNTRL_OFFSET);
+
+ psv = (ttccs->scale_clk_ctrl_reg_old &
+ TTC_CLK_CNTRL_PSV_MASK) >>
+ TTC_CLK_CNTRL_PSV_SHIFT;
+ if (ndata->new_rate < ndata->old_rate)
+ psv -= factor;
+ else
+ psv += factor;
+
+ /* prescaler within legal range? */
+ if (psv & ~(TTC_CLK_CNTRL_PSV_MASK >> TTC_CLK_CNTRL_PSV_SHIFT))
+ return NOTIFY_BAD;
+
+ ttccs->scale_clk_ctrl_reg_new = ttccs->scale_clk_ctrl_reg_old &
+ ~TTC_CLK_CNTRL_PSV_MASK;
+ ttccs->scale_clk_ctrl_reg_new |= psv << TTC_CLK_CNTRL_PSV_SHIFT;
+
+
+ /* scale down: adjust divider in post-change notification */
+ if (ndata->new_rate < ndata->old_rate)
+ return NOTIFY_DONE;
+
+ /* scale up: adjust divider now - before frequency change */
+ writel_relaxed(ttccs->scale_clk_ctrl_reg_new,
+ ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET);
+ break;
+ }
+ case POST_RATE_CHANGE:
+ /* scale up: pre-change notification did the adjustment */
+ if (ndata->new_rate > ndata->old_rate)
+ return NOTIFY_OK;
+
+ /* scale down: adjust divider now - after frequency change */
+ writel_relaxed(ttccs->scale_clk_ctrl_reg_new,
+ ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET);
+ break;
+
+ case ABORT_RATE_CHANGE:
+ /* we have to undo the adjustment in case we scale up */
+ if (ndata->new_rate < ndata->old_rate)
+ return NOTIFY_OK;
+
+ /* restore original register value */
+ writel_relaxed(ttccs->scale_clk_ctrl_reg_old,
+ ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET);
+ /* fall through */
+ default:
+ return NOTIFY_DONE;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static void __init ttc_setup_clocksource(struct clk *clk, void __iomem *base,
+ u32 timer_width)
+{
+ struct ttc_timer_clocksource *ttccs;
+ int err;
+
+ ttccs = kzalloc(sizeof(*ttccs), GFP_KERNEL);
+ if (WARN_ON(!ttccs))
+ return;
+
+ ttccs->ttc.clk = clk;
+
+ err = clk_prepare_enable(ttccs->ttc.clk);
+ if (WARN_ON(err)) {
+ kfree(ttccs);
+ return;
+ }
+
+ ttccs->ttc.freq = clk_get_rate(ttccs->ttc.clk);
+
+ ttccs->ttc.clk_rate_change_nb.notifier_call =
+ ttc_rate_change_clocksource_cb;
+ ttccs->ttc.clk_rate_change_nb.next = NULL;
+ if (clk_notifier_register(ttccs->ttc.clk,
+ &ttccs->ttc.clk_rate_change_nb))
+ pr_warn("Unable to register clock notifier.\n");
+
+ ttccs->ttc.base_addr = base;
+ ttccs->cs.name = "ttc_clocksource";
+ ttccs->cs.rating = 200;
+ ttccs->cs.read = __ttc_clocksource_read;
+ ttccs->cs.mask = CLOCKSOURCE_MASK(timer_width);
+ ttccs->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+ /*
+ * Setup the clock source counter to be an incrementing counter
+ * with no interrupt and it rolls over at 0xFFFF. Pre-scale
+ * it by 32 also. Let it start running now.
+ */
+ writel_relaxed(0x0, ttccs->ttc.base_addr + TTC_IER_OFFSET);
+ writel_relaxed(CLK_CNTRL_PRESCALE | CLK_CNTRL_PRESCALE_EN,
+ ttccs->ttc.base_addr + TTC_CLK_CNTRL_OFFSET);
+ writel_relaxed(CNT_CNTRL_RESET,
+ ttccs->ttc.base_addr + TTC_CNT_CNTRL_OFFSET);
+
+ err = clocksource_register_hz(&ttccs->cs, ttccs->ttc.freq / PRESCALE);
+ if (WARN_ON(err)) {
+ kfree(ttccs);
+ return;
+ }
+
+ ttc_sched_clock_val_reg = base + TTC_COUNT_VAL_OFFSET;
+ sched_clock_register(ttc_sched_clock_read, timer_width,
+ ttccs->ttc.freq / PRESCALE);
+}
+
+static int ttc_rate_change_clockevent_cb(struct notifier_block *nb,
+ unsigned long event, void *data)
+{
+ struct clk_notifier_data *ndata = data;
+ struct ttc_timer *ttc = to_ttc_timer(nb);
+ struct ttc_timer_clockevent *ttcce = container_of(ttc,
+ struct ttc_timer_clockevent, ttc);
+
+ switch (event) {
+ case POST_RATE_CHANGE:
+ /* update cached frequency */
+ ttc->freq = ndata->new_rate;
+
+ clockevents_update_freq(&ttcce->ce, ndata->new_rate / PRESCALE);
+
+ /* fall through */
+ case PRE_RATE_CHANGE:
+ case ABORT_RATE_CHANGE:
+ default:
+ return NOTIFY_DONE;
+ }
+}
+
+static void __init ttc_setup_clockevent(struct clk *clk,
+ void __iomem *base, u32 irq)
+{
+ struct ttc_timer_clockevent *ttcce;
+ int err;
+
+ ttcce = kzalloc(sizeof(*ttcce), GFP_KERNEL);
+ if (WARN_ON(!ttcce))
+ return;
+
+ ttcce->ttc.clk = clk;
+
+ err = clk_prepare_enable(ttcce->ttc.clk);
+ if (WARN_ON(err)) {
+ kfree(ttcce);
+ return;
+ }
+
+ ttcce->ttc.clk_rate_change_nb.notifier_call =
+ ttc_rate_change_clockevent_cb;
+ ttcce->ttc.clk_rate_change_nb.next = NULL;
+ if (clk_notifier_register(ttcce->ttc.clk,
+ &ttcce->ttc.clk_rate_change_nb))
+ pr_warn("Unable to register clock notifier.\n");
+ ttcce->ttc.freq = clk_get_rate(ttcce->ttc.clk);
+
+ ttcce->ttc.base_addr = base;
+ ttcce->ce.name = "ttc_clockevent";
+ ttcce->ce.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+ ttcce->ce.set_next_event = ttc_set_next_event;
+ ttcce->ce.set_state_shutdown = ttc_shutdown;
+ ttcce->ce.set_state_periodic = ttc_set_periodic;
+ ttcce->ce.set_state_oneshot = ttc_shutdown;
+ ttcce->ce.tick_resume = ttc_resume;
+ ttcce->ce.rating = 200;
+ ttcce->ce.irq = irq;
+ ttcce->ce.cpumask = cpu_possible_mask;
+
+ /*
+ * Setup the clock event timer to be an interval timer which
+ * is prescaled by 32 using the interval interrupt. Leave it
+ * disabled for now.
+ */
+ writel_relaxed(0x23, ttcce->ttc.base_addr + TTC_CNT_CNTRL_OFFSET);
+ writel_relaxed(CLK_CNTRL_PRESCALE | CLK_CNTRL_PRESCALE_EN,
+ ttcce->ttc.base_addr + TTC_CLK_CNTRL_OFFSET);
+ writel_relaxed(0x1, ttcce->ttc.base_addr + TTC_IER_OFFSET);
+
+ err = request_irq(irq, ttc_clock_event_interrupt,
+ IRQF_TIMER, ttcce->ce.name, ttcce);
+ if (WARN_ON(err)) {
+ kfree(ttcce);
+ return;
+ }
+
+ clockevents_config_and_register(&ttcce->ce,
+ ttcce->ttc.freq / PRESCALE, 1, 0xfffe);
+}
+
+/**
+ * ttc_timer_init - Initialize the timer
+ *
+ * Initializes the timer hardware and register the clock source and clock event
+ * timers with Linux kernal timer framework
+ */
+static void __init ttc_timer_init(struct device_node *timer)
+{
+ unsigned int irq;
+ void __iomem *timer_baseaddr;
+ struct clk *clk_cs, *clk_ce;
+ static int initialized;
+ int clksel;
+ u32 timer_width = 16;
+
+ if (initialized)
+ return;
+
+ initialized = 1;
+
+ /*
+ * Get the 1st Triple Timer Counter (TTC) block from the device tree
+ * and use it. Note that the event timer uses the interrupt and it's the
+ * 2nd TTC hence the irq_of_parse_and_map(,1)
+ */
+ timer_baseaddr = of_iomap(timer, 0);
+ if (!timer_baseaddr) {
+ pr_err("ERROR: invalid timer base address\n");
+ BUG();
+ }
+
+ irq = irq_of_parse_and_map(timer, 1);
+ if (irq <= 0) {
+ pr_err("ERROR: invalid interrupt number\n");
+ BUG();
+ }
+
+ of_property_read_u32(timer, "timer-width", &timer_width);
+
+ clksel = readl_relaxed(timer_baseaddr + TTC_CLK_CNTRL_OFFSET);
+ clksel = !!(clksel & TTC_CLK_CNTRL_CSRC_MASK);
+ clk_cs = of_clk_get(timer, clksel);
+ if (IS_ERR(clk_cs)) {
+ pr_err("ERROR: timer input clock not found\n");
+ BUG();
+ }
+
+ clksel = readl_relaxed(timer_baseaddr + 4 + TTC_CLK_CNTRL_OFFSET);
+ clksel = !!(clksel & TTC_CLK_CNTRL_CSRC_MASK);
+ clk_ce = of_clk_get(timer, clksel);
+ if (IS_ERR(clk_ce)) {
+ pr_err("ERROR: timer input clock not found\n");
+ BUG();
+ }
+
+ ttc_setup_clocksource(clk_cs, timer_baseaddr, timer_width);
+ ttc_setup_clockevent(clk_ce, timer_baseaddr + 4, irq);
+
+ pr_info("%s #0 at %p, irq=%d\n", timer->name, timer_baseaddr, irq);
+}
+
+CLOCKSOURCE_OF_DECLARE(ttc, "cdns,ttc", ttc_timer_init);