[PATCH v2 5/5] ARM: zynq: add clk binding support to the ttc

Josh Cartwright
2012-11-08T19:54:21Z

Add support for retrieving TTC configuration from device tree. This
includes the ability to pull information about the driving clocks from
the of_clk bindings.

Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
---
arch/arm/boot/dts/zynq-7000.dtsi | 53 ++++++++
arch/arm/boot/dts/zynq-zc702.dts | 10 ++
arch/arm/mach-zynq/timer.c | 287 ++++++++++++++++++++++-----------------
3 files changed, 228 insertions(+), 122 deletions(-)

diff --git a/arch/arm/boot/dts/zynq-7000.dtsi b/arch/arm/boot/dts/zynq-7000.dtsi
index c975c2d..5914b56 100644
--- a/arch/arm/boot/dts/zynq-7000.dtsi
+++ b/arch/arm/boot/dts/zynq-7000.dtsi
@@ -109,5 +109,58 @@
};
};
};
+
+ ttc0: ttc0@f8001000 {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ compatible = "xlnx,ttc";
+ reg = <0xF8001000 0x1000>;
+ clocks = <&cpu_clk 3>;
+ clock-names = "cpu_1x";
+ clock-ranges;
+
+ ttc0_0: ttc0.0 {
+ status = "disabled";
+ reg = <0>;
+ interrupts = <0 10 4>;
+ };
+ ttc0_1: ttc0.1 {
+ status = "disabled";
+ reg = <1>;
+ interrupts = <0 11 4>;
+ };
+ ttc0_2: ttc0.2 {
+ status = "disabled";
+ reg = <2>;
+ interrupts = <0 12 4>;
+ };
+ };
+
+ ttc1: ttc1@f8002000 {
+ #interrupt-parent = <&intc>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ compatible = "xlnx,ttc";
+ reg = <0xF8002000 0x1000>;
+ clocks = <&cpu_clk 3>;
+ clock-names = "cpu_1x";
+ clock-ranges;
+
+ ttc1_0: ttc1.0 {
+ status = "disabled";
+ reg = <0>;
+ interrupts = <0 37 4>;
+ };
+ ttc1_1: ttc1.1 {
+ status = "disabled";
+ reg = <1>;
+ interrupts = <0 38 4>;
+ };
+ ttc1_2: ttc1.2 {
+ status = "disabled";
+ reg = <2>;
+ interrupts = <0 39 4>;
+ };
+ };
};
};
diff --git a/arch/arm/boot/dts/zynq-zc702.dts b/arch/arm/boot/dts/zynq-zc702.dts
index 86f44d5..c772942 100644
--- a/arch/arm/boot/dts/zynq-zc702.dts
+++ b/arch/arm/boot/dts/zynq-zc702.dts
@@ -32,3 +32,13 @@
&ps_clk {
clock-frequency = <33333330>;
};
+
+&ttc0_0 {
+ status = "ok";
+ compatible = "xlnx,ttc-counter-clocksource";
+};
+
+&ttc0_1 {
+ status = "ok";
+ compatible = "xlnx,ttc-counter-clockevent";
+};
diff --git a/arch/arm/mach-zynq/timer.c b/arch/arm/mach-zynq/timer.c
index c93cbe5..9662306 100644
--- a/arch/arm/mach-zynq/timer.c
+++ b/arch/arm/mach-zynq/timer.c
@@ -23,31 +23,15 @@
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+#include <linux/clk-provider.h>

#include <mach/zynq_soc.h>
#include "common.h"

-#define IRQ_TIMERCOUNTER0 42
-
-/*
- * This driver configures the 2 16-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 will be 200MHz. With the
- * pre-scaler of 32, the timers are clocked at 6.25MHz (160ns resolution).
- */
-#define XTTCPSS_CLOCKSOURCE 0 /* Timer 1 as a generic timekeeping */
-#define XTTCPSS_CLOCKEVENT 1 /* Timer 2 as a clock event */
-
-#define XTTCPSS_TIMER_BASE TTC0_BASE
-#define XTTCPCC_EVENT_TIMER_IRQ (IRQ_TIMERCOUNTER0 + 1)
/*
* Timer Register Offset Definitions of Timer 1, Increment base address by 4
* and use same offsets for Timer 2
@@ -64,9 +48,14 @@

#define XTTCPSS_CNT_CNTRL_DISABLE_MASK 0x1

-/* Setup the timers to use pre-scaling */
-
-#define TIMER_RATE (PERIPHERAL_CLOCK_RATE / 32)
+/* 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)

/**
* struct xttcpss_timer - This definition defines local timer structure
@@ -74,11 +63,25 @@
* @base_addr: Base address of timer
**/
struct xttcpss_timer {
- void __iomem *base_addr;
+ void __iomem *base_addr;
+};
+
+struct xttcpss_timer_clocksource {
+ struct xttcpss_timer xttc;
+ struct clocksource cs;
};

-static struct xttcpss_timer timers[2];
-static struct clock_event_device xttcpss_clockevent;
+#define to_xttcpss_timer_clksrc(x) \
+ container_of(x, struct xttcpss_timer_clocksource, cs)
+
+struct xttcpss_timer_clockevent {
+ struct xttcpss_timer xttc;
+ struct clock_event_device ce;
+ struct clk *clk;
+};
+
+#define to_xttcpss_timer_clkevent(x) \
+ container_of(x, struct xttcpss_timer_clockevent, ce)

/**
* xttcpss_set_interval - Set the timer interval value
@@ -100,7 +103,7 @@ static void xttcpss_set_interval(struct xttcpss_timer *timer,

/* Reset the counter (0x10) so that it starts from 0, one-shot
mode makes this needed for timing to be right. */
- ctrl_reg |= 0x10;
+ ctrl_reg |= CNT_CNTRL_RESET;
ctrl_reg &= ~XTTCPSS_CNT_CNTRL_DISABLE_MASK;
__raw_writel(ctrl_reg, timer->base_addr + XTTCPSS_CNT_CNTRL_OFFSET);
}
@@ -115,90 +118,31 @@ static void xttcpss_set_interval(struct xttcpss_timer *timer,
**/
static irqreturn_t xttcpss_clock_event_interrupt(int irq, void *dev_id)
{
- struct clock_event_device *evt = &xttcpss_clockevent;
- struct xttcpss_timer *timer = dev_id;
+ struct xttcpss_timer_clockevent *xttce = dev_id;
+ struct xttcpss_timer *timer = &xttce->xttc;

/* Acknowledge the interrupt and call event handler */
__raw_writel(__raw_readl(timer->base_addr + XTTCPSS_ISR_OFFSET),
timer->base_addr + XTTCPSS_ISR_OFFSET);

- evt->event_handler(evt);
+ xttce->ce.event_handler(&xttce->ce);

return IRQ_HANDLED;
}

-static struct irqaction event_timer_irq = {
- .name = "xttcpss clockevent",
- .flags = IRQF_DISABLED | IRQF_TIMER,
- .handler = xttcpss_clock_event_interrupt,
-};
-
/**
- * xttcpss_timer_hardware_init - Initialize the timer hardware
- *
- * Initialize the hardware to start the clock source, get the clock
- * event timer ready to use, and hook up the interrupt.
- **/
-static void __init xttcpss_timer_hardware_init(void)
-{
- /* 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.
- */
- timers[XTTCPSS_CLOCKSOURCE].base_addr = XTTCPSS_TIMER_BASE;
-
- __raw_writel(0x0, timers[XTTCPSS_CLOCKSOURCE].base_addr +
- XTTCPSS_IER_OFFSET);
- __raw_writel(0x9, timers[XTTCPSS_CLOCKSOURCE].base_addr +
- XTTCPSS_CLK_CNTRL_OFFSET);
- __raw_writel(0x10, timers[XTTCPSS_CLOCKSOURCE].base_addr +
- XTTCPSS_CNT_CNTRL_OFFSET);
-
- /* Setup the clock event timer to be an interval timer which
- * is prescaled by 32 using the interval interrupt. Leave it
- * disabled for now.
- */
-
- timers[XTTCPSS_CLOCKEVENT].base_addr = XTTCPSS_TIMER_BASE + 4;
-
- __raw_writel(0x23, timers[XTTCPSS_CLOCKEVENT].base_addr +
- XTTCPSS_CNT_CNTRL_OFFSET);
- __raw_writel(0x9, timers[XTTCPSS_CLOCKEVENT].base_addr +
- XTTCPSS_CLK_CNTRL_OFFSET);
- __raw_writel(0x1, timers[XTTCPSS_CLOCKEVENT].base_addr +
- XTTCPSS_IER_OFFSET);
-
- /* Setup IRQ the clock event timer */
- event_timer_irq.dev_id = &timers[XTTCPSS_CLOCKEVENT];
- setup_irq(XTTCPCC_EVENT_TIMER_IRQ, &event_timer_irq);
-}
-
-/**
- * __raw_readl_cycles - Reads the timer counter register
+ * __xttc_clocksource_read - Reads the timer counter register
*
* returns: Current timer counter register value
**/
-static cycle_t __raw_readl_cycles(struct clocksource *cs)
+static cycle_t __xttc_clocksource_read(struct clocksource *cs)
{
- struct xttcpss_timer *timer = &timers[XTTCPSS_CLOCKSOURCE];
+ struct xttcpss_timer *timer = &to_xttcpss_timer_clksrc(cs)->xttc;

return (cycle_t)__raw_readl(timer->base_addr +
XTTCPSS_COUNT_VAL_OFFSET);
}

-
-/*
- * Instantiate and initialize the clock source structure
- */
-static struct clocksource clocksource_xttcpss = {
- .name = "xttcpss_timer1",
- .rating = 200, /* Reasonable clock source */
- .read = __raw_readl_cycles,
- .mask = CLOCKSOURCE_MASK(16),
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
-};
-
-
/**
* xttcpss_set_next_event - Sets the time interval for next event
*
@@ -210,7 +154,8 @@ static struct clocksource clocksource_xttcpss = {
static int xttcpss_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
- struct xttcpss_timer *timer = &timers[XTTCPSS_CLOCKEVENT];
+ struct xttcpss_timer_clockevent *xttce = to_xttcpss_timer_clkevent(evt);
+ struct xttcpss_timer *timer = &xttce->xttc;

xttcpss_set_interval(timer, cycles);
return 0;
@@ -225,12 +170,15 @@ static int xttcpss_set_next_event(unsigned long cycles,
static void xttcpss_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
- struct xttcpss_timer *timer = &timers[XTTCPSS_CLOCKEVENT];
+ struct xttcpss_timer_clockevent *xttce = to_xttcpss_timer_clkevent(evt);
+ struct xttcpss_timer *timer = &xttce->xttc;
u32 ctrl_reg;

switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
- xttcpss_set_interval(timer, TIMER_RATE / HZ);
+ xttcpss_set_interval(timer,
+ DIV_ROUND_CLOSEST(clk_get_rate(xttce->clk),
+ PRESCALE * HZ));
break;
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
@@ -251,15 +199,106 @@ static void xttcpss_set_mode(enum clock_event_mode mode,
}
}

-/*
- * Instantiate and initialize the clock event structure
- */
-static struct clock_event_device xttcpss_clockevent = {
- .name = "xttcpss_timer2",
- .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
- .set_next_event = xttcpss_set_next_event,
- .set_mode = xttcpss_set_mode,
- .rating = 200,
+static void __init zynq_ttc_setup_clocksource(struct device_node *np,
+ void __iomem *base)
+{
+ struct xttcpss_timer_clocksource *ttccs;
+ struct clk *clk;
+ int err;
+ u32 reg;
+
+ ttccs = kzalloc(sizeof(*ttccs), GFP_KERNEL);
+ if (WARN_ON(!ttccs))
+ return;
+
+ err = of_property_read_u32(np, "reg", &reg);
+ if (WARN_ON(err))
+ return;
+
+ clk = of_clk_get_by_name(np, "cpu_1x");
+ if (WARN_ON(IS_ERR(clk)))
+ return;
+
+ err = clk_prepare_enable(clk);
+ if (WARN_ON(err))
+ return;
+
+ ttccs->xttc.base_addr = base + reg * 4;
+
+ ttccs->cs.name = np->name;
+ ttccs->cs.rating = 200;
+ ttccs->cs.read = __xttc_clocksource_read;
+ ttccs->cs.mask = CLOCKSOURCE_MASK(16);
+ ttccs->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+
+ __raw_writel(0x0, ttccs->xttc.base_addr + XTTCPSS_IER_OFFSET);
+ __raw_writel(CLK_CNTRL_PRESCALE | CLK_CNTRL_PRESCALE_EN,
+ ttccs->xttc.base_addr + XTTCPSS_CLK_CNTRL_OFFSET);
+ __raw_writel(CNT_CNTRL_RESET,
+ ttccs->xttc.base_addr + XTTCPSS_CNT_CNTRL_OFFSET);
+
+ err = clocksource_register_hz(&ttccs->cs, clk_get_rate(clk) / PRESCALE);
+ if (WARN_ON(err))
+ return;
+}
+
+static void __init zynq_ttc_setup_clockevent(struct device_node *np,
+ void __iomem *base)
+{
+ struct xttcpss_timer_clockevent *ttcce;
+ int err, irq;
+ u32 reg;
+
+ ttcce = kzalloc(sizeof(*ttcce), GFP_KERNEL);
+ if (WARN_ON(!ttcce))
+ return;
+
+ err = of_property_read_u32(np, "reg", &reg);
+ if (WARN_ON(err))
+ return;
+
+ ttcce->xttc.base_addr = base + reg * 4;
+
+ ttcce->clk = of_clk_get_by_name(np, "cpu_1x");
+ if (WARN_ON(IS_ERR(ttcce->clk)))
+ return;
+
+ err = clk_prepare_enable(ttcce->clk);
+ if (WARN_ON(err))
+ return;
+
+ irq = irq_of_parse_and_map(np, 0);
+ if (WARN_ON(!irq))
+ return;
+
+ ttcce->ce.name = np->name;
+ ttcce->ce.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+ ttcce->ce.set_next_event = xttcpss_set_next_event;
+ ttcce->ce.set_mode = xttcpss_set_mode;
+ ttcce->ce.rating = 200;
+ ttcce->ce.irq = irq;
+
+ __raw_writel(0x23, ttcce->xttc.base_addr + XTTCPSS_CNT_CNTRL_OFFSET);
+ __raw_writel(CLK_CNTRL_PRESCALE | CLK_CNTRL_PRESCALE_EN,
+ ttcce->xttc.base_addr + XTTCPSS_CLK_CNTRL_OFFSET);
+ __raw_writel(0x1, ttcce->xttc.base_addr + XTTCPSS_IER_OFFSET);
+
+ err = request_irq(irq, xttcpss_clock_event_interrupt, IRQF_TIMER,
+ np->name, ttcce);
+ if (WARN_ON(err))
+ return;
+
+ clockevents_config_and_register(&ttcce->ce,
+ clk_get_rate(ttcce->clk) / PRESCALE,
+ 1, 0xfffe);
+}
+
+static const __initconst struct of_device_id zynq_ttc_match[] = {
+ { .compatible = "xlnx,ttc-counter-clocksource",
+ .data = zynq_ttc_setup_clocksource, },
+ { .compatible = "xlnx,ttc-counter-clockevent",
+ .data = zynq_ttc_setup_clockevent, },
+ {}
};

/**
@@ -270,21 +309,25 @@ static struct clock_event_device xttcpss_clockevent = {
**/
void __init xttcpss_timer_init(void)
{
- xttcpss_timer_hardware_init();
- clocksource_register_hz(&clocksource_xttcpss, TIMER_RATE);
-
- /* Calculate the parameters to allow the clockevent to operate using
- integer math
- */
- clockevents_calc_mult_shift(&xttcpss_clockevent, TIMER_RATE, 4);
-
- xttcpss_clockevent.max_delta_ns =
- clockevent_delta2ns(0xfffe, &xttcpss_clockevent);
- xttcpss_clockevent.min_delta_ns =
- clockevent_delta2ns(1, &xttcpss_clockevent);
-
- /* Indicate that clock event is on 1st CPU as SMP boot needs it */
-
- xttcpss_clockevent.cpumask = cpumask_of(0);
- clockevents_register_device(&xttcpss_clockevent);
+ struct device_node *np;
+
+ for_each_compatible_node(np, NULL, "xlnx,ttc") {
+ struct device_node *np_chld;
+ void __iomem *base;
+
+ base = of_iomap(np, 0);
+ if (WARN_ON(!base))
+ return;
+
+ for_each_available_child_of_node(np, np_chld) {
+ int (*cb)(struct device_node *np, void __iomem *base);
+ const struct of_device_id *match;
+
+ match = of_match_node(zynq_ttc_match, np_chld);
+ if (match) {
+ cb = match->data;
+ cb(np_chld, base);
+ }
+ }
+ }
}
--
1.8.0