On 12/11/2013 07:00 PM, Ivan Khoronzhuk wrote:
Add broadcast clock-event device for the Keystone arch.
The timer can be configured as a general-purpose 64-bit timer,
dual general-purpose 32-bit timers. When configured as dual 32-bit
timers, each half can operate in conjunction (chain mode) or
independently (unchained mode) of each other.
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxx>
---
drivers/clocksource/Makefile | 1 +
drivers/clocksource/timer-keystone.c | 223 ++++++++++++++++++++++++++++++++++
2 files changed, 224 insertions(+)
create mode 100644 drivers/clocksource/timer-keystone.c
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 33621ef..2acf3fc 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -36,3 +36,4 @@ obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o
obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o
obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o
obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) += dummy_timer.o
+obj-$(CONFIG_ARCH_KEYSTONE) += timer-keystone.o
diff --git a/drivers/clocksource/timer-keystone.c b/drivers/clocksource/timer-keystone.c
new file mode 100644
index 0000000..4a8083a
--- /dev/null
+++ b/drivers/clocksource/timer-keystone.c
@@ -0,0 +1,223 @@
+/*
+ * Keystone broadcast clock-event
+ *
+ * Copyright 2013 Texas Instruments, Inc.
+ *
+ * Author: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define TIMER_NAME "timer64-event"
+
+/* Timer register offsets */
+#define TIM12 0x10
+#define TIM34 0x14
+#define PRD12 0x18
+#define PRD34 0x1c
+#define TCR 0x20
+#define TGCR 0x24
+#define INTCTLSTAT 0x44
+
+/* Timer register bitfields */
+#define TCR_ENAMODE_MASK 0xC0
+#define TCR_ENAMODE_ONESHOT_MASK 0x40
+#define TCR_ENAMODE_PERIODIC_MASK 0x80
+
+#define TGCR_TIM_UNRESET_MASK 0x03
+#define INTCTLSTAT_ENINT_MASK 0x01
+
+/**
+ * struct keystone_timer: holds timer's data
+ * @base: timer memory base address
+ * @clk_rate: source clock rate
+ * @irqacrion: interrupt action descriptor
+ * @event_dev: event device based on timer
+ */
+static struct keystone_timer {
+ void __iomem *base;
+ unsigned long clk_rate;
+ struct irqaction irqaction;
+ struct clock_event_device event_dev;
+} timer;
+
+static inline u32 keystone_timer_readl(unsigned long rg)
+{
+ return readl(timer.base + rg);
+}
+
+static inline void keystone_timer_writel(u32 val, unsigned long rg)
+{
+ writel(val, timer.base + rg);
+}
+
+/**
+ * keystone_timer_config: configures timer to work in oneshot/periodic modes, in
+ * other cases disables timer.
+ * @ mode: mode to configure
+ * @ period: cycles number to configure for
+ */
+static int keystone_timer_config(u64 period, enum clock_event_mode mode)
+{
+ u32 tcr;
+
+ tcr = keystone_timer_readl(TCR);
+
+ /* disable timer */
+ tcr &= ~(TCR_ENAMODE_MASK);
+ keystone_timer_writel(tcr, TCR);
Please move this write after the switch (cf. linked comment below)
+ /* set enable mode or leave disabled timer */
+ switch (mode) {
+ case CLOCK_EVT_MODE_ONESHOT:
+ tcr |= TCR_ENAMODE_ONESHOT_MASK;
+ break;
+ case CLOCK_EVT_MODE_PERIODIC:
+ tcr |= TCR_ENAMODE_PERIODIC_MASK;
+ break;
+ default:
+ return 0;
Shouldn't you return an error ?
+ }
+
+ /* reset counter to zero, set new period */
+ keystone_timer_writel(0, TIM12);
+ keystone_timer_writel(0, TIM34);
+ keystone_timer_writel(period & 0xffffffff, PRD12);
+ keystone_timer_writel(period >> 32, PRD34);
+
+ /* enable timer */
+ keystone_timer_writel(tcr, TCR);
+ return 0;
+}
+
+static irqreturn_t keystone_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = &timer.event_dev;
+
+ evt->event_handler(evt);
+ return IRQ_HANDLED;
+}
+
+static int keystone_set_next_event(unsigned long cycles,
+ struct clock_event_device *evt)
+{
+ return keystone_timer_config(cycles, evt->mode);
+}
+
+static void keystone_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ u64 period;
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ period = timer.clk_rate / (HZ);
+ keystone_timer_config(period, CLOCK_EVT_MODE_PERIODIC);
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_ONESHOT:
+ keystone_timer_config(0, CLOCK_EVT_MODE_SHUTDOWN);
I don't really this code assuming the side effect of specifying a
unsupported mode will disable the timer.
+ default:
+ break;
+ }
+}
+
+static void __init keystone_timer_init(struct device_node *np)
+{
+ struct clock_event_device *event_dev = &timer.event_dev;
+ struct irqaction *irqaction = &timer.irqaction;
+ unsigned long rate;
+ struct clk *clk;
+ int irq, error;
+ u32 tgcr;
+
+ irq = irq_of_parse_and_map(np, 0);
+ if (irq == NO_IRQ) {
+ pr_err("%s: failed to map interrupts\n", __func__);
+ return;
+ }
+
+ timer.base = of_iomap(np, 0);
+ if (!timer.base) {
+ pr_err("%s: failed to map registers\n", __func__);
+ return;
+ }
+
+ clk = of_clk_get(np, 0);
+ if (!clk) {
+ pr_err("%s: failed to get clock\n", __func__);
+ iounmap(timer.base);
+ return;
+ }
+
+ error = clk_prepare_enable(clk);
+ if (error) {
+ pr_err("%s: failed to enable clock\n", __func__);
+ goto err;
+ }
+
+ rate = clk_get_rate(clk);
+
+ /* disable, use internal clock source */
+ keystone_timer_writel(0, TCR);
+
+ /* reset timer as 64-bit, no pre-scaler, plus features are disabled */
+ tgcr = 0;
+ keystone_timer_writel(0, TGCR);
+
+ /* unreset timer */
+ tgcr |= TGCR_TIM_UNRESET_MASK;
+ keystone_timer_writel(tgcr, TGCR);
+
+ /* init counter to zero */
+ keystone_timer_writel(0, TIM12);
+ keystone_timer_writel(0, TIM34);
+
+ timer.clk_rate = rate;
+
+ /* enable timer interrupts */
+ keystone_timer_writel(INTCTLSTAT_ENINT_MASK, INTCTLSTAT);
+
+ keystone_timer_config(0, CLOCK_EVT_MODE_UNUSED);
Same comment here.
+ /* init irqaction */
+ irqaction->flags = IRQF_TIMER;
+ irqaction->handler = keystone_timer_interrupt;
+ irqaction->name = TIMER_NAME;
+ irqaction->dev_id = (void *)&timer;
+ error = setup_irq(irq, irqaction);
+ if (error) {
+ pr_err("%s: failed to setup irq\n", __func__);
+ goto err;
+ }
+
+ /* setup clockevent */
+ event_dev->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+ event_dev->set_next_event = keystone_set_next_event;
+ event_dev->set_mode = keystone_set_mode;
+ event_dev->cpumask = cpu_all_mask;
+ event_dev->owner = THIS_MODULE;
+ event_dev->name = TIMER_NAME;
+
+ clockevents_config_and_register(event_dev, rate, 1, ULONG_MAX);
+
+ pr_info("keystone timer clock @%lu Hz\n", rate);
+ return;
+err:
+ clk_put(clk);
+ iounmap(timer.base);
+}
+
+CLOCKSOURCE_OF_DECLARE(keystone_timer, "ti,keystone-timer",
+ keystone_timer_init);
--
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