[PATCH v4 06/15] ARM: mxs: Add timer support
Shawn Guo
shawn.guo at freescale.com
Thu Dec 9 10:12:41 EST 2010
There are 2 versions of the timrot on Freescale MXS-based SoCs.
The v1 on MX23 only gets 16 bits counter, while v2 on MX28
extends the counter to 32 bits.
The implementation uses two timers, one for clock_event and
another for clocksource. MX28 uses timer0 and timer1, while
MX23 uses timer0 and timer3.
Signed-off-by: Shawn Guo <shawn.guo at freescale.com>
---
Changes for v4:
- Change inclusion of hardware.h to mxs.h
- Use two timers on MX28 also to simpify timrotv2_set_next_event()
- MX23 and MX28 share the common timrot base address, so it can be
a hard-assignment.
- Pass &clockevent_mxs to mxs_timer_interrupt via mxs_timer_irq.dev_id
- Fix code of setting far-far future
- Change printk to pr_info and pr_err
- Change timrotv2 min_delta_ns to 0xf
Changes for v3:
- Use term clock_event over next_event and clocksource over get_cycles
- Split BV_TIMROT_TIMCTRLn_SELECT__32KHZ_XTAL into two definitions for v1 and v2 respectively
- Turn timrot_get_cycles() into timrotv1_get_cycles() and timrotv2_get_cycles()
- Turn timrot_set_next_event() into timrotv1_set_next_event() and timrotv2_set_next_event()
- Skip flag IRQF_DISABLED
- Remove unncessary IRQ disabling in mxs_set_mode()
- Change shift of clocksource_mxs to 17
Changes for v2:
- Fix a bug in timrot_set_next_event(). It should read
HW_TIMROT_RUNNING_COUNTn to get the current counts.
arch/arm/mach-mxs/timer.c | 270 +++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 270 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/mach-mxs/timer.c
diff --git a/arch/arm/mach-mxs/timer.c b/arch/arm/mach-mxs/timer.c
new file mode 100644
index 0000000..75f2805
--- /dev/null
+++ b/arch/arm/mach-mxs/timer.c
@@ -0,0 +1,270 @@
+/*
+ * Copyright (C) 2000-2001 Deep Blue Solutions
+ * Copyright (C) 2002 Shane Nay (shane at minirl.com)
+ * Copyright (C) 2006-2007 Pavel Pisa (ppisa at pikron.com)
+ * Copyright (C) 2008 Juergen Beisert (kernel at pengutronix.de)
+ * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/clockchips.h>
+#include <linux/clk.h>
+
+#include <asm/mach/time.h>
+#include <mach/mxs.h>
+#include <mach/common.h>
+
+/*
+ * There are 2 versions of the timrot on Freescale MXS-based SoCs.
+ * The v1 on MX23 only gets 16 bits counter, while v2 on MX28
+ * extends the counter to 32 bits.
+ *
+ * The implementation uses two timers, one for clock_event and
+ * another for clocksource. MX28 uses timer0 and timer1, while
+ * MX23 uses timer0 and timer3.
+ */
+#define timrot_is_v1() (cpu_is_mx23())
+
+#define HW_TIMROT_ROTCTRL 0x00
+#define HW_TIMROT_TIMCTRLn(n) (0x20 + (n) * 0x40)
+#define HW_TIMROT_RUNNING_COUNTn(n) (0x30 + (n) * 0x40)
+#define HW_TIMROT_FIXED_COUNTn(n) (0x40 + (n) * 0x40)
+#define BM_TIMROT_TIMCTRLn_RELOAD (1 << 6)
+#define BM_TIMROT_TIMCTRLn_UPDATE (1 << 7)
+#define BM_TIMROT_TIMCTRLn_IRQ_EN (1 << 14)
+#define BM_TIMROT_TIMCTRLn_IRQ (1 << 15)
+#define BP_TIMROT_TIMCTRLn_SELECT 0
+#define BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL 0x8
+#define BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL 0xb
+
+static struct clock_event_device clockevent_mxs;
+static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_UNUSED;
+
+static void __iomem *timer_base = MXS_IO_ADDRESS(MXS_TIMROT_BASE_ADDR);
+
+static inline void timrot_irq_disable(void)
+{
+ __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN,
+ timer_base + HW_TIMROT_TIMCTRLn(0) + MXS_CLR_ADDR);
+}
+
+static inline void timrot_irq_enable(void)
+{
+ __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN,
+ timer_base + HW_TIMROT_TIMCTRLn(0) + MXS_SET_ADDR);
+}
+
+static void timrot_irq_acknowledge(void)
+{
+ __raw_writel(BM_TIMROT_TIMCTRLn_IRQ,
+ timer_base + HW_TIMROT_TIMCTRLn(0) + MXS_CLR_ADDR);
+}
+
+static cycle_t timrotv1_get_cycles(struct clocksource *cs)
+{
+ return ~((__raw_readl(timer_base + HW_TIMROT_RUNNING_COUNTn(1))
+ & 0xffff0000) >> 16);
+}
+
+static cycle_t timrotv2_get_cycles(struct clocksource *cs)
+{
+ return ~__raw_readl(timer_base + HW_TIMROT_RUNNING_COUNTn(1));
+}
+
+static int timrotv1_set_next_event(unsigned long evt,
+ struct clock_event_device *dev)
+{
+ /* timrot decrements the count */
+ __raw_writel(evt, timer_base + HW_TIMROT_RUNNING_COUNTn(0));
+
+ return 0;
+}
+
+static int timrotv2_set_next_event(unsigned long evt,
+ struct clock_event_device *dev)
+{
+ /* timrot decrements the count */
+ __raw_writel(evt, timer_base + HW_TIMROT_FIXED_COUNTn(0));
+
+ return 0;
+}
+
+static irqreturn_t mxs_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ timrot_irq_acknowledge();
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction mxs_timer_irq = {
+ .name = "MXS Timer Tick",
+ .dev_id = &clockevent_mxs,
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = mxs_timer_interrupt,
+};
+
+#ifdef DEBUG
+static const char *clock_event_mode_label[] = {
+ [CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
+ [CLOCK_EVT_MODE_ONESHOT] = "CLOCK_EVT_MODE_ONESHOT",
+ [CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
+ [CLOCK_EVT_MODE_UNUSED] = "CLOCK_EVT_MODE_UNUSED"
+};
+#endif /* DEBUG */
+
+static void mxs_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ /* Disable interrupt in timer module */
+ timrot_irq_disable();
+
+ if (mode != clockevent_mode) {
+ /* Set event time into the furthest future */
+ if (timrot_is_v1())
+ __raw_writel(0xffff,
+ timer_base + HW_TIMROT_RUNNING_COUNTn(1));
+ else
+ __raw_writel(0xffffffff,
+ timer_base + HW_TIMROT_FIXED_COUNTn(1));
+
+ /* Clear pending interrupt */
+ timrot_irq_acknowledge();
+ }
+
+#ifdef DEBUG
+ pr_info("%s: changing mode from %s to %s\n", __func__,
+ clock_event_mode_label[clockevent_mode],
+ clock_event_mode_label[mode]);
+#endif /* DEBUG */
+
+ /* Remember timer mode */
+ clockevent_mode = mode;
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ pr_err("%s: Periodic mode is not implemented\n", __func__);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ timrot_irq_enable();
+ break;
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_RESUME:
+ /* Left event sources disabled, no more interrupts appear */
+ break;
+ }
+}
+
+static struct clock_event_device clockevent_mxs = {
+ .name = "mxs_timrot",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .shift = 32,
+ .set_mode = mxs_set_mode,
+ .set_next_event = timrotv2_set_next_event,
+ .rating = 200,
+};
+
+static int __init mxs_clockevent_init(struct clk *timer_clk)
+{
+ unsigned int c = clk_get_rate(timer_clk);
+
+ clockevent_mxs.mult = div_sc(c, NSEC_PER_SEC, clockevent_mxs.shift);
+ clockevent_mxs.cpumask = cpumask_of(0);
+ if (timrot_is_v1()) {
+ clockevent_mxs.set_next_event = timrotv1_set_next_event;
+ clockevent_mxs.max_delta_ns =
+ clockevent_delta2ns(0xfffe, &clockevent_mxs);
+ clockevent_mxs.min_delta_ns =
+ clockevent_delta2ns(0xf, &clockevent_mxs);
+ } else {
+ clockevent_mxs.max_delta_ns =
+ clockevent_delta2ns(0xfffffffe, &clockevent_mxs);
+ clockevent_mxs.min_delta_ns =
+ clockevent_delta2ns(0xf, &clockevent_mxs);
+ }
+
+ clockevents_register_device(&clockevent_mxs);
+
+ return 0;
+}
+
+static struct clocksource clocksource_mxs = {
+ .name = "mxs_timer",
+ .rating = 200,
+ .read = timrotv2_get_cycles,
+ .mask = CLOCKSOURCE_MASK(32),
+ .shift = 17,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int __init mxs_clocksource_init(struct clk *timer_clk)
+{
+ unsigned int c = clk_get_rate(timer_clk);
+
+ if (timrot_is_v1()) {
+ clocksource_mxs.read = timrotv1_get_cycles;
+ clocksource_mxs.mask = CLOCKSOURCE_MASK(16);
+ }
+ clocksource_mxs.mult = clocksource_hz2mult(c, clocksource_mxs.shift);
+ clocksource_register(&clocksource_mxs);
+
+ return 0;
+}
+
+void __init mxs_timer_init(struct clk *timer_clk, int irq)
+{
+ clk_enable(timer_clk);
+
+ /*
+ * Initialize timers to a known state
+ */
+ mxs_reset_block(timer_base + HW_TIMROT_ROTCTRL);
+
+ /* timer0 is for clock_event */
+ __raw_writel((timrot_is_v1() ?
+ BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
+ BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL) |
+ BM_TIMROT_TIMCTRLn_UPDATE |
+ BM_TIMROT_TIMCTRLn_IRQ_EN,
+ timer_base + HW_TIMROT_TIMCTRLn(0));
+
+ /* timer1 is for clocksource */
+ __raw_writel((timrot_is_v1() ?
+ BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
+ BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL) |
+ BM_TIMROT_TIMCTRLn_RELOAD,
+ timer_base + HW_TIMROT_TIMCTRLn(1));
+
+ /* set timer1 fixed count to the maximum */
+ if (timrot_is_v1())
+ __raw_writel(0xffff,
+ timer_base + HW_TIMROT_RUNNING_COUNTn(1));
+ else
+ __raw_writel(0xffffffff,
+ timer_base + HW_TIMROT_FIXED_COUNTn(1));
+
+ /* init and register the timer to the framework */
+ mxs_clocksource_init(timer_clk);
+ mxs_clockevent_init(timer_clk);
+
+ /* Make irqs happen */
+ setup_irq(irq, &mxs_timer_irq);
+}
--
1.7.1
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