From: Stuart Menefy <[email protected]>
This is a simple driver for the global timer module found in the Cortex
A9-MP cores from revision r1p0 onwards. This should be able to perform
the functions of the system timer and the local timer in an SMP system.
The global timer has the following features:
The global timer is a 64-bit incrementing counter with an
auto-incrementing feature. It continues incrementing after sending
interrupts. The global timer is memory mapped in the private memory
region.
The global timer is accessible to all Cortex-A9 processors in the
cluster. Each Cortex-A9 processor has a private 64-bit comparator that
is used to assert a private interrupt when the global timer has reached
the comparator value. All the Cortex-A9 processors in a design use the
banked ID, ID27, for this interrupt. ID27 is sent to the Interrupt
Controller as a Private Peripheral Interrupt. The global timer is
clocked by PERIPHCLK.
Signed-off-by: Stuart Menefy <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
CC: Arnd Bergmann <[email protected]>
CC: Rob Herring <[email protected]>
CC: Linus Walleij <[email protected]>
CC: Will Deacon <[email protected]>
---
Thankyou for reveiwing the v5 patch.
This patch is split out of the orignal 10 patches submitted for Stixxxx SOC
support to arm-kernel mailing list. This patch has undergone few cycles of
reviews in arm-kernel mailing list.
This patch is generated on top of timers/core branch.
Arnd already picked up SOC support patches [4-10] and merged them via arm-soc
tree for 3.11.
If its not too late can this patch be considered for 3.11 via clocksource tree?
This patch has no build dependencies.
Thanks,
srini
Changes since v5:
- moved to using cpu notifiers as suggested by Stephen Boyd.
- removed un-necessary headers as suggested by Stephen Boyd.
- patch rebased on top of timers/core.
Changes since v4:
All the comments are from Thomas G.
- disabled irq and comp enable bits while setting one-shot mode.
- remove double pointer usage of clock_event_device structure.
- remove spaces from device name.
- remove few un-necessary comments.
- Fix error checks and error case handling in global_timer_of_register
Changes since v3:
- Arnd suggested to replaced all __raw_readl/__raw_writel with
readl/writel or readl_relaxed/writel_relaxed(for optimized path)
as __raw* apis are not Endian safe.
Changes since v2:
- cleaned up arm-global-timer code for non-dt as suggested by Linus W and
- fixed minmum clock tick setting pointed by Linus W.
Changes since RFC:
Most of the comments are suggested by Linus W.
- moved to drivers/clocksource.
- added revision check in driver.
- removed unused header file.
- moved to u64 from union gt_counter
- comments added in get_counter
- removed leftover debug code.
- moved code to use __raw_readl/writel.
- used DIV_ROUND_CLOSEST
- added check in interrupt handler.
- expanded CE and CS acronyms usage.
- Fixed minimum clock ticks value.
- move to use clocksource_register_hz
- added arch sched_clock support.
- added ERRATA 740657 workaround.
.../devicetree/bindings/arm/global_timer.txt | 21 ++
drivers/clocksource/Kconfig | 13 +
drivers/clocksource/Makefile | 1 +
drivers/clocksource/arm_global_timer.c | 325 ++++++++++++++++++++
4 files changed, 360 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/arm/global_timer.txt
create mode 100644 drivers/clocksource/arm_global_timer.c
diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
new file mode 100644
index 0000000..b64abac
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/global_timer.txt
@@ -0,0 +1,21 @@
+
+* ARM Global Timer
+ Cortex-A9 are often associated with a per-core Global timer.
+
+** Timer node required properties:
+
+- compatible : Should be "arm,cortex-a9-global-timer"
+ Driver supports versions r2p0 and above.
+
+- interrupts : One interrupt to each core
+
+- reg : Specify the base address and the size of the GT timer
+ register window.
+
+Example:
+
+ timer@2c000600 {
+ compatible = "arm,cortex-a9-global-timer";
+ reg = <0x2c000600 0x20>;
+ interrupts = <1 13 0xf01>;
+ };
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 0a04257..1cb3756 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -67,6 +67,19 @@ config ARM_ARCH_TIMER
bool
select CLKSRC_OF if OF
+config ARM_GLOBAL_TIMER
+ bool
+ select CLKSRC_OF if OF
+ help
+ This options enables support for the ARM global timer unit
+
+config CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
+ bool
+ depends on ARM_GLOBAL_TIMER
+ default y
+ help
+ Use ARM global timer clock source as sched_clock
+
config CLKSRC_METAG_GENERIC
def_bool y if METAG
help
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 9ba8b4d..7f985e3 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -30,5 +30,6 @@ obj-$(CONFIG_CLKSRC_SAMSUNG_PWM) += samsung_pwm_timer.o
obj-$(CONFIG_VF_PIT_TIMER) += vf_pit_timer.o
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
diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c
new file mode 100644
index 0000000..ac830a3
--- /dev/null
+++ b/drivers/clocksource/arm_global_timer.c
@@ -0,0 +1,325 @@
+/*
+ * drivers/clocksource/arm_global_timer.c
+ *
+ * Copyright (C) 2013 STMicroelectronics (R&D) Limited.
+ * Author: Stuart Menefy <[email protected]>
+ * Author: Srinivas Kandagatla <[email protected]>
+ *
+ * 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/init.h>
+#include <linux/interrupt.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/cpu.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+
+#include <asm/sched_clock.h>
+#include <asm/cputype.h>
+
+#define GT_COUNTER0 0x00
+#define GT_COUNTER1 0x04
+
+#define GT_CONTROL 0x08
+#define GT_CONTROL_TIMER_ENABLE BIT(0) /* this bit is NOT banked */
+#define GT_CONTROL_COMP_ENABLE BIT(1) /* banked */
+#define GT_CONTROL_IRQ_ENABLE BIT(2) /* banked */
+#define GT_CONTROL_AUTO_INC BIT(3) /* banked */
+
+#define GT_INT_STATUS 0x0c
+#define GT_INT_STATUS_EVENT_FLAG BIT(0)
+
+#define GT_COMP0 0x10
+#define GT_COMP1 0x14
+#define GT_AUTO_INC 0x18
+
+/*
+ * We are expecting to be clocked by the ARM peripheral clock.
+ *
+ * Note: it is assumed we are using a prescaler value of zero, so this is
+ * the units for all operations.
+ */
+static void __iomem *gt_base;
+static unsigned long gt_clk_rate;
+static int gt_ppi;
+static struct clock_event_device __percpu *gt_evt;
+
+/*
+ * To get the value from the Global Timer Counter register proceed as follows:
+ * 1. Read the upper 32-bit timer counter register
+ * 2. Read the lower 32-bit timer counter register
+ * 3. Read the upper 32-bit timer counter register again. If the value is
+ * different to the 32-bit upper value read previously, go back to step 2.
+ * Otherwise the 64-bit timer counter value is correct.
+ */
+static u64 gt_counter_read(void)
+{
+ u64 counter;
+ u32 lower;
+ u32 upper, old_upper;
+
+ upper = readl_relaxed(gt_base + GT_COUNTER1);
+ do {
+ old_upper = upper;
+ lower = readl_relaxed(gt_base + GT_COUNTER0);
+ upper = readl_relaxed(gt_base + GT_COUNTER1);
+ } while (upper != old_upper);
+
+ counter = upper;
+ counter <<= 32;
+ counter |= lower;
+ return counter;
+}
+
+/**
+ * To ensure that updates to comparator value register do not set the
+ * Interrupt Status Register proceed as follows:
+ * 1. Clear the Comp Enable bit in the Timer Control Register.
+ * 2. Write the lower 32-bit Comparator Value Register.
+ * 3. Write the upper 32-bit Comparator Value Register.
+ * 4. Set the Comp Enable bit and, if necessary, the IRQ enable bit.
+ */
+static void gt_compare_set(unsigned long delta, int periodic)
+{
+ u64 counter = gt_counter_read();
+ unsigned long ctrl = readl(gt_base + GT_CONTROL);
+
+ counter += delta;
+ ctrl &= ~(GT_CONTROL_COMP_ENABLE | GT_CONTROL_IRQ_ENABLE);
+
+ writel(ctrl, gt_base + GT_CONTROL);
+ writel(lower_32_bits(counter), gt_base + GT_COMP0);
+ writel(upper_32_bits(counter), gt_base + GT_COMP1);
+
+ if (periodic) {
+ writel(delta, gt_base + GT_AUTO_INC);
+ ctrl |= GT_CONTROL_AUTO_INC;
+ }
+
+ ctrl |= GT_CONTROL_COMP_ENABLE | GT_CONTROL_IRQ_ENABLE;
+ writel(ctrl, gt_base + GT_CONTROL);
+}
+
+static void gt_clockevent_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *clk)
+{
+ unsigned long ctrl;
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ gt_compare_set(DIV_ROUND_CLOSEST(gt_clk_rate, HZ), 1);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ ctrl = readl(gt_base + GT_CONTROL);
+ ctrl &= ~(GT_CONTROL_COMP_ENABLE |
+ GT_CONTROL_IRQ_ENABLE | GT_CONTROL_AUTO_INC);
+ writel(ctrl, gt_base + GT_CONTROL);
+ break;
+ default:
+ break;
+ }
+}
+
+static int gt_clockevent_set_next_event(unsigned long evt,
+ struct clock_event_device *unused)
+{
+ gt_compare_set(evt, 0);
+ return 0;
+}
+
+static irqreturn_t gt_clockevent_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ if (readl_relaxed(gt_base + GT_INT_STATUS) &
+ GT_INT_STATUS_EVENT_FLAG) {
+ /**
+ * ERRATA 740657( Global Timer can send 2 interrupts for
+ * the same event in single-shot mode)
+ * Workaround:
+ * Either disable single-shot mode.
+ * Or
+ * Modify the Interrupt Handler to avoid the
+ * offending sequence. This is achieved by clearing
+ * the Global Timer flag _after_ having incremented
+ * the Comparator register value to a higher value.
+ */
+ if (!(readl_relaxed(gt_base + GT_CONTROL) &
+ GT_CONTROL_AUTO_INC))
+ gt_compare_set(ULONG_MAX, 0);
+
+ writel_relaxed(GT_INT_STATUS_EVENT_FLAG,
+ gt_base + GT_INT_STATUS);
+
+ evt->event_handler(evt);
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+}
+
+static int __cpuinit gt_clockevents_init(struct clock_event_device *clk)
+{
+ int cpu = smp_processor_id();
+
+ clk->name = "arm_global_timer";
+ clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+ clk->set_mode = gt_clockevent_set_mode;
+ clk->set_next_event = gt_clockevent_set_next_event;
+ clk->cpumask = cpumask_of(cpu);
+ clk->rating = 300;
+ clk->irq = gt_ppi;
+ clockevents_config_and_register(clk, gt_clk_rate,
+ 1, 0xffffffff);
+ enable_percpu_irq(clk->irq, IRQ_TYPE_NONE);
+ return 0;
+}
+
+static void gt_clockevents_stop(struct clock_event_device *clk)
+{
+ gt_clockevent_set_mode(CLOCK_EVT_MODE_UNUSED, clk);
+ disable_percpu_irq(clk->irq);
+}
+
+static cycle_t gt_clocksource_read(struct clocksource *cs)
+{
+ return gt_counter_read();
+}
+
+static struct clocksource gt_clocksource = {
+ .name = "arm_global_timer",
+ .rating = 300,
+ .read = gt_clocksource_read,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+#ifdef CONFIG_CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
+static u32 notrace gt_sched_clock_read(void)
+{
+ return gt_counter_read();
+}
+#endif
+
+static void __init gt_clocksource_init(void)
+{
+ writel(0, gt_base + GT_CONTROL);
+ writel(0, gt_base + GT_COUNTER0);
+ writel(0, gt_base + GT_COUNTER1);
+ /* enables timer on all the cores */
+ writel(GT_CONTROL_TIMER_ENABLE, gt_base + GT_CONTROL);
+
+#ifdef CONFIG_CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
+ setup_sched_clock(gt_sched_clock_read, 32, gt_clk_rate);
+#endif
+ clocksource_register_hz(>_clocksource, gt_clk_rate);
+}
+
+static int __cpuinit gt_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_STARTING:
+ gt_clockevents_init(this_cpu_ptr(gt_evt));
+ break;
+ case CPU_DYING:
+ gt_clockevents_stop(this_cpu_ptr(gt_evt));
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+static struct notifier_block gt_cpu_nb __cpuinitdata = {
+ .notifier_call = gt_cpu_notify,
+};
+
+static void __init global_timer_of_register(struct device_node *np)
+{
+ struct clk *gt_clk;
+ int err = 0;
+
+ /*
+ * In r2p0 the comparators for each processor with the global timer
+ * fire when the timer value is greater than or equal to. In previous
+ * revisions the comparators fired when the timer value was equal to.
+ */
+ if ((read_cpuid_id() & 0xf0000f) < 0x200000) {
+ pr_warn("global-timer: non support for this cpu version.\n");
+ return;
+ }
+
+ gt_ppi = irq_of_parse_and_map(np, 0);
+ if (!gt_ppi) {
+ pr_warn("global-timer: unable to parse irq\n");
+ return;
+ }
+
+ gt_base = of_iomap(np, 0);
+ if (!gt_base) {
+ pr_warn("global-timer: invalid base address\n");
+ return;
+ }
+
+ gt_clk = of_clk_get(np, 0);
+ if (!IS_ERR(gt_clk)) {
+ err = clk_prepare_enable(gt_clk);
+ if (err)
+ goto out_unmap;
+ } else {
+ pr_warn("global-timer: clk not found\n");
+ err = -EINVAL;
+ goto out_unmap;
+ }
+
+ gt_clk_rate = clk_get_rate(gt_clk);
+ gt_evt = alloc_percpu(struct clock_event_device);
+ if (!gt_evt) {
+ pr_warn("global-timer: can't allocate memory\n");
+ err = -ENOMEM;
+ goto out_clk;
+ }
+
+ err = request_percpu_irq(gt_ppi, gt_clockevent_interrupt,
+ "gt", gt_evt);
+ if (err) {
+ pr_warn("global-timer: can't register interrupt %d (%d)\n",
+ gt_ppi, err);
+ goto out_free;
+ }
+
+ err = register_cpu_notifier(>_cpu_nb);
+ if (err) {
+ pr_warn("global-timer: unable to register cpu notifier.\n");
+ goto out_irq;
+ }
+
+ /* Immediately configure the timer on the boot CPU */
+ gt_clocksource_init();
+ gt_clockevents_init(this_cpu_ptr(gt_evt));
+
+ return;
+
+out_irq:
+ free_percpu_irq(gt_ppi, gt_evt);
+out_free:
+ free_percpu(gt_evt);
+out_clk:
+ clk_disable_unprepare(gt_clk);
+out_unmap:
+ iounmap(gt_base);
+ WARN(err, "ARM Global timer register failed (%d)\n", err);
+}
+
+/* Only tested on r2p2 and r3p0 */
+CLOCKSOURCE_OF_DECLARE(arm_gt, "arm,cortex-a9-global-timer",
+ global_timer_of_register);
--
1.7.6.5
On Tue, 25 Jun 2013, Srinivas KANDAGATLA wrote:
> If its not too late can this patch be considered for 3.11 via clocksource tree?
Sure. No worry, though I noticed a little detail when reading through it
again. See below.
> +/**
> + * To ensure that updates to comparator value register do not set the
> + * Interrupt Status Register proceed as follows:
> + * 1. Clear the Comp Enable bit in the Timer Control Register.
> + * 2. Write the lower 32-bit Comparator Value Register.
> + * 3. Write the upper 32-bit Comparator Value Register.
> + * 4. Set the Comp Enable bit and, if necessary, the IRQ enable bit.
> + */
> +static void gt_compare_set(unsigned long delta, int periodic)
> +{
> + u64 counter = gt_counter_read();
> + unsigned long ctrl = readl(gt_base + GT_CONTROL);
Why are you reading the control register back over and over? All you
need to preserve is the GT_CONTROL_TIMER_ENABLE bit. So you can spare
that read out and just do
ctrl = GT_CONTROL_TIMER_ENABLE;
writel(ctrl, gt_base + GT_CONTROL);
> +static irqreturn_t gt_clockevent_interrupt(int irq, void *dev_id)
> +{
> + struct clock_event_device *evt = dev_id;
> +
> + if (readl_relaxed(gt_base + GT_INT_STATUS) &
> + GT_INT_STATUS_EVENT_FLAG) {
If you negate the check and return IRQ_NONE, you save one indent level
for the real code.
> + /**
> + * ERRATA 740657( Global Timer can send 2 interrupts for
> + * the same event in single-shot mode)
> + * Workaround:
> + * Either disable single-shot mode.
> + * Or
> + * Modify the Interrupt Handler to avoid the
> + * offending sequence. This is achieved by clearing
> + * the Global Timer flag _after_ having incremented
> + * the Comparator register value to a higher value.
> + */
> + if (!(readl_relaxed(gt_base + GT_CONTROL) &
> + GT_CONTROL_AUTO_INC))
Again, no need to read from the hardware.
if (evt->mode == CLOCK_EVT_MODE_ONESHOT)
tells you what you need to know.
Thanks,
tglx
Thanks for the comments.
On 25/06/13 14:17, Thomas Gleixner wrote:
> On Tue, 25 Jun 2013, Srinivas KANDAGATLA wrote:
>> If its not too late can this patch be considered for 3.11 via clocksource tree?
>
> Sure. No worry, though I noticed a little detail when reading through it
> again. See below.
>
>> +/**
>> + * To ensure that updates to comparator value register do not set the
>> + * Interrupt Status Register proceed as follows:
>> + * 1. Clear the Comp Enable bit in the Timer Control Register.
>> + * 2. Write the lower 32-bit Comparator Value Register.
>> + * 3. Write the upper 32-bit Comparator Value Register.
>> + * 4. Set the Comp Enable bit and, if necessary, the IRQ enable bit.
>> + */
>> +static void gt_compare_set(unsigned long delta, int periodic)
>> +{
>> + u64 counter = gt_counter_read();
>> + unsigned long ctrl = readl(gt_base + GT_CONTROL);
>
> Why are you reading the control register back over and over? All you
> need to preserve is the GT_CONTROL_TIMER_ENABLE bit. So you can spare
> that read out and just do
>
> ctrl = GT_CONTROL_TIMER_ENABLE;
> writel(ctrl, gt_base + GT_CONTROL);
Logically you are right we could do as you suggested, However its not
implicit that which bits are going to be cleared. Its more to do with
readability of the code.
If you still insist I can change it.
>
>> +static irqreturn_t gt_clockevent_interrupt(int irq, void *dev_id)
>> +{
>> + struct clock_event_device *evt = dev_id;
>> +
>> + if (readl_relaxed(gt_base + GT_INT_STATUS) &
>> + GT_INT_STATUS_EVENT_FLAG) {
>
> If you negate the check and return IRQ_NONE, you save one indent level
> for the real code.
>
Am ok either way, I will do it in the next version.
>> + /**
>> + * ERRATA 740657( Global Timer can send 2 interrupts for
>> + * the same event in single-shot mode)
>> + * Workaround:
>> + * Either disable single-shot mode.
>> + * Or
>> + * Modify the Interrupt Handler to avoid the
>> + * offending sequence. This is achieved by clearing
>> + * the Global Timer flag _after_ having incremented
>> + * the Comparator register value to a higher value.
>> + */
>> + if (!(readl_relaxed(gt_base + GT_CONTROL) &
>> + GT_CONTROL_AUTO_INC))
>
> Again, no need to read from the hardware.
>
> if (evt->mode == CLOCK_EVT_MODE_ONESHOT)
Yes, we can get it from evt->mode. I will do it in next version.
>
> tells you what you need to know.
>
> Thanks,
>
> tglx
>
>
On Tue, 25 Jun 2013, Srinivas KANDAGATLA wrote:
> On 25/06/13 14:17, Thomas Gleixner wrote:
> > On Tue, 25 Jun 2013, Srinivas KANDAGATLA wrote:
> >> +static void gt_compare_set(unsigned long delta, int periodic)
> >> +{
> >> + u64 counter = gt_counter_read();
> >> + unsigned long ctrl = readl(gt_base + GT_CONTROL);
> >
> > Why are you reading the control register back over and over? All you
> > need to preserve is the GT_CONTROL_TIMER_ENABLE bit. So you can spare
> > that read out and just do
> >
> > ctrl = GT_CONTROL_TIMER_ENABLE;
> > writel(ctrl, gt_base + GT_CONTROL);
>
> Logically you are right we could do as you suggested, However its not
> implicit that which bits are going to be cleared. Its more to do with
> readability of the code.
> If you still insist I can change it.
I'm not insisting. I just pointed out, that you can save cycles in a
hotpath. :)
Thanks,
tglx
Hi Srinivas,
On Tue, Jun 25, 2013 at 10:31:18AM +0100, Srinivas KANDAGATLA wrote:
> From: Stuart Menefy <[email protected]>
>
> This is a simple driver for the global timer module found in the Cortex
> A9-MP cores from revision r1p0 onwards. This should be able to perform
> the functions of the system timer and the local timer in an SMP system.
>
> The global timer has the following features:
> The global timer is a 64-bit incrementing counter with an
> auto-incrementing feature. It continues incrementing after sending
> interrupts. The global timer is memory mapped in the private memory
> region.
> The global timer is accessible to all Cortex-A9 processors in the
> cluster. Each Cortex-A9 processor has a private 64-bit comparator that
> is used to assert a private interrupt when the global timer has reached
> the comparator value. All the Cortex-A9 processors in a design use the
> banked ID, ID27, for this interrupt. ID27 is sent to the Interrupt
> Controller as a Private Peripheral Interrupt. The global timer is
> clocked by PERIPHCLK.
>
> Signed-off-by: Stuart Menefy <[email protected]>
> Signed-off-by: Srinivas Kandagatla <[email protected]>
> Reviewed-by: Thomas Gleixner <[email protected]>
> CC: Arnd Bergmann <[email protected]>
> CC: Rob Herring <[email protected]>
> CC: Linus Walleij <[email protected]>
> CC: Will Deacon <[email protected]>
> ---
>
> Thankyou for reveiwing the v5 patch.
> This patch is split out of the orignal 10 patches submitted for Stixxxx SOC
> support to arm-kernel mailing list. This patch has undergone few cycles of
> reviews in arm-kernel mailing list.
>
> This patch is generated on top of timers/core branch.
>
> Arnd already picked up SOC support patches [4-10] and merged them via arm-soc
> tree for 3.11.
>
> If its not too late can this patch be considered for 3.11 via clocksource tree?
> This patch has no build dependencies.
>
> Thanks,
> srini
>
> Changes since v5:
> - moved to using cpu notifiers as suggested by Stephen Boyd.
> - removed un-necessary headers as suggested by Stephen Boyd.
> - patch rebased on top of timers/core.
>
> Changes since v4:
> All the comments are from Thomas G.
> - disabled irq and comp enable bits while setting one-shot mode.
> - remove double pointer usage of clock_event_device structure.
> - remove spaces from device name.
> - remove few un-necessary comments.
> - Fix error checks and error case handling in global_timer_of_register
>
> Changes since v3:
> - Arnd suggested to replaced all __raw_readl/__raw_writel with
> readl/writel or readl_relaxed/writel_relaxed(for optimized path)
> as __raw* apis are not Endian safe.
>
> Changes since v2:
> - cleaned up arm-global-timer code for non-dt as suggested by Linus W and
> - fixed minmum clock tick setting pointed by Linus W.
>
> Changes since RFC:
> Most of the comments are suggested by Linus W.
> - moved to drivers/clocksource.
> - added revision check in driver.
> - removed unused header file.
> - moved to u64 from union gt_counter
> - comments added in get_counter
> - removed leftover debug code.
> - moved code to use __raw_readl/writel.
> - used DIV_ROUND_CLOSEST
> - added check in interrupt handler.
> - expanded CE and CS acronyms usage.
> - Fixed minimum clock ticks value.
> - move to use clocksource_register_hz
> - added arch sched_clock support.
> - added ERRATA 740657 workaround.
>
> .../devicetree/bindings/arm/global_timer.txt | 21 ++
> drivers/clocksource/Kconfig | 13 +
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/arm_global_timer.c | 325 ++++++++++++++++++++
> 4 files changed, 360 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/arm/global_timer.txt
> create mode 100644 drivers/clocksource/arm_global_timer.c
>
> diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
> new file mode 100644
> index 0000000..b64abac
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/global_timer.txt
> @@ -0,0 +1,21 @@
> +
> +* ARM Global Timer
> + Cortex-A9 are often associated with a per-core Global timer.
> +
> +** Timer node required properties:
> +
> +- compatible : Should be "arm,cortex-a9-global-timer"
> + Driver supports versions r2p0 and above.
> +
> +- interrupts : One interrupt to each core
> +
> +- reg : Specify the base address and the size of the GT timer
> + register window.
> +
> +Example:
> +
> + timer@2c000600 {
> + compatible = "arm,cortex-a9-global-timer";
> + reg = <0x2c000600 0x20>;
> + interrupts = <1 13 0xf01>;
> + };
Isn't a 'clocks' entry missing here?
Sören
Thanks for your comments,
On 25/06/13 22:14, Sören Brinkmann wrote:
>> +Example:
>> > +
>> > + timer@2c000600 {
>> > + compatible = "arm,cortex-a9-global-timer";
>> > + reg = <0x2c000600 0x20>;
>> > + interrupts = <1 13 0xf01>;
>> > + };
> Isn't a 'clocks' entry missing here?
Yep, I will add it in v7.
Thanks,
srini