From: Donghoon Yu <hoony.yu@samsung.com>

On Arm64 platforms the Exynos MCT driver can be built as a module. On
boot (and even after boot) the arch_timer is used as the clocksource and
tick timer. Once the MCT driver is loaded, it can be used as the wakeup
source for the arch_timer.

Signed-off-by: Donghoon Yu <hoony.yu@samsung.com>
Signed-off-by: Youngmin Nam <youngmin.nam@samsung.com>
[original commit from https://android.googlesource.com/kernel/gs/+/8a52a8288ec7d88ff78f0b37480dbb0e9c65bbfd]
Reviewed-by: Youngmin Nam <youngmin.nam@samsung.com>
Tested-by: Youngmin Nam <youngmin.nam@samsung.com>
Signed-off-by: Will McVicker <willmcvicker@google.com>
---
 drivers/clocksource/Kconfig      |  3 +-
 drivers/clocksource/exynos_mct.c | 51 ++++++++++++++++++++++++++------
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 645f517a1ac2..d657c8ddc96b 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -451,7 +451,8 @@ config ATMEL_TCB_CLKSRC
 	  Support for Timer Counter Blocks on Atmel SoCs.
 
 config CLKSRC_EXYNOS_MCT
-	bool "Exynos multi core timer driver" if COMPILE_TEST
+	tristate "Exynos multi core timer driver" if ARM64
+	default y if ARCH_EXYNOS || COMPILE_TEST
 	depends on ARM || ARM64
 	depends on ARCH_ARTPEC || ARCH_EXYNOS || COMPILE_TEST
 	help
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 62febeb4e1de..5075ebe052a7 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -15,9 +15,11 @@
 #include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/percpu.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
+#include <linux/platform_device.h>
 #include <linux/clocksource.h>
 #include <linux/sched_clock.h>
 
@@ -217,6 +219,7 @@ static struct clocksource mct_frc = {
 	.mask		= CLOCKSOURCE_MASK(32),
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 	.resume		= exynos4_frc_resume,
+	.owner		= THIS_MODULE,
 };
 
 /*
@@ -241,7 +244,7 @@ static cycles_t exynos4_read_current_timer(void)
 }
 #endif
 
-static int __init exynos4_clocksource_init(bool frc_shared)
+static int exynos4_clocksource_init(bool frc_shared)
 {
 	/*
 	 * When the frc is shared, the main processor should have already
@@ -336,6 +339,7 @@ static struct clock_event_device mct_comp_device = {
 	.set_state_oneshot	= mct_set_state_shutdown,
 	.set_state_oneshot_stopped = mct_set_state_shutdown,
 	.tick_resume		= mct_set_state_shutdown,
+	.owner			= THIS_MODULE,
 };
 
 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
@@ -476,6 +480,7 @@ static int exynos4_mct_starting_cpu(unsigned int cpu)
 	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
 			CLOCK_EVT_FEAT_PERCPU;
 	evt->rating = MCT_CLKEVENTS_RATING;
+	evt->owner = THIS_MODULE;
 
 	exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
 
@@ -511,7 +516,7 @@ static int exynos4_mct_dying_cpu(unsigned int cpu)
 	return 0;
 }
 
-static int __init exynos4_timer_resources(struct device_node *np)
+static int exynos4_timer_resources(struct device_node *np)
 {
 	struct clk *mct_clk, *tick_clk;
 
@@ -539,7 +544,7 @@ static int __init exynos4_timer_resources(struct device_node *np)
  * @local_idx: array mapping CPU numbers to local timer indices
  * @nr_local: size of @local_idx array
  */
-static int __init exynos4_timer_interrupts(struct device_node *np,
+static int exynos4_timer_interrupts(struct device_node *np,
 					   unsigned int int_type,
 					   const u32 *local_idx,
 					   size_t nr_local)
@@ -652,7 +657,7 @@ static int __init exynos4_timer_interrupts(struct device_node *np,
 	return err;
 }
 
-static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
+static int mct_init_dt(struct device_node *np, unsigned int int_type)
 {
 	bool frc_shared = of_property_read_bool(np, "samsung,frc-shared");
 	u32 local_idx[MCT_NR_LOCAL] = {0};
@@ -700,15 +705,43 @@ static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
 	return exynos4_clockevent_init();
 }
 
-
-static int __init mct_init_spi(struct device_node *np)
+static int mct_init_spi(struct device_node *np)
 {
 	return mct_init_dt(np, MCT_INT_SPI);
 }
 
-static int __init mct_init_ppi(struct device_node *np)
+static int mct_init_ppi(struct device_node *np)
 {
 	return mct_init_dt(np, MCT_INT_PPI);
 }
-TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
-TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
+
+static int exynos4_mct_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int (*mct_init)(struct device_node *np);
+
+	mct_init = of_device_get_match_data(dev);
+	if (!mct_init)
+		return -EINVAL;
+
+	return mct_init(dev->of_node);
+}
+
+static const struct of_device_id exynos4_mct_match_table[] = {
+	{ .compatible = "samsung,exynos4210-mct", .data = &mct_init_spi, },
+	{ .compatible = "samsung,exynos4412-mct", .data = &mct_init_ppi, },
+	{}
+};
+MODULE_DEVICE_TABLE(of, exynos4_mct_match_table);
+
+static struct platform_driver exynos4_mct_driver = {
+	.probe		= exynos4_mct_probe,
+	.driver		= {
+		.name	= "exynos-mct",
+		.of_match_table = exynos4_mct_match_table,
+	},
+};
+module_platform_driver(exynos4_mct_driver);
+
+MODULE_DESCRIPTION("Exynos Multi Core Timer Driver");
+MODULE_LICENSE("GPL");
-- 
2.50.0.rc2.761.g2dc52ea45b-goog

Hi Will,


On 20/06/2025 20:17, Will McVicker wrote:

[ ... ]

> -TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
> -TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);

Was these changes tested on the ARM32 Exynos platforms ? Especially did 
you check if there is no boot time regression ?

> +static int exynos4_mct_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	int (*mct_init)(struct device_node *np);
> +
> +	mct_init = of_device_get_match_data(dev);
> +	if (!mct_init)
> +		return -EINVAL;
> +
> +	return mct_init(dev->of_node);
> +}
> +
> +static const struct of_device_id exynos4_mct_match_table[] = {
> +	{ .compatible = "samsung,exynos4210-mct", .data = &mct_init_spi, },
> +	{ .compatible = "samsung,exynos4412-mct", .data = &mct_init_ppi, },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, exynos4_mct_match_table);
> +
> +static struct platform_driver exynos4_mct_driver = {
> +	.probe		= exynos4_mct_probe,
> +	.driver		= {
> +		.name	= "exynos-mct",
> +		.of_match_table = exynos4_mct_match_table,
> +	},
> +};
> +module_platform_driver(exynos4_mct_driver);
> +
> +MODULE_DESCRIPTION("Exynos Multi Core Timer Driver");
> +MODULE_LICENSE("GPL");


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On Fri, Jun 20, 2025 at 11:17:08AM -0700, Will McVicker wrote:
> From: Donghoon Yu <hoony.yu@samsung.com>
> 
> On Arm64 platforms the Exynos MCT driver can be built as a module. On
> boot (and even after boot) the arch_timer is used as the clocksource and
> tick timer. Once the MCT driver is loaded, it can be used as the wakeup
> source for the arch_timer.
> 
> Signed-off-by: Donghoon Yu <hoony.yu@samsung.com>
> Signed-off-by: Youngmin Nam <youngmin.nam@samsung.com>
> [original commit from https://android.googlesource.com/kernel/gs/+/8a52a8288ec7d88ff78f0b37480dbb0e9c65bbfd]
> Reviewed-by: Youngmin Nam <youngmin.nam@samsung.com>
> Tested-by: Youngmin Nam <youngmin.nam@samsung.com>
> Signed-off-by: Will McVicker <willmcvicker@google.com>
> ---

...

> -static int __init mct_init_spi(struct device_node *np)

__init_or_module

> +static int mct_init_spi(struct device_node *np)
>  {
>  	return mct_init_dt(np, MCT_INT_SPI);
>  }
>  
> -static int __init mct_init_ppi(struct device_node *np)
> +static int mct_init_ppi(struct device_node *np)
>  {
>  	return mct_init_dt(np, MCT_INT_PPI);
>  }
> -TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
> -TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);

Are you sure this is not going to hurt the ARM platforms ? Here the
timer is enabled very early in the boot process while with this change
the timer will be available later.

> +static int exynos4_mct_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	int (*mct_init)(struct device_node *np);
> +
> +	mct_init = of_device_get_match_data(dev);
> +	if (!mct_init)
> +		return -EINVAL;
> +
> +	return mct_init(dev->of_node);
> +}
> +
> +static const struct of_device_id exynos4_mct_match_table[] = {
> +	{ .compatible = "samsung,exynos4210-mct", .data = &mct_init_spi, },
> +	{ .compatible = "samsung,exynos4412-mct", .data = &mct_init_ppi, },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, exynos4_mct_match_table);
> +
> +static struct platform_driver exynos4_mct_driver = {
> +	.probe		= exynos4_mct_probe,
> +	.driver		= {
> +		.name	= "exynos-mct",
> +		.of_match_table = exynos4_mct_match_table,
> +	},
> +};
> +module_platform_driver(exynos4_mct_driver);
> +
> +MODULE_DESCRIPTION("Exynos Multi Core Timer Driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.50.0.rc2.761.g2dc52ea45b-goog
> 

-- 

 <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

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On 06/24/2025, Daniel Lezcano wrote:
> On Fri, Jun 20, 2025 at 11:17:08AM -0700, Will McVicker wrote:
> > From: Donghoon Yu <hoony.yu@samsung.com>
> > 
> > On Arm64 platforms the Exynos MCT driver can be built as a module. On
> > boot (and even after boot) the arch_timer is used as the clocksource and
> > tick timer. Once the MCT driver is loaded, it can be used as the wakeup
> > source for the arch_timer.
> > 
> > Signed-off-by: Donghoon Yu <hoony.yu@samsung.com>
> > Signed-off-by: Youngmin Nam <youngmin.nam@samsung.com>
> > [original commit from https://android.googlesource.com/kernel/gs/+/8a52a8288ec7d88ff78f0b37480dbb0e9c65bbfd]
> > Reviewed-by: Youngmin Nam <youngmin.nam@samsung.com>
> > Tested-by: Youngmin Nam <youngmin.nam@samsung.com>
> > Signed-off-by: Will McVicker <willmcvicker@google.com>
> > ---
> 
> ...
> 
> > -static int __init mct_init_spi(struct device_node *np)
> 
> __init_or_module

Thanks, I'll update in v5.

> 
> > +static int mct_init_spi(struct device_node *np)
> >  {
> >  	return mct_init_dt(np, MCT_INT_SPI);
> >  }
> >  
> > -static int __init mct_init_ppi(struct device_node *np)
> > +static int mct_init_ppi(struct device_node *np)
> >  {
> >  	return mct_init_dt(np, MCT_INT_PPI);
> >  }
> > -TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
> > -TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
> 
> Are you sure this is not going to hurt the ARM platforms ? Here the
> timer is enabled very early in the boot process while with this change
> the timer will be available later.

I took a second look at the TIMER_OF_DECLARE() macro and FWICT the timer will
only be enabled "very early" via timer_probe() if "MODULE" is not defined which
is only defined when this specific driver is compiled as a module. Note, this
"MODULE" define is not the same as the Kconfig option "CONFIG_MODULES".
That is why in my v1 and v2 patch [1] I had:

 #ifdef MODULE
   ...
   module_platform_driver(exynos4_mct_driver);
 #else
   TIMER_OF_DECLARE(...)
   TIMER_OF_DECLARE(...)
 #endif

However, I dropped that since Saravana mentioned that we should not be using
TIMER_OF_DECLARE() for drivers that can be modules. I don't have an ARM Exynos
device to verify dropping TIMER_OF_DECLARE() is safe. So if you and Saravana
agree, I can work on creating a patch to define TIMER_OF_DECLARE_MODULE() like
you proposed in [2] to handle this for all the drivers that are used for both ARM and
ARM64 SoCs.

Thanks,
Will

[1] https://lore.kernel.org/all/6e6b0f5f-ac60-48bb-af6c-fa58658d2639@linaro.org/
[2] https://lore.kernel.org/all/f2f914aa-c554-4135-afaa-f075537ed929@linaro.org/

<snip>

Hi Will,

sorry I missed to add you in Cc but the following proposal help in the 
module conversion:

https://lore.kernel.org/all/20250625085715.889837-1-daniel.lezcano@linaro.org/


On 25/06/2025 01:47, William McVicker wrote:
> On 06/24/2025, Daniel Lezcano wrote:
>> On Fri, Jun 20, 2025 at 11:17:08AM -0700, Will McVicker wrote:
>>> From: Donghoon Yu <hoony.yu@samsung.com>
>>>
>>> On Arm64 platforms the Exynos MCT driver can be built as a module. On
>>> boot (and even after boot) the arch_timer is used as the clocksource and
>>> tick timer. Once the MCT driver is loaded, it can be used as the wakeup
>>> source for the arch_timer.
>>>
>>> Signed-off-by: Donghoon Yu <hoony.yu@samsung.com>
>>> Signed-off-by: Youngmin Nam <youngmin.nam@samsung.com>
>>> [original commit from https://android.googlesource.com/kernel/gs/+/8a52a8288ec7d88ff78f0b37480dbb0e9c65bbfd]
>>> Reviewed-by: Youngmin Nam <youngmin.nam@samsung.com>
>>> Tested-by: Youngmin Nam <youngmin.nam@samsung.com>
>>> Signed-off-by: Will McVicker <willmcvicker@google.com>
>>> ---
>>
>> ...
>>
>>> -static int __init mct_init_spi(struct device_node *np)
>>
>> __init_or_module
> 
> Thanks, I'll update in v5.
> 
>>
>>> +static int mct_init_spi(struct device_node *np)
>>>   {
>>>   	return mct_init_dt(np, MCT_INT_SPI);
>>>   }
>>>   
>>> -static int __init mct_init_ppi(struct device_node *np)
>>> +static int mct_init_ppi(struct device_node *np)
>>>   {
>>>   	return mct_init_dt(np, MCT_INT_PPI);
>>>   }
>>> -TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
>>> -TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
>>
>> Are you sure this is not going to hurt the ARM platforms ? Here the
>> timer is enabled very early in the boot process while with this change
>> the timer will be available later.
> 
> I took a second look at the TIMER_OF_DECLARE() macro and FWICT the timer will
> only be enabled "very early" via timer_probe() if "MODULE" is not defined which
> is only defined when this specific driver is compiled as a module. Note, this
> "MODULE" define is not the same as the Kconfig option "CONFIG_MODULES".
> That is why in my v1 and v2 patch [1] I had:
> 
>   #ifdef MODULE
>     ...
>     module_platform_driver(exynos4_mct_driver);
>   #else
>     TIMER_OF_DECLARE(...)
>     TIMER_OF_DECLARE(...)
>   #endif
> 
> However, I dropped that since Saravana mentioned that we should not be using
> TIMER_OF_DECLARE() for drivers that can be modules. I don't have an ARM Exynos
> device to verify dropping TIMER_OF_DECLARE() is safe. So if you and Saravana
> agree, I can work on creating a patch to define TIMER_OF_DECLARE_MODULE() like
> you proposed in [2] to handle this for all the drivers that are used for both ARM and
> ARM64 SoCs.
> 
> Thanks,
> Will
> 
> [1] https://lore.kernel.org/all/6e6b0f5f-ac60-48bb-af6c-fa58658d2639@linaro.org/
> [2] https://lore.kernel.org/all/f2f914aa-c554-4135-afaa-f075537ed929@linaro.org/
> 
> <snip>


-- 
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The following commit has been merged into the timers/clocksource branch of tip:

Commit-ID:     338007c44c7f97a068c455fef5a49a49cc9389de
Gitweb:        https://git.kernel.org/tip/338007c44c7f97a068c455fef5a49a49cc9389de
Author:        Donghoon Yu <hoony.yu@samsung.com>
AuthorDate:    Fri, 20 Jun 2025 11:17:08 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Fri, 25 Jul 2025 12:06:18 +02:00

clocksource/drivers/exynos_mct: Add module support

On Arm64 platforms the Exynos MCT driver can be built as a module. On
boot (and even after boot) the arch_timer is used as the clocksource and
tick timer. Once the MCT driver is loaded, it can be used as the wakeup
source for the arch_timer.

Original commit from:

  https://android.googlesource.com/kernel/gs/+/8a52a8288ec7d88ff78f0b37480dbb0e9c65bbfd]

Signed-off-by: Donghoon Yu <hoony.yu@samsung.com>
Signed-off-by: Youngmin Nam <youngmin.nam@samsung.com>
Signed-off-by: Will McVicker <willmcvicker@google.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250620181719.1399856-6-willmcvicker@google.com
---
 drivers/clocksource/Kconfig      |  3 +-
 drivers/clocksource/exynos_mct.c | 51 +++++++++++++++++++++++++------
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 645f517..d657c8d 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -451,7 +451,8 @@ config ATMEL_TCB_CLKSRC
 	  Support for Timer Counter Blocks on Atmel SoCs.
 
 config CLKSRC_EXYNOS_MCT
-	bool "Exynos multi core timer driver" if COMPILE_TEST
+	tristate "Exynos multi core timer driver" if ARM64
+	default y if ARCH_EXYNOS || COMPILE_TEST
 	depends on ARM || ARM64
 	depends on ARCH_ARTPEC || ARCH_EXYNOS || COMPILE_TEST
 	help
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 62febeb..5075ebe 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -15,9 +15,11 @@
 #include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/percpu.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
+#include <linux/platform_device.h>
 #include <linux/clocksource.h>
 #include <linux/sched_clock.h>
 
@@ -217,6 +219,7 @@ static struct clocksource mct_frc = {
 	.mask		= CLOCKSOURCE_MASK(32),
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 	.resume		= exynos4_frc_resume,
+	.owner		= THIS_MODULE,
 };
 
 /*
@@ -241,7 +244,7 @@ static cycles_t exynos4_read_current_timer(void)
 }
 #endif
 
-static int __init exynos4_clocksource_init(bool frc_shared)
+static int exynos4_clocksource_init(bool frc_shared)
 {
 	/*
 	 * When the frc is shared, the main processor should have already
@@ -336,6 +339,7 @@ static struct clock_event_device mct_comp_device = {
 	.set_state_oneshot	= mct_set_state_shutdown,
 	.set_state_oneshot_stopped = mct_set_state_shutdown,
 	.tick_resume		= mct_set_state_shutdown,
+	.owner			= THIS_MODULE,
 };
 
 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
@@ -476,6 +480,7 @@ static int exynos4_mct_starting_cpu(unsigned int cpu)
 	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
 			CLOCK_EVT_FEAT_PERCPU;
 	evt->rating = MCT_CLKEVENTS_RATING;
+	evt->owner = THIS_MODULE;
 
 	exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
 
@@ -511,7 +516,7 @@ static int exynos4_mct_dying_cpu(unsigned int cpu)
 	return 0;
 }
 
-static int __init exynos4_timer_resources(struct device_node *np)
+static int exynos4_timer_resources(struct device_node *np)
 {
 	struct clk *mct_clk, *tick_clk;
 
@@ -539,7 +544,7 @@ static int __init exynos4_timer_resources(struct device_node *np)
  * @local_idx: array mapping CPU numbers to local timer indices
  * @nr_local: size of @local_idx array
  */
-static int __init exynos4_timer_interrupts(struct device_node *np,
+static int exynos4_timer_interrupts(struct device_node *np,
 					   unsigned int int_type,
 					   const u32 *local_idx,
 					   size_t nr_local)
@@ -652,7 +657,7 @@ out_irq:
 	return err;
 }
 
-static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
+static int mct_init_dt(struct device_node *np, unsigned int int_type)
 {
 	bool frc_shared = of_property_read_bool(np, "samsung,frc-shared");
 	u32 local_idx[MCT_NR_LOCAL] = {0};
@@ -700,15 +705,43 @@ static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
 	return exynos4_clockevent_init();
 }
 
-
-static int __init mct_init_spi(struct device_node *np)
+static int mct_init_spi(struct device_node *np)
 {
 	return mct_init_dt(np, MCT_INT_SPI);
 }
 
-static int __init mct_init_ppi(struct device_node *np)
+static int mct_init_ppi(struct device_node *np)
 {
 	return mct_init_dt(np, MCT_INT_PPI);
 }
-TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
-TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
+
+static int exynos4_mct_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int (*mct_init)(struct device_node *np);
+
+	mct_init = of_device_get_match_data(dev);
+	if (!mct_init)
+		return -EINVAL;
+
+	return mct_init(dev->of_node);
+}
+
+static const struct of_device_id exynos4_mct_match_table[] = {
+	{ .compatible = "samsung,exynos4210-mct", .data = &mct_init_spi, },
+	{ .compatible = "samsung,exynos4412-mct", .data = &mct_init_ppi, },
+	{}
+};
+MODULE_DEVICE_TABLE(of, exynos4_mct_match_table);
+
+static struct platform_driver exynos4_mct_driver = {
+	.probe		= exynos4_mct_probe,
+	.driver		= {
+		.name	= "exynos-mct",
+		.of_match_table = exynos4_mct_match_table,
+	},
+};
+module_platform_driver(exynos4_mct_driver);
+
+MODULE_DESCRIPTION("Exynos Multi Core Timer Driver");
+MODULE_LICENSE("GPL");

The following commit has been merged into the timers/clocksource branch of tip:

Commit-ID:     5d86e479193babb6487c33bc01a464c54933eba6
Gitweb:        https://git.kernel.org/tip/5d86e479193babb6487c33bc01a464c54933eba6
Author:        Donghoon Yu <hoony.yu@samsung.com>
AuthorDate:    Fri, 20 Jun 2025 11:17:08 -07:00
Committer:     Daniel Lezcano <daniel.lezcano@linaro.org>
CommitterDate: Tue, 15 Jul 2025 13:00:51 +02:00

clocksource/drivers/exynos_mct: Add module support

On Arm64 platforms the Exynos MCT driver can be built as a module. On
boot (and even after boot) the arch_timer is used as the clocksource and
tick timer. Once the MCT driver is loaded, it can be used as the wakeup
source for the arch_timer.

Signed-off-by: Donghoon Yu <hoony.yu@samsung.com>
Signed-off-by: Youngmin Nam <youngmin.nam@samsung.com>
[original commit from https://android.googlesource.com/kernel/gs/+/8a52a8288ec7d88ff78f0b37480dbb0e9c65bbfd]
Reviewed-by: Youngmin Nam <youngmin.nam@samsung.com>
Tested-by: Youngmin Nam <youngmin.nam@samsung.com>
Signed-off-by: Will McVicker <willmcvicker@google.com>
Link: https://lore.kernel.org/r/20250620181719.1399856-6-willmcvicker@google.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/Kconfig      |  3 +-
 drivers/clocksource/exynos_mct.c | 51 +++++++++++++++++++++++++------
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 645f517..d657c8d 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -451,7 +451,8 @@ config ATMEL_TCB_CLKSRC
 	  Support for Timer Counter Blocks on Atmel SoCs.
 
 config CLKSRC_EXYNOS_MCT
-	bool "Exynos multi core timer driver" if COMPILE_TEST
+	tristate "Exynos multi core timer driver" if ARM64
+	default y if ARCH_EXYNOS || COMPILE_TEST
 	depends on ARM || ARM64
 	depends on ARCH_ARTPEC || ARCH_EXYNOS || COMPILE_TEST
 	help
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 62febeb..5075ebe 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -15,9 +15,11 @@
 #include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/percpu.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
+#include <linux/platform_device.h>
 #include <linux/clocksource.h>
 #include <linux/sched_clock.h>
 
@@ -217,6 +219,7 @@ static struct clocksource mct_frc = {
 	.mask		= CLOCKSOURCE_MASK(32),
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 	.resume		= exynos4_frc_resume,
+	.owner		= THIS_MODULE,
 };
 
 /*
@@ -241,7 +244,7 @@ static cycles_t exynos4_read_current_timer(void)
 }
 #endif
 
-static int __init exynos4_clocksource_init(bool frc_shared)
+static int exynos4_clocksource_init(bool frc_shared)
 {
 	/*
 	 * When the frc is shared, the main processor should have already
@@ -336,6 +339,7 @@ static struct clock_event_device mct_comp_device = {
 	.set_state_oneshot	= mct_set_state_shutdown,
 	.set_state_oneshot_stopped = mct_set_state_shutdown,
 	.tick_resume		= mct_set_state_shutdown,
+	.owner			= THIS_MODULE,
 };
 
 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
@@ -476,6 +480,7 @@ static int exynos4_mct_starting_cpu(unsigned int cpu)
 	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
 			CLOCK_EVT_FEAT_PERCPU;
 	evt->rating = MCT_CLKEVENTS_RATING;
+	evt->owner = THIS_MODULE;
 
 	exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
 
@@ -511,7 +516,7 @@ static int exynos4_mct_dying_cpu(unsigned int cpu)
 	return 0;
 }
 
-static int __init exynos4_timer_resources(struct device_node *np)
+static int exynos4_timer_resources(struct device_node *np)
 {
 	struct clk *mct_clk, *tick_clk;
 
@@ -539,7 +544,7 @@ static int __init exynos4_timer_resources(struct device_node *np)
  * @local_idx: array mapping CPU numbers to local timer indices
  * @nr_local: size of @local_idx array
  */
-static int __init exynos4_timer_interrupts(struct device_node *np,
+static int exynos4_timer_interrupts(struct device_node *np,
 					   unsigned int int_type,
 					   const u32 *local_idx,
 					   size_t nr_local)
@@ -652,7 +657,7 @@ out_irq:
 	return err;
 }
 
-static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
+static int mct_init_dt(struct device_node *np, unsigned int int_type)
 {
 	bool frc_shared = of_property_read_bool(np, "samsung,frc-shared");
 	u32 local_idx[MCT_NR_LOCAL] = {0};
@@ -700,15 +705,43 @@ static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
 	return exynos4_clockevent_init();
 }
 
-
-static int __init mct_init_spi(struct device_node *np)
+static int mct_init_spi(struct device_node *np)
 {
 	return mct_init_dt(np, MCT_INT_SPI);
 }
 
-static int __init mct_init_ppi(struct device_node *np)
+static int mct_init_ppi(struct device_node *np)
 {
 	return mct_init_dt(np, MCT_INT_PPI);
 }
-TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
-TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
+
+static int exynos4_mct_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int (*mct_init)(struct device_node *np);
+
+	mct_init = of_device_get_match_data(dev);
+	if (!mct_init)
+		return -EINVAL;
+
+	return mct_init(dev->of_node);
+}
+
+static const struct of_device_id exynos4_mct_match_table[] = {
+	{ .compatible = "samsung,exynos4210-mct", .data = &mct_init_spi, },
+	{ .compatible = "samsung,exynos4412-mct", .data = &mct_init_ppi, },
+	{}
+};
+MODULE_DEVICE_TABLE(of, exynos4_mct_match_table);
+
+static struct platform_driver exynos4_mct_driver = {
+	.probe		= exynos4_mct_probe,
+	.driver		= {
+		.name	= "exynos-mct",
+		.of_match_table = exynos4_mct_match_table,
+	},
+};
+module_platform_driver(exynos4_mct_driver);
+
+MODULE_DESCRIPTION("Exynos Multi Core Timer Driver");
+MODULE_LICENSE("GPL");