[PATCH v2 6/7] clocksource/drivers/exynos_mct: Add module support

Will McVicker
2025-04-03T00:06:50Z

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]
Signed-off-by: Will McVicker <willmcvicker@google.com>
---
drivers/clocksource/Kconfig | 3 +-
drivers/clocksource/exynos_mct.c | 49 +++++++++++++++++++++++++++-----
2 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 487c85259967..e89373827c3a 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -443,7 +443,8 @@ 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..8943274378be 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>

@@ -241,7 +243,7 @@ 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
@@ -511,7 +513,7 @@ 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 +541,7 @@ 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 +654,7 @@ 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 +702,48 @@ 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);
}
+
+#ifdef MODULE
+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);
+#else
TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
+#endif
+
+MODULE_DESCRIPTION("Exynos Multi Core Timer Driver");
+MODULE_LICENSE("GPL");
--
2.49.0.472.ge94155a9ec-goog