[PATCH v5 0/4] Support timer drivers as loadable modules

[PATCH v5 0/4] Support timer drivers as loadable modules

[walter.chang]

From: Walter Chang <walter.chang@mediatek.com>

This set of patches aims to make SoC related timer drivers, such as 
timer-mediatek.c become loadable modules for the Generic Kernel Image
(GKI).

This driver registers an always-on timer as tick_broadcast_device on 
MediaTek SoCs. If the system does not load this module at startup, 
system will also boot normally by using built-in `bc_hrtimer` instead.
Besides, the previous experiment [1] indicates that the SYST/GPT, in 
combination with a loadable module, is fully operational.

The first three patches export functions and remove __init markings to 
support loadable timer modules.

The fourth patch makes timer-mediatek.c become loadable module for GKI.

[1]
https://lore.kernel.org/all/32777456f8e0f98e4cd5b950f421d21f71b149cf.camel@mediatek.com/#t

[v5]
- Add Signed-off-by tags in all patches
- Add Acked-by tags and Reviewed-by tags

[v4]
- Fix review comments pointed by Angelo

[v3]
- Rebase on linux-next

[v2]
- Convert timer-mediatek.c driver to loadable module

Chun-Hung Wu (4):
  time/sched_clock: Export sched_clock_register()
  clocksource/drivers/mmio: Export clocksource_mmio_init()
  clocksource/drivers/timer-of: Remove __init markings
  clocksource/drivers/timer-mediatek: Make timer-mediatek become
    loadable module

 drivers/clocksource/Kconfig          |  2 +-
 drivers/clocksource/mmio.c           |  8 ++++---
 drivers/clocksource/timer-mediatek.c | 33 ++++++++++++++++++++++++++++
 drivers/clocksource/timer-of.c       | 23 +++++++++----------
 drivers/clocksource/timer-of.h       |  6 ++---
 kernel/time/sched_clock.c            |  4 ++--
 6 files changed, 56 insertions(+), 20 deletions(-)

-- 
2.18.0


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[PATCH v5 1/4] time/sched_clock: Export sched_clock_register()

[walter.chang]

From: Chun-Hung Wu <chun-hung.wu@mediatek.com>

clocksource driver may use sched_clock_register()
to resigter itself as a sched_clock source.
Export it to support building such driver
as module, like timer-mediatek.c

Signed-off-by: Chun-Hung Wu <chun-hung.wu@mediatek.com>
Signed-off-by: Walter Chang <walter.chang@mediatek.com>
Acked-by: John Stultz <jstultz@google.com>
---
 kernel/time/sched_clock.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index 8464c5acc913..8e49e87d1221 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -150,8 +150,7 @@ static enum hrtimer_restart sched_clock_poll(struct hrtimer *hrt)
 	return HRTIMER_RESTART;
 }
 
-void __init
-sched_clock_register(u64 (*read)(void), int bits, unsigned long rate)
+void sched_clock_register(u64 (*read)(void), int bits, unsigned long rate)
 {
 	u64 res, wrap, new_mask, new_epoch, cyc, ns;
 	u32 new_mult, new_shift;
@@ -223,6 +222,7 @@ sched_clock_register(u64 (*read)(void), int bits, unsigned long rate)
 
 	pr_debug("Registered %pS as sched_clock source\n", read);
 }
+EXPORT_SYMBOL_GPL(sched_clock_register);
 
 void __init generic_sched_clock_init(void)
 {
-- 
2.18.0


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Re: [PATCH v5 1/4] time/sched_clock: Export sched_clock_register()

[Carlos Llamas]

On Wed, May 17, 2023 at 10:25:45AM +0800, walter.chang@mediatek.com wrote:
> From: Chun-Hung Wu <chun-hung.wu@mediatek.com>
> 
> clocksource driver may use sched_clock_register()
> to resigter itself as a sched_clock source.

nit: typo s/resigter/register

> Export it to support building such driver
> as module, like timer-mediatek.c
> 
> Signed-off-by: Chun-Hung Wu <chun-hung.wu@mediatek.com>
> Signed-off-by: Walter Chang <walter.chang@mediatek.com>
> Acked-by: John Stultz <jstultz@google.com>
> ---

Reviewed-by: Carlos Llamas <cmllamas@google.com>

Thanks

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[PATCH v5 2/4] clocksource/drivers/mmio: Export clocksource_mmio_init()

[walter.chang]

From: Chun-Hung Wu <chun-hung.wu@mediatek.com>

Export clocksource_mmio_init() and clocksource_mmio_readl_up()
to support building clocksource driver as module,
such as timer-mediatek.c.

Signed-off-by: Chun-Hung Wu <chun-hung.wu@mediatek.com>
Signed-off-by: Walter Chang <walter.chang@mediatek.com>
Acked-by: John Stultz <jstultz@google.com>
---
 drivers/clocksource/mmio.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/clocksource/mmio.c b/drivers/clocksource/mmio.c
index 9de751531831..b08b2f9d7a8b 100644
--- a/drivers/clocksource/mmio.c
+++ b/drivers/clocksource/mmio.c
@@ -21,6 +21,7 @@ u64 clocksource_mmio_readl_up(struct clocksource *c)
 {
 	return (u64)readl_relaxed(to_mmio_clksrc(c)->reg);
 }
+EXPORT_SYMBOL_GPL(clocksource_mmio_readl_up);
 
 u64 clocksource_mmio_readl_down(struct clocksource *c)
 {
@@ -46,9 +47,9 @@ u64 clocksource_mmio_readw_down(struct clocksource *c)
  * @bits:	Number of valid bits
  * @read:	One of clocksource_mmio_read*() above
  */
-int __init clocksource_mmio_init(void __iomem *base, const char *name,
-	unsigned long hz, int rating, unsigned bits,
-	u64 (*read)(struct clocksource *))
+int clocksource_mmio_init(void __iomem *base, const char *name,
+			  unsigned long hz, int rating, unsigned bits,
+			  u64 (*read)(struct clocksource *))
 {
 	struct clocksource_mmio *cs;
 
@@ -68,3 +69,4 @@ int __init clocksource_mmio_init(void __iomem *base, const char *name,
 
 	return clocksource_register_hz(&cs->clksrc, hz);
 }
+EXPORT_SYMBOL_GPL(clocksource_mmio_init);
-- 
2.18.0


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[PATCH v5 3/4] clocksource/drivers/timer-of: Remove __init markings

[walter.chang]

From: Chun-Hung Wu <chun-hung.wu@mediatek.com>

Remove __init markings to allow timer drivers
can be compiled as modules.

Signed-off-by: Chun-Hung Wu <chun-hung.wu@mediatek.com>
Signed-off-by: Walter Chang <walter.chang@mediatek.com>
Acked-by: John Stultz <jstultz@google.com>
---
 drivers/clocksource/timer-of.c | 23 ++++++++++++-----------
 drivers/clocksource/timer-of.h |  6 +++---
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/clocksource/timer-of.c b/drivers/clocksource/timer-of.c
index c3f54d9912be..59bc5921acad 100644
--- a/drivers/clocksource/timer-of.c
+++ b/drivers/clocksource/timer-of.c
@@ -19,7 +19,7 @@
  *
  * Free the irq resource
  */
-static __init void timer_of_irq_exit(struct of_timer_irq *of_irq)
+static void timer_of_irq_exit(struct of_timer_irq *of_irq)
 {
 	struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
 
@@ -47,8 +47,8 @@ static __init void timer_of_irq_exit(struct of_timer_irq *of_irq)
  *
  * Returns 0 on success, < 0 otherwise
  */
-static __init int timer_of_irq_init(struct device_node *np,
-				    struct of_timer_irq *of_irq)
+static int timer_of_irq_init(struct device_node *np,
+			     struct of_timer_irq *of_irq)
 {
 	int ret;
 	struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
@@ -91,7 +91,7 @@ static __init int timer_of_irq_init(struct device_node *np,
  *
  * Disables and releases the refcount on the clk
  */
-static __init void timer_of_clk_exit(struct of_timer_clk *of_clk)
+static void timer_of_clk_exit(struct of_timer_clk *of_clk)
 {
 	of_clk->rate = 0;
 	clk_disable_unprepare(of_clk->clk);
@@ -107,8 +107,8 @@ static __init void timer_of_clk_exit(struct of_timer_clk *of_clk)
  *
  * Returns 0 on success, < 0 otherwise
  */
-static __init int timer_of_clk_init(struct device_node *np,
-				    struct of_timer_clk *of_clk)
+static int timer_of_clk_init(struct device_node *np,
+			     struct of_timer_clk *of_clk)
 {
 	int ret;
 
@@ -146,13 +146,13 @@ static __init int timer_of_clk_init(struct device_node *np,
 	goto out;
 }
 
-static __init void timer_of_base_exit(struct of_timer_base *of_base)
+static void timer_of_base_exit(struct of_timer_base *of_base)
 {
 	iounmap(of_base->base);
 }
 
-static __init int timer_of_base_init(struct device_node *np,
-				     struct of_timer_base *of_base)
+static int timer_of_base_init(struct device_node *np,
+			      struct of_timer_base *of_base)
 {
 	of_base->base = of_base->name ?
 		of_io_request_and_map(np, of_base->index, of_base->name) :
@@ -165,7 +165,7 @@ static __init int timer_of_base_init(struct device_node *np,
 	return 0;
 }
 
-int __init timer_of_init(struct device_node *np, struct timer_of *to)
+int timer_of_init(struct device_node *np, struct timer_of *to)
 {
 	int ret = -EINVAL;
 	int flags = 0;
@@ -209,6 +209,7 @@ int __init timer_of_init(struct device_node *np, struct timer_of *to)
 		timer_of_base_exit(&to->of_base);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(timer_of_init);
 
 /**
  * timer_of_cleanup - release timer_of resources
@@ -217,7 +218,7 @@ int __init timer_of_init(struct device_node *np, struct timer_of *to)
  * Release the resources that has been used in timer_of_init().
  * This function should be called in init error cases
  */
-void __init timer_of_cleanup(struct timer_of *to)
+void timer_of_cleanup(struct timer_of *to)
 {
 	if (to->flags & TIMER_OF_IRQ)
 		timer_of_irq_exit(&to->of_irq);
diff --git a/drivers/clocksource/timer-of.h b/drivers/clocksource/timer-of.h
index a5478f3e8589..5d1472846346 100644
--- a/drivers/clocksource/timer-of.h
+++ b/drivers/clocksource/timer-of.h
@@ -66,9 +66,9 @@ static inline unsigned long timer_of_period(struct timer_of *to)
 	return to->of_clk.period;
 }
 
-extern int __init timer_of_init(struct device_node *np,
-				struct timer_of *to);
+extern int timer_of_init(struct device_node *np,
+			 struct timer_of *to);
 
-extern void __init timer_of_cleanup(struct timer_of *to);
+extern void timer_of_cleanup(struct timer_of *to);
 
 #endif
-- 
2.18.0


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[PATCH v5 4/4] clocksource/drivers/timer-mediatek: Make timer-mediatek become loadable module

[walter.chang]

From: Chun-Hung Wu <chun-hung.wu@mediatek.com>

Make the timer-mediatek driver which can register
an always-on timer as tick_broadcast_device on
MediaTek SoCs become loadable module in GKI.

Signed-off-by: Chun-Hung Wu <chun-hung.wu@mediatek.com>
Signed-off-by: Walter Chang <walter.chang@mediatek.com>
Tested-by: Walter Chang <walter.chang@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/clocksource/Kconfig          |  2 +-
 drivers/clocksource/timer-mediatek.c | 33 ++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 526382dc7482..62103c0807f7 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -472,7 +472,7 @@ config SYS_SUPPORTS_SH_CMT
 	bool
 
 config MTK_TIMER
-	bool "Mediatek timer driver" if COMPILE_TEST
+	tristate "MediaTek timer driver"
 	depends on HAS_IOMEM
 	select TIMER_OF
 	select CLKSRC_MMIO
diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
index 7bcb4a3f26fb..afeacb509481 100644
--- a/drivers/clocksource/timer-mediatek.c
+++ b/drivers/clocksource/timer-mediatek.c
@@ -13,6 +13,9 @@
 #include <linux/clocksource.h>
 #include <linux/interrupt.h>
 #include <linux/irqreturn.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
 #include <linux/sched_clock.h>
 #include <linux/slab.h>
 #include "timer-of.h"
@@ -337,5 +340,35 @@ static int __init mtk_gpt_init(struct device_node *node)
 
 	return 0;
 }
+
+#ifndef MODULE
 TIMER_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_gpt_init);
 TIMER_OF_DECLARE(mtk_mt6765, "mediatek,mt6765-timer", mtk_syst_init);
+#else
+static int mtk_timer_probe(struct platform_device *pdev)
+{
+	int (*timer_init)(struct device_node *node);
+	struct device_node *np = pdev->dev.of_node;
+
+	timer_init = of_device_get_match_data(&pdev->dev);
+	return timer_init(np);
+}
+
+static const struct of_device_id mtk_timer_match_table[] = {
+	{ .compatible = "mediatek,mt6577-timer", .data = mtk_gpt_init },
+	{ .compatible = "mediatek,mt6765-timer", .data = mtk_syst_init },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver mtk_timer_driver = {
+	.probe = mtk_timer_probe,
+	.driver = {
+		.name = "mediatek-timer",
+		.of_match_table = mtk_timer_match_table,
+	},
+};
+module_platform_driver(mtk_timer_driver);
+
+MODULE_DESCRIPTION("MediaTek Timer driver");
+MODULE_LICENSE("GPL v2");
+#endif
-- 
2.18.0


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Re: [PATCH v5 4/4] clocksource/drivers/timer-mediatek: Make timer-mediatek become loadable module

[Alexandre Mergnat]

On 17/05/2023 04:25, walter.chang@mediatek.com wrote:
> Make the timer-mediatek driver which can register
> an always-on timer as tick_broadcast_device on
> MediaTek SoCs become loadable module in GKI.

Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>



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Re: [PATCH v5 0/4] Support timer drivers as loadable modules

[Daniel Lezcano]

As I already said, I'm not very comfortable with these changes and the 
potential impact it can have on the overall time framework.

I will pick the series if Thomas gives its Acked-by

Thanks


On 17/05/2023 04:25, walter.chang@mediatek.com wrote:
> From: Walter Chang <walter.chang@mediatek.com>
> 
> This set of patches aims to make SoC related timer drivers, such as
> timer-mediatek.c become loadable modules for the Generic Kernel Image
> (GKI).
> 
> This driver registers an always-on timer as tick_broadcast_device on
> MediaTek SoCs. If the system does not load this module at startup,
> system will also boot normally by using built-in `bc_hrtimer` instead.
> Besides, the previous experiment [1] indicates that the SYST/GPT, in
> combination with a loadable module, is fully operational.
> 
> The first three patches export functions and remove __init markings to
> support loadable timer modules.
> 
> The fourth patch makes timer-mediatek.c become loadable module for GKI.
> 
> [1]
> https://lore.kernel.org/all/32777456f8e0f98e4cd5b950f421d21f71b149cf.camel@mediatek.com/#t
> 
> [v5]
> - Add Signed-off-by tags in all patches
> - Add Acked-by tags and Reviewed-by tags
> 
> [v4]
> - Fix review comments pointed by Angelo
> 
> [v3]
> - Rebase on linux-next
> 
> [v2]
> - Convert timer-mediatek.c driver to loadable module
> 
> Chun-Hung Wu (4):
>    time/sched_clock: Export sched_clock_register()
>    clocksource/drivers/mmio: Export clocksource_mmio_init()
>    clocksource/drivers/timer-of: Remove __init markings
>    clocksource/drivers/timer-mediatek: Make timer-mediatek become
>      loadable module
> 
>   drivers/clocksource/Kconfig          |  2 +-
>   drivers/clocksource/mmio.c           |  8 ++++---
>   drivers/clocksource/timer-mediatek.c | 33 ++++++++++++++++++++++++++++
>   drivers/clocksource/timer-of.c       | 23 +++++++++----------
>   drivers/clocksource/timer-of.h       |  6 ++---
>   kernel/time/sched_clock.c            |  4 ++--
>   6 files changed, 56 insertions(+), 20 deletions(-)
> 

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