[PATCH 00/12] clocksource: improve Atmel TCB timer driver

[PATCH 00/12] clocksource: improve Atmel TCB timer driver

[Alexandre Belloni]

Hi,

This series immproves the Atmel TCB clocksource driver to address the
most urgent shortcomings:
 - the current tcb_clksrc driver is probed too late to be able to be used at
   boot and we now have SoCs that don't have a PIT. They currently are not able
   to boot an upstream kernel.
 - using the PIT doesn't work well with preempt-rt because its interrupt is
   shared (in particular with the UART) and their interrupt flags are
   incompatible). This also happen with the threadedirq command line
   switch.
 - there is currently no high resolution sched_clock.

The plan is to get those changes upstream as soon as possible as they
arre fixing real issues that people are facing. There are further
changes needed on the clocksource driver to try to stop wasting a TCB
channel.
the PWM TCB driver will also be changed to actually used the reviewed
binding and this will allow to get rif of atmel_tclib.

Alexandre Belloni (12):
  ARM: at91: move SoC specific definitions to SoC folder
  misc: atmel_tclib: drop AVR32 support
  misc: atmel_tclib: move definitions to header file
  clocksource/drivers/tcb_clksrc: stop depending on atmel_tclib
  clocksource/drivers/tcb_clksrc: Use tcb as sched_clock
  ARM: at91: Implement clocksource selection
  clocksource/drivers/tcb_clksrc: move Kconfig option
  clocksource/drivers/timer-atmel-pit: rework Kconfig option
  clocksource/drivers/tcb_clksrc: Rename the file for consistency
  ARM: configs: at91: unselect PIT
  misc: atmel_tclib: do not probe already used TCBs
  clocksource/drivers/timer-atmel-tcb: Use ARRAY_SIZE instead of  
    hardcoded size

 arch/arm/configs/at91_dt_defconfig            |   1 +
 arch/arm/configs/sama5_defconfig              |   1 +
 arch/arm/mach-at91/Kconfig                    |  23 ++++
 drivers/clocksource/Kconfig                   |  12 +-
 drivers/clocksource/Makefile                  |   2 +-
 .../{tcb_clksrc.c => timer-atmel-tcb.c}       | 123 ++++++++++++------
 drivers/misc/Kconfig                          |  24 ----
 drivers/misc/atmel_tclib.c                    |  37 +-----
 drivers/pwm/pwm-atmel-tcb.c                   |   2 +-
 .../atmel_tc.h => soc/at91/atmel_tcb.h}       |  25 +++-
 10 files changed, 146 insertions(+), 104 deletions(-)
 rename drivers/clocksource/{tcb_clksrc.c => timer-atmel-tcb.c} (81%)
 rename include/{linux/atmel_tc.h => soc/at91/atmel_tcb.h} (95%)

-- 
2.20.1

[PATCH 01/12] ARM: at91: move SoC specific definitions to SoC folder

[Alexandre Belloni]

Move linux/atmel_tc.h to the SoC specific folder include/soc/at91.

Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/clocksource/tcb_clksrc.c                   | 2 +-
 drivers/misc/atmel_tclib.c                         | 2 +-
 drivers/pwm/pwm-atmel-tcb.c                        | 2 +-
 include/{linux/atmel_tc.h => soc/at91/atmel_tcb.h} | 4 ++--
 4 files changed, 5 insertions(+), 5 deletions(-)
 rename include/{linux/atmel_tc.h => soc/at91/atmel_tcb.h} (99%)

diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
index 43f4d5c4d6fa..138a12090149 100644
--- a/drivers/clocksource/tcb_clksrc.c
+++ b/drivers/clocksource/tcb_clksrc.c
@@ -11,7 +11,7 @@
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/syscore_ops.h>
-#include <linux/atmel_tc.h>
+#include <soc/at91/atmel_tcb.h>
 
 
 /*
diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c
index ac24a4bd63f7..194f774ab3a1 100644
--- a/drivers/misc/atmel_tclib.c
+++ b/drivers/misc/atmel_tclib.c
@@ -1,4 +1,3 @@
-#include <linux/atmel_tc.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/init.h>
@@ -10,6 +9,7 @@
 #include <linux/slab.h>
 #include <linux/export.h>
 #include <linux/of.h>
+#include <soc/at91/atmel_tcb.h>
 
 /*
  * This is a thin library to solve the problem of how to portably allocate
diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c
index 0d0f8376bc35..d7e92fd552e4 100644
--- a/drivers/pwm/pwm-atmel-tcb.c
+++ b/drivers/pwm/pwm-atmel-tcb.c
@@ -17,7 +17,7 @@
 #include <linux/ioport.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
-#include <linux/atmel_tc.h>
+#include <soc/at91/atmel_tcb.h>
 #include <linux/pwm.h>
 #include <linux/of_device.h>
 #include <linux/slab.h>
diff --git a/include/linux/atmel_tc.h b/include/soc/at91/atmel_tcb.h
similarity index 99%
rename from include/linux/atmel_tc.h
rename to include/soc/at91/atmel_tcb.h
index 468fdfa643f0..c3c7200ce151 100644
--- a/include/linux/atmel_tc.h
+++ b/include/soc/at91/atmel_tcb.h
@@ -7,8 +7,8 @@
  * (at your option) any later version.
  */
 
-#ifndef ATMEL_TC_H
-#define ATMEL_TC_H
+#ifndef __SOC_ATMEL_TCB_H
+#define __SOC_ATMEL_TCB_H
 
 #include <linux/compiler.h>
 #include <linux/list.h>
-- 
2.20.1

Re: [PATCH 01/12] ARM: at91: move SoC specific definitions to SoC folder

[Thierry Reding]

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On Wed, Apr 03, 2019 at 04:11:09PM +0200, Alexandre Belloni wrote:
> Move linux/atmel_tc.h to the SoC specific folder include/soc/at91.
> 
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> ---
>  drivers/clocksource/tcb_clksrc.c                   | 2 +-
>  drivers/misc/atmel_tclib.c                         | 2 +-
>  drivers/pwm/pwm-atmel-tcb.c                        | 2 +-
>  include/{linux/atmel_tc.h => soc/at91/atmel_tcb.h} | 4 ++--
>  4 files changed, 5 insertions(+), 5 deletions(-)
>  rename include/{linux/atmel_tc.h => soc/at91/atmel_tcb.h} (99%)
> 
> diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
> index 43f4d5c4d6fa..138a12090149 100644
> --- a/drivers/clocksource/tcb_clksrc.c
> +++ b/drivers/clocksource/tcb_clksrc.c
> @@ -11,7 +11,7 @@
>  #include <linux/io.h>
>  #include <linux/platform_device.h>
>  #include <linux/syscore_ops.h>
> -#include <linux/atmel_tc.h>
> +#include <soc/at91/atmel_tcb.h>
>  
>  
>  /*
> diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c
> index ac24a4bd63f7..194f774ab3a1 100644
> --- a/drivers/misc/atmel_tclib.c
> +++ b/drivers/misc/atmel_tclib.c
> @@ -1,4 +1,3 @@
> -#include <linux/atmel_tc.h>
>  #include <linux/clk.h>
>  #include <linux/err.h>
>  #include <linux/init.h>
> @@ -10,6 +9,7 @@
>  #include <linux/slab.h>
>  #include <linux/export.h>
>  #include <linux/of.h>
> +#include <soc/at91/atmel_tcb.h>
>  
>  /*
>   * This is a thin library to solve the problem of how to portably allocate
> diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c
> index 0d0f8376bc35..d7e92fd552e4 100644
> --- a/drivers/pwm/pwm-atmel-tcb.c
> +++ b/drivers/pwm/pwm-atmel-tcb.c
> @@ -17,7 +17,7 @@
>  #include <linux/ioport.h>
>  #include <linux/io.h>
>  #include <linux/platform_device.h>
> -#include <linux/atmel_tc.h>
> +#include <soc/at91/atmel_tcb.h>

Sort this below the linux/* includes. With that:

Acked-by: Thierry Reding <thierry.reding@gmail.com>

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Re: [PATCH 01/12] ARM: at91: move SoC specific definitions to SoC folder

[Arnd Bergmann]

On Wed, Apr 3, 2019 at 9:36 PM Thierry Reding <thierry.reding@gmail.com> wrote:
>
> On Wed, Apr 03, 2019 at 04:11:09PM +0200, Alexandre Belloni wrote:
> > Move linux/atmel_tc.h to the SoC specific folder include/soc/at91.
> >
> > Cc: Thierry Reding <thierry.reding@gmail.com>
> > Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

>
> Acked-by: Thierry Reding <thierry.reding@gmail.com>

Acked-by: Arnd Bergmann <arnd@arndb.de>

[PATCH 02/12] misc: atmel_tclib: drop AVR32 support

[Alexandre Belloni]

AVR32 is gone from the kernel, remove its support from tclib.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/misc/atmel_tclib.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c
index 194f774ab3a1..3af27ce7e514 100644
--- a/drivers/misc/atmel_tclib.c
+++ b/drivers/misc/atmel_tclib.c
@@ -17,18 +17,10 @@
  * share individual timers between different drivers.
  */
 
-#if defined(CONFIG_AVR32)
-/* AVR32 has these divide PBB */
-const u8 atmel_tc_divisors[5] = { 0, 4, 8, 16, 32, };
-EXPORT_SYMBOL(atmel_tc_divisors);
-
-#elif defined(CONFIG_ARCH_AT91)
 /* AT91 has these divide MCK */
 const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
 EXPORT_SYMBOL(atmel_tc_divisors);
 
-#endif
-
 static DEFINE_SPINLOCK(tc_list_lock);
 static LIST_HEAD(tc_list);
 
-- 
2.20.1

[PATCH 03/12] misc: atmel_tclib: move definitions to header file

[Alexandre Belloni]

Move atmel_tc_divisors and atmel_tcb_dt_ids definitions to the header file
so they can be used without using tclib.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/misc/atmel_tclib.c   | 24 ------------------------
 include/soc/at91/atmel_tcb.h | 21 ++++++++++++++++++++-
 2 files changed, 20 insertions(+), 25 deletions(-)

diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c
index 3af27ce7e514..c79190525862 100644
--- a/drivers/misc/atmel_tclib.c
+++ b/drivers/misc/atmel_tclib.c
@@ -17,10 +17,6 @@
  * share individual timers between different drivers.
  */
 
-/* AT91 has these divide MCK */
-const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
-EXPORT_SYMBOL(atmel_tc_divisors);
-
 static DEFINE_SPINLOCK(tc_list_lock);
 static LIST_HEAD(tc_list);
 
@@ -72,26 +68,6 @@ void atmel_tc_free(struct atmel_tc *tc)
 EXPORT_SYMBOL_GPL(atmel_tc_free);
 
 #if defined(CONFIG_OF)
-static struct atmel_tcb_config tcb_rm9200_config = {
-	.counter_width = 16,
-};
-
-static struct atmel_tcb_config tcb_sam9x5_config = {
-	.counter_width = 32,
-};
-
-static const struct of_device_id atmel_tcb_dt_ids[] = {
-	{
-		.compatible = "atmel,at91rm9200-tcb",
-		.data = &tcb_rm9200_config,
-	}, {
-		.compatible = "atmel,at91sam9x5-tcb",
-		.data = &tcb_sam9x5_config,
-	}, {
-		/* sentinel */
-	}
-};
-
 MODULE_DEVICE_TABLE(of, atmel_tcb_dt_ids);
 #endif
 
diff --git a/include/soc/at91/atmel_tcb.h b/include/soc/at91/atmel_tcb.h
index c3c7200ce151..cb0c5f53cd46 100644
--- a/include/soc/at91/atmel_tcb.h
+++ b/include/soc/at91/atmel_tcb.h
@@ -76,8 +76,27 @@ extern struct atmel_tc *atmel_tc_alloc(unsigned block);
 extern void atmel_tc_free(struct atmel_tc *tc);
 
 /* platform-specific ATMEL_TC_TIMER_CLOCKx divisors (0 means 32KiHz) */
-extern const u8 atmel_tc_divisors[5];
+static const u8 atmel_tc_divisors[] = { 2, 8, 32, 128, 0, };
 
+static const struct atmel_tcb_config tcb_rm9200_config = {
+	.counter_width = 16,
+};
+
+static const struct atmel_tcb_config tcb_sam9x5_config = {
+	.counter_width = 32,
+};
+
+static const struct of_device_id atmel_tcb_dt_ids[] = {
+	{
+		.compatible = "atmel,at91rm9200-tcb",
+		.data = &tcb_rm9200_config,
+	}, {
+		.compatible = "atmel,at91sam9x5-tcb",
+		.data = &tcb_sam9x5_config,
+	}, {
+		/* sentinel */
+	}
+};
 
 /*
  * Two registers have block-wide controls.  These are: configuring the three
-- 
2.20.1

Re: [PATCH 03/12] misc: atmel_tclib: move definitions to header file

[Daniel Lezcano]

On 03/04/2019 16:11, Alexandre Belloni wrote:
> Move atmel_tc_divisors and atmel_tcb_dt_ids definitions to the header file
> so they can be used without using tclib.

Why not kill those structure and use the TIMER_OF_DECLARE with the
corresponding probe function which will initialize to 16 or 32 counter
width?



> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> ---
>  drivers/misc/atmel_tclib.c   | 24 ------------------------
>  include/soc/at91/atmel_tcb.h | 21 ++++++++++++++++++++-
>  2 files changed, 20 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c
> index 3af27ce7e514..c79190525862 100644
> --- a/drivers/misc/atmel_tclib.c
> +++ b/drivers/misc/atmel_tclib.c
> @@ -17,10 +17,6 @@
>   * share individual timers between different drivers.
>   */
>  
> -/* AT91 has these divide MCK */
> -const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
> -EXPORT_SYMBOL(atmel_tc_divisors);
> -
>  static DEFINE_SPINLOCK(tc_list_lock);
>  static LIST_HEAD(tc_list);
>  
> @@ -72,26 +68,6 @@ void atmel_tc_free(struct atmel_tc *tc)
>  EXPORT_SYMBOL_GPL(atmel_tc_free);
>  
>  #if defined(CONFIG_OF)
> -static struct atmel_tcb_config tcb_rm9200_config = {
> -	.counter_width = 16,
> -};
> -
> -static struct atmel_tcb_config tcb_sam9x5_config = {
> -	.counter_width = 32,
> -};
> -
> -static const struct of_device_id atmel_tcb_dt_ids[] = {
> -	{
> -		.compatible = "atmel,at91rm9200-tcb",
> -		.data = &tcb_rm9200_config,
> -	}, {
> -		.compatible = "atmel,at91sam9x5-tcb",
> -		.data = &tcb_sam9x5_config,
> -	}, {
> -		/* sentinel */
> -	}
> -};
> -
>  MODULE_DEVICE_TABLE(of, atmel_tcb_dt_ids);
>  #endif
>  
> diff --git a/include/soc/at91/atmel_tcb.h b/include/soc/at91/atmel_tcb.h
> index c3c7200ce151..cb0c5f53cd46 100644
> --- a/include/soc/at91/atmel_tcb.h
> +++ b/include/soc/at91/atmel_tcb.h
> @@ -76,8 +76,27 @@ extern struct atmel_tc *atmel_tc_alloc(unsigned block);
>  extern void atmel_tc_free(struct atmel_tc *tc);
>  
>  /* platform-specific ATMEL_TC_TIMER_CLOCKx divisors (0 means 32KiHz) */
> -extern const u8 atmel_tc_divisors[5];
> +static const u8 atmel_tc_divisors[] = { 2, 8, 32, 128, 0, };
>  
> +static const struct atmel_tcb_config tcb_rm9200_config = {
> +	.counter_width = 16,
> +};
> +
> +static const struct atmel_tcb_config tcb_sam9x5_config = {
> +	.counter_width = 32,
> +};
> +
> +static const struct of_device_id atmel_tcb_dt_ids[] = {
> +	{
> +		.compatible = "atmel,at91rm9200-tcb",
> +		.data = &tcb_rm9200_config,
> +	}, {
> +		.compatible = "atmel,at91sam9x5-tcb",
> +		.data = &tcb_sam9x5_config,
> +	}, {
> +		/* sentinel */
> +	}
> +};
>  
>  /*
>   * Two registers have block-wide controls.  These are: configuring the three
> 


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

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
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Re: [PATCH 03/12] misc: atmel_tclib: move definitions to header file

[Alexandre Belloni]

On 11/04/2019 17:00:26+0200, Daniel Lezcano wrote:
> On 03/04/2019 16:11, Alexandre Belloni wrote:
> > Move atmel_tc_divisors and atmel_tcb_dt_ids definitions to the header file
> > so they can be used without using tclib.
> 
> Why not kill those structure and use the TIMER_OF_DECLARE with the
> corresponding probe function which will initialize to 16 or 32 counter
> width?
> 

I'm dropping this patch and the structures but doing the differentiation
with TIMER_OF_DECLARE is not possible as this has to match
"atmel,tcb-timer" and the differentiation is done on the parent
compatible.

> 
> 
> > Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> > ---
> >  drivers/misc/atmel_tclib.c   | 24 ------------------------
> >  include/soc/at91/atmel_tcb.h | 21 ++++++++++++++++++++-
> >  2 files changed, 20 insertions(+), 25 deletions(-)
> > 
> > diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c
> > index 3af27ce7e514..c79190525862 100644
> > --- a/drivers/misc/atmel_tclib.c
> > +++ b/drivers/misc/atmel_tclib.c
> > @@ -17,10 +17,6 @@
> >   * share individual timers between different drivers.
> >   */
> >  
> > -/* AT91 has these divide MCK */
> > -const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
> > -EXPORT_SYMBOL(atmel_tc_divisors);
> > -
> >  static DEFINE_SPINLOCK(tc_list_lock);
> >  static LIST_HEAD(tc_list);
> >  
> > @@ -72,26 +68,6 @@ void atmel_tc_free(struct atmel_tc *tc)
> >  EXPORT_SYMBOL_GPL(atmel_tc_free);
> >  
> >  #if defined(CONFIG_OF)
> > -static struct atmel_tcb_config tcb_rm9200_config = {
> > -	.counter_width = 16,
> > -};
> > -
> > -static struct atmel_tcb_config tcb_sam9x5_config = {
> > -	.counter_width = 32,
> > -};
> > -
> > -static const struct of_device_id atmel_tcb_dt_ids[] = {
> > -	{
> > -		.compatible = "atmel,at91rm9200-tcb",
> > -		.data = &tcb_rm9200_config,
> > -	}, {
> > -		.compatible = "atmel,at91sam9x5-tcb",
> > -		.data = &tcb_sam9x5_config,
> > -	}, {
> > -		/* sentinel */
> > -	}
> > -};
> > -
> >  MODULE_DEVICE_TABLE(of, atmel_tcb_dt_ids);
> >  #endif
> >  
> > diff --git a/include/soc/at91/atmel_tcb.h b/include/soc/at91/atmel_tcb.h
> > index c3c7200ce151..cb0c5f53cd46 100644
> > --- a/include/soc/at91/atmel_tcb.h
> > +++ b/include/soc/at91/atmel_tcb.h
> > @@ -76,8 +76,27 @@ extern struct atmel_tc *atmel_tc_alloc(unsigned block);
> >  extern void atmel_tc_free(struct atmel_tc *tc);
> >  
> >  /* platform-specific ATMEL_TC_TIMER_CLOCKx divisors (0 means 32KiHz) */
> > -extern const u8 atmel_tc_divisors[5];
> > +static const u8 atmel_tc_divisors[] = { 2, 8, 32, 128, 0, };
> >  
> > +static const struct atmel_tcb_config tcb_rm9200_config = {
> > +	.counter_width = 16,
> > +};
> > +
> > +static const struct atmel_tcb_config tcb_sam9x5_config = {
> > +	.counter_width = 32,
> > +};
> > +
> > +static const struct of_device_id atmel_tcb_dt_ids[] = {
> > +	{
> > +		.compatible = "atmel,at91rm9200-tcb",
> > +		.data = &tcb_rm9200_config,
> > +	}, {
> > +		.compatible = "atmel,at91sam9x5-tcb",
> > +		.data = &tcb_sam9x5_config,
> > +	}, {
> > +		/* sentinel */
> > +	}
> > +};
> >  
> >  /*
> >   * Two registers have block-wide controls.  These are: configuring the three
> > 
> 
> 
> -- 
>  <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
> 
> Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
> <http://twitter.com/#!/linaroorg> Twitter |
> <http://www.linaro.org/linaro-blog/> Blog
> 

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

[PATCH 04/12] clocksource/drivers/tcb_clksrc: stop depending on atmel_tclib

[Alexandre Belloni]

atmel_tclib is probed too late in the boot process to be able to use the
TCB as the boot clocksource. This is an issue for SoCs without the PIT
(sams70, samv70 and samv71 families) as they simply currently can't boot.

Get rid of the atmel_tclib dependency and probe everything on our own using
the correct device tree binding.

This also allows getting rid of ATMEL_TCB_CLKSRC_BLOCK and makes the driver
a bit more flexible as the TCB is not hardcoded in the kernel anymore.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/clocksource/tcb_clksrc.c | 103 +++++++++++++++++++------------
 drivers/misc/Kconfig             |  14 +----
 2 files changed, 66 insertions(+), 51 deletions(-)

diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
index 138a12090149..c7eec9808289 100644
--- a/drivers/clocksource/tcb_clksrc.c
+++ b/drivers/clocksource/tcb_clksrc.c
@@ -9,7 +9,8 @@
 #include <linux/err.h>
 #include <linux/ioport.h>
 #include <linux/io.h>
-#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
 #include <linux/syscore_ops.h>
 #include <soc/at91/atmel_tcb.h>
 
@@ -28,13 +29,6 @@
  *     source, used in either periodic or oneshot mode.  This runs
  *     at 32 KiHZ, and can handle delays of up to two seconds.
  *
- * A boot clocksource and clockevent source are also currently needed,
- * unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so
- * this code can be used when init_timers() is called, well before most
- * devices are set up.  (Some low end AT91 parts, which can run uClinux,
- * have only the timers in one TC block... they currently don't support
- * the tclib code, because of that initialization issue.)
- *
  * REVISIT behavior during system suspend states... we should disable
  * all clocks and save the power.  Easily done for clockevent devices,
  * but clocksources won't necessarily get the needed notifications.
@@ -112,7 +106,6 @@ void tc_clksrc_resume(struct clocksource *cs)
 }
 
 static struct clocksource clksrc = {
-	.name           = "tcb_clksrc",
 	.rating         = 200,
 	.read           = tc_get_cycles,
 	.mask           = CLOCKSOURCE_MASK(32),
@@ -214,7 +207,6 @@ static int tc_next_event(unsigned long delta, struct clock_event_device *d)
 
 static struct tc_clkevt_device clkevt = {
 	.clkevt	= {
-		.name			= "tc_clkevt",
 		.features		= CLOCK_EVT_FEAT_PERIODIC |
 					  CLOCK_EVT_FEAT_ONESHOT,
 		/* Should be lower than at91rm9200's system timer */
@@ -330,33 +322,64 @@ static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_id
 	writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
 }
 
-static int __init tcb_clksrc_init(void)
+static int __init tcb_clksrc_init(struct device_node *node)
 {
-	static char bootinfo[] __initdata
-		= KERN_DEBUG "%s: tc%d at %d.%03d MHz\n";
-
-	struct platform_device *pdev;
-	struct atmel_tc *tc;
+	struct atmel_tc tc;
 	struct clk *t0_clk;
+	const struct of_device_id *match;
+	int irq;
 	u32 rate, divided_rate = 0;
 	int best_divisor_idx = -1;
 	int clk32k_divisor_idx = -1;
 	int i;
 	int ret;
 
-	tc = atmel_tc_alloc(CONFIG_ATMEL_TCB_CLKSRC_BLOCK);
-	if (!tc) {
-		pr_debug("can't alloc TC for clocksource\n");
-		return -ENODEV;
-	}
-	tcaddr = tc->regs;
-	pdev = tc->pdev;
+	/* Protect against multiple calls */
+	if (tcaddr)
+		return 0;
+
+	tc.regs = of_iomap(node->parent, 0);
+	if (!tc.regs)
+		return -ENXIO;
+
+	t0_clk = of_clk_get_by_name(node->parent, "t0_clk");
+	if (IS_ERR(t0_clk))
+		return PTR_ERR(t0_clk);
+
+	tc.slow_clk = of_clk_get_by_name(node->parent, "slow_clk");
+	if (IS_ERR(tc.slow_clk))
+		return PTR_ERR(tc.slow_clk);
+
+	irq = of_irq_get(node->parent, 0);
+	if (irq <= 0)
+		return -EINVAL;
+
+	tc.clk[0] = t0_clk;
+	tc.clk[1] = of_clk_get_by_name(node->parent, "t1_clk");
+	if (IS_ERR(tc.clk[1]))
+		tc.clk[1] = t0_clk;
+	tc.clk[2] = of_clk_get_by_name(node->parent, "t2_clk");
+	if (IS_ERR(tc.clk[2]))
+		tc.clk[2] = t0_clk;
+
+	tc.irq[0] = irq;
+	tc.irq[1] = of_irq_get(node->parent, 1);
+	if (tc.irq[1] <= 0)
+		tc.irq[1] = irq;
+	tc.irq[2] = of_irq_get(node->parent, 2);
+	if (tc.irq[2] <= 0)
+		tc.irq[2] = irq;
+
+	match = of_match_node(atmel_tcb_dt_ids, node->parent);
+	tc.tcb_config = match->data;
+
+	for (i = 0; i < ARRAY_SIZE(tc.irq); i++)
+		writel(ATMEL_TC_ALL_IRQ, tc.regs + ATMEL_TC_REG(i, IDR));
 
-	t0_clk = tc->clk[0];
 	ret = clk_prepare_enable(t0_clk);
 	if (ret) {
 		pr_debug("can't enable T0 clk\n");
-		goto err_free_tc;
+		return ret;
 	}
 
 	/* How fast will we be counting?  Pick something over 5 MHz.  */
@@ -381,27 +404,29 @@ static int __init tcb_clksrc_init(void)
 		best_divisor_idx = i;
 	}
 
-
-	printk(bootinfo, clksrc.name, CONFIG_ATMEL_TCB_CLKSRC_BLOCK,
-			divided_rate / 1000000,
+	clksrc.name = kbasename(node->parent->full_name);
+	clkevt.clkevt.name = kbasename(node->parent->full_name);
+	pr_debug("%s at %d.%03d MHz\n", clksrc.name, divided_rate / 1000000,
 			((divided_rate % 1000000) + 500) / 1000);
 
-	if (tc->tcb_config && tc->tcb_config->counter_width == 32) {
+	tcaddr = tc.regs;
+
+	if (tc.tcb_config->counter_width == 32) {
 		/* use apropriate function to read 32 bit counter */
 		clksrc.read = tc_get_cycles32;
 		/* setup ony channel 0 */
-		tcb_setup_single_chan(tc, best_divisor_idx);
+		tcb_setup_single_chan(&tc, best_divisor_idx);
 	} else {
-		/* tclib will give us three clocks no matter what the
+		/* we have three clocks no matter what the
 		 * underlying platform supports.
 		 */
-		ret = clk_prepare_enable(tc->clk[1]);
+		ret = clk_prepare_enable(tc.clk[1]);
 		if (ret) {
 			pr_debug("can't enable T1 clk\n");
 			goto err_disable_t0;
 		}
 		/* setup both channel 0 & 1 */
-		tcb_setup_dual_chan(tc, best_divisor_idx);
+		tcb_setup_dual_chan(&tc, best_divisor_idx);
 	}
 
 	/* and away we go! */
@@ -410,7 +435,7 @@ static int __init tcb_clksrc_init(void)
 		goto err_disable_t1;
 
 	/* channel 2:  periodic and oneshot timer support */
-	ret = setup_clkevents(tc, clk32k_divisor_idx);
+	ret = setup_clkevents(&tc, clk32k_divisor_idx);
 	if (ret)
 		goto err_unregister_clksrc;
 
@@ -420,14 +445,14 @@ static int __init tcb_clksrc_init(void)
 	clocksource_unregister(&clksrc);
 
 err_disable_t1:
-	if (!tc->tcb_config || tc->tcb_config->counter_width != 32)
-		clk_disable_unprepare(tc->clk[1]);
+	if (tc.tcb_config->counter_width != 32)
+		clk_disable_unprepare(tc.clk[1]);
 
 err_disable_t0:
 	clk_disable_unprepare(t0_clk);
 
-err_free_tc:
-	atmel_tc_free(tc);
+	tcaddr = NULL;
+
 	return ret;
 }
-arch_initcall(tcb_clksrc_init);
+TIMER_OF_DECLARE(atmel_tcb_clksrc, "atmel,tcb-timer", tcb_clksrc_init);
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 42ab8ec92a04..268a01d3d6f3 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -61,7 +61,8 @@ config ATMEL_TCLIB
 
 config ATMEL_TCB_CLKSRC
 	bool "TC Block Clocksource"
-	depends on ATMEL_TCLIB
+	depends on ARCH_AT91
+	select TIMER_OF if OF
 	default y
 	help
 	  Select this to get a high precision clocksource based on a
@@ -72,17 +73,6 @@ config ATMEL_TCB_CLKSRC
 	  may be used as a clock event device supporting oneshot mode
 	  (delays of up to two seconds) based on the 32 KiHz clock.
 
-config ATMEL_TCB_CLKSRC_BLOCK
-	int
-	depends on ATMEL_TCB_CLKSRC
-	default 0
-	range 0 1
-	help
-	  Some chips provide more than one TC block, so you have the
-	  choice of which one to use for the clock framework.  The other
-	  TC can be used for other purposes, such as PWM generation and
-	  interval timing.
-
 config DUMMY_IRQ
 	tristate "Dummy IRQ handler"
 	default n
-- 
2.20.1

Re: [PATCH 04/12] clocksource/drivers/tcb_clksrc: stop depending on atmel_tclib

[Daniel Lezcano]

On 03/04/2019 16:11, Alexandre Belloni wrote:
> atmel_tclib is probed too late in the boot process to be able to use the
> TCB as the boot clocksource. This is an issue for SoCs without the PIT
> (sams70, samv70 and samv71 families) as they simply currently can't boot.
> 
> Get rid of the atmel_tclib dependency and probe everything on our own using
> the correct device tree binding.
> 
> This also allows getting rid of ATMEL_TCB_CLKSRC_BLOCK and makes the driver
> a bit more flexible as the TCB is not hardcoded in the kernel anymore.
> 
> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> ---
>  drivers/clocksource/tcb_clksrc.c | 103 +++++++++++++++++++------------
>  drivers/misc/Kconfig             |  14 +----
>  2 files changed, 66 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
> index 138a12090149..c7eec9808289 100644
> --- a/drivers/clocksource/tcb_clksrc.c
> +++ b/drivers/clocksource/tcb_clksrc.c
> @@ -9,7 +9,8 @@
>  #include <linux/err.h>
>  #include <linux/ioport.h>
>  #include <linux/io.h>
> -#include <linux/platform_device.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
>  #include <linux/syscore_ops.h>
>  #include <soc/at91/atmel_tcb.h>
>  
> @@ -28,13 +29,6 @@
>   *     source, used in either periodic or oneshot mode.  This runs
>   *     at 32 KiHZ, and can handle delays of up to two seconds.
>   *
> - * A boot clocksource and clockevent source are also currently needed,
> - * unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so
> - * this code can be used when init_timers() is called, well before most
> - * devices are set up.  (Some low end AT91 parts, which can run uClinux,
> - * have only the timers in one TC block... they currently don't support
> - * the tclib code, because of that initialization issue.)
> - *
>   * REVISIT behavior during system suspend states... we should disable
>   * all clocks and save the power.  Easily done for clockevent devices,
>   * but clocksources won't necessarily get the needed notifications.
> @@ -112,7 +106,6 @@ void tc_clksrc_resume(struct clocksource *cs)
>  }
>  
>  static struct clocksource clksrc = {
> -	.name           = "tcb_clksrc",
>  	.rating         = 200,
>  	.read           = tc_get_cycles,
>  	.mask           = CLOCKSOURCE_MASK(32),
> @@ -214,7 +207,6 @@ static int tc_next_event(unsigned long delta, struct clock_event_device *d)
>  
>  static struct tc_clkevt_device clkevt = {
>  	.clkevt	= {
> -		.name			= "tc_clkevt",
>  		.features		= CLOCK_EVT_FEAT_PERIODIC |
>  					  CLOCK_EVT_FEAT_ONESHOT,
>  		/* Should be lower than at91rm9200's system timer */
> @@ -330,33 +322,64 @@ static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_id
>  	writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
>  }
>  
> -static int __init tcb_clksrc_init(void)
> +static int __init tcb_clksrc_init(struct device_node *node)
>  {
> -	static char bootinfo[] __initdata
> -		= KERN_DEBUG "%s: tc%d at %d.%03d MHz\n";
> -
> -	struct platform_device *pdev;
> -	struct atmel_tc *tc;
> +	struct atmel_tc tc;
>  	struct clk *t0_clk;
> +	const struct of_device_id *match;
> +	int irq;
>  	u32 rate, divided_rate = 0;
>  	int best_divisor_idx = -1;
>  	int clk32k_divisor_idx = -1;
>  	int i;
>  	int ret;
>  
> -	tc = atmel_tc_alloc(CONFIG_ATMEL_TCB_CLKSRC_BLOCK);
> -	if (!tc) {
> -		pr_debug("can't alloc TC for clocksource\n");
> -		return -ENODEV;
> -	}
> -	tcaddr = tc->regs;
> -	pdev = tc->pdev;
> +	/* Protect against multiple calls */
> +	if (tcaddr)
> +		return 0;
> +
> +	tc.regs = of_iomap(node->parent, 0);
> +	if (!tc.regs)
> +		return -ENXIO;
> +
> +	t0_clk = of_clk_get_by_name(node->parent, "t0_clk");
> +	if (IS_ERR(t0_clk))
> +		return PTR_ERR(t0_clk);
> +
> +	tc.slow_clk = of_clk_get_by_name(node->parent, "slow_clk");
> +	if (IS_ERR(tc.slow_clk))
> +		return PTR_ERR(tc.slow_clk);
> +
> +	irq = of_irq_get(node->parent, 0);
> +	if (irq <= 0)
> +		return -EINVAL;
> +
> +	tc.clk[0] = t0_clk;
> +	tc.clk[1] = of_clk_get_by_name(node->parent, "t1_clk");
> +	if (IS_ERR(tc.clk[1]))
> +		tc.clk[1] = t0_clk;
> +	tc.clk[2] = of_clk_get_by_name(node->parent, "t2_clk");
> +	if (IS_ERR(tc.clk[2]))
> +		tc.clk[2] = t0_clk;
> +	tc.irq[0] = irq;
> +	tc.irq[1] = of_irq_get(node->parent, 1);
> +	if (tc.irq[1] <= 0)
> +		tc.irq[1] = irq;
> +	tc.irq[2] = of_irq_get(node->parent, 2);
> +	if (tc.irq[2] <= 0)
> +		tc.irq[2] = irq;

Why are clk[1/2] and irq[1/2] defaulting back to t0 in case of error?


[ ... ]



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Re: [PATCH 04/12] clocksource/drivers/tcb_clksrc: stop depending on atmel_tclib

[Alexandre Belloni]

On 11/04/2019 18:19:34+0200, Daniel Lezcano wrote:
> > +	tc.clk[0] = t0_clk;
> > +	tc.clk[1] = of_clk_get_by_name(node->parent, "t1_clk");
> > +	if (IS_ERR(tc.clk[1]))
> > +		tc.clk[1] = t0_clk;
> > +	tc.clk[2] = of_clk_get_by_name(node->parent, "t2_clk");
> > +	if (IS_ERR(tc.clk[2]))
> > +		tc.clk[2] = t0_clk;
> > +	tc.irq[0] = irq;
> > +	tc.irq[1] = of_irq_get(node->parent, 1);
> > +	if (tc.irq[1] <= 0)
> > +		tc.irq[1] = irq;
> > +	tc.irq[2] = of_irq_get(node->parent, 2);
> > +	if (tc.irq[2] <= 0)
> > +		tc.irq[2] = irq;
> 
> Why are clk[1/2] and irq[1/2] defaulting back to t0 in case of error?
> 

This is how the DT binding is madewhen the same IRQ/clk is used for all
the channels of the TCB, then it is only specified once. Unfortunately,
this has to be kept to keep backward DT compatibility. Still, I'm
reworking the irq paring as the driver only needs the irq for channel 2.

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

[PATCH 05/12] clocksource/drivers/tcb_clksrc: Use tcb as sched_clock

[Alexandre Belloni]

Now that the driver is registered early enough, use the TCB as the
sched_clock which is much more accurate than the jiffies implementation.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/clocksource/tcb_clksrc.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
index c7eec9808289..10350dffd157 100644
--- a/drivers/clocksource/tcb_clksrc.c
+++ b/drivers/clocksource/tcb_clksrc.c
@@ -11,6 +11,7 @@
 #include <linux/io.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
+#include <linux/sched_clock.h>
 #include <linux/syscore_ops.h>
 #include <soc/at91/atmel_tcb.h>
 
@@ -114,6 +115,16 @@ static struct clocksource clksrc = {
 	.resume		= tc_clksrc_resume,
 };
 
+static u64 notrace tc_sched_clock_read(void)
+{
+	return tc_get_cycles(&clksrc);
+}
+
+static u64 notrace tc_sched_clock_read32(void)
+{
+	return tc_get_cycles32(&clksrc);
+}
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 
 struct tc_clkevt_device {
@@ -327,6 +338,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
 	struct atmel_tc tc;
 	struct clk *t0_clk;
 	const struct of_device_id *match;
+	u64 (*tc_sched_clock)(void);
 	int irq;
 	u32 rate, divided_rate = 0;
 	int best_divisor_idx = -1;
@@ -416,6 +428,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
 		clksrc.read = tc_get_cycles32;
 		/* setup ony channel 0 */
 		tcb_setup_single_chan(&tc, best_divisor_idx);
+		tc_sched_clock = tc_sched_clock_read32;
 	} else {
 		/* we have three clocks no matter what the
 		 * underlying platform supports.
@@ -427,6 +440,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
 		}
 		/* setup both channel 0 & 1 */
 		tcb_setup_dual_chan(&tc, best_divisor_idx);
+		tc_sched_clock = tc_sched_clock_read;
 	}
 
 	/* and away we go! */
@@ -439,6 +453,8 @@ static int __init tcb_clksrc_init(struct device_node *node)
 	if (ret)
 		goto err_unregister_clksrc;
 
+	sched_clock_register(tc_sched_clock, 32, divided_rate);
+
 	return 0;
 
 err_unregister_clksrc:
-- 
2.20.1

[PATCH 06/12] ARM: at91: Implement clocksource selection

[Alexandre Belloni]

Allow selecting and unselecting the PIT clocksource driver so it doesn't
have to be compiled when unused.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 arch/arm/mach-at91/Kconfig | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
index 903f23c309df..da1d97a06c53 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -107,6 +107,29 @@ config SOC_AT91SAM9
 	    AT91SAM9X35
 	    AT91SAM9XE
 
+comment "Clocksource driver selection"
+
+config ATMEL_CLOCKSOURCE_PIT
+	bool "Periodic Interval Timer (PIT) support"
+	depends on SOC_AT91SAM9 || SOC_SAMA5
+	default SOC_AT91SAM9 || SOC_SAMA5
+	select ATMEL_PIT
+	help
+	  Select this to get a clocksource based on the Atmel Periodic Interval
+	  Timer. It has a relatively low resolution and the TC Block clocksource
+	  should be preferred.
+
+config ATMEL_CLOCKSOURCE_TCB
+	bool "Timer Counter Blocks (TCB) support"
+	default SOC_AT91RM9200 || SOC_AT91SAM9 || SOC_SAMA5
+	select ATMEL_TCB_CLKSRC
+	help
+	  Select this to get a high precision clocksource based on a
+	  TC block with a 5+ MHz base clock rate.
+	  On platforms with 16-bit counters, two timer channels are combined
+	  to make a single 32-bit timer.
+	  It can also be used as a clock event device supporting oneshot mode.
+
 config HAVE_AT91_UTMI
 	bool
 
-- 
2.20.1

[PATCH 07/12] clocksource/drivers/tcb_clksrc: move Kconfig option

[Alexandre Belloni]

Move the ATMEL_TCB_CLKSRC option to drivers/clocksource and make it silent
if COMPILE_TEST is not selected.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/clocksource/Kconfig |  7 +++++++
 drivers/misc/Kconfig        | 14 --------------
 2 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 171502a356aa..e38ef4906e30 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -410,6 +410,13 @@ config ATMEL_ST
 	help
 	  Support for the Atmel ST timer.
 
+config ATMEL_TCB_CLKSRC
+	bool "Atmel TC Block timer driver" if COMPILE_TEST
+	depends on HAS_IOMEM
+	select TIMER_OF if OF
+	help
+	  Support for Timer Counter Blocks on Atmel SoCs.
+
 config CLKSRC_EXYNOS_MCT
 	bool "Exynos multi core timer driver" if COMPILE_TEST
 	depends on ARM || ARM64
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 268a01d3d6f3..c84033909395 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -59,20 +59,6 @@ config ATMEL_TCLIB
 	  blocks found on many Atmel processors.  This facilitates using
 	  these blocks by different drivers despite processor differences.
 
-config ATMEL_TCB_CLKSRC
-	bool "TC Block Clocksource"
-	depends on ARCH_AT91
-	select TIMER_OF if OF
-	default y
-	help
-	  Select this to get a high precision clocksource based on a
-	  TC block with a 5+ MHz base clock rate.  Two timer channels
-	  are combined to make a single 32-bit timer.
-
-	  When GENERIC_CLOCKEVENTS is defined, the third timer channel
-	  may be used as a clock event device supporting oneshot mode
-	  (delays of up to two seconds) based on the 32 KiHz clock.
-
 config DUMMY_IRQ
 	tristate "Dummy IRQ handler"
 	default n
-- 
2.20.1

[PATCH 08/12] clocksource/drivers/timer-atmel-pit: rework Kconfig option

[Alexandre Belloni]

Allow building the PIT driver when COMPILE_TEST is enabled. Also remove its
default value so it can be disabled.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/clocksource/Kconfig | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index e38ef4906e30..c73736f87600 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -399,8 +399,11 @@ config ARMV7M_SYSTICK
 	  This options enables support for the ARMv7M system timer unit
 
 config ATMEL_PIT
+	bool "Atmel PIT support" if COMPILE_TEST
+	depends on HAS_IOMEM
 	select TIMER_OF if OF
-	def_bool SOC_AT91SAM9 || SOC_SAMA5
+	help
+	  Support for the Periodic Interval Timer found on Atmel SoCs.
 
 config ATMEL_ST
 	bool "Atmel ST timer support" if COMPILE_TEST
-- 
2.20.1

[PATCH 09/12] clocksource/drivers/tcb_clksrc: Rename the file for consistency

[Alexandre Belloni]

For the sake of consistency, let's rename the file to a name similar
to other file names in this directory.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/clocksource/Makefile                            | 2 +-
 drivers/clocksource/{tcb_clksrc.c => timer-atmel-tcb.c} | 0
 2 files changed, 1 insertion(+), 1 deletion(-)
 rename drivers/clocksource/{tcb_clksrc.c => timer-atmel-tcb.c} (100%)

diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index be6e0fbc7489..923b9b60c909 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -3,7 +3,7 @@ obj-$(CONFIG_TIMER_OF)		+= timer-of.o
 obj-$(CONFIG_TIMER_PROBE)	+= timer-probe.o
 obj-$(CONFIG_ATMEL_PIT)		+= timer-atmel-pit.o
 obj-$(CONFIG_ATMEL_ST)		+= timer-atmel-st.o
-obj-$(CONFIG_ATMEL_TCB_CLKSRC)	+= tcb_clksrc.o
+obj-$(CONFIG_ATMEL_TCB_CLKSRC)	+= timer-atmel-tcb.o
 obj-$(CONFIG_X86_PM_TIMER)	+= acpi_pm.o
 obj-$(CONFIG_SCx200HR_TIMER)	+= scx200_hrt.o
 obj-$(CONFIG_CS5535_CLOCK_EVENT_SRC)	+= timer-cs5535.o
diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/timer-atmel-tcb.c
similarity index 100%
rename from drivers/clocksource/tcb_clksrc.c
rename to drivers/clocksource/timer-atmel-tcb.c
-- 
2.20.1

[PATCH 10/12] ARM: configs: at91: unselect PIT

[Alexandre Belloni]

The PIT is not required anymore to successfully boot and may actually harm
in case preempt-rt is used because the PIT interrupt is shared.
Disable it so the TCB clocksource is used.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 arch/arm/configs/at91_dt_defconfig | 1 +
 arch/arm/configs/sama5_defconfig   | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/arm/configs/at91_dt_defconfig b/arch/arm/configs/at91_dt_defconfig
index e4b1be66b3f5..c8876d0ca41a 100644
--- a/arch/arm/configs/at91_dt_defconfig
+++ b/arch/arm/configs/at91_dt_defconfig
@@ -19,6 +19,7 @@ CONFIG_ARCH_MULTI_V5=y
 CONFIG_ARCH_AT91=y
 CONFIG_SOC_AT91RM9200=y
 CONFIG_SOC_AT91SAM9=y
+# CONFIG_ATMEL_CLOCKSOURCE_PIT is not set
 CONFIG_AEABI=y
 CONFIG_UACCESS_WITH_MEMCPY=y
 CONFIG_ZBOOT_ROM_TEXT=0x0
diff --git a/arch/arm/configs/sama5_defconfig b/arch/arm/configs/sama5_defconfig
index b0026f73083d..10ebc9481f72 100644
--- a/arch/arm/configs/sama5_defconfig
+++ b/arch/arm/configs/sama5_defconfig
@@ -20,6 +20,7 @@ CONFIG_ARCH_AT91=y
 CONFIG_SOC_SAMA5D2=y
 CONFIG_SOC_SAMA5D3=y
 CONFIG_SOC_SAMA5D4=y
+# CONFIG_ATMEL_CLOCKSOURCE_PIT is not set
 CONFIG_AEABI=y
 CONFIG_UACCESS_WITH_MEMCPY=y
 CONFIG_ZBOOT_ROM_TEXT=0x0
-- 
2.20.1

[PATCH 11/12] misc: atmel_tclib: do not probe already used TCBs

[Alexandre Belloni]

The TCBs that have children are using the new (proper) DT bindings and
don't need to be handled by tclib.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/misc/atmel_tclib.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c
index c79190525862..b610cc894cd8 100644
--- a/drivers/misc/atmel_tclib.c
+++ b/drivers/misc/atmel_tclib.c
@@ -79,6 +79,9 @@ static int __init tc_probe(struct platform_device *pdev)
 	struct resource	*r;
 	unsigned int	i;
 
+	if (of_get_child_count(pdev->dev.of_node))
+		return 0;
+
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
 		return -EINVAL;
-- 
2.20.1

Re: [PATCH 11/12] misc: atmel_tclib: do not probe already used TCBs

[Greg Kroah-Hartman]

On Wed, Apr 03, 2019 at 04:11:19PM +0200, Alexandre Belloni wrote:
> The TCBs that have children are using the new (proper) DT bindings and
> don't need to be handled by tclib.
> 
> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> ---
>  drivers/misc/atmel_tclib.c | 3 +++
>  1 file changed, 3 insertions(+)
> 

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[PATCH 12/12] clocksource/drivers/timer-atmel-tcb: Use ARRAY_SIZE instead of hardcoded size

[Alexandre Belloni]

Use ARRAY_SIZE to replace the hardcoded size so we will never have a
mismatch.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/clocksource/timer-atmel-tcb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clocksource/timer-atmel-tcb.c b/drivers/clocksource/timer-atmel-tcb.c
index 10350dffd157..eab5beadf2ca 100644
--- a/drivers/clocksource/timer-atmel-tcb.c
+++ b/drivers/clocksource/timer-atmel-tcb.c
@@ -396,7 +396,7 @@ static int __init tcb_clksrc_init(struct device_node *node)
 
 	/* How fast will we be counting?  Pick something over 5 MHz.  */
 	rate = (u32) clk_get_rate(t0_clk);
-	for (i = 0; i < 5; i++) {
+	for (i = 0; i < ARRAY_SIZE(atmel_tc_divisors); i++) {
 		unsigned divisor = atmel_tc_divisors[i];
 		unsigned tmp;
 
-- 
2.20.1

Re: [PATCH 00/12] clocksource: improve Atmel TCB timer driver

[Daniel Lezcano]

Hi Alexandre,

except the comment for 3/12, the series looks good to me.



On 03/04/2019 16:11, Alexandre Belloni wrote:
> Hi,
> 
> This series immproves the Atmel TCB clocksource driver to address the
> most urgent shortcomings:
>  - the current tcb_clksrc driver is probed too late to be able to be used at
>    boot and we now have SoCs that don't have a PIT. They currently are not able
>    to boot an upstream kernel.
>  - using the PIT doesn't work well with preempt-rt because its interrupt is
>    shared (in particular with the UART) and their interrupt flags are
>    incompatible). This also happen with the threadedirq command line
>    switch.
>  - there is currently no high resolution sched_clock.
> 
> The plan is to get those changes upstream as soon as possible as they
> arre fixing real issues that people are facing. There are further
> changes needed on the clocksource driver to try to stop wasting a TCB
> channel.
> the PWM TCB driver will also be changed to actually used the reviewed
> binding and this will allow to get rif of atmel_tclib.
> 
> Alexandre Belloni (12):
>   ARM: at91: move SoC specific definitions to SoC folder
>   misc: atmel_tclib: drop AVR32 support
>   misc: atmel_tclib: move definitions to header file
>   clocksource/drivers/tcb_clksrc: stop depending on atmel_tclib
>   clocksource/drivers/tcb_clksrc: Use tcb as sched_clock
>   ARM: at91: Implement clocksource selection
>   clocksource/drivers/tcb_clksrc: move Kconfig option
>   clocksource/drivers/timer-atmel-pit: rework Kconfig option
>   clocksource/drivers/tcb_clksrc: Rename the file for consistency
>   ARM: configs: at91: unselect PIT
>   misc: atmel_tclib: do not probe already used TCBs
>   clocksource/drivers/timer-atmel-tcb: Use ARRAY_SIZE instead of  
>     hardcoded size
> 
>  arch/arm/configs/at91_dt_defconfig            |   1 +
>  arch/arm/configs/sama5_defconfig              |   1 +
>  arch/arm/mach-at91/Kconfig                    |  23 ++++
>  drivers/clocksource/Kconfig                   |  12 +-
>  drivers/clocksource/Makefile                  |   2 +-
>  .../{tcb_clksrc.c => timer-atmel-tcb.c}       | 123 ++++++++++++------
>  drivers/misc/Kconfig                          |  24 ----
>  drivers/misc/atmel_tclib.c                    |  37 +-----
>  drivers/pwm/pwm-atmel-tcb.c                   |   2 +-
>  .../atmel_tc.h => soc/at91/atmel_tcb.h}       |  25 +++-
>  10 files changed, 146 insertions(+), 104 deletions(-)
>  rename drivers/clocksource/{tcb_clksrc.c => timer-atmel-tcb.c} (81%)
>  rename include/{linux/atmel_tc.h => soc/at91/atmel_tcb.h} (95%)
> 


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