[PATCH 0/4] Add support for the Cortex A5 global timer

[PATCH 0/4] Add support for the Cortex A5 global timer

[Matthew Leach]

This patch series adds support for the global timer with the Cortex
A5. This is relatively simple patch series and mainly consists of:

 - Update a check in the drive probe code for an unusable global timer
   to be non-specific to the A9.
 - Add the appropriate device tree node and Kconfig options.
 - Add a compatible node for the specifc A5 global timer in the DT
   binding.

Any comments welcome.
Matt

Matthew Leach (4):
  clocksource: arm_global_timer: Only check for unusable timer on A9
  documentaion: DT: allow a A5 compatible string in global timer
  dts: ca5: add the global timer for the A5
  KConfig: Vexpress: build the ARM_GLOBAL_TIMER with vexpress platform

 Documentation/devicetree/bindings/arm/global_timer.txt |  6 ++++--
 arch/arm/boot/dts/vexpress-v2p-ca5s.dts                | 10 +++++++++-
 arch/arm/mach-vexpress/Kconfig                         |  1 +
 drivers/clocksource/arm_global_timer.c                 |  5 +++--
 4 files changed, 17 insertions(+), 5 deletions(-)

-- 
1.8.5.3

[PATCH 1/4] clocksource: arm_global_timer: Only check for unusable timer on A9

[Matthew Leach]

The check for a usable global timer in the probe code does not enquire
which CPU we are currently running on. This can cause the driver to
incorrectly assume we have an unusable global timer if we are running
on a CPU other than A9.

Before checking the CPU revision, ensure we are running on an A9 CPU.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
---
 drivers/clocksource/arm_global_timer.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c
index 0fc31d0..60e5a170 100644
--- a/drivers/clocksource/arm_global_timer.c
+++ b/drivers/clocksource/arm_global_timer.c
@@ -246,11 +246,12 @@ static void __init global_timer_of_register(struct device_node *np)
 	int err = 0;
 
 	/*
-	 * In r2p0 the comparators for each processor with the global timer
+	 * In A9 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) {
+	if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9
+	    && (read_cpuid_id() & 0xf0000f) < 0x200000) {
 		pr_warn("global-timer: non support for this cpu version.\n");
 		return;
 	}
-- 
1.8.5.3

[PATCH 2/4] documentaion: DT: allow a A5 compatible string in global timer

[Matthew Leach]

The global timer is present on the Cortex A5. Add a compatibility
string to the DT binding to allow a Cortex A5 global timer.

Signed-off-by: Matthew Leach <matthew.leach@arm.com>
---
 Documentation/devicetree/bindings/arm/global_timer.txt | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
index 1e54898..0932891 100644
--- a/Documentation/devicetree/bindings/arm/global_timer.txt
+++ b/Documentation/devicetree/bindings/arm/global_timer.txt
@@ -4,8 +4,10 @@
 
 ** Timer node required properties:
 
-- compatible : Should be "arm,cortex-a9-global-timer"
-		Driver supports versions r2p0 and above.
+- compatible : should contain
+	     * "arm,cortex-a5-global-timer" for Cortex-A5 global timers.
+	     * "arm,cortex-a9-global-timer" for Cortex-A9 global timers
+	         or any compatible implementation.
 
 - interrupts : One interrupt to each core
 
-- 
1.8.5.3

[PATCH 3/4] dts: ca5: add the global timer for the A5

[Matthew Leach]

The Cortex A5 contains a global timer: add the appropriate device tree
node.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
---
 arch/arm/boot/dts/vexpress-v2p-ca5s.dts | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/vexpress-v2p-ca5s.dts b/arch/arm/boot/dts/vexpress-v2p-ca5s.dts
index c544a55..d2709b7 100644
--- a/arch/arm/boot/dts/vexpress-v2p-ca5s.dts
+++ b/arch/arm/boot/dts/vexpress-v2p-ca5s.dts
@@ -88,6 +88,14 @@
 		interrupts = <1 13 0x304>;
 	};
 
+	timer at 2c000200 {
+		compatible = "arm,cortex-a5-global-timer",
+		             "arm,cortex-a9-global-timer";
+		reg = <0x2c000200 0x20>;
+		interrupts = <1 11 0x304>;
+		clocks = <&oscclk0>;
+	};
+
 	watchdog at 2c000620 {
 		compatible = "arm,cortex-a5-twd-wdt";
 		reg = <0x2c000620 0x20>;
@@ -120,7 +128,7 @@
 		compatible = "arm,vexpress,config-bus";
 		arm,vexpress,config-bridge = <&v2m_sysreg>;
 
-		osc at 0 {
+		oscclk0: osc at 0 {
 			/* CPU and internal AXI reference clock */
 			compatible = "arm,vexpress-osc";
 			arm,vexpress-sysreg,func = <1 0>;
-- 
1.8.5.3

[PATCH 4/4] KConfig: Vexpress: build the ARM_GLOBAL_TIMER with vexpress platform

[Matthew Leach]

The Cortex A5 now contains bindings for the global timer
driver. Ensure that the driver is built with a vexpress platform.

Signed-off-by: Matthew Leach <matthew.leach@arm.com>
---
 arch/arm/mach-vexpress/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/mach-vexpress/Kconfig b/arch/arm/mach-vexpress/Kconfig
index 4a70be4..4fb2a65 100644
--- a/arch/arm/mach-vexpress/Kconfig
+++ b/arch/arm/mach-vexpress/Kconfig
@@ -4,6 +4,7 @@ config ARCH_VEXPRESS
 	select ARCH_SUPPORTS_BIG_ENDIAN
 	select ARM_AMBA
 	select ARM_GIC
+	select ARM_GLOBAL_TIMER
 	select ARM_TIMER_SP804
 	select COMMON_CLK
 	select COMMON_CLK_VERSATILE
-- 
1.8.5.3

[PATCH 2/4] documentaion: DT: allow a A5 compatible string in global timer

[Mark Rutland]

On Mon, Mar 10, 2014 at 11:51:32AM +0000, Matthew Leach wrote:
> The global timer is present on the Cortex A5. Add a compatibility
> string to the DT binding to allow a Cortex A5 global timer.
> 
> Signed-off-by: Matthew Leach <matthew.leach@arm.com>

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
>  Documentation/devicetree/bindings/arm/global_timer.txt | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
> index 1e54898..0932891 100644
> --- a/Documentation/devicetree/bindings/arm/global_timer.txt
> +++ b/Documentation/devicetree/bindings/arm/global_timer.txt
> @@ -4,8 +4,10 @@
>  
>  ** Timer node required properties:
>  
> -- compatible : Should be "arm,cortex-a9-global-timer"
> -		Driver supports versions r2p0 and above.
> +- compatible : should contain
> +	     * "arm,cortex-a5-global-timer" for Cortex-A5 global timers.
> +	     * "arm,cortex-a9-global-timer" for Cortex-A9 global timers
> +	         or any compatible implementation.
>  
>  - interrupts : One interrupt to each core
>  
> -- 
> 1.8.5.3
> 

[PATCH 2/4] documentaion: DT: allow a A5 compatible string in global timer

[Rob Herring]

On Mon, Mar 10, 2014 at 6:51 AM, Matthew Leach <matthew.leach@arm.com> wrote:
> The global timer is present on the Cortex A5. Add a compatibility
> string to the DT binding to allow a Cortex A5 global timer.
>
> Signed-off-by: Matthew Leach <matthew.leach@arm.com>
> ---
>  Documentation/devicetree/bindings/arm/global_timer.txt | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
> index 1e54898..0932891 100644
> --- a/Documentation/devicetree/bindings/arm/global_timer.txt
> +++ b/Documentation/devicetree/bindings/arm/global_timer.txt
> @@ -4,8 +4,10 @@
>
>  ** Timer node required properties:
>
> -- compatible : Should be "arm,cortex-a9-global-timer"
> -               Driver supports versions r2p0 and above.

Shouldn't you keep this information for the A9?

> +- compatible : should contain
> +            * "arm,cortex-a5-global-timer" for Cortex-A5 global timers.
> +            * "arm,cortex-a9-global-timer" for Cortex-A9 global timers
> +                or any compatible implementation.
>
>  - interrupts : One interrupt to each core
>
> --
> 1.8.5.3
>
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 2/4] documentaion: DT: allow a A5 compatible string in global timer

[Rob Herring]

On Mon, Mar 10, 2014 at 6:51 AM, Matthew Leach <matthew.leach@arm.com> wrote:
> The global timer is present on the Cortex A5. Add a compatibility
> string to the DT binding to allow a Cortex A5 global timer.

Also, please use get_maintainers.pl so you copy the right people and list.

Rob

>
> Signed-off-by: Matthew Leach <matthew.leach@arm.com>
> ---
>  Documentation/devicetree/bindings/arm/global_timer.txt | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
> index 1e54898..0932891 100644
> --- a/Documentation/devicetree/bindings/arm/global_timer.txt
> +++ b/Documentation/devicetree/bindings/arm/global_timer.txt
> @@ -4,8 +4,10 @@
>
>  ** Timer node required properties:
>
> -- compatible : Should be "arm,cortex-a9-global-timer"
> -               Driver supports versions r2p0 and above.
> +- compatible : should contain
> +            * "arm,cortex-a5-global-timer" for Cortex-A5 global timers.
> +            * "arm,cortex-a9-global-timer" for Cortex-A9 global timers
> +                or any compatible implementation.
>
>  - interrupts : One interrupt to each core
>
> --
> 1.8.5.3
>
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 2/4] documentaion: DT: allow a A5 compatible string in global timer

[Mark Rutland]

On Mon, Mar 10, 2014 at 04:27:09PM +0000, Rob Herring wrote:
> On Mon, Mar 10, 2014 at 6:51 AM, Matthew Leach <matthew.leach@arm.com> wrote:
> > The global timer is present on the Cortex A5. Add a compatibility
> > string to the DT binding to allow a Cortex A5 global timer.
> >
> > Signed-off-by: Matthew Leach <matthew.leach@arm.com>
> > ---
> >  Documentation/devicetree/bindings/arm/global_timer.txt | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
> > index 1e54898..0932891 100644
> > --- a/Documentation/devicetree/bindings/arm/global_timer.txt
> > +++ b/Documentation/devicetree/bindings/arm/global_timer.txt
> > @@ -4,8 +4,10 @@
> >
> >  ** Timer node required properties:
> >
> > -- compatible : Should be "arm,cortex-a9-global-timer"
> > -               Driver supports versions r2p0 and above.
> 
> Shouldn't you keep this information for the A9?

To me it feels like documenting the driver rather than the binding for
the hardware.

I'm happy to retain notes about the constraints imposed by Linux
drivers, but I'd prefer if it were the exception rather than the rule.

Mark.

> 
> > +- compatible : should contain
> > +            * "arm,cortex-a5-global-timer" for Cortex-A5 global timers.
> > +            * "arm,cortex-a9-global-timer" for Cortex-A9 global timers
> > +                or any compatible implementation.
> >
> >  - interrupts : One interrupt to each core
> >
> > --
> > 1.8.5.3
> >
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

[PATCH 2/4] documentaion: DT: allow a A5 compatible string in global timer

[Rob Herring]

On Mon, Mar 10, 2014 at 11:51 AM, Mark Rutland <mark.rutland@arm.com> wrote:
> On Mon, Mar 10, 2014 at 04:27:09PM +0000, Rob Herring wrote:
>> On Mon, Mar 10, 2014 at 6:51 AM, Matthew Leach <matthew.leach@arm.com> wrote:
>> > The global timer is present on the Cortex A5. Add a compatibility
>> > string to the DT binding to allow a Cortex A5 global timer.
>> >
>> > Signed-off-by: Matthew Leach <matthew.leach@arm.com>
>> > ---
>> >  Documentation/devicetree/bindings/arm/global_timer.txt | 6 ++++--
>> >  1 file changed, 4 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
>> > index 1e54898..0932891 100644
>> > --- a/Documentation/devicetree/bindings/arm/global_timer.txt
>> > +++ b/Documentation/devicetree/bindings/arm/global_timer.txt
>> > @@ -4,8 +4,10 @@
>> >
>> >  ** Timer node required properties:
>> >
>> > -- compatible : Should be "arm,cortex-a9-global-timer"
>> > -               Driver supports versions r2p0 and above.
>>
>> Shouldn't you keep this information for the A9?
>
> To me it feels like documenting the driver rather than the binding for
> the hardware.
>
> I'm happy to retain notes about the constraints imposed by Linux
> drivers, but I'd prefer if it were the exception rather than the rule.

Isn't the driver constraint based on the global timer h/w being broken
on pre r2p0? If it is truly a Linux limitation that could be fixed,
then I agree.

Rob

[PATCH 2/4] documentaion: DT: allow a A5 compatible string in global timer

[Mark Rutland]

On Mon, Mar 10, 2014 at 05:57:32PM +0000, Rob Herring wrote:
> On Mon, Mar 10, 2014 at 11:51 AM, Mark Rutland <mark.rutland@arm.com> wrote:
> > On Mon, Mar 10, 2014 at 04:27:09PM +0000, Rob Herring wrote:
> >> On Mon, Mar 10, 2014 at 6:51 AM, Matthew Leach <matthew.leach@arm.com> wrote:
> >> > The global timer is present on the Cortex A5. Add a compatibility
> >> > string to the DT binding to allow a Cortex A5 global timer.
> >> >
> >> > Signed-off-by: Matthew Leach <matthew.leach@arm.com>
> >> > ---
> >> >  Documentation/devicetree/bindings/arm/global_timer.txt | 6 ++++--
> >> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >> >
> >> > diff --git a/Documentation/devicetree/bindings/arm/global_timer.txt b/Documentation/devicetree/bindings/arm/global_timer.txt
> >> > index 1e54898..0932891 100644
> >> > --- a/Documentation/devicetree/bindings/arm/global_timer.txt
> >> > +++ b/Documentation/devicetree/bindings/arm/global_timer.txt
> >> > @@ -4,8 +4,10 @@
> >> >
> >> >  ** Timer node required properties:
> >> >
> >> > -- compatible : Should be "arm,cortex-a9-global-timer"
> >> > -               Driver supports versions r2p0 and above.
> >>
> >> Shouldn't you keep this information for the A9?
> >
> > To me it feels like documenting the driver rather than the binding for
> > the hardware.
> >
> > I'm happy to retain notes about the constraints imposed by Linux
> > drivers, but I'd prefer if it were the exception rather than the rule.
> 
> Isn't the driver constraint based on the global timer h/w being broken
> on pre r2p0? If it is truly a Linux limitation that could be fixed,
> then I agree.

Unfortunately, I must admit ignorance on this matter.

>From a quick look, the comparator behaviour on Cortex-A9 cores prior to
r2p0 seems to make it unusable in practice (though I'm not aware of the
precise behaviour, perhaps there is some possible workaround).

We can note the problem in the binding document, but we don't need to
refer to any particular driver. :)

Cheers,
Mark.