[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Linus Walleij]

On Tue, Dec 3, 2013 at 12:15 PM, Hanjun Guo <hanjun.guo@linaro.org> wrote:

> +       /* if can't be initialised from DT, try ACPI way */
> +       if (!arch_timer_get_rate())
> +               arch_timer_acpi_init();
> +
>         arch_timer_rate = arch_timer_get_rate();

This looks a bit fragile. Having a call like arch_timer_get_rate()
to check whether there is a DT node for the timer doesn't seem
right, can you refactor the code to provide some
has_arch_timer_node() or similar call instead, so it's a bit easier
to understand & maintain at least?

Yours,
Linus Walleij

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Hanjun Guo]

On 2013?12?03? 20:27, Linus Walleij wrote:
> On Tue, Dec 3, 2013 at 12:15 PM, Hanjun Guo <hanjun.guo@linaro.org> wrote:
>
>> +       /* if can't be initialised from DT, try ACPI way */
>> +       if (!arch_timer_get_rate())
>> +               arch_timer_acpi_init();
>> +
>>          arch_timer_rate = arch_timer_get_rate();
> This looks a bit fragile. Having a call like arch_timer_get_rate()
> to check whether there is a DT node for the timer doesn't seem
> right, can you refactor the code to provide some
> has_arch_timer_node() or similar call instead, so it's a bit easier
> to understand & maintain at least?

Good point, thanks for the guidance.
I will introduce has_arch_timer_node() as you said and use
it as follows:

if (has_arch_timer_node())
clocksource_of_init();
esle
arch_timer_acpi_init(); /* try ACPI way */

Is this make sense to you?

Thanks
Hanjun

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Linus Walleij]

On Tue, Dec 3, 2013 at 2:52 PM, Hanjun Guo <hanjun.guo@linaro.org> wrote:

> I will introduce has_arch_timer_node() as you said and use
> it as follows:
>
> if (has_arch_timer_node())
> clocksource_of_init();
> esle
> arch_timer_acpi_init(); /* try ACPI way */
>
> Is this make sense to you?

Sure, go head.

Thanks,
Linus Walleij

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Mark Rutland]

On Tue, Dec 03, 2013 at 02:13:49PM +0000, Linus Walleij wrote:
> On Tue, Dec 3, 2013 at 2:52 PM, Hanjun Guo <hanjun.guo@linaro.org> wrote:
> 
> > I will introduce has_arch_timer_node() as you said and use
> > it as follows:
> >
> > if (has_arch_timer_node())
> > clocksource_of_init();
> > esle
> > arch_timer_acpi_init(); /* try ACPI way */
> >
> > Is this make sense to you?

What does arch_timer_acpi_init() do? Is it just detecting the presence
of the timer, or grabbing the rate from a property in an ACPI table?

Mark.

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Hanjun Guo]

On 2013?12?03? 22:43, Mark Rutland wrote:
> On Tue, Dec 03, 2013 at 02:13:49PM +0000, Linus Walleij wrote:
>> On Tue, Dec 3, 2013 at 2:52 PM, Hanjun Guo <hanjun.guo@linaro.org> wrote:
>>
>>> I will introduce has_arch_timer_node() as you said and use
>>> it as follows:
>>>
>>> if (has_arch_timer_node())
>>> clocksource_of_init();
>>> esle
>>> arch_timer_acpi_init(); /* try ACPI way */
>>>
>>> Is this make sense to you?
> What does arch_timer_acpi_init() do? Is it just detecting the presence
> of the timer, or grabbing the rate from a property in an ACPI table?

It seems that you didn't get the PATCH 1/2, and my part1/part2 patch set
is also missing, I will resend all the patch set, sorry for the noise.

Thanks
Hanjun

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Olof Johansson]

On Tue, Dec 03, 2013 at 09:52:30PM +0800, Hanjun Guo wrote:
> On 2013?12?03? 20:27, Linus Walleij wrote:
> >On Tue, Dec 3, 2013 at 12:15 PM, Hanjun Guo <hanjun.guo@linaro.org> wrote:
> >
> >>+       /* if can't be initialised from DT, try ACPI way */
> >>+       if (!arch_timer_get_rate())
> >>+               arch_timer_acpi_init();
> >>+
> >>         arch_timer_rate = arch_timer_get_rate();
> >This looks a bit fragile. Having a call like arch_timer_get_rate()
> >to check whether there is a DT node for the timer doesn't seem
> >right, can you refactor the code to provide some
> >has_arch_timer_node() or similar call instead, so it's a bit easier
> >to understand & maintain at least?
> 
> Good point, thanks for the guidance.
> I will introduce has_arch_timer_node() as you said and use
> it as follows:
> 
> if (has_arch_timer_node())
> clocksource_of_init();
> esle
> arch_timer_acpi_init(); /* try ACPI way */
> 
> Is this make sense to you?

Even when we boot with ACPI, the boot stub will still create a minimal
DTB. We should just make sure that the clocksource (which will be
architectured timers anyway, I believe?) is described in that stub.

I would rather do that than have dual-path booting in the lowlevel setup, it
increases test requirements and makes it hard for someone without ACPI hardware
to check for regressions in this code, etc.


-Olof

[RFC part3 PATCH 1/2] clocksource / arch_timer: Use ACPI GTDT table to initialize arch timer

[Rob Herring]

On Tue, Dec 3, 2013 at 5:15 AM, Hanjun Guo <hanjun.guo@linaro.org> wrote:
> ACPI GTDT (Generic Timer Description Table) contains information for
> arch timer initialization, this patch use this table to probe arm timer.
>
> GTDT table is used for ARM/ARM64 only, please refer to chapter 5.2.24
> of ACPI 5.0 spec for detailed inforamtion
>
> Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
> ---
>  drivers/clocksource/arm_arch_timer.c |  129 ++++++++++++++++++++++++++++++----
>  include/clocksource/arm_arch_timer.h |    7 +-
>  2 files changed, 120 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 95fb944..c968041 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -21,6 +21,7 @@
>  #include <linux/io.h>
>  #include <linux/slab.h>
>  #include <linux/sched_clock.h>
> +#include <linux/acpi.h>
>
>  #include <asm/arch_timer.h>
>  #include <asm/virt.h>
> @@ -632,20 +633,8 @@ static void __init arch_timer_common_init(void)
>         arch_timer_arch_init();
>  }
>
> -static void __init arch_timer_init(struct device_node *np)
> +static void __init arch_timer_init(void)
>  {
> -       int i;
> -
> -       if (arch_timers_present & ARCH_CP15_TIMER) {
> -               pr_warn("arch_timer: multiple nodes in dt, skipping\n");
> -               return;
> -       }
> -
> -       arch_timers_present |= ARCH_CP15_TIMER;
> -       for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
> -               arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
> -       arch_timer_detect_rate(NULL, np);
> -
>         /*
>          * If HYP mode is available, we know that the physical timer
>          * has been configured to be accessible from PL1. Use it, so
> @@ -667,8 +656,118 @@ static void __init arch_timer_init(struct device_node *np)
>         arch_timer_register();
>         arch_timer_common_init();
>  }
> -CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_init);
> -CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_init);
> +
> +static void __init arch_timer_of_init(struct device_node *np)
> +{
> +       int i;
> +
> +       if (arch_timers_present & ARCH_CP15_TIMER) {
> +               pr_warn("arch_timer: multiple nodes in dt, skipping\n");
> +               return;
> +       }
> +
> +       arch_timers_present |= ARCH_CP15_TIMER;
> +       for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
> +               arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
> +       arch_timer_detect_rate(NULL, np);
> +
> +       arch_timer_init();
> +}
> +CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
> +CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);
> +
> +#ifdef CONFIG_ACPI
> +void __init arch_timer_acpi_init(void)
> +{
> +       struct acpi_table_gtdt *gtdt;
> +       acpi_size tbl_size;
> +       int trigger, polarity;
> +       void __iomem *base = NULL;
> +
> +       if (acpi_disabled)

Wouldn't the core ACPI code never call this function if ACPI is disabled?

> +               return;
> +
> +       if (arch_timers_present & ARCH_CP15_TIMER) {
> +               pr_warn("arch_timer: already initialized, skipping\n");
> +               return;
> +       }
> +
> +       if (ACPI_FAILURE(acpi_get_table_with_size(ACPI_SIG_GTDT, 0,
> +                       (struct acpi_table_header **)&gtdt, &tbl_size))) {
> +               pr_err("arch_timer: GTDT table not defined\n");
> +               return;
> +       }
> +
> +       arch_timers_present |= ARCH_CP15_TIMER;

So you have marked the timer as initialized, but then may fail on
error later on here.

> +
> +       /*
> +        * Get the timer frequency. Since there is no frequency info
> +        * in the GTDT table, so we should read it from CNTFREG register
> +        * or hard code here to wait for the new ACPI spec available.
> +        */
> +       if (!gtdt->address) {
> +               arch_timer_rate = arch_timer_get_cntfrq();
> +       } else {
> +               base = ioremap(gtdt->address, CNTFRQ);
> +               if (!base) {
> +                       pr_warn("arch_timer: unable to map arch timer base address\n");
> +                       return;
> +               }
> +
> +               arch_timer_rate = readl_relaxed(base + CNTFRQ);
> +               iounmap(base);

This is for memory mapped timer? If so, then isn't setting
ARCH_CP15_TIMER the wrong thing to do?

> +       }
> +
> +       if (!arch_timer_rate) {
> +               /* Hard code here to set frequence ? */
> +               pr_warn("arch_timer: Could not get frequency from GTDT table or CNTFREG\n");
> +       }
> +
> +       if (gtdt->secure_pl1_interrupt) {

Really, I think the kernel should just ignore the secure interrupt.
The DT code has the same issue, but that doesn't affect the code size.

> +               trigger = (gtdt->secure_pl1_flags & ACPI_GTDT_INTERRUPT_MODE) ?
> +                       ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;

Why not use the already defined linux irq trigger types here and make
acpi_register_gsi use them?

> +               polarity =
> +                       (gtdt->secure_pl1_flags & ACPI_GTDT_INTERRUPT_POLARITY)
> +                       ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
> +               arch_timer_ppi[0] = acpi_register_gsi(NULL,
> +                               gtdt->secure_pl1_interrupt, trigger, polarity);
> +       }
> +       if (gtdt->non_secure_pl1_interrupt) {
> +               trigger =
> +                       (gtdt->non_secure_pl1_flags & ACPI_GTDT_INTERRUPT_MODE)
> +                       ? ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
> +               polarity =
> +               (gtdt->non_secure_pl1_flags & ACPI_GTDT_INTERRUPT_POLARITY)
> +                       ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
> +               arch_timer_ppi[1] = acpi_register_gsi(NULL,
> +                       gtdt->non_secure_pl1_interrupt, trigger, polarity);
> +       }
> +       if (gtdt->virtual_timer_interrupt) {
> +               trigger = (gtdt->virtual_timer_flags & ACPI_GTDT_INTERRUPT_MODE)
> +                       ? ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
> +               polarity =
> +               (gtdt->virtual_timer_flags & ACPI_GTDT_INTERRUPT_POLARITY)
> +                       ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
> +               arch_timer_ppi[2] = acpi_register_gsi(NULL,
> +                       gtdt->virtual_timer_interrupt, trigger, polarity);
> +       }
> +       if (gtdt->non_secure_pl2_interrupt) {
> +               trigger =
> +                       (gtdt->non_secure_pl2_flags & ACPI_GTDT_INTERRUPT_MODE)
> +                       ? ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
> +               polarity =
> +               (gtdt->non_secure_pl2_flags & ACPI_GTDT_INTERRUPT_POLARITY)
> +                       ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
> +               arch_timer_ppi[3] = acpi_register_gsi(NULL,
> +                       gtdt->non_secure_pl2_interrupt, trigger, polarity);
> +       }
> +
> +       early_acpi_os_unmap_memory(gtdt, tbl_size);

Who did the mapping? acpi_get_table_with_size? I think the core code
should handle the mapping and unmapping of ACPI tables. We don't want
to have to duplicate this in every initialization function. This seems
error prone.

Rob

[RFC part3 PATCH 1/2] clocksource / arch_timer: Use ACPI GTDT table to initialize arch timer

[Hanjun Guo]

On 2013?12?04? 23:33, Rob Herring wrote:
> On Tue, Dec 3, 2013 at 5:15 AM, Hanjun Guo <hanjun.guo@linaro.org> wrote:
[...]
>> +#ifdef CONFIG_ACPI
>> +void __init arch_timer_acpi_init(void)
>> +{
>> +       struct acpi_table_gtdt *gtdt;
>> +       acpi_size tbl_size;
>> +       int trigger, polarity;
>> +       void __iomem *base = NULL;
>> +
>> +       if (acpi_disabled)
> Wouldn't the core ACPI code never call this function if ACPI is disabled?

You inspired me for patches to remove some redundant if (acpi_disabled)
check for the current ACPI code, but this function will be called even
ACPI is disabled.

>> +               return;
>> +
>> +       if (arch_timers_present & ARCH_CP15_TIMER) {
>> +               pr_warn("arch_timer: already initialized, skipping\n");
>> +               return;
>> +       }
>> +
>> +       if (ACPI_FAILURE(acpi_get_table_with_size(ACPI_SIG_GTDT, 0,
>> +                       (struct acpi_table_header **)&gtdt, &tbl_size))) {
>> +               pr_err("arch_timer: GTDT table not defined\n");
>> +               return;
>> +       }
>> +
>> +       arch_timers_present |= ARCH_CP15_TIMER;
> So you have marked the timer as initialized, but then may fail on
> error later on here.
>
>> +
>> +       /*
>> +        * Get the timer frequency. Since there is no frequency info
>> +        * in the GTDT table, so we should read it from CNTFREG register
>> +        * or hard code here to wait for the new ACPI spec available.
>> +        */
>> +       if (!gtdt->address) {
>> +               arch_timer_rate = arch_timer_get_cntfrq();
>> +       } else {
>> +               base = ioremap(gtdt->address, CNTFRQ);
>> +               if (!base) {
>> +                       pr_warn("arch_timer: unable to map arch timer base address\n");
>> +                       return;
>> +               }
>> +
>> +               arch_timer_rate = readl_relaxed(base + CNTFRQ);
>> +               iounmap(base);
> This is for memory mapped timer? If so, then isn't setting
> ARCH_CP15_TIMER the wrong thing to do?

I'm trying to do that but it is wrong as you said, I will remove above code
and only keep

arch_timer_rate = arch_timer_get_cntfrq() here.

>> +       }
>> +
>> +       if (!arch_timer_rate) {
>> +               /* Hard code here to set frequence ? */
>> +               pr_warn("arch_timer: Could not get frequency from GTDT table or CNTFREG\n");
>> +       }
>> +
>> +       if (gtdt->secure_pl1_interrupt) {
> Really, I think the kernel should just ignore the secure interrupt.
> The DT code has the same issue, but that doesn't affect the code size.
>
>> +               trigger = (gtdt->secure_pl1_flags & ACPI_GTDT_INTERRUPT_MODE) ?
>> +                       ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
> Why not use the already defined linux irq trigger types here and make
> acpi_register_gsi use them?
>
>> +               polarity =
>> +                       (gtdt->secure_pl1_flags & ACPI_GTDT_INTERRUPT_POLARITY)
>> +                       ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
>> +               arch_timer_ppi[0] = acpi_register_gsi(NULL,
>> +                               gtdt->secure_pl1_interrupt, trigger, polarity);
>> +       }
>> +       if (gtdt->non_secure_pl1_interrupt) {
>> +               trigger =
>> +                       (gtdt->non_secure_pl1_flags & ACPI_GTDT_INTERRUPT_MODE)
>> +                       ? ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
>> +               polarity =
>> +               (gtdt->non_secure_pl1_flags & ACPI_GTDT_INTERRUPT_POLARITY)
>> +                       ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
>> +               arch_timer_ppi[1] = acpi_register_gsi(NULL,
>> +                       gtdt->non_secure_pl1_interrupt, trigger, polarity);
>> +       }
>> +       if (gtdt->virtual_timer_interrupt) {
>> +               trigger = (gtdt->virtual_timer_flags & ACPI_GTDT_INTERRUPT_MODE)
>> +                       ? ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
>> +               polarity =
>> +               (gtdt->virtual_timer_flags & ACPI_GTDT_INTERRUPT_POLARITY)
>> +                       ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
>> +               arch_timer_ppi[2] = acpi_register_gsi(NULL,
>> +                       gtdt->virtual_timer_interrupt, trigger, polarity);
>> +       }
>> +       if (gtdt->non_secure_pl2_interrupt) {
>> +               trigger =
>> +                       (gtdt->non_secure_pl2_flags & ACPI_GTDT_INTERRUPT_MODE)
>> +                       ? ACPI_EDGE_SENSITIVE : ACPI_LEVEL_SENSITIVE;
>> +               polarity =
>> +               (gtdt->non_secure_pl2_flags & ACPI_GTDT_INTERRUPT_POLARITY)
>> +                       ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
>> +               arch_timer_ppi[3] = acpi_register_gsi(NULL,
>> +                       gtdt->non_secure_pl2_interrupt, trigger, polarity);
>> +       }
>> +
>> +       early_acpi_os_unmap_memory(gtdt, tbl_size);
> Who did the mapping? acpi_get_table_with_size? I think the core code
> should handle the mapping and unmapping of ACPI tables. We don't want
> to have to duplicate this in every initialization function. This seems
> error prone.

Yes, you are right, I will use the ACPI core function acpi_table_parse()
to fix it, thanks for you guidance.

Hanjun

[RFC part3 PATCH 0/2] Using ACPI GTDT table to initialize arch timer

[Hanjun Guo]

This is the last part of patch set for core of ARM64 ACPI, and is based
on the patch set part2 "Using ACPI MADT table to initialise SMP and GIC".

ACPI GTDT (Generic Timer Description Table) is used for ARM/ARM64 only,
and contains the information for arch timer initialisation.

This patch trys to convert the arch timer to ACPI using GTDT. 

After this patch set was posted, we already finished the SMP, GIC and
arch timer initialisation, which all are essential for ARM64 core system
running, then we will focus on converting the device drivers to ACPI.

Here is the GTDT ASL code I used:
---
 platforms/foundation-v8.acpi/gtdt.asl |   35 ++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/platforms/foundation-v8.acpi/gtdt.asl b/platforms/foundation-v8.acpi/gtdt.asl
index 18c821a..714d61c 100644
--- a/platforms/foundation-v8.acpi/gtdt.asl
+++ b/platforms/foundation-v8.acpi/gtdt.asl
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2013, Al Stone <al.stone@linaro.org>
+ *                     Hanjun Guo <hanjun.guo@linaro.org>
  * 
  * [GTDT] Generic Timer Description Table
  * Format: [ByteLength]  FieldName : HexFieldValue
@@ -21,22 +22,32 @@
 [0004]              Flags (decoded below) : 00000001
                            Memory Present : 1
 
-[0004]               Secure PL1 Interrupt : 00000000
-[0004]         SPL1 Flags (decoded below) : 00000000
-                             Trigger Mode : 0
+/* In Foundation model's dts file, the last cell of interrupts
+ * is 0xff01, it means its cpu mask is FF, and trigger type
+ * and flag is 1 = low-to-high edge triggered.
+ * 
+ * so in ACPI the Trigger Mode is 1 - Edge triggered, and 
+ * Polarity is 0 - Active high as ACPI spec describled.
+ *
+ * using direct mapping for hwirqs, it means that we using
+ * ID [16, 31] for PPI, not [0, 15] used in FDT.
+ */
+[0004]               Secure PL1 Interrupt : 0000001d
+[0004]         SPL1 Flags (decoded below) : 00000001
+                             Trigger Mode : 1
                                  Polarity : 0
 
-[0004]           Non-Secure PL1 Interrupt : 00000000
-[0004]        NSPL1 Flags (decoded below) : 00000000
-                             Trigger Mode : 0
+[0004]           Non-Secure PL1 Interrupt : 0000001e
+[0004]        NSPL1 Flags (decoded below) : 00000001
+                             Trigger Mode : 1
                                  Polarity : 0
 
-[0004]            Virtual Timer Interrupt : 00000000
-[0004]           VT Flags (decoded below) : 00000000
-                             Trigger Mode : 0
+[0004]            Virtual Timer Interrupt : 0000001b
+[0004]           VT Flags (decoded below) : 00000001
+                             Trigger Mode : 1
                                  Polarity : 0
 
-[0004]           Non-Secure PL2 Interrupt : 00000000
-[0004]        NSPL2 Flags (decoded below) : 00000000
-                             Trigger Mode : 0
+[0004]           Non-Secure PL2 Interrupt : 0000001a
+[0004]        NSPL2 Flags (decoded below) : 00000001
+                             Trigger Mode : 1
                                  Polarity : 0

Hanjun Guo (2):
  clocksource / arch_timer: Use ACPI GTDT table to initialize arch
    timer
  ARM64 / clocksource: Use arch_timer_acpi_init()

 arch/arm64/kernel/time.c             |    4 ++
 drivers/clocksource/arm_arch_timer.c |  129 ++++++++++++++++++++++++++++++----
 include/clocksource/arm_arch_timer.h |    7 +-
 3 files changed, 124 insertions(+), 16 deletions(-)

-- 
1.7.9.5

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Hanjun Guo]

Use arch_timer_acpi_init() on ARM64 to initialise arch timer
in ACPI way when DT is not available.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
---
 arch/arm64/kernel/time.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
index 29c39d5..fb009da 100644
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -67,6 +67,10 @@ void __init time_init(void)
 
 	clocksource_of_init();
 
+	/* if can't be initialised from DT, try ACPI way */
+	if (!arch_timer_get_rate())
+		arch_timer_acpi_init();
+
 	arch_timer_rate = arch_timer_get_rate();
 	if (!arch_timer_rate)
 		panic("Unable to initialise architected timer.\n");
-- 
1.7.9.5

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Mark Rutland]

On Tue, Dec 03, 2013 at 04:41:31PM +0000, Hanjun Guo wrote:
> Use arch_timer_acpi_init() on ARM64 to initialise arch timer
> in ACPI way when DT is not available.
> 
> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
> ---
>  arch/arm64/kernel/time.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
> index 29c39d5..fb009da 100644
> --- a/arch/arm64/kernel/time.c
> +++ b/arch/arm64/kernel/time.c
> @@ -67,6 +67,10 @@ void __init time_init(void)
>  
>  	clocksource_of_init();
>  
> +	/* if can't be initialised from DT, try ACPI way */
> +	if (!arch_timer_get_rate())
> +		arch_timer_acpi_init();
> +

As mentioned on the previous patch, I think for the timebeing we should
rely on CNTFREQ.

Additionally, if you need to do this we should have an analagous
mechanism to clocksource_of_init() that performs this initialisation for
ACPI, and here we can call a clocksource_*_init function that does the
right thing.

There's no need for this file to know anything about ACPI.

Mark.

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Hanjun Guo]

On 2013?12?04? 01:08, Mark Rutland wrote:
> On Tue, Dec 03, 2013 at 04:41:31PM +0000, Hanjun Guo wrote:
>> Use arch_timer_acpi_init() on ARM64 to initialise arch timer
>> in ACPI way when DT is not available.
>>
>> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
>> ---
>>   arch/arm64/kernel/time.c |    4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
>> index 29c39d5..fb009da 100644
>> --- a/arch/arm64/kernel/time.c
>> +++ b/arch/arm64/kernel/time.c
>> @@ -67,6 +67,10 @@ void __init time_init(void)
>>   
>>   	clocksource_of_init();
>>   
>> +	/* if can't be initialised from DT, try ACPI way */
>> +	if (!arch_timer_get_rate())
>> +		arch_timer_acpi_init();
>> +
> As mentioned on the previous patch, I think for the timebeing we should
> rely on CNTFREQ.
>
> Additionally, if you need to do this we should have an analagous
> mechanism to clocksource_of_init() that performs this initialisation for
> ACPI, and here we can call a clocksource_*_init function that does the
> right thing.
>
> There's no need for this file to know anything about ACPI.

Oh, Amit already have some patches to introduce clocksource_acpi_init()
like clocksource_of_init() did, please refer to the link below.

http://marc.info/?l=linaro-acpi&m=138131929721943&w=2

is this the idea you mentioned in your comments?

Thanks
Hanjun

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Mark Rutland]

On Wed, Dec 04, 2013 at 02:27:22PM +0000, Hanjun Guo wrote:
> On 2013?12?04? 01:08, Mark Rutland wrote:
> > On Tue, Dec 03, 2013 at 04:41:31PM +0000, Hanjun Guo wrote:
> >> Use arch_timer_acpi_init() on ARM64 to initialise arch timer
> >> in ACPI way when DT is not available.
> >>
> >> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
> >> ---
> >>   arch/arm64/kernel/time.c |    4 ++++
> >>   1 file changed, 4 insertions(+)
> >>
> >> diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
> >> index 29c39d5..fb009da 100644
> >> --- a/arch/arm64/kernel/time.c
> >> +++ b/arch/arm64/kernel/time.c
> >> @@ -67,6 +67,10 @@ void __init time_init(void)
> >>   
> >>   	clocksource_of_init();
> >>   
> >> +	/* if can't be initialised from DT, try ACPI way */
> >> +	if (!arch_timer_get_rate())
> >> +		arch_timer_acpi_init();
> >> +
> > As mentioned on the previous patch, I think for the timebeing we should
> > rely on CNTFREQ.
> >
> > Additionally, if you need to do this we should have an analagous
> > mechanism to clocksource_of_init() that performs this initialisation for
> > ACPI, and here we can call a clocksource_*_init function that does the
> > right thing.
> >
> > There's no need for this file to know anything about ACPI.
> 
> Oh, Amit already have some patches to introduce clocksource_acpi_init()
> like clocksource_of_init() did, please refer to the link below.
> 
> http://marc.info/?l=linaro-acpi&m=138131929721943&w=2
> 
> is this the idea you mentioned in your comments?

Something along those lines is far better than hardcoding
arch_timer_acpi_init here.

Thanks,
Mark.

[RFC part3 PATCH 2/2] ARM64 / clocksource: Use arch_timer_acpi_init()

[Hanjun Guo]

On 2013?12?04? 23:07, Mark Rutland wrote:
> On Wed, Dec 04, 2013 at 02:27:22PM +0000, Hanjun Guo wrote:
>> On 2013?12?04? 01:08, Mark Rutland wrote:
>>> On Tue, Dec 03, 2013 at 04:41:31PM +0000, Hanjun Guo wrote:
>>>> Use arch_timer_acpi_init() on ARM64 to initialise arch timer
>>>> in ACPI way when DT is not available.
>>>>
>>>> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
>>>> ---
>>>>    arch/arm64/kernel/time.c |    4 ++++
>>>>    1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
>>>> index 29c39d5..fb009da 100644
>>>> --- a/arch/arm64/kernel/time.c
>>>> +++ b/arch/arm64/kernel/time.c
>>>> @@ -67,6 +67,10 @@ void __init time_init(void)
>>>>    
>>>>    	clocksource_of_init();
>>>>    
>>>> +	/* if can't be initialised from DT, try ACPI way */
>>>> +	if (!arch_timer_get_rate())
>>>> +		arch_timer_acpi_init();
>>>> +
>>> As mentioned on the previous patch, I think for the timebeing we should
>>> rely on CNTFREQ.
>>>
>>> Additionally, if you need to do this we should have an analagous
>>> mechanism to clocksource_of_init() that performs this initialisation for
>>> ACPI, and here we can call a clocksource_*_init function that does the
>>> right thing.
>>>
>>> There's no need for this file to know anything about ACPI.
>> Oh, Amit already have some patches to introduce clocksource_acpi_init()
>> like clocksource_of_init() did, please refer to the link below.
>>
>> http://marc.info/?l=linaro-acpi&m=138131929721943&w=2
>>
>> is this the idea you mentioned in your comments?
> Something along those lines is far better than hardcoding
> arch_timer_acpi_init here.

Thanks for the suggestion, will update it.

Hanjun