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* [RFC PATCH v1] xen/arm: split the init_xen_time() in 2 parts
@ 2015-01-23 15:49 Oleksandr Tyshchenko
  2015-01-26 13:32 ` Julien Grall
  0 siblings, 1 reply; 3+ messages in thread
From: Oleksandr Tyshchenko @ 2015-01-23 15:49 UTC (permalink / raw)
  To: xen-devel; +Cc: julien.grall, tim, ian.campbell, stefano.stabellini

Create preinit_xen_time() and move to it minimum required
subset of operations needed to properly initialized
cpu_khz and boot_count vars. This is allow us to use udelay()
immediately after the call.

Signed-off-by: Oleksandr Tyshchenko <oleksandr.tyshchenko@globallogic.com>
CC: Julien Grall <julien.grall@linaro.org>
---
 xen/arch/arm/setup.c   |  2 ++
 xen/arch/arm/time.c    | 71 ++++++++++++++++++++++++++++++++------------------
 xen/include/xen/time.h |  1 +
 3 files changed, 48 insertions(+), 26 deletions(-)

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index f49569d..dbd7d5a 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -743,6 +743,8 @@ void __init start_xen(unsigned long boot_phys_offset,
 
     init_IRQ();
 
+    preinit_xen_time();
+
     dt_uart_init();
     console_init_preirq();
     console_init_ring();
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 455f217..b2560db 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -61,25 +61,56 @@ unsigned int timer_get_irq(enum timer_ppi ppi)
     return muldiv64(ns, 1000 * cpu_khz, SECONDS(1));
 }
 
-/* Set up the timer on the boot CPU */
-int __init init_xen_time(void)
+static __init struct dt_device_node *find_timer_node(void)
+{
+	static const struct dt_device_match timer_ids[] __initconst =
+	{
+	    DT_MATCH_TIMER,
+	    { /* sentinel */ },
+	};
+
+	return dt_find_matching_node(NULL, timer_ids);
+}
+
+/* Set up the timer on the boot CPU (early init function) */
+int __init preinit_xen_time(void)
 {
-    static const struct dt_device_match timer_ids[] __initconst =
-    {
-        DT_MATCH_TIMER,
-        { /* sentinel */ },
-    };
     struct dt_device_node *dev;
     int res;
-    unsigned int i;
     u32 rate;
 
-    dev = dt_find_matching_node(NULL, timer_ids);
+    dev = find_timer_node();
     if ( !dev )
         panic("Unable to find a compatible timer in the device tree");
 
     dt_device_set_used_by(dev, DOMID_XEN);
 
+    res = platform_init_time();
+    if ( res )
+        panic("Timer: Cannot initialize platform timer");
+
+    res = dt_property_read_u32(dev, "clock-frequency", &rate);
+    if ( res )
+        cpu_khz = rate / 1000;
+    else
+        cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
+
+    boot_count = READ_SYSREG64(CNTPCT_EL0);
+
+    return 0;
+}
+
+/* Set up the timer on the boot CPU (late init function) */
+int __init init_xen_time(void)
+{
+    struct dt_device_node *dev;
+    int res;
+    unsigned int i;
+
+    dev = find_timer_node();
+    if ( !dev )
+        panic("Unable to find a compatible timer in the device tree");
+
     /* Retrieve all IRQs for the timer */
     for ( i = TIMER_PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++ )
     {
@@ -90,27 +121,15 @@ int __init init_xen_time(void)
         timer_irq[i] = res;
     }
 
-    printk("Generic Timer IRQ: phys=%u hyp=%u virt=%u\n",
-           timer_irq[TIMER_PHYS_NONSECURE_PPI],
-           timer_irq[TIMER_HYP_PPI],
-           timer_irq[TIMER_VIRT_PPI]);
-
-    res = platform_init_time();
-    if ( res )
-        panic("Timer: Cannot initialize platform timer");
-
     /* Check that this CPU supports the Generic Timer interface */
     if ( !cpu_has_gentimer )
         panic("CPU does not support the Generic Timer v1 interface");
 
-    res = dt_property_read_u32(dev, "clock-frequency", &rate);
-    if ( res )
-        cpu_khz = rate / 1000;
-    else
-        cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
-
-    boot_count = READ_SYSREG64(CNTPCT_EL0);
-    printk("Using generic timer at %lu KHz\n", cpu_khz);
+    printk("Generic Timer IRQ: phys=%u hyp=%u virt=%u Freq: %lu KHz\n",
+           timer_irq[TIMER_PHYS_NONSECURE_PPI],
+           timer_irq[TIMER_HYP_PPI],
+           timer_irq[TIMER_VIRT_PPI],
+           cpu_khz);
 
     return 0;
 }
diff --git a/xen/include/xen/time.h b/xen/include/xen/time.h
index 709501f..fc49f71 100644
--- a/xen/include/xen/time.h
+++ b/xen/include/xen/time.h
@@ -12,6 +12,7 @@
 #include <public/xen.h>
 
 extern int init_xen_time(void);
+extern int preinit_xen_time(void);
 extern void cstate_restore_tsc(void);
 
 extern unsigned long cpu_khz;
-- 
1.9.1

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [RFC PATCH v1] xen/arm: split the init_xen_time() in 2 parts
  2015-01-23 15:49 [RFC PATCH v1] xen/arm: split the init_xen_time() in 2 parts Oleksandr Tyshchenko
@ 2015-01-26 13:32 ` Julien Grall
  2015-01-26 13:54   ` Oleksandr Tyshchenko
  0 siblings, 1 reply; 3+ messages in thread
From: Julien Grall @ 2015-01-26 13:32 UTC (permalink / raw)
  To: Oleksandr Tyshchenko, xen-devel; +Cc: tim, ian.campbell, stefano.stabellini

Hi Oleksandr,

Thank you for the patch. See few comments below.

On 23/01/15 15:49, Oleksandr Tyshchenko wrote:
> Create preinit_xen_time() and move to it minimum required
> subset of operations needed to properly initialized
> cpu_khz and boot_count vars. This is allow us to use udelay()
> immediately after the call.
> 
> Signed-off-by: Oleksandr Tyshchenko <oleksandr.tyshchenko@globallogic.com>
> CC: Julien Grall <julien.grall@linaro.org>
> ---
>  xen/arch/arm/setup.c   |  2 ++
>  xen/arch/arm/time.c    | 71 ++++++++++++++++++++++++++++++++------------------
>  xen/include/xen/time.h |  1 +
>  3 files changed, 48 insertions(+), 26 deletions(-)
> 
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index f49569d..dbd7d5a 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -743,6 +743,8 @@ void __init start_xen(unsigned long boot_phys_offset,
>  
>      init_IRQ();
>  
> +    preinit_xen_time();
> +
>      dt_uart_init();
>      console_init_preirq();
>      console_init_ring();
> diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
> index 455f217..b2560db 100644
> --- a/xen/arch/arm/time.c
> +++ b/xen/arch/arm/time.c
> @@ -61,25 +61,56 @@ unsigned int timer_get_irq(enum timer_ppi ppi)
>      return muldiv64(ns, 1000 * cpu_khz, SECONDS(1));
>  }
>  
> -/* Set up the timer on the boot CPU */
> -int __init init_xen_time(void)
> +static __init struct dt_device_node *find_timer_node(void)
> +{
> +	static const struct dt_device_match timer_ids[] __initconst =
> +	{
> +	    DT_MATCH_TIMER,
> +	    { /* sentinel */ },
> +	};
> +
> +	return dt_find_matching_node(NULL, timer_ids);
> +}

If you store the device tree pointer into a static variable, you won't
able to look at twice the node (in preinit_xen_time and init_xen_time).

> +
> +/* Set up the timer on the boot CPU (early init function) */
> +int __init preinit_xen_time(void)

You always return 0 and never check the return. Please use void.

>  {
> -    static const struct dt_device_match timer_ids[] __initconst =
> -    {
> -        DT_MATCH_TIMER,
> -        { /* sentinel */ },
> -    };
>      struct dt_device_node *dev;
>      int res;
> -    unsigned int i;
>      u32 rate;
>  
> -    dev = dt_find_matching_node(NULL, timer_ids);
> +    dev = find_timer_node();
>      if ( !dev )
>          panic("Unable to find a compatible timer in the device tree");
>  
>      dt_device_set_used_by(dev, DOMID_XEN);
>  
> +    res = platform_init_time();

If you move platform_init_time in preinit_xen_time, you also have to
move platform_init before calling preinit_xen_time.

Regards,

-- 
Julien Grall

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [RFC PATCH v1] xen/arm: split the init_xen_time() in 2 parts
  2015-01-26 13:32 ` Julien Grall
@ 2015-01-26 13:54   ` Oleksandr Tyshchenko
  0 siblings, 0 replies; 3+ messages in thread
From: Oleksandr Tyshchenko @ 2015-01-26 13:54 UTC (permalink / raw)
  To: Julien Grall
  Cc: Stefano Stabellini, Tim Deegan, Ian Campbell,
	xen-devel@lists.xen.org

On Mon, Jan 26, 2015 at 3:32 PM, Julien Grall <julien.grall@linaro.org> wrote:
> Hi Oleksandr,
Hi Julien
Thank you for your comments.
>
> Thank you for the patch. See few comments below.
>
> On 23/01/15 15:49, Oleksandr Tyshchenko wrote:
>> Create preinit_xen_time() and move to it minimum required
>> subset of operations needed to properly initialized
>> cpu_khz and boot_count vars. This is allow us to use udelay()
>> immediately after the call.
>>
>> Signed-off-by: Oleksandr Tyshchenko <oleksandr.tyshchenko@globallogic.com>
>> CC: Julien Grall <julien.grall@linaro.org>
>> ---
>>  xen/arch/arm/setup.c   |  2 ++
>>  xen/arch/arm/time.c    | 71 ++++++++++++++++++++++++++++++++------------------
>>  xen/include/xen/time.h |  1 +
>>  3 files changed, 48 insertions(+), 26 deletions(-)
>>
>> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
>> index f49569d..dbd7d5a 100644
>> --- a/xen/arch/arm/setup.c
>> +++ b/xen/arch/arm/setup.c
>> @@ -743,6 +743,8 @@ void __init start_xen(unsigned long boot_phys_offset,
>>
>>      init_IRQ();
>>
>> +    preinit_xen_time();
>> +
>>      dt_uart_init();
>>      console_init_preirq();
>>      console_init_ring();
>> diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
>> index 455f217..b2560db 100644
>> --- a/xen/arch/arm/time.c
>> +++ b/xen/arch/arm/time.c
>> @@ -61,25 +61,56 @@ unsigned int timer_get_irq(enum timer_ppi ppi)
>>      return muldiv64(ns, 1000 * cpu_khz, SECONDS(1));
>>  }
>>
>> -/* Set up the timer on the boot CPU */
>> -int __init init_xen_time(void)
>> +static __init struct dt_device_node *find_timer_node(void)
>> +{
>> +     static const struct dt_device_match timer_ids[] __initconst =
>> +     {
>> +         DT_MATCH_TIMER,
>> +         { /* sentinel */ },
>> +     };
>> +
>> +     return dt_find_matching_node(NULL, timer_ids);
>> +}
>
> If you store the device tree pointer into a static variable, you won't
> able to look at twice the node (in preinit_xen_time and init_xen_time).
Agree.

>
>> +
>> +/* Set up the timer on the boot CPU (early init function) */
>> +int __init preinit_xen_time(void)
>
> You always return 0 and never check the return. Please use void.
ok

>
>>  {
>> -    static const struct dt_device_match timer_ids[] __initconst =
>> -    {
>> -        DT_MATCH_TIMER,
>> -        { /* sentinel */ },
>> -    };
>>      struct dt_device_node *dev;
>>      int res;
>> -    unsigned int i;
>>      u32 rate;
>>
>> -    dev = dt_find_matching_node(NULL, timer_ids);
>> +    dev = find_timer_node();
>>      if ( !dev )
>>          panic("Unable to find a compatible timer in the device tree");
>>
>>      dt_device_set_used_by(dev, DOMID_XEN);
>>
>> +    res = platform_init_time();
>
> If you move platform_init_time in preinit_xen_time, you also have to
> move platform_init before calling preinit_xen_time.
ok

>
> Regards,
>
> --
> Julien Grall



-- 

Oleksandr Tyshchenko | Embedded Dev
GlobalLogic
www.globallogic.com

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2015-01-23 15:49 [RFC PATCH v1] xen/arm: split the init_xen_time() in 2 parts Oleksandr Tyshchenko
2015-01-26 13:32 ` Julien Grall
2015-01-26 13:54   ` Oleksandr Tyshchenko

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