On Thu, Apr 26, 2012 at 23:10:36, J, KEERTHY wrote:
> From: Jean Pihet <[email protected]>
>
> Now that omap_test_timeout is only accessible from mach-omap2/,
> introduce a similar function for SR.
>
> This change makes the SmartReflex implementation ready for the move
> to drivers/.
>
> Signed-off-by: Jean Pihet <[email protected]>
> Signed-off-by: J Keerthy <[email protected]>
> ---
> arch/arm/mach-omap2/smartreflex.c | 12 ++++++------
> include/linux/power/smartreflex.h | 23 ++++++++++++++++++++++-
> 2 files changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/smartreflex.c b/arch/arm/mach-omap2/smartreflex.c
> index d859277..acef08d 100644
> --- a/arch/arm/mach-omap2/smartreflex.c
> +++ b/arch/arm/mach-omap2/smartreflex.c
> @@ -289,9 +289,9 @@ static void sr_v1_disable(struct omap_sr *sr)
> * Wait for SR to be disabled.
> * wait until ERRCONFIG.MCUDISACKINTST = 1. Typical latency is 1us.
> */
> - omap_test_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
> - ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
> - timeout);
> + sr_test_cond_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
> + ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
> + timeout);
>
> if (timeout >= SR_DISABLE_TIMEOUT)
> dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
> @@ -334,9 +334,9 @@ static void sr_v2_disable(struct omap_sr *sr)
> * Wait for SR to be disabled.
> * wait until IRQSTATUS.MCUDISACKINTST = 1. Typical latency is 1us.
> */
> - omap_test_timeout((sr_read_reg(sr, IRQSTATUS) &
> - IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
> - timeout);
> + sr_test_cond_timeout((sr_read_reg(sr, IRQSTATUS) &
> + IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
> + timeout);
>
> if (timeout >= SR_DISABLE_TIMEOUT)
> dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
> diff --git a/include/linux/power/smartreflex.h b/include/linux/power/smartreflex.h
> index 884eaee..78b795e 100644
> --- a/include/linux/power/smartreflex.h
> +++ b/include/linux/power/smartreflex.h
> @@ -22,7 +22,7 @@
>
> #include <linux/types.h>
> #include <linux/platform_device.h>
> -
> +#include <linux/delay.h>
> #include <plat/voltage.h>
>
> /*
> @@ -168,6 +168,27 @@ struct omap_sr {
> };
>
> /**
> + * test_cond_timeout - busy-loop, testing a condition
> + * @cond: condition to test until it evaluates to true
> + * @timeout: maximum number of microseconds in the timeout
> + * @index: loop index (integer)
> + *
> + * Loop waiting for @cond to become true or until at least @timeout
> + * microseconds have passed. To use, define some integer @index in the
> + * calling code. After running, if @index == @timeout, then the loop has
> + * timed out.
> + *
> + * Copied from omap_test_timeout */
> +#define sr_test_cond_timeout(cond, timeout, index) \
> +({ \
> + for (index = 0; index < timeout; index++) { \
> + if (cond) \
> + break; \
> + udelay(1); \
> + } \
> +})
I think we can use time_after()/time_before() APIs for timeout and cpu_relax() for
tight loops instead of udelay().
Regards
AnilKumar
On Fri, May 4, 2012 at 2:42 PM, AnilKumar, Chimata <[email protected]> wrote:
> On Thu, Apr 26, 2012 at 23:10:36, J, KEERTHY wrote:
>> From: Jean Pihet <[email protected]>
>>
>> Now that omap_test_timeout is only accessible from mach-omap2/,
>> introduce a similar function for SR.
>>
>> This change makes the SmartReflex implementation ready for the move
>> to drivers/.
>>
>> Signed-off-by: Jean Pihet <[email protected]>
>> Signed-off-by: J Keerthy <[email protected]>
>> ---
>> ?arch/arm/mach-omap2/smartreflex.c | ? 12 ++++++------
>> ?include/linux/power/smartreflex.h | ? 23 ++++++++++++++++++++++-
>> ?2 files changed, 28 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/smartreflex.c b/arch/arm/mach-omap2/smartreflex.c
>> index d859277..acef08d 100644
>> --- a/arch/arm/mach-omap2/smartreflex.c
>> +++ b/arch/arm/mach-omap2/smartreflex.c
>> @@ -289,9 +289,9 @@ static void sr_v1_disable(struct omap_sr *sr)
>> ? ? ? ?* Wait for SR to be disabled.
>> ? ? ? ?* wait until ERRCONFIG.MCUDISACKINTST = 1. Typical latency is 1us.
>> ? ? ? ?*/
>> - ? ? omap_test_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
>> - ? ? ? ? ? ? ? ? ? ? ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
>> - ? ? ? ? ? ? ? ? ? ? timeout);
>> + ? ? sr_test_cond_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
>> + ? ? ? ? ? ? ? ? ? ? ? ? ?ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ?timeout);
>>
>> ? ? ? if (timeout >= SR_DISABLE_TIMEOUT)
>> ? ? ? ? ? ? ? dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
>> @@ -334,9 +334,9 @@ static void sr_v2_disable(struct omap_sr *sr)
>> ? ? ? ?* Wait for SR to be disabled.
>> ? ? ? ?* wait until IRQSTATUS.MCUDISACKINTST = 1. Typical latency is 1us.
>> ? ? ? ?*/
>> - ? ? omap_test_timeout((sr_read_reg(sr, IRQSTATUS) &
>> - ? ? ? ? ? ? ? ? ? ? IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
>> - ? ? ? ? ? ? ? ? ? ? timeout);
>> + ? ? sr_test_cond_timeout((sr_read_reg(sr, IRQSTATUS) &
>> + ? ? ? ? ? ? ? ? ? ? ? ? ?IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ?timeout);
>>
>> ? ? ? if (timeout >= SR_DISABLE_TIMEOUT)
>> ? ? ? ? ? ? ? dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
>> diff --git a/include/linux/power/smartreflex.h b/include/linux/power/smartreflex.h
>> index 884eaee..78b795e 100644
>> --- a/include/linux/power/smartreflex.h
>> +++ b/include/linux/power/smartreflex.h
>> @@ -22,7 +22,7 @@
>>
>> ?#include <linux/types.h>
>> ?#include <linux/platform_device.h>
>> -
>> +#include <linux/delay.h>
>> ?#include <plat/voltage.h>
>>
>> ?/*
>> @@ -168,6 +168,27 @@ struct omap_sr {
>> ?};
>>
>> ?/**
>> + * test_cond_timeout - busy-loop, testing a condition
>> + * @cond: condition to test until it evaluates to true
>> + * @timeout: maximum number of microseconds in the timeout
>> + * @index: loop index (integer)
>> + *
>> + * Loop waiting for @cond to become true or until at least @timeout
>> + * microseconds have passed. ?To use, define some integer @index in the
>> + * calling code. ?After running, if @index == @timeout, then the loop has
>> + * timed out.
>> + *
>> + * Copied from omap_test_timeout */
>> +#define sr_test_cond_timeout(cond, timeout, index) ? ? ? ? ? \
>> +({ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
>> + ? ? for (index = 0; index < timeout; index++) { ? ? ? ? ? ? \
>> + ? ? ? ? ? ? if (cond) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
>> + ? ? ? ? ? ? ? ? ? ? break; ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?\
>> + ? ? ? ? ? ? udelay(1); ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?\
>> + ? ? } ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
>> +})
>
> I think we can use time_after()/time_before() APIs for timeout and cpu_relax() for
> tight loops instead of udelay().
cpu_relax() changes the priority everytime to low and will yield to
another thread.
Considering that we are checking the condition every microsecond does it make
some saving using cpu_relax().
>
> Regards
> AnilKumar
--
Regards and Thanks,
Keerthy
On Mon, May 07, 2012 at 10:51:53, J, KEERTHY wrote:
> On Fri, May 4, 2012 at 2:42 PM, AnilKumar, Chimata <[email protected]> wrote:
> > On Thu, Apr 26, 2012 at 23:10:36, J, KEERTHY wrote:
> >> From: Jean Pihet <[email protected]>
> >>
> >> Now that omap_test_timeout is only accessible from mach-omap2/,
> >> introduce a similar function for SR.
> >>
> >> This change makes the SmartReflex implementation ready for the move
> >> to drivers/.
> >>
> >> Signed-off-by: Jean Pihet <[email protected]>
> >> Signed-off-by: J Keerthy <[email protected]>
> >> ---
> >> ?arch/arm/mach-omap2/smartreflex.c | ? 12 ++++++------
> >> ?include/linux/power/smartreflex.h | ? 23 ++++++++++++++++++++++-
> >> ?2 files changed, 28 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/arch/arm/mach-omap2/smartreflex.c b/arch/arm/mach-omap2/smartreflex.c
> >> index d859277..acef08d 100644
> >> --- a/arch/arm/mach-omap2/smartreflex.c
> >> +++ b/arch/arm/mach-omap2/smartreflex.c
> >> @@ -289,9 +289,9 @@ static void sr_v1_disable(struct omap_sr *sr)
> >> ? ? ? ?* Wait for SR to be disabled.
> >> ? ? ? ?* wait until ERRCONFIG.MCUDISACKINTST = 1. Typical latency is 1us.
> >> ? ? ? ?*/
> >> - ? ? omap_test_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
> >> - ? ? ? ? ? ? ? ? ? ? ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
> >> - ? ? ? ? ? ? ? ? ? ? timeout);
> >> + ? ? sr_test_cond_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
> >> + ? ? ? ? ? ? ? ? ? ? ? ? ?ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
> >> + ? ? ? ? ? ? ? ? ? ? ? ? ?timeout);
> >>
> >> ? ? ? if (timeout >= SR_DISABLE_TIMEOUT)
> >> ? ? ? ? ? ? ? dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
> >> @@ -334,9 +334,9 @@ static void sr_v2_disable(struct omap_sr *sr)
> >> ? ? ? ?* Wait for SR to be disabled.
> >> ? ? ? ?* wait until IRQSTATUS.MCUDISACKINTST = 1. Typical latency is 1us.
> >> ? ? ? ?*/
> >> - ? ? omap_test_timeout((sr_read_reg(sr, IRQSTATUS) &
> >> - ? ? ? ? ? ? ? ? ? ? IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
> >> - ? ? ? ? ? ? ? ? ? ? timeout);
> >> + ? ? sr_test_cond_timeout((sr_read_reg(sr, IRQSTATUS) &
> >> + ? ? ? ? ? ? ? ? ? ? ? ? ?IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
> >> + ? ? ? ? ? ? ? ? ? ? ? ? ?timeout);
> >>
> >> ? ? ? if (timeout >= SR_DISABLE_TIMEOUT)
> >> ? ? ? ? ? ? ? dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
> >> diff --git a/include/linux/power/smartreflex.h b/include/linux/power/smartreflex.h
> >> index 884eaee..78b795e 100644
> >> --- a/include/linux/power/smartreflex.h
> >> +++ b/include/linux/power/smartreflex.h
> >> @@ -22,7 +22,7 @@
> >>
> >> ?#include <linux/types.h>
> >> ?#include <linux/platform_device.h>
> >> -
> >> +#include <linux/delay.h>
> >> ?#include <plat/voltage.h>
> >>
> >> ?/*
> >> @@ -168,6 +168,27 @@ struct omap_sr {
> >> ?};
> >>
> >> ?/**
> >> + * test_cond_timeout - busy-loop, testing a condition
> >> + * @cond: condition to test until it evaluates to true
> >> + * @timeout: maximum number of microseconds in the timeout
> >> + * @index: loop index (integer)
> >> + *
> >> + * Loop waiting for @cond to become true or until at least @timeout
> >> + * microseconds have passed. ?To use, define some integer @index in the
> >> + * calling code. ?After running, if @index == @timeout, then the loop has
> >> + * timed out.
> >> + *
> >> + * Copied from omap_test_timeout */
> >> +#define sr_test_cond_timeout(cond, timeout, index) ? ? ? ? ? \
> >> +({ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
> >> + ? ? for (index = 0; index < timeout; index++) { ? ? ? ? ? ? \
> >> + ? ? ? ? ? ? if (cond) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
> >> + ? ? ? ? ? ? ? ? ? ? break; ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?\
> >> + ? ? ? ? ? ? udelay(1); ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?\
> >> + ? ? } ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
> >> +})
> >
> > I think we can use time_after()/time_before() APIs for timeout and cpu_relax() for
> > tight loops instead of udelay().
>
> cpu_relax() changes the priority everytime to low and will yield to
> another thread.
> Considering that we are checking the condition every microsecond does it make
> some saving using cpu_relax().
>
cpu_relax() does not involve any priority changes or scheduling AFAICS.
Have a look at this thread:
http://www.spinics.net/lists/netdev/msg151699.html
Regards
AnilKumar
On Tue, May 8, 2012 at 3:47 PM, AnilKumar, Chimata <[email protected]> wrote:
> On Mon, May 07, 2012 at 10:51:53, J, KEERTHY wrote:
>> On Fri, May 4, 2012 at 2:42 PM, AnilKumar, Chimata <[email protected]> wrote:
>> > On Thu, Apr 26, 2012 at 23:10:36, J, KEERTHY wrote:
>> >> From: Jean Pihet <[email protected]>
>> >>
>> >> Now that omap_test_timeout is only accessible from mach-omap2/,
>> >> introduce a similar function for SR.
>> >>
>> >> This change makes the SmartReflex implementation ready for the move
>> >> to drivers/.
>> >>
>> >> Signed-off-by: Jean Pihet <[email protected]>
>> >> Signed-off-by: J Keerthy <[email protected]>
>> >> ---
>> >> ?arch/arm/mach-omap2/smartreflex.c | ? 12 ++++++------
>> >> ?include/linux/power/smartreflex.h | ? 23 ++++++++++++++++++++++-
>> >> ?2 files changed, 28 insertions(+), 7 deletions(-)
>> >>
>> >> diff --git a/arch/arm/mach-omap2/smartreflex.c b/arch/arm/mach-omap2/smartreflex.c
>> >> index d859277..acef08d 100644
>> >> --- a/arch/arm/mach-omap2/smartreflex.c
>> >> +++ b/arch/arm/mach-omap2/smartreflex.c
>> >> @@ -289,9 +289,9 @@ static void sr_v1_disable(struct omap_sr *sr)
>> >> ? ? ? ?* Wait for SR to be disabled.
>> >> ? ? ? ?* wait until ERRCONFIG.MCUDISACKINTST = 1. Typical latency is 1us.
>> >> ? ? ? ?*/
>> >> - ? ? omap_test_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
>> >> - ? ? ? ? ? ? ? ? ? ? ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
>> >> - ? ? ? ? ? ? ? ? ? ? timeout);
>> >> + ? ? sr_test_cond_timeout((sr_read_reg(sr, ERRCONFIG_V1) &
>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ?ERRCONFIG_MCUDISACKINTST), SR_DISABLE_TIMEOUT,
>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ?timeout);
>> >>
>> >> ? ? ? if (timeout >= SR_DISABLE_TIMEOUT)
>> >> ? ? ? ? ? ? ? dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
>> >> @@ -334,9 +334,9 @@ static void sr_v2_disable(struct omap_sr *sr)
>> >> ? ? ? ?* Wait for SR to be disabled.
>> >> ? ? ? ?* wait until IRQSTATUS.MCUDISACKINTST = 1. Typical latency is 1us.
>> >> ? ? ? ?*/
>> >> - ? ? omap_test_timeout((sr_read_reg(sr, IRQSTATUS) &
>> >> - ? ? ? ? ? ? ? ? ? ? IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
>> >> - ? ? ? ? ? ? ? ? ? ? timeout);
>> >> + ? ? sr_test_cond_timeout((sr_read_reg(sr, IRQSTATUS) &
>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ?IRQSTATUS_MCUDISABLEACKINT), SR_DISABLE_TIMEOUT,
>> >> + ? ? ? ? ? ? ? ? ? ? ? ? ?timeout);
>> >>
>> >> ? ? ? if (timeout >= SR_DISABLE_TIMEOUT)
>> >> ? ? ? ? ? ? ? dev_warn(&sr->pdev->dev, "%s: Smartreflex disable timedout\n",
>> >> diff --git a/include/linux/power/smartreflex.h b/include/linux/power/smartreflex.h
>> >> index 884eaee..78b795e 100644
>> >> --- a/include/linux/power/smartreflex.h
>> >> +++ b/include/linux/power/smartreflex.h
>> >> @@ -22,7 +22,7 @@
>> >>
>> >> ?#include <linux/types.h>
>> >> ?#include <linux/platform_device.h>
>> >> -
>> >> +#include <linux/delay.h>
>> >> ?#include <plat/voltage.h>
>> >>
>> >> ?/*
>> >> @@ -168,6 +168,27 @@ struct omap_sr {
>> >> ?};
>> >>
>> >> ?/**
>> >> + * test_cond_timeout - busy-loop, testing a condition
>> >> + * @cond: condition to test until it evaluates to true
>> >> + * @timeout: maximum number of microseconds in the timeout
>> >> + * @index: loop index (integer)
>> >> + *
>> >> + * Loop waiting for @cond to become true or until at least @timeout
>> >> + * microseconds have passed. ?To use, define some integer @index in the
>> >> + * calling code. ?After running, if @index == @timeout, then the loop has
>> >> + * timed out.
>> >> + *
>> >> + * Copied from omap_test_timeout */
>> >> +#define sr_test_cond_timeout(cond, timeout, index) ? ? ? ? ? \
>> >> +({ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
>> >> + ? ? for (index = 0; index < timeout; index++) { ? ? ? ? ? ? \
>> >> + ? ? ? ? ? ? if (cond) ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
>> >> + ? ? ? ? ? ? ? ? ? ? break; ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?\
>> >> + ? ? ? ? ? ? udelay(1); ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?\
>> >> + ? ? } ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? \
>> >> +})
>> >
>> > I think we can use time_after()/time_before() APIs for timeout and cpu_relax() for
>> > tight loops instead of udelay().
>>
>> cpu_relax() changes the priority everytime to low and will yield to
>> another thread.
>> Considering that we are checking the condition every microsecond does it make
>> some saving using cpu_relax().
>>
>
> cpu_relax() does not involve any priority changes or scheduling AFAICS.
> Have a look at this thread:
>
> http://www.spinics.net/lists/netdev/msg151699.html
Thanks. My bad. I meant yielding to another thread with in a space
of 1uS.
>
> Regards
> AnilKumar
>
--
Regards and Thanks,
Keerthy