RE: [PATCH v4] Thermal: exynos: Add sysfs node supporting exynos'semulation mode.

From: Zhang Rui
Date: Wed Nov 07 2012 - 01:36:33 EST

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On Thu, 2012-11-01 at 23:13 -0600, R, Durgadoss wrote:
> Hi Lee,
>
> > -----Original Message-----
> > From: Jonghwa Lee [mailto:jonghwa3.lee@xxxxxxxxxxx]
> > Sent: Friday, November 02, 2012 7:55 AM
> > To: linux-pm@xxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx; Brown, Len; R, Durgadoss; Rafael J.
> > Wysocki; Amit Dinel Kachhap; MyungJoo Ham; Kyungmin Park; Jonghwa Lee
> > Subject: [PATCH v4] Thermal: exynos: Add sysfs node supporting exynos's
> > emulation mode.
> >
> > This patch supports exynos's emulation mode with newly created sysfs node.
> > Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal
> > management unit. Thermal emulation mode supports software debug for
> > TMU's
> > operation. User can set temperature manually with software code and TMU
> > will read current temperature from user value not from sensor's value.
> > This patch includes also documentary placed under
> > Documentation/thermal/.
> >
>
first of all, what would happen if overheat happens during emulation?

I just had a thought about if we can introduce this to the generic
thermal layer.
to do this, we only need to:
1) introduce tz->emulation
2) introduce thermal_get_temp()
static int thermal_get_temp(tz) {
if (tz->emulation)
return tz->emulation;
else
return tz->ops->get_temp(tz);
}
3) replace tz->ops->get_temp() with thermal_get_temp() in thermal layer
4) introduce /sys/class/thermal/thermal_zoneX/emulation
5) when setting /sys/class/thermal/thermal_zoneX/emulation,
a) set tz->emulation
b) invoke thermal_zone_device_update();
this is a pure software emulation solution but it would work on all
generic thermal layer users.

do you think this proposal would work properly?
if yes, I'd like to see if it is valuable for the other platform thermal
drivers.

thanks,
rui
> Thanks for fixing the comments.
> Please CC linux-acpi, when you submit thermal patches, going forward.
> I am CCing Rui for now, for him to review/merge this patch.
>
> Reviewed-by: Durgadoss R <durgadoss.r@xxxxxxxxx>
>
> Thanks,
> Durga
>
> > Signed-off-by: Jonghwa Lee <jonghwa3.lee@xxxxxxxxxxx>
> > ---
> > v4
> > - Fix Typo.
> > - Remove unnecessary codes.
> > - Add comments about feature of exynos emulation operation to the
> > document.
> >
> > v3
> > - Remove unnecessay variables.
> > - Do some code clean in exynos_tmu_emulation_store().
> > - Make wrapping function of sysfs node creation function to use
> > #ifdefs in minimum.
> >
> > v2
> > exynos_thermal.c
> > - Fix build error occured by wrong emulation control register name.
> > - Remove exynos5410 dependent codes.
> > exynos_thermal_emulation
> > - Align indentation.
> >
> > Documentation/thermal/exynos_thermal_emulation | 56
> > +++++++++++++++
> > drivers/thermal/Kconfig | 9 +++
> > drivers/thermal/exynos_thermal.c | 91
> > ++++++++++++++++++++++++
> > 3 files changed, 156 insertions(+), 0 deletions(-)
> > create mode 100644 Documentation/thermal/exynos_thermal_emulation
> >
> > diff --git a/Documentation/thermal/exynos_thermal_emulation
> > b/Documentation/thermal/exynos_thermal_emulation
> > new file mode 100644
> > index 0000000..a6ea06f
> > --- /dev/null
> > +++ b/Documentation/thermal/exynos_thermal_emulation
> > @@ -0,0 +1,56 @@
> > +EXYNOS EMULATION MODE
> > +========================
> > +
> > +Copyright (C) 2012 Samsung Electronics
> > +
> > +Written by Jonghwa Lee <jonghwa3.lee@xxxxxxxxxxx>
> > +
> > +Description
> > +-----------
> > +
> > +Exynos 4x12 (4212, 4412) and 5 series provide emulation mode for thermal
> > management unit.
> > +Thermal emulation mode supports software debug for TMU's operation.
> > User can set temperature
> > +manually with software code and TMU will read current temperature from
> > user value not from
> > +sensor's value.
> > +
> > +Enabling CONFIG_EXYNOS_THERMAL_EMUL option will make this support
> > in available.
> > +When it's enabled, sysfs node will be created under
> > +/sys/bus/platform/devices/'exynos device name'/ with name of
> > 'emulation'.
> > +
> > +The sysfs node, 'emulation', will contain value 0 for the initial state. When
> > you input any
> > +temperature you want to update to sysfs node, it automatically enable
> > emulation mode and
> > +current temperature will be changed into it.
> > +(Exynos also supports user changable delay time which would be used to
> > delay of
> > + changing temperature. However, this node only uses same delay of real
> > sensing time, 938us.)
> > +
> > +Exynos emulation mode requires synchronous of value changing and
> > enabling. It means when you
> > +want to update the any value of delay or next temperature, then you have
> > to enable emulation
> > +mode at the same time. (Or you have to keep the mode enabling.) If you
> > don't, it fails to
> > +change the value to updated one and just use last succeessful value
> > repeatedly. That's why
> > +this node gives users the right to change termerpature only. Just one
> > interface makes it more
> > +simply to use.
> > +
> > +Disabling emulation mode only requires writing value 0 to sysfs node.
> > +
> > +
> > +TEMP 120 |
> > + |
> > + 100 |
> > + |
> > + 80 |
> > + | +-----------
> > + 60 | | |
> > + | +-------------| |
> > + 40 | | | |
> > + | | | |
> > + 20 | | | +----------
> > + | | | | |
> > + 0
> > |______________|_____________|__________|__________|_______
> > __
> > + A A A A TIME
> > + |<----->| |<----->| |<----->| |
> > + | 938us | | | | | |
> > +emulation : 0 50 | 70 | 20 | 0
> > +current temp : sensor 50 70 20 sensor
> > +
> > +
> > +
> > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> > index e1cb6bd..c02a66c 100644
> > --- a/drivers/thermal/Kconfig
> > +++ b/drivers/thermal/Kconfig
> > @@ -55,3 +55,12 @@ config EXYNOS_THERMAL
> > help
> > If you say yes here you get support for TMU (Thermal Managment
> > Unit) on SAMSUNG EXYNOS series of SoC.
> > +
> > +config EXYNOS_THERMAL_EMUL
> > + bool "EXYNOS TMU emulation mode support"
> > + depends on !CPU_EXYNOS4210 && EXYNOS_THERMAL
> > + help
> > + Exynos 4412 and 4414 and 5 series has emulation mode on TMU.
> > + Enable this option will be make sysfs node in exynos thermal
> > platform
> > + device directory to support emulation mode. With emulation mode
> > sysfs
> > + node, you can manually input temperature to TMU for simulation
> > purpose.
> > diff --git a/drivers/thermal/exynos_thermal.c
> > b/drivers/thermal/exynos_thermal.c
> > index fd03e85..eebd4e5 100644
> > --- a/drivers/thermal/exynos_thermal.c
> > +++ b/drivers/thermal/exynos_thermal.c
> > @@ -99,6 +99,14 @@
> > #define IDLE_INTERVAL 10000
> > #define MCELSIUS 1000
> >
> > +#ifdef CONFIG_EXYNOS_THERMAL_EMUL
> > +#define EXYNOS_EMUL_TIME 0x57F0
> > +#define EXYNOS_EMUL_TIME_SHIFT 16
> > +#define EXYNOS_EMUL_DATA_SHIFT 8
> > +#define EXYNOS_EMUL_DATA_MASK 0xFF
> > +#define EXYNOS_EMUL_ENABLE 0x1
> > +#endif /* CONFIG_EXYNOS_THERMAL_EMUL */
> > +
> > /* CPU Zone information */
> > #define PANIC_ZONE 4
> > #define WARN_ZONE 3
> > @@ -832,6 +840,82 @@ static inline struct exynos_tmu_platform_data
> > *exynos_get_driver_data(
> > return (struct exynos_tmu_platform_data *)
> > platform_get_device_id(pdev)->driver_data;
> > }
> > +
> > +#ifdef CONFIG_EXYNOS_THERMAL_EMUL
> > +static ssize_t exynos_tmu_emulation_show(struct device *dev,
> > + struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct platform_device *pdev = container_of(dev,
> > + struct platform_device, dev);
> > + struct exynos_tmu_data *data = platform_get_drvdata(pdev);
> > + unsigned int reg;
> > + u8 temp_code;
> > + int temp = 0;
> > +
> > + mutex_lock(&data->lock);
> > + clk_enable(data->clk);
> > + reg = readl(data->base + EXYNOS_EMUL_CON);
> > + clk_disable(data->clk);
> > + mutex_unlock(&data->lock);
> > +
> > + if (reg & EXYNOS_EMUL_ENABLE) {
> > + reg >>= EXYNOS_EMUL_DATA_SHIFT;
> > + temp_code = reg & EXYNOS_EMUL_DATA_MASK;
> > + temp = code_to_temp(data, temp_code);
> > + }
> > +
> > + return sprintf(buf, "%d\n", temp);
> > +}
> > +
> > +static ssize_t exynos_tmu_emulation_store(struct device *dev,
> > + struct device_attribute *attr,
> > + const char *buf, size_t count)
> > +{
> > + struct platform_device *pdev = container_of(dev,
> > + struct platform_device, dev);
> > + struct exynos_tmu_data *data = platform_get_drvdata(pdev);
> > + unsigned int reg;
> > + int temp;
> > +
> > + if (!sscanf(buf, "%d\n", &temp) || temp < 0)
> > + return -EINVAL;
> > +
> > + mutex_lock(&data->lock);
> > + clk_enable(data->clk);
> > +
> > + reg = readl(data->base + EXYNOS_EMUL_CON);
> > +
> > + if (temp)
> > + reg = (EXYNOS_EMUL_TIME << EXYNOS_EMUL_TIME_SHIFT)
> > |
> > + (temp_to_code(data, temp) <<
> > EXYNOS_EMUL_DATA_SHIFT) |
> > + EXYNOS_EMUL_ENABLE;
> > + else
> > + reg &= ~EXYNOS_EMUL_ENABLE;
> > +
> > + writel(reg, data->base + EXYNOS_EMUL_CON);
> > +
> > + clk_disable(data->clk);
> > + mutex_unlock(&data->lock);
> > +
> > + return count;
> > +}
> > +
> > +static DEVICE_ATTR(emulation, 0644, exynos_tmu_emulation_show,
> > + exynos_tmu_emulation_store);
> > +static int create_emulation_sysfs(struct device *dev)
> > +{
> > + return device_create_file(dev, &dev_attr_emulation);
> > +}
> > +static void remove_emulation_sysfs(struct device *dev)
> > +{
> > + device_remove_file(dev, &dev_attr_emulation);
> > +}
> > +#else
> > +static inline int create_emulation_sysfs(struct device *dev) {return 0;}
> > +static inline void remove_emulation_sysfs(struct device *dev){}
> > +#endif
> > +
> > static int __devinit exynos_tmu_probe(struct platform_device *pdev)
> > {
> > struct exynos_tmu_data *data;
> > @@ -930,6 +1014,11 @@ static int __devinit exynos_tmu_probe(struct
> > platform_device *pdev)
> > dev_err(&pdev->dev, "Failed to register thermal
> > interface\n");
> > goto err_clk;
> > }
> > +
> > + ret = create_emulation_sysfs(&pdev->dev);
> > + if (ret)
> > + dev_err(&pdev->dev, "Failed to create emulation mode
> > sysfs node\n");
> > +
> > return 0;
> > err_clk:
> > platform_set_drvdata(pdev, NULL);
> > @@ -941,6 +1030,8 @@ static int __devexit exynos_tmu_remove(struct
> > platform_device *pdev)
> > {
> > struct exynos_tmu_data *data = platform_get_drvdata(pdev);
> >
> > + remove_emulation_sysfs(&pdev->dev);
> > +
> > exynos_tmu_control(pdev, false);
> >
> > exynos_unregister_thermal();
> > --
> > 1.7.4.1
>

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Next message: Kumar Amit Mehta: "[PATCH] staging: tidspbridge: dynload: dload_internal.h: fix for coding style issue"
Previous message: Shiraz Hashim: "Re: possibility of parent clock selection through DT"
In reply to: R, Durgadoss: "RE: [PATCH v4] Thermal: exynos: Add sysfs node supporting exynos'semulation mode."
Next in thread: R, Durgadoss: "RE: [PATCH v4] Thermal: exynos: Add sysfs node supporting exynos'semulation mode."
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