Re: Patch[2/2]:hwmon:Adding_Threshold_Support_to_Coretemp.c

Guenter Roeck
2011-01-04T19:42:00Z

On Tue, Dec 28, 2010 at 03:56:57PM +0530, R, Durgadoss wrote:
> Hi,
>
> I am submitting a patch to enable core thermal threshold
> Support to coretemp.c. There are two core thermal thresholds
> available through sysfs interfaces temp1_max and temp1_max_hyst.
> The temp1_max_alarm is set when temperature reaches or crosses
> above temp1_max or drops below temp1_max_hyst.
>
> This patch is generated against stable Linux-2.6 kernel.
>
> Kindly review and merge.
> ----------------------------------------------------------------
> From: Durgadoss R <durgadoss.r@intel.com>
>
> Date: Sun, 19 Dec 2010 22:44:54 +0530
> Subject: [PATCH 2/2] hwmon:Adding_Threshold_Support_to_Coretemp
>
> This patch adds core thermal thresholds support to coretemp.
> These thresholds can be configured via the sysfs interfaces temp1_max
> and temp1_max_hyst. An interrupt is generated when CPU temperature
> goes above temp1_max or drops below temp1_max_hyst.
>
> Signed-off-by: Durgadoss R <durgadoss.r@intel.com>

Fenghua Yu <fenghua.yu@intel.com> as driver maintainer will have to Ack this patch.

Driver fails to build if MCE is not configured.

drivers/built-in.o: In function `config_thresh_intrpt':
coretemp.c:(.devinit.text+0xd909): undefined reference to `platform_thermal_notify'
coretemp.c:(.devinit.text+0xd91b): undefined reference to `platform_thermal_notify'
make: *** [.tmp_vmlinux1] Error 1

It also fails to build if APIC is not defined. See below. After that I gave up
trying more combinations. _Please_ do your homework.

> ---
> Documentation/hwmon/coretemp | 8 ++
> drivers/hwmon/coretemp.c | 214 ++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 202 insertions(+), 20 deletions(-)
>
> diff --git a/Documentation/hwmon/coretemp b/Documentation/hwmon/coretemp
> index 25568f8..615fdbe 100644
> --- a/Documentation/hwmon/coretemp
> +++ b/Documentation/hwmon/coretemp
> @@ -29,6 +29,14 @@ the Out-Of-Spec bit. Following table summarizes the exported sysfs files:
>
> temp1_input - Core temperature (in millidegrees Celsius).
> temp1_max - All cooling devices should be turned on (on Core2).
> + Initialized with IA32_TEMPERATURE_TARGET if supported,
> + otherwise initialized with (tjmax - 20). When the CPU
> + temperature reaches this temperature, an interrupt is
> + generated and temp1_max_alarm is set.
> +temp1_max_hyst - If the CPU temperature falls below than temperature,

... falls below _this_ temperature ...

> + an interrupt is generated and temp1_max_alarm is reset.
> +temp1_max_alarm - Set if the temperature reaches or exceeds temp1_max.
> + Reset if the temperature drops to or below temp1_max_hyst.
> temp1_crit - Maximum junction temperature (in millidegrees Celsius).
> temp1_crit_alarm - Set when Out-of-spec bit is set, never clears.
> Correct CPU operation is no longer guaranteed.
> diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
> index 42de98d..025902f 100644
> --- a/drivers/hwmon/coretemp.c
> +++ b/drivers/hwmon/coretemp.c
> @@ -36,11 +36,12 @@
> #include <asm/msr.h>
> #include <asm/processor.h>
> #include <asm/smp.h>
> +#include <asm/mce.h>
>
> #define DRVNAME "coretemp"
>
> -typedef enum { SHOW_TEMP, SHOW_TJMAX, SHOW_TTARGET, SHOW_LABEL,
> - SHOW_NAME } SHOW;
> +enum attributes { SHOW_TEMP, SHOW_TJMAX, CORE_TTARGET, CORE_TMIN, SHOW_LABEL,
> + SHOW_NAME, SHOW_CRIT_ALARM, SHOW_MAX_ALARM } attrs;
>
This defines a global variable named attrs. Not a good idea. You do not have to specify "attrs" here.

> /*
> * Functions declaration
> @@ -59,9 +60,14 @@ struct coretemp_data {
> int temp;
> int tjmax;
> int ttarget;
> - u8 alarm;
> + int tmin;
> + u8 max_alarm;
> + u8 crit_alarm;
> };
>
> +static void update_alarm(struct coretemp_data *data);
> +static int set_core_threshold(struct coretemp_data *data, int temp, int thres);
> +
Please keep with other function forward references. Yes, I know you need the struct,
but that doesn't have to be defined when you declare the forward references.
Or define the struct first and then all the forward declarations.

> /*
> * Sysfs stuff
> */
> @@ -83,9 +89,15 @@ static ssize_t show_name(struct device *dev, struct device_attribute
> static ssize_t show_alarm(struct device *dev, struct device_attribute
> *devattr, char *buf)
> {
> - struct coretemp_data *data = coretemp_update_device(dev);
> - /* read the Out-of-spec log, never clear */
> - return sprintf(buf, "%d\n", data->alarm);
> + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> + struct coretemp_data *data = dev_get_drvdata(dev);
> +
> + update_alarm(data);
> + if (attr->index == SHOW_CRIT_ALARM)
> + /* read the Out-of-spec log, never clear */
> + return sprintf(buf, "%d\n", data->crit_alarm);
> +
Since the if () statement includes a comment, it is better to add { } to improve
readability.

> + return sprintf(buf, "%d\n", data->max_alarm);
> }
>
> static ssize_t show_temp(struct device *dev,
> @@ -93,33 +105,67 @@ static ssize_t show_temp(struct device *dev,
> {
> struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> struct coretemp_data *data = coretemp_update_device(dev);
> - int err;
> + int err = -EINVAL;
>
> - if (attr->index == SHOW_TEMP)
> + switch (attr->index) {
> + case SHOW_TEMP:
> err = data->valid ? sprintf(buf, "%d\n", data->temp) : -EAGAIN;
> - else if (attr->index == SHOW_TJMAX)
> + break;
> + case SHOW_TJMAX:
> err = sprintf(buf, "%d\n", data->tjmax);
> - else
> + break;
> + case CORE_TTARGET:
> err = sprintf(buf, "%d\n", data->ttarget);
> + break;
> + case CORE_TMIN:
> + err = sprintf(buf, "%d\n", data->tmin);
> + break;
> + }
> +
> return err;
> }
>
> +
> +static ssize_t store_temp(struct device *dev,
> + struct device_attribute *devattr, const char *buf, size_t count)
> +{
> + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> + struct coretemp_data *data = dev_get_drvdata(dev);
> + unsigned long val;
> + int err;
> +
> + if (strict_strtoul(buf, 10, &val))
> + return -EINVAL;
> +
> + err = set_core_threshold(data, val, attr->index);
> +
> + return err ? err : count;
> +}
> +
> static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL,
> SHOW_TEMP);
> static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO, show_temp, NULL,
> SHOW_TJMAX);
> -static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL,
> - SHOW_TTARGET);
> -static DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL);
> +static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp,
> + store_temp, CORE_TTARGET);
> +static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, show_temp,
> + store_temp, CORE_TMIN);
> +static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
> + SHOW_CRIT_ALARM);
> +static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
> + SHOW_MAX_ALARM);
> static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, show_name, NULL, SHOW_LABEL);
> static SENSOR_DEVICE_ATTR(name, S_IRUGO, show_name, NULL, SHOW_NAME);
>
> static struct attribute *coretemp_attributes[] = {
> &sensor_dev_attr_name.dev_attr.attr,
> &sensor_dev_attr_temp1_label.dev_attr.attr,
> - &dev_attr_temp1_crit_alarm.attr,
> + &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
> &sensor_dev_attr_temp1_input.dev_attr.attr,
> &sensor_dev_attr_temp1_crit.dev_attr.attr,
> + &sensor_dev_attr_temp1_max.dev_attr.attr,
> + &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
> + &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
> NULL
> };
>
> @@ -127,6 +173,26 @@ static const struct attribute_group coretemp_group = {
> .attrs = coretemp_attributes,
> };
>
> +static void update_alarm(struct coretemp_data *data)
> +{
> + u32 eax, edx;
> +
> + rdmsr_on_cpu(data->id, MSR_IA32_THERM_STATUS, &eax, &edx);
> +
> + /* Update the critical temperature alarm */
> + data->crit_alarm = (eax >> 5) & 1;
> +
> + /* Temperature reached threshold1 */
> + if (eax & THERM_LOG_THRESHOLD1)
> + data->max_alarm = 1;
> + /* Temperature reached threshold0 */
> + else if (eax & THERM_LOG_THRESHOLD0)
> + data->max_alarm = 0;
> + /* If none of these cases, don't update max_alarm */
> +
> + return;
> +}
> +
> static struct coretemp_data *coretemp_update_device(struct device *dev)
> {
> struct coretemp_data *data = dev_get_drvdata(dev);
> @@ -138,7 +204,6 @@ static struct coretemp_data *coretemp_update_device(struct device *dev)
>
> data->valid = 0;
> rdmsr_on_cpu(data->id, MSR_IA32_THERM_STATUS, &eax, &edx);
> - data->alarm = (eax >> 5) & 1;
> /* update only if data has been valid */
> if (eax & 0x80000000) {
> data->temp = data->tjmax - (((eax >> 16)
> @@ -298,6 +363,106 @@ static void __devinit get_ucode_rev_on_cpu(void *edx)
> rdmsr(MSR_IA32_UCODE_REV, eax, *(u32 *)edx);
> }
>
> +/* Platform thermal Interrupt Handler */
> +static int coretemp_interrupt(__u64 msr_val)
> +{
> +

That blank line isn't really needed.

> + if (msr_val & THERM_LOG_THRESHOLD0) {
> + if (!(msr_val & THERM_STATUS_THRESHOLD0))
> + pr_info("%s:Lower Threshold Reached\n", __func__);

Info with each interrupt seems to be excessive. I would suggest to make it a debug message
if you really think it is needed. And __func__ should not be needed at all.

> + /* Reset the Threshold0 interrupt */
> + wrmsrl(MSR_IA32_THERM_STATUS, msr_val & ~THERM_LOG_THRESHOLD0);
> + }
> +
> + if (msr_val & THERM_LOG_THRESHOLD1) {
> + if (msr_val & THERM_STATUS_THRESHOLD1)
> + pr_info("%s:Upper Threshold Reached\n", __func__);

Same here.

> + /* Reset the Threshold1 interrupt */
> + wrmsrl(MSR_IA32_THERM_STATUS, msr_val & ~THERM_LOG_THRESHOLD1);
> + }
> +
> + return 0;
> +}
> +
> +static void configure_apic(void *info)
> +{
> + u32 l;
> + int *flag = (int *)info;
> +
> + l = apic_read(APIC_LVTTHMR);
> +
> + if (*flag) /* Non-Zero flag Masks the APIC */
> + apic_write(APIC_LVTTHMR, l | APIC_LVT_MASKED);
> + else /* Zero flag UnMasks the APIC */
> + apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
> +}
> +
Fails to build if one manages to have APIC undefined (eg on a 32 bit kernel
with coretemp enabled and local APIC disabled).

drivers/hwmon/coretemp.c: In function ‘configure_apic’:
drivers/hwmon/coretemp.c:393: error: implicit declaration of function ‘apic_read’
drivers/hwmon/coretemp.c:396: error: implicit declaration of function ‘apic_write’

> +static int set_core_threshold(struct coretemp_data *data, int temp, int thres)
> +{
> + u32 eax, edx;
> + int diff;
> + int flag = 1;
> +
> + if (temp > data->tjmax)
> + return -EINVAL;
> +
> + mutex_lock(&data->update_lock);
> +
> + diff = (data->tjmax - temp)/1000;
> +
> + /* Mask the APIC */
> + smp_call_function_single(data->id, &configure_apic, &flag, 1);
> +
> + rdmsr_on_cpu(data->id, MSR_IA32_THERM_INTERRUPT, &eax, &edx);
> +
> + if (thres == CORE_TMIN) {
> + eax = (eax & ~THERM_MASK_THRESHOLD0) |
> + (diff << THERM_SHIFT_THRESHOLD0);
> + data->tmin = temp;
> + } else {
> + eax = (eax & ~THERM_MASK_THRESHOLD1) |
> + (diff << THERM_SHIFT_THRESHOLD1);
> + data->ttarget = temp;
> + }
> +
> + wrmsr_on_cpu(data->id, MSR_IA32_THERM_INTERRUPT, eax, edx);
> +
> + /* Unmask the APIC */
> + flag = 0;
> + smp_call_function_single(data->id, &configure_apic, &flag, 1);
> +
> + mutex_unlock(&data->update_lock);
> + return 0;
> +}
> +
> +static int __devinit config_thresh_intrpt(struct coretemp_data *data,
> + int enable)
> +{
> + u32 eax, edx;
> + int flag = 1; /* Non-Zero Flag masks the apic */
> +
> + smp_call_function_single(data->id, &configure_apic, &flag, 1);
> +
> + rdmsr_on_cpu(data->id, MSR_IA32_THERM_INTERRUPT, &eax, &edx);
> +
> + if (enable) {
> + eax |= (THERM_INT_THRESHOLD0_ENABLE |
> + THERM_INT_THRESHOLD1_ENABLE);
> + platform_thermal_notify = coretemp_interrupt;
> + } else {
> + eax &= (~(THERM_INT_THRESHOLD0_ENABLE |
> + THERM_INT_THRESHOLD1_ENABLE));
> + platform_thermal_notify = NULL;
> + }
> +
> + wrmsr_on_cpu(data->id, MSR_IA32_THERM_INTERRUPT, eax, edx);
> +
> + flag = 0; /*Flag should be zero to unmask the apic */
> + smp_call_function_single(data->id, &configure_apic, &flag, 1);
> +
> + return 0;
> +}
> +
> static int __devinit coretemp_probe(struct platform_device *pdev)
> {
> struct coretemp_data *data;
> @@ -351,6 +516,10 @@ static int __devinit coretemp_probe(struct platform_device *pdev)
> }
>
> data->tjmax = get_tjmax(c, data->id, &pdev->dev);
> + /* Initialize ttarget value. If IA32_TEMPERATURE_TARGET is
> + * supported, this value will be over written below

overwritten

> + */
> + data->ttarget = data->tjmax - 20000;
> platform_set_drvdata(pdev, data);
>
> /*
> @@ -368,13 +537,18 @@ static int __devinit coretemp_probe(struct platform_device *pdev)
> } else {
> data->ttarget = data->tjmax -
> (((eax >> 8) & 0xff) * 1000);
> - err = device_create_file(&pdev->dev,
> - &sensor_dev_attr_temp1_max.dev_attr);
> - if (err)
> - goto exit_free;
> }
> }
>
> + /* Enable threshold interrupt support */
> + config_thresh_intrpt(data, 1);
> +
> + /* Set Initial Core thresholds.
> + * The lower and upper threshold values here are assumed
> + */
> + set_core_threshold(data, 0, CORE_TMIN);
> + set_core_threshold(data, data->ttarget, CORE_TTARGET);
> +

I think I asked before ... are the threshold registers known to be supported on all intel CPUs
with coretemp support, or is some detection needed ?

> if ((err = sysfs_create_group(&pdev->dev.kobj, &coretemp_group)))
> goto exit_dev;
>
> @@ -404,7 +578,7 @@ static int __devexit coretemp_remove(struct platform_device *pdev)
>
> hwmon_device_unregister(data->hwmon_dev);
> sysfs_remove_group(&pdev->dev.kobj, &coretemp_group);
> - device_remove_file(&pdev->dev, &sensor_dev_attr_temp1_max.dev_attr);
> + config_thresh_intrpt(data, 0);
> platform_set_drvdata(pdev, NULL);
> kfree(data);
> return 0;
> --
> 1.6.5.2
>

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