On Tue, Nov 08, 2022 at 03:50:51PM +0800, Zhang Rui wrote:
> Tjmax value retrieved from MSR_IA32_TEMPERATURE_TARGET can be changed at
> runtime when the Intel SST-PP (Intel Speed Select Technology -
> Performance Profile) level is changed. As a result, the ttarget value
> also becomes dyamic.
>
> Improve the code to always get updated ttarget value.
>
> Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> ---
> drivers/hwmon/coretemp.c | 69 ++++++++++++++++++++++++++++------------
> 1 file changed, 48 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
> index 5292f7844860..d6084600862f 100644
> --- a/drivers/hwmon/coretemp.c
> +++ b/drivers/hwmon/coretemp.c
> @@ -69,7 +69,6 @@ MODULE_PARM_DESC(tjmax, "TjMax value in degrees Celsius");
> */
> struct temp_data {
> int temp;
> - int ttarget;
> int tjmax;
> unsigned long last_updated;
> unsigned int cpu;
> @@ -96,6 +95,7 @@ struct platform_data {
> };
>
> static int get_tjmax(struct temp_data *tdata, struct device *dev);
> +static int get_ttarget(struct temp_data *tdata, struct device *dev);
Please rearrange to code to avoid forward declarations.
>
> /* Keep track of how many zone pointers we allocated in init() */
> static int max_zones __read_mostly;
> @@ -150,8 +150,17 @@ static ssize_t show_ttarget(struct device *dev,
> {
> struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> struct platform_data *pdata = dev_get_drvdata(dev);
> + struct temp_data *tdata = pdata->core_data[attr->index];
> + int ttarget;
> +
> + mutex_lock(&tdata->update_lock);
Is that mutex really necessary ? I don't immediately see the need
for it.
> + ttarget = get_ttarget(tdata, dev);
> + mutex_unlock(&tdata->update_lock);
>
> - return sprintf(buf, "%d\n", pdata->core_data[attr->index]->ttarget);
> + if (ttarget >= 0)
> + return sprintf(buf, "%d\n", ttarget);
> + else
> + return ttarget;
else after return is unnecessary. Much better would be
if (ttarget < 0)
return ttarget;
return sprintf(buf, "%d\n", ttarget);
> }
>
> static ssize_t show_temp(struct device *dev,
> @@ -393,6 +402,38 @@ static int get_tjmax(struct temp_data *tdata, struct device *dev)
> return tdata->tjmax;
> }
>
> +static int get_ttarget(struct temp_data *tdata, struct device *dev)
> +{
> + u32 eax, edx;
> + struct cpuinfo_x86 *c = &cpu_data(tdata->cpu);
> + int tj_max, ttarget_offset, ret;
Please use tjmax for consistency.
> +
> + /*
> + * ttarget is valid only if tjmax can be retrieved from
> + * MSR_IA32_TEMPERATURE_TARGET
> + */
> + if (tdata->tjmax)
> + return -ENODEV;
> +
> + if (c->x86_model <= 0xe || c->x86_model == 0x1c)
> + return -ENODEV;
> +
Does it really make sense to re-check this each time the target temperature
is read ?
> + /*
> + * Read the still undocumented bits 8:15 of IA32_TEMPERATURE_TARGET.
> + * The target temperature is available on older CPUs but not in this
> + * register. Atoms don't have the register at all.
> + */
> + ret = rdmsr_safe_on_cpu(tdata->cpu, MSR_IA32_TEMPERATURE_TARGET,
> + &eax, &edx);
Please watch multi-line alignment.
> + if (ret)
> + return ret;
> +
> + tj_max = (eax >> 16) & 0xff;
> + ttarget_offset = (eax >> 8) & 0xff;
> +
> + return (tj_max - ttarget_offset) * 1000;
> +}
> +
> static int create_core_attrs(struct temp_data *tdata, struct device *dev,
> int attr_no)
> {
> @@ -468,9 +509,8 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu,
> {
> struct temp_data *tdata;
> struct platform_data *pdata = platform_get_drvdata(pdev);
> - struct cpuinfo_x86 *c = &cpu_data(cpu);
> u32 eax, edx;
> - int err, index, attr_no, tjmax;
> + int err, index, attr_no;
>
> /*
> * Find attr number for sysfs:
> @@ -504,23 +544,10 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu,
> if (err)
> goto exit_free;
>
> - /* We can access status register. Get Critical Temperature */
> - tjmax = get_tjmax(tdata, &pdev->dev);
> -
> - /*
> - * Read the still undocumented bits 8:15 of IA32_TEMPERATURE_TARGET.
> - * The target temperature is available on older CPUs but not in this
> - * register. Atoms don't have the register at all.
> - */
> - if (c->x86_model > 0xe && c->x86_model != 0x1c) {
> - err = rdmsr_safe_on_cpu(cpu, MSR_IA32_TEMPERATURE_TARGET,
> - &eax, &edx);
> - if (!err) {
> - tdata->ttarget
> - = tjmax - ((eax >> 8) & 0xff) * 1000;
> - tdata->attr_size++;
> - }
> - }
> + /* Make sure tdata->tjmax is a valid indicator for dynamic/static tjmax */
> + get_tjmax(tdata, &pdev->dev);
> + if (get_ttarget(tdata, &pdev->dev) >= 0)
> + tdata->attr_size++;
>
> pdata->core_data[attr_no] = tdata;
>
