[Intel-xe] [PATCH v2 2/3] drm/xe/hwmon: Protect hwmon rw attributes with hwmon_lock

Nilawar, Badal badal.nilawar at intel.com
Thu Oct 26 10:17:01 UTC 2023



On 19-10-2023 12:04, Gupta, Anshuman wrote:
> 
> 
>> -----Original Message-----
>> From: Nilawar, Badal <badal.nilawar at intel.com>
>> Sent: Thursday, October 19, 2023 12:34 AM
>> To: intel-xe at lists.freedesktop.org
>> Cc: Gupta, Anshuman <anshuman.gupta at intel.com>; Dixit, Ashutosh
>> <ashutosh.dixit at intel.com>; andi.shyti at linux.intel.com; Tauro, Riana
>> <riana.tauro at intel.com>; Vivi, Rodrigo <rodrigo.vivi at intel.com>
>> Subject: [PATCH v2 2/3] drm/xe/hwmon: Protect hwmon rw attributes with
>> hwmon_lock
>>
>> Take hwmon_lock while accessing hwmon rw attributes. For readonly
>> attributes its not required to take lock as reads are protected by sysfs layer and
>> therefore sequential.
> This patch should only have functionality related to locking, why this is adding
> xe_hwmon_power_curr_crit_write and xe_hwmon_power_curr_crit_read ?
Sure, will add these functions to refactor patch.
>>
>> Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
>> Cc: Anshuman Gupta <anshuman.gupta at intel.com>
>> Signed-off-by: Badal Nilawar <badal.nilawar at intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_hwmon.c | 92 ++++++++++++++++++++--------------
>> -
>>   1 file changed, 52 insertions(+), 40 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_hwmon.c
>> b/drivers/gpu/drm/xe/xe_hwmon.c index 08c7289723ae..c87d028f1955
>> 100644
>> --- a/drivers/gpu/drm/xe/xe_hwmon.c
>> +++ b/drivers/gpu/drm/xe/xe_hwmon.c
>> @@ -47,7 +47,7 @@ struct xe_hwmon_energy_info {  struct xe_hwmon {
>>   	struct device *hwmon_dev;
>>   	struct xe_gt *gt;
>> -	struct mutex hwmon_lock; /* rmw operations*/
>> +	struct mutex hwmon_lock; /* For rw attributes */
> Make this Kernel Doc comment, and this is wrongly placed here in .c , structure are declared
> In headers in all xe files, and requires kernel doc comment.
Sure will add kernel doc comment. Struct added here as it is used only 
in this file. Infact in drivers/gpu/drm/xe/xe_mocs.c has structures 
defined in it.

Regards,
Badal
> Thanks,
> Anshuman Gupta.
>>   	int scl_shift_power;
>>   	int scl_shift_energy;
>>   	struct xe_hwmon_energy_info ei;	/*  Energy info for
>> energy1_input */
>> @@ -135,11 +135,13 @@ static void xe_hwmon_power_max_read(struct
>> xe_hwmon *hwmon, long *value)  {
>>   	u64 reg_val, min, max;
>>
>> +	mutex_lock(&hwmon->hwmon_lock);
>> +
>>   	xe_hwmon_process_reg(hwmon, REG_PKG_RAPL_LIMIT,
>> REG_READ32, &reg_val, 0, 0);
>>   	/* Check if PL1 limit is disabled */
>>   	if (!(reg_val & PKG_PWR_LIM_1_EN)) {
>>   		*value = PL1_DISABLE;
>> -		return;
>> +		goto unlock;
>>   	}
>>
>>   	reg_val = REG_FIELD_GET(PKG_PWR_LIM_1, reg_val); @@ -153,12
>> +155,17 @@ static void xe_hwmon_power_max_read(struct xe_hwmon
>> *hwmon, long *value)
>>
>>   	if (min && max)
>>   		*value = clamp_t(u64, *value, min, max);
>> +unlock:
>> +	mutex_unlock(&hwmon->hwmon_lock);
>>   }
>>
>>   static int xe_hwmon_power_max_write(struct xe_hwmon *hwmon, long
>> value)  {
>> +	int ret = 0;
>>   	u64 reg_val;
>>
>> +	mutex_lock(&hwmon->hwmon_lock);
>> +
>>   	/* Disable PL1 limit and verify, as limit cannot be disabled on all
>> platforms */
>>   	if (value == PL1_DISABLE) {
>>   		xe_hwmon_process_reg(hwmon, REG_PKG_RAPL_LIMIT,
>> REG_RMW32, &reg_val, @@ -166,8 +173,10 @@ static int
>> xe_hwmon_power_max_write(struct xe_hwmon *hwmon, long value)
>>   		xe_hwmon_process_reg(hwmon, REG_PKG_RAPL_LIMIT,
>> REG_READ32, &reg_val,
>>   				     PKG_PWR_LIM_1_EN, 0);
>>
>> -		if (reg_val & PKG_PWR_LIM_1_EN)
>> -			return -EOPNOTSUPP;
>> +		if (reg_val & PKG_PWR_LIM_1_EN) {
>> +			ret = -EOPNOTSUPP;
>> +			goto unlock;
>> +		}
>>   	}
>>
>>   	/* Computation in 64-bits to avoid overflow. Round to nearest. */
>> @@ -176,8 +185,9 @@ static int xe_hwmon_power_max_write(struct
>> xe_hwmon *hwmon, long value)
>>
>>   	xe_hwmon_process_reg(hwmon, REG_PKG_RAPL_LIMIT,
>> REG_RMW32, &reg_val,
>>   			     PKG_PWR_LIM_1_EN | PKG_PWR_LIM_1, reg_val);
>> -
>> -	return 0;
>> +unlock:
>> +	mutex_unlock(&hwmon->hwmon_lock);
>> +	return ret;
>>   }
>>
>>   static void xe_hwmon_power_rated_max_read(struct xe_hwmon *hwmon,
>> long *value) @@ -215,8 +225,6 @@ xe_hwmon_energy_get(struct
>> xe_hwmon *hwmon, long *energy)
>>   	struct xe_hwmon_energy_info *ei = &hwmon->ei;
>>   	u64 reg_val;
>>
>> -	mutex_lock(&hwmon->hwmon_lock);
>> -
>>   	xe_hwmon_process_reg(hwmon, REG_PKG_ENERGY_STATUS,
>> REG_READ32,
>>   			     &reg_val, 0, 0);
>>
>> @@ -229,8 +237,6 @@ xe_hwmon_energy_get(struct xe_hwmon *hwmon,
>> long *energy)
>>
>>   	*energy = mul_u64_u32_shr(ei->accum_energy, SF_ENERGY,
>>   				  hwmon->scl_shift_energy);
>> -
>> -	mutex_unlock(&hwmon->hwmon_lock);
>>   }
>>
>>   static const struct hwmon_channel_info *hwmon_info[] = { @@ -260,6
>> +266,38 @@ static int xe_hwmon_pcode_write_i1(struct xe_gt *gt, u32 uval)
>>   			      uval);
>>   }
>>
>> +static int xe_hwmon_power_curr_crit_read(struct xe_hwmon *hwmon, long
>> +*value, u32 scale_factor) {
>> +	int ret;
>> +	u32 uval;
>> +
>> +	mutex_lock(&hwmon->hwmon_lock);
>> +
>> +	ret = xe_hwmon_pcode_read_i1(hwmon->gt, &uval);
>> +	if (ret)
>> +		goto unlock;
>> +
>> +	*value =
>> mul_u64_u32_shr(REG_FIELD_GET(POWER_SETUP_I1_DATA_MASK, uval),
>> +				 scale_factor, POWER_SETUP_I1_SHIFT);
>> +unlock:
>> +	mutex_unlock(&hwmon->hwmon_lock);
>> +	return ret;
>> +}
>> +
>> +static int xe_hwmon_power_curr_crit_write(struct xe_hwmon *hwmon, long
>> +value, u32 scale_factor) {
>> +	int ret;
>> +	u32 uval;
>> +
>> +	mutex_lock(&hwmon->hwmon_lock);
>> +
>> +	uval = DIV_ROUND_CLOSEST_ULL(value << POWER_SETUP_I1_SHIFT,
>> scale_factor);
>> +	ret = xe_hwmon_pcode_write_i1(hwmon->gt, uval);
>> +
>> +	mutex_unlock(&hwmon->hwmon_lock);
>> +	return ret;
>> +}
>> +
>>   static void xe_hwmon_get_voltage(struct xe_hwmon *hwmon, long *value)  {
>>   	u64 reg_val;
>> @@ -291,9 +329,6 @@ xe_hwmon_power_is_visible(struct xe_hwmon
>> *hwmon, u32 attr, int chan)  static int  xe_hwmon_power_read(struct
>> xe_hwmon *hwmon, u32 attr, int chan, long *val)  {
>> -	int ret;
>> -	u32 uval;
>> -
>>   	switch (attr) {
>>   	case hwmon_power_max:
>>   		xe_hwmon_power_max_read(hwmon, val);
>> @@ -302,14 +337,7 @@ xe_hwmon_power_read(struct xe_hwmon
>> *hwmon, u32 attr, int chan, long *val)
>>   		xe_hwmon_power_rated_max_read(hwmon, val);
>>   		return 0;
>>   	case hwmon_power_crit:
>> -		ret = xe_hwmon_pcode_read_i1(hwmon->gt, &uval);
>> -		if (ret)
>> -			return ret;
>> -		if (!(uval & POWER_SETUP_I1_WATTS))
>> -			return -ENODEV;
>> -		*val =
>> mul_u64_u32_shr(REG_FIELD_GET(POWER_SETUP_I1_DATA_MASK, uval),
>> -				       SF_POWER, POWER_SETUP_I1_SHIFT);
>> -		return 0;
>> +		return xe_hwmon_power_curr_crit_read(hwmon, val,
>> SF_POWER);
>>   	default:
>>   		return -EOPNOTSUPP;
>>   	}
>> @@ -318,14 +346,11 @@ xe_hwmon_power_read(struct xe_hwmon
>> *hwmon, u32 attr, int chan, long *val)  static int
>> xe_hwmon_power_write(struct xe_hwmon *hwmon, u32 attr, int chan, long
>> val)  {
>> -	u32 uval;
>> -
>>   	switch (attr) {
>>   	case hwmon_power_max:
>>   		return xe_hwmon_power_max_write(hwmon, val);
>>   	case hwmon_power_crit:
>> -		uval = DIV_ROUND_CLOSEST_ULL(val <<
>> POWER_SETUP_I1_SHIFT, SF_POWER);
>> -		return xe_hwmon_pcode_write_i1(hwmon->gt, uval);
>> +		return xe_hwmon_power_curr_crit_write(hwmon, val,
>> SF_POWER);
>>   	default:
>>   		return -EOPNOTSUPP;
>>   	}
>> @@ -348,19 +373,9 @@ xe_hwmon_curr_is_visible(const struct xe_hwmon
>> *hwmon, u32 attr)  static int  xe_hwmon_curr_read(struct xe_hwmon
>> *hwmon, u32 attr, long *val)  {
>> -	int ret;
>> -	u32 uval;
>> -
>>   	switch (attr) {
>>   	case hwmon_curr_crit:
>> -		ret = xe_hwmon_pcode_read_i1(hwmon->gt, &uval);
>> -		if (ret)
>> -			return ret;
>> -		if (uval & POWER_SETUP_I1_WATTS)
>> -			return -ENODEV;
>> -		*val =
>> mul_u64_u32_shr(REG_FIELD_GET(POWER_SETUP_I1_DATA_MASK, uval),
>> -				       SF_CURR, POWER_SETUP_I1_SHIFT);
>> -		return 0;
>> +		return xe_hwmon_power_curr_crit_read(hwmon, val,
>> SF_CURR);
>>   	default:
>>   		return -EOPNOTSUPP;
>>   	}
>> @@ -369,12 +384,9 @@ xe_hwmon_curr_read(struct xe_hwmon *hwmon,
>> u32 attr, long *val)  static int  xe_hwmon_curr_write(struct xe_hwmon
>> *hwmon, u32 attr, long val)  {
>> -	u32 uval;
>> -
>>   	switch (attr) {
>>   	case hwmon_curr_crit:
>> -		uval = DIV_ROUND_CLOSEST_ULL(val <<
>> POWER_SETUP_I1_SHIFT, SF_CURR);
>> -		return xe_hwmon_pcode_write_i1(hwmon->gt, uval);
>> +		return xe_hwmon_power_curr_crit_write(hwmon, val,
>> SF_CURR);
>>   	default:
>>   		return -EOPNOTSUPP;
>>   	}
>> --
>> 2.25.1
> 


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