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

Gupta, Anshuman anshuman.gupta at intel.com
Thu Oct 19 06:34:59 UTC 2023



> -----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 ?
> 
> 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.
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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