Re: [PATCH] drm/i915: Update rps frequencies for BXT

[Imre Deak <imre.deak@intel.com>]

On to, 2015-06-25 at 14:54 -0700, Bob Paauwe wrote:
> Broxton is using a different register and different bit ordering
> for rps status capabilities.
> 
> Also GT perf freqency register is different for Broxton so update
> that.
> 
> Signed-off-by: Bob Paauwe <bob.j.paauwe@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c | 21 ++++++++++++++++-----
>  drivers/gpu/drm/i915/i915_reg.h     |  2 ++
>  drivers/gpu/drm/i915/intel_pm.c     | 16 ++++++++++++----
>  3 files changed, 30 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index f3b8062..8a2a456a 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -1132,9 +1132,9 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
>  			   (rgvstat & MEMSTAT_PSTATE_MASK) >> MEMSTAT_PSTATE_SHIFT);
>  	} else if (IS_GEN6(dev) || (IS_GEN7(dev) && !IS_VALLEYVIEW(dev)) ||
>  		   IS_BROADWELL(dev) || IS_GEN9(dev)) {
> -		u32 gt_perf_status = I915_READ(GEN6_GT_PERF_STATUS);
> -		u32 rp_state_limits = I915_READ(GEN6_RP_STATE_LIMITS);
> -		u32 rp_state_cap = I915_READ(GEN6_RP_STATE_CAP);
> +		u32 rp_state_limits;
> +		u32 gt_perf_status;
> +		u32 rp_state_cap;
>  		u32 rpmodectl, rpinclimit, rpdeclimit;
>  		u32 rpstat, cagf, reqf;
>  		u32 rpupei, rpcurup, rpprevup;
> @@ -1142,6 +1142,15 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
>  		u32 pm_ier, pm_imr, pm_isr, pm_iir, pm_mask;
>  		int max_freq;
>  
> +		rp_state_limits = I915_READ(GEN6_RP_STATE_LIMITS);
> +		if (IS_BROXTON(dev)) {
> +			rp_state_cap = I915_READ(BXT_RP_STATE_CAP);
> +			gt_perf_status = I915_READ(BXT_GT_PERF_STATUS);
> +		} else {
> +			rp_state_cap = I915_READ(GEN6_RP_STATE_CAP);
> +			gt_perf_status = I915_READ(GEN6_GT_PERF_STATUS);
> +		}
> +
>  		/* RPSTAT1 is in the GT power well */
>  		ret = mutex_lock_interruptible(&dev->struct_mutex);
>  		if (ret)
> @@ -1229,7 +1238,8 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
>  		seq_printf(m, "Down threshold: %d%%\n",
>  			   dev_priv->rps.down_threshold);
>  
> -		max_freq = (rp_state_cap & 0xff0000) >> 16;
> +		max_freq = (IS_BROXTON(dev) ? rp_state_cap >> 0 :
> +			    rp_state_cap >> 16) & 0xff;
>  		max_freq *= (IS_SKYLAKE(dev) ? GEN9_FREQ_SCALER : 1);
>  		seq_printf(m, "Lowest (RPN) frequency: %dMHz\n",
>  			   intel_gpu_freq(dev_priv, max_freq));
> @@ -1239,7 +1249,8 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
>  		seq_printf(m, "Nominal (RP1) frequency: %dMHz\n",
>  			   intel_gpu_freq(dev_priv, max_freq));
>  
> -		max_freq = rp_state_cap & 0xff;
> +		max_freq = (IS_BROXTON(dev) ? rp_state_cap >> 16 :
> +			    rp_state_cap >> 0) & 0xff;
>  		max_freq *= (IS_SKYLAKE(dev) ? GEN9_FREQ_SCALER : 1);
>  		seq_printf(m, "Max non-overclocked (RP0) frequency: %dMHz\n",
>  			   intel_gpu_freq(dev_priv, max_freq));
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index fa9ccb87..17b5ca2 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2734,8 +2734,10 @@ enum skl_disp_power_wells {
>  #define GEN6_GT_THREAD_STATUS_CORE_MASK 0x7
>  
>  #define GEN6_GT_PERF_STATUS	(MCHBAR_MIRROR_BASE_SNB + 0x5948)
> +#define BXT_GT_PERF_STATUS      (MCHBAR_MIRROR_BASE_SNB + 0x7070)

Nitpick: the format in GT_PERF_STATUS is the same on SKL and BXT so you
could have redefined GEN6_GT_PERF_STATUS to be a wrapper macro similar
to what you did in v1 of this patch.

>  #define GEN6_RP_STATE_LIMITS	(MCHBAR_MIRROR_BASE_SNB + 0x5994)
>  #define GEN6_RP_STATE_CAP	(MCHBAR_MIRROR_BASE_SNB + 0x5998)
> +#define BXT_RP_STATE_CAP        0x138170
>  
>  #define INTERVAL_1_28_US(us)	(((us) * 100) >> 7)
>  #define INTERVAL_1_33_US(us)	(((us) * 3)   >> 2)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 32ff034..213da42 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4288,13 +4288,21 @@ static void gen6_init_rps_frequencies(struct drm_device *dev)
>  	u32 ddcc_status = 0;
>  	int ret;
>  
> -	rp_state_cap = I915_READ(GEN6_RP_STATE_CAP);
>  	/* All of these values are in units of 50MHz */

On SKL/BXT the unit is 16.66MHz, so the above comment could be
clarified.

>  	dev_priv->rps.cur_freq		= 0;
>  	/* static values from HW: RP0 > RP1 > RPn (min_freq) */
> -	dev_priv->rps.rp0_freq		= (rp_state_cap >>  0) & 0xff;
> -	dev_priv->rps.rp1_freq		= (rp_state_cap >>  8) & 0xff;
> -	dev_priv->rps.min_freq		= (rp_state_cap >> 16) & 0xff;
> +	if (IS_BROXTON(dev)) {
> +		rp_state_cap = I915_READ(BXT_RP_STATE_CAP);
> +		dev_priv->rps.rp0_freq = (rp_state_cap >> 16) & 0xff;
> +		dev_priv->rps.rp1_freq = (rp_state_cap >>  8) & 0xff;
> +		dev_priv->rps.min_freq = (rp_state_cap >>  0) & 0xff;
> +	} else {
> +		rp_state_cap = I915_READ(GEN6_RP_STATE_CAP);
> +		dev_priv->rps.rp0_freq = (rp_state_cap >>  0) & 0xff;
> +		dev_priv->rps.rp1_freq = (rp_state_cap >>  8) & 0xff;
> +		dev_priv->rps.min_freq = (rp_state_cap >> 16) & 0xff;
> +	}
> +

Nitpick: this could be factored out to a separate function returning
rpn,rp0,rp1 which could be also used then in i915_frequency_info.

All the above can be addressed as a follow-up, so this patch looks ok to
me:
Reviewed-by: Imre Deak <imre.deak@intel.com>

>  	if (IS_SKYLAKE(dev)) {
>  		/* Store the frequency values in 16.66 MHZ units, which is
>  		   the natural hardware unit for SKL */


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