Re: [PATCH 8/9] drm/i915/bdw: Implement a basic PM interrupt handler

S, Deepak
2014-02-07T06:43:27Z

On Wed, Jan 29, 2014 at 9:55 AM, Ben Widawsky
> <benjamin.widawsky@intel.com <mailto:benjamin.widawsky@intel.com>> wrote:
>
> Almost all of it is reusable from the existing code. The primary
> difference is we need to do even less in the interrupt handler, since
> interrupts are not shared in the same way.
>
> The patch is mostly a copy-paste of the existing snb+ code, with updates
> to the relevant parts requiring changes to the interrupt handling. As
> such it /should/ be relatively trivial. It's highly likely that I missed
> some places where I need a gen8 version of the PM interrupts, but it has
> become invisible to me by now.
>
> This patch could probably be split into adding the new functions,
> followed by actually handling the interrupts. Since the code is
> currently disabled (and broken) I think the patch stands better by
> itself.
>
> Signed-off-by: Ben Widawsky <ben@bwidawsk.net <mailto:ben@bwidawsk.net>>
> ---
> drivers/gpu/drm/i915/i915_irq.c | 80
> ++++++++++++++++++++++++++++++++++++++--
> drivers/gpu/drm/i915/i915_reg.h | 1 +
> drivers/gpu/drm/i915/intel_drv.h | 2 +
> drivers/gpu/drm/i915/intel_pm.c | 39 +++++++++++++++++++-
> 4 files changed, 117 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c
> b/drivers/gpu/drm/i915/i915_irq.c
> index 72ade87..ab0c7ac 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -214,6 +214,53 @@ static bool ivb_can_enable_err_int(struct
> drm_device *dev)
> return true;
> }
>
> +/**
> + * bdw_update_pm_irq - update GT interrupt 2
> + * @dev_priv: driver private
> + * @interrupt_mask: mask of interrupt bits to update
> + * @enabled_irq_mask: mask of interrupt bits to enable
> + *
> + * Copied from the snb function, updated with relevant register
> offsets
> + */
> +static void bdw_update_pm_irq(struct drm_i915_private *dev_priv,
> + uint32_t interrupt_mask,
> + uint32_t enabled_irq_mask)
> +{
> + uint32_t new_val;
> +
> + assert_spin_locked(&dev_priv->irq_lock);
> +
> + if (dev_priv->pc8.irqs_disabled) {
> + WARN(1, "IRQs disabled\n");
> + dev_priv->pc8.regsave.gen6_pmimr &= ~interrupt_mask;
> + dev_priv->pc8.regsave.gen6_pmimr |= (~enabled_irq_mask &
> + interrupt_mask);
> + return;
> + }
> +
> + new_val = dev_priv->pm_irq_mask;
> + new_val &= ~interrupt_mask;
> + new_val |= (~enabled_irq_mask & interrupt_mask);
> +
> + if (new_val != dev_priv->pm_irq_mask) {
> + dev_priv->pm_irq_mask = new_val;
> + I915_WRITE(GEN8_GT_IMR(2), I915_READ(GEN8_GT_IMR(2)) |
> + dev_priv->pm_irq_mask);
> + POSTING_READ(GEN8_GT_IMR(2));
> + }
> +}
> +
> +void bdw_enable_pm_irq(struct drm_i915_private *dev_priv, uint32_t
> mask)
> +{
> + bdw_update_pm_irq(dev_priv, mask, mask);
> +}
> +
> +void bdw_disable_pm_irq(struct drm_i915_private *dev_priv, uint32_t
> mask)
> +{
> + bdw_update_pm_irq(dev_priv, mask, 0);
> +}
> +
> +
> static bool cpt_can_enable_serr_int(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -997,11 +1044,15 @@ static void gen6_pm_rps_work(struct
> work_struct *work)
> pm_iir = dev_priv->rps.pm_iir;
> dev_priv->rps.pm_iir = 0;
> /* Make sure not to corrupt PMIMR state used by ringbuffer
> code */
> - snb_enable_pm_irq(dev_priv, GEN6_PM_RPS_EVENTS);
> + if (IS_BROADWELL(dev_priv->dev))
> + bdw_enable_pm_irq(dev_priv, GEN6_PM_RPS_EVENTS);
> + else {
> + /* Make sure we didn't queue anything we're not
> going to process. */
> + snb_enable_pm_irq(dev_priv, GEN6_PM_RPS_EVENTS);
> + WARN_ON(pm_iir & ~GEN6_PM_RPS_EVENTS);
> + }
> spin_unlock_irq(&dev_priv->irq_lock);
>
> - /* Make sure we didn't queue anything we're not going to
> process. */
> - WARN_ON(pm_iir & ~GEN6_PM_RPS_EVENTS);
>
> if ((pm_iir & GEN6_PM_RPS_EVENTS) == 0)
> return;
> @@ -1192,6 +1243,19 @@ static void snb_gt_irq_handler(struct
> drm_device *dev,
> ivybridge_parity_error_irq_handler(dev, gt_iir);
> }
>
> +static void gen8_rps_irq_handler(struct drm_i915_private *dev_priv,
> u32 pm_iir)
> +{
> + if ((pm_iir & GEN6_PM_RPS_EVENTS) == 0)
> + return;
> +
> + spin_lock(&dev_priv->irq_lock);
> + dev_priv->rps.pm_iir |= pm_iir & GEN6_PM_RPS_EVENTS;
> + bdw_disable_pm_irq(dev_priv, pm_iir & GEN6_PM_RPS_EVENTS);
> + spin_unlock(&dev_priv->irq_lock);
> +
> + queue_work(dev_priv->wq, &dev_priv->rps.work);
> +}

We can use the "gen6_rps_irq_handler" right?

> static irqreturn_t gen8_gt_irq_handler(struct drm_device *dev,
> struct drm_i915_private
> *dev_priv,
> u32 master_ctl)
> @@ -1227,6 +1291,16 @@ static irqreturn_t gen8_gt_irq_handler(struct
> drm_device *dev,
> DRM_ERROR("The master control interrupt
> lied (GT1)!\n");
> }
>
> + if (master_ctl & GEN8_GT_PM_IRQ) {
> + tmp = I915_READ(GEN8_GT_IIR(2));
> + if (tmp & GEN6_PM_RPS_EVENTS) {
> + ret = IRQ_HANDLED;
> + gen8_rps_irq_handler(dev_priv, tmp);
> + I915_WRITE(GEN8_GT_IIR(1), tmp &
> GEN6_PM_RPS_EVENTS);
> + } else
> + DRM_ERROR("The master control interrupt lied
> (PM)!\n");
> + }
> +
> if (master_ctl & GEN8_GT_VECS_IRQ) {
> tmp = I915_READ(GEN8_GT_IIR(3));
> if (tmp) {
> diff --git a/drivers/gpu/drm/i915/i915_reg.h
> b/drivers/gpu/drm/i915/i915_reg.h
> index d77720e..f9e582e 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -4024,6 +4024,7 @@
> #define GEN8_DE_PIPE_A_IRQ (1<<16)
> #define GEN8_DE_PIPE_IRQ(pipe) (1<<(16+pipe))
> #define GEN8_GT_VECS_IRQ (1<<6)
> +#define GEN8_GT_PM_IRQ (1<<4)
> #define GEN8_GT_VCS2_IRQ (1<<3)
> #define GEN8_GT_VCS1_IRQ (1<<2)
> #define GEN8_GT_BCS_IRQ (1<<1)
> diff --git a/drivers/gpu/drm/i915/intel_drv.h
> b/drivers/gpu/drm/i915/intel_drv.h
> index 44067bc..7b49779 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -608,6 +608,8 @@ void ilk_enable_gt_irq(struct drm_i915_private
> *dev_priv, uint32_t mask);
> void ilk_disable_gt_irq(struct drm_i915_private *dev_priv,
> uint32_t mask);
> void snb_enable_pm_irq(struct drm_i915_private *dev_priv, uint32_t
> mask);
> void snb_disable_pm_irq(struct drm_i915_private *dev_priv,
> uint32_t mask);
> +void bdw_enable_pm_irq(struct drm_i915_private *dev_priv, uint32_t
> mask);
> +void bdw_disable_pm_irq(struct drm_i915_private *dev_priv, uint32_t
> mask);
> void hsw_pc8_disable_interrupts(struct drm_device *dev);
> void hsw_pc8_restore_interrupts(struct drm_device *dev);
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c
> b/drivers/gpu/drm/i915/intel_pm.c
> index deaaaf2..a5c9142 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3091,6 +3091,25 @@ void valleyview_set_rps(struct drm_device
> *dev, u8 val)
> trace_intel_gpu_freq_change(vlv_gpu_freq(dev_priv, val));
> }
>
> +static void gen8_disable_rps_interrupts(struct drm_device *dev)
> +{
> + struct drm_i915_private *dev_priv = dev->dev_private;
> +
> + I915_WRITE(GEN6_PMINTRMSK, 0xffffffff);
> + I915_WRITE(GEN8_GT_IER(2), I915_READ(GEN8_GT_IER(2)) &
> + ~GEN6_PM_RPS_EVENTS);
> + /* Complete PM interrupt masking here doesn't race with the
> rps work
> + * item again unmasking PM interrupts because that is using
> a different
> + * register (PMIMR) to mask PM interrupts. The only risk is
> in leaving
> + * stale bits in PMIIR and PMIMR which gen6_enable_rps will
> clean up. */
> +
> + spin_lock_irq(&dev_priv->irq_lock);
> + dev_priv->rps.pm_iir = 0;
> + spin_unlock_irq(&dev_priv->irq_lock);
> +
> + I915_WRITE(GEN8_GT_IIR(2), GEN6_PM_RPS_EVENTS);
> +}
> +
> static void gen6_disable_rps_interrupts(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -3116,7 +3135,10 @@ static void gen6_disable_rps(struct
> drm_device *dev)
> I915_WRITE(GEN6_RC_CONTROL, 0);
> I915_WRITE(GEN6_RPNSWREQ, 1 << 31);
>
> - gen6_disable_rps_interrupts(dev);
> + if (IS_BROADWELL(dev))
> + gen8_disable_rps_interrupts(dev);
> + else
> + gen6_disable_rps_interrupts(dev);
> }
>
> static void valleyview_disable_rps(struct drm_device *dev)
> @@ -3161,6 +3183,19 @@ int intel_enable_rc6(const struct drm_device
> *dev)
> return INTEL_RC6_ENABLE;
> }
>
> +static void gen8_enable_rps_interrupts(struct drm_device *dev)
> +{
> + struct drm_i915_private *dev_priv = dev->dev_private;
> +
> + spin_lock_irq(&dev_priv->irq_lock);
> + WARN_ON(dev_priv->rps.pm_iir);
> + bdw_enable_pm_irq(dev_priv, GEN6_PM_RPS_EVENTS);
> + I915_WRITE(GEN8_GT_IIR(2), GEN6_PM_RPS_EVENTS);
> + spin_unlock_irq(&dev_priv->irq_lock);
> +
> + I915_WRITE(GEN6_PMINTRMSK, ~GEN6_PM_RPS_EVENTS);
> +}

As per the spec, I think we need to unmask bit 31 also, if not i don't
this we will get PM inetrrupts.

> static void gen6_enable_rps_interrupts(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -3263,7 +3298,7 @@ static void gen8_enable_rps(struct drm_device
> *dev)
>
> gen6_set_rps(dev, (I915_READ(GEN6_GT_PERF_STATUS) & 0xff00)
> >> 8);
>
> - gen6_enable_rps_interrupts(dev);
> + gen8_enable_rps_interrupts(dev);
>
> gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);
> }
> --
> 1.8.5.3
>
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