[Intel-gfx] [PATCH 8/8] drm/i915/icl: Use hw engine class, instance to find irq handler

Daniele Ceraolo Spurio daniele.ceraolospurio at intel.com
Fri Mar 16 19:37:23 UTC 2018



On 16/03/18 11:28, Michel Thierry wrote:
> On 3/16/2018 5:14 AM, Mika Kuoppala wrote:
>> Interrupt identity register we already read from hardware
>> contains engine class and instance fields. Leverage
>> these fields to find correct engine to handle the interrupt.
>>
>> v3: rebase on top of rps intr
>>      use correct class / instance limits (Michel)
>>
>> Suggested-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
>> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>> Cc: Michel Thierry <michel.thierry at intel.com>
>> Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_irq.c | 80 
>> +++++++++++++++--------------------------
>>   drivers/gpu/drm/i915/i915_reg.h |  4 ++-
>>   2 files changed, 31 insertions(+), 53 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_irq.c 
>> b/drivers/gpu/drm/i915/i915_irq.c
>> index 8c4510ffe625..dd2fb2d0457f 100644
>> --- a/drivers/gpu/drm/i915/i915_irq.c
>> +++ b/drivers/gpu/drm/i915/i915_irq.c
>> @@ -413,8 +413,8 @@ static void gen6_disable_pm_irq(struct 
>> drm_i915_private *dev_priv, u32 disable_m
>>   }
>>   static u32
>> -gen11_gt_engine_intr(struct drm_i915_private * const i915,
>> -             const unsigned int bank, const unsigned int bit);
>> +gen11_gt_engine_identity(struct drm_i915_private * const i915,
>> +             const unsigned int bank, const unsigned int bit);
>>   void gen11_reset_rps_interrupts(struct drm_i915_private *dev_priv)
>>   {
>> @@ -428,7 +428,7 @@ void gen11_reset_rps_interrupts(struct 
>> drm_i915_private *dev_priv)
>>        */
>>       dw = I915_READ_FW(GEN11_GT_INTR_DW0);
>>       while (dw & BIT(GEN11_GTPM)) {
>> -        gen11_gt_engine_intr(dev_priv, 0, GEN11_GTPM);
>> +        gen11_gt_engine_identity(dev_priv, 0, GEN11_GTPM);
>>           I915_WRITE_FW(GEN11_GT_INTR_DW0, BIT(GEN11_GTPM));
>>           dw = I915_READ_FW(GEN11_GT_INTR_DW0);
>>       }
>> @@ -2771,50 +2771,9 @@ static void __fini_wedge(struct wedge_me *w)
>>            (W)->i915;                            \
>>            __fini_wedge((W)))
>> -static void
>> -gen11_gt_engine_irq_handler(struct drm_i915_private * const i915,
>> -                const unsigned int bank,
>> -                const unsigned int engine_n,
>> -                const u16 iir)
>> -{
>> -    struct intel_engine_cs ** const engine = i915->engine;
>> -
>> -    switch (bank) {
>> -    case 0:
>> -        switch (engine_n) {
>> -
>> -        case GEN11_RCS0:
>> -            return gen8_cs_irq_handler(engine[RCS], iir);
>> -
>> -        case GEN11_BCS:
>> -            return gen8_cs_irq_handler(engine[BCS], iir);
>> -
>> -        case GEN11_GTPM:
>> -            return gen6_rps_irq_handler(i915, iir);
>> -        }
>> -    case 1:
>> -        switch (engine_n) {
>> -
>> -        case GEN11_VCS(0):
>> -            return gen8_cs_irq_handler(engine[_VCS(0)], iir);
>> -        case GEN11_VCS(1):
>> -            return gen8_cs_irq_handler(engine[_VCS(1)], iir);
>> -        case GEN11_VCS(2):
>> -            return gen8_cs_irq_handler(engine[_VCS(2)], iir);
>> -        case GEN11_VCS(3):
>> -            return gen8_cs_irq_handler(engine[_VCS(3)], iir);
>> -
>> -        case GEN11_VECS(0):
>> -            return gen8_cs_irq_handler(engine[_VECS(0)], iir);
>> -        case GEN11_VECS(1):
>> -            return gen8_cs_irq_handler(engine[_VECS(1)], iir);
>> -        }
>> -    }
>> -}
>> -
>>   static u32
>> -gen11_gt_engine_intr(struct drm_i915_private * const i915,
>> -             const unsigned int bank, const unsigned int bit)
>> +gen11_gt_engine_identity(struct drm_i915_private * const i915,
>> +             const unsigned int bank, const unsigned int bit)
>>   {
>>       void __iomem * const regs = i915->regs;
>>       u32 timeout_ts;
>> @@ -2841,7 +2800,26 @@ gen11_gt_engine_intr(struct drm_i915_private * 
>> const i915,
>>       raw_reg_write(regs, GEN11_INTR_IDENTITY_REG(bank),
>>                 GEN11_INTR_DATA_VALID);
>> -    return ident & GEN11_INTR_ENGINE_MASK;
>> +    return ident;
>> +}
>> +
>> +static void
>> +gen11_gt_identity_handler(struct drm_i915_private * const i915,
>> +              const u32 identity)
>> +{
>> +    const u8 class = GEN11_INTR_ENGINE_CLASS(identity);
>> +    const u8 instance = GEN11_INTR_ENGINE_INSTANCE(identity);
>> +    const u16 iir = GEN11_INTR_ENGINE_MASK(identity);
>> +
>> +    if (unlikely(!iir))
>> +        return;
>> +
>> +    if (class <= MAX_ENGINE_CLASS && instance <= MAX_ENGINE_INSTANCE)
>> +        return gen8_cs_irq_handler(i915->engine_class[class][instance],
>> +                       iir);
>> +
>> +    if (class == GEN11_GTPM)
>> +        return gen6_rps_irq_handler(i915, iir);
> 
> Hi,
> 
> GEN11_GTPM should be
>      [Class ID] == 'OTHER_CLASS (4)', and
>      [Engine Id] == 1.
> (I'm looking at bspec 20944)
> 
> So not only the GPTM check needs to be before the
>    if (class <= MAX_ENGINE_CLASS),
> 
> but it can't use GEN11_GTPM either.
> 
> -Michel
> 

I'm not fully convinced about checking against MAX_ENGINE_CLASS or 
MAX_ENGINE_INSTANCE, since we do have cases that are within those values 
but are still invalid (e.g. VCS1). Maybe we can just do something 
simpler (that should still be safe) like:

	/* OTHER_CLASS is for interrupts not comings from an engine */
	if (class != OTHER_CLASS) {
		engine = i915->engine_class[class][instance];
		if (likely(engine))
			return gen8_cs_irq_handler(...);
	} else {
		if (instance == 1)
			return gen6_rps_irq_handler(...);

		/* more cases incoming (e.g. GuC) */
	}

> 
>>   }
>>   static void
>> @@ -2866,12 +2844,10 @@ gen11_gt_irq_handler(struct drm_i915_private * 
>> const i915,
>>           }
>>           for_each_set_bit(bit, &intr_dw, 32) {
>> -            const u16 iir = gen11_gt_engine_intr(i915, bank, bit);
>> -
>> -            if (unlikely(!iir))
>> -                continue;
>> +            const u32 ident = gen11_gt_engine_identity(i915,
>> +                                   bank, bit);
>> -            gen11_gt_engine_irq_handler(i915, bank, bit, iir);
>> +            gen11_gt_identity_handler(i915, ident);
>>           }
>>           /* Clear must be after shared has been served for engine */
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h 
>> b/drivers/gpu/drm/i915/i915_reg.h
>> index f3cc77690124..74a8f454e8a0 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -6826,7 +6826,9 @@ enum {
>>   #define GEN11_INTR_IDENTITY_REG0    _MMIO(0x190060)
>>   #define GEN11_INTR_IDENTITY_REG1    _MMIO(0x190064)
>>   #define  GEN11_INTR_DATA_VALID        (1 << 31)
>> -#define  GEN11_INTR_ENGINE_MASK        (0xffff)
>> +#define  GEN11_INTR_ENGINE_MASK(x)    ((x) & 0xffff)
>> +#define  GEN11_INTR_ENGINE_CLASS(x)    (((x) & GENMASK(18, 16)) >> 16)
>> +#define  GEN11_INTR_ENGINE_INSTANCE(x)    (((x) & GENMASK(25, 20)) >> 
>> 20)
>>   #define GEN11_INTR_IDENTITY_REG(x)    _MMIO(0x190060 + (x * 4))
>>


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