Re: [PATCH 56/89] drm/i915: Gen9 shadowed registers

[Bob Wang <zhe1.wang@intel.com>]

On 09/24/2014 02:36 PM, Mika Kuoppala wrote:
> Damien Lespiau <damien.lespiau@intel.com> writes:
>
>> From: Zhe Wang <zhe1.wang@intel.com>
>>
>> For MMIO registers which are shadowed, force wake is not needed to
>> write to these registers.
>>
>> v2: Rebase on top of nightly (Damien)
>>
>> Signed-off-by: Zhe Wang <zhe1.wang@intel.com>
>> Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
>> ---
>>   drivers/gpu/drm/i915/intel_uncore.c | 26 +++++++++++++++++++++++++-
>>   1 file changed, 25 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
>> index f289f4f..ce1214b 100644
>> --- a/drivers/gpu/drm/i915/intel_uncore.c
>> +++ b/drivers/gpu/drm/i915/intel_uncore.c
>> @@ -1028,13 +1028,37 @@ chv_write##x(struct drm_i915_private *dev_priv, off_t reg, u##x val, bool trace)
>>   	REG_WRITE_FOOTER; \
>>   }
>>   
>> +static const u32 gen9_shadowed_regs[] = {
>> +	FORCEWAKE_MEDIA_GEN9,
>> +	FORCEWAKE_RENDER_GEN9,
>> +	FORCEWAKE_BLITTER_GEN9,
> You might want to move the ring tails first on the list
> and forcewake regs to bottom, to reflect the popularity
> of access.
good suggestion. a better order I can think of. comments welcomed.

RING_TAIL(RENDER_RING_BASE),
RING_TAIL(GEN6_BSD_RING_BASE),
RING_TAIL(VEBOX_RING_BASE),
RING_TAIL(BLT_RING_BASE),
FORCEWAKE_BLITTER_GEN9,
FORCEWAKE_RENDER_GEN9,
FORCEWAKE_MEDIA_GEN9,
GEN6_RPNSWREQ,
GEN6_RC_VIDEO_FREQ,


>> +	GEN6_RPNSWREQ,
>> +	GEN6_RC_VIDEO_FREQ,
>> +	RING_TAIL(RENDER_RING_BASE),
>> +	RING_TAIL(GEN6_BSD_RING_BASE),
>> +	RING_TAIL(VEBOX_RING_BASE),
>> +	RING_TAIL(BLT_RING_BASE),
>> +	/* TODO: Other registers are not yet used */
> I think we need exec list ones here also, but couldn't find
> certain proof. Atleast with bdw we are missing them.
>
> -Mika
Good catch. Execlist ones are on the list. We need to add those since 
execlist is enabled.
>> +};
>> +
>> +static bool is_gen9_shadowed(struct drm_i915_private *dev_priv, u32 reg)
>> +{
>> +	int i;
>> +	for (i = 0; i < ARRAY_SIZE(gen9_shadowed_regs); i++)
>> +		if (reg == gen9_shadowed_regs[i])
>> +			return true;
>> +
>> +	return false;
>> +}
>> +
>>   #define __gen9_write(x) \
>>   static void \
>>   gen9_write##x(struct drm_i915_private *dev_priv, off_t reg, u##x val, \
>>   		bool trace) { \
>>   	REG_WRITE_HEADER; \
>>   	if (!NEEDS_FORCE_WAKE((dev_priv), (reg)) || \
>> -			FORCEWAKE_GEN9_UNCORE_RANGE_OFFSET(reg)) { \
>> +			FORCEWAKE_GEN9_UNCORE_RANGE_OFFSET(reg) || \
>> +			is_gen9_shadowed(dev_priv, reg)) { \
>>   		__raw_i915_write##x(dev_priv, reg, val); \
>>   	} else { \
>>   		unsigned fwengine = 0; \
>> -- 
>> 1.8.3.1
>>
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