Re: [Intel-gfx] [PATCH v2 09/12] drm/i915/uncore: Add GSI offset to uncore

[Matt Roper <matthew.d.roper@intel.com>]

On Tue, Sep 06, 2022 at 04:14:21PM +0530, Iddamsetty, Aravind wrote:
> 
> 
> On 03-09-2022 05:02, Matt Roper wrote:
> > GT non-engine registers (referred to as "GSI" registers by the spec)
> > have the same relative offsets on standalone media as they do on the
> > primary GT, just with an additional "GSI offset" added to their MMIO
> > address.  If we store this GSI offset in the standalone media's
> > intel_uncore structure, it can be automatically applied to all GSI reg
> > reads/writes that happen on that GT, allowing us to re-use our existing
> > GT code with minimal changes.
> > 
> > Forcewake and shadowed register tables for the media GT (which will be
> > added in a future patch) are listed as final addresses that already
> > include the GSI offset, so we also need to add the GSI offset before
> > doing lookups of registers in one of those tables.
> > 
> > Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> > Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> > ---
> >  drivers/gpu/drm/i915/gt/intel_gt.c       | 17 ++++++++++++++---
> >  drivers/gpu/drm/i915/intel_device_info.h |  4 +++-
> >  drivers/gpu/drm/i915/intel_uncore.c      | 10 ++++++++--
> >  drivers/gpu/drm/i915/intel_uncore.h      | 22 ++++++++++++++++++++--
> >  4 files changed, 45 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
> > index fbb5e32979a4..a6ed11b933eb 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_gt.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_gt.c
> > @@ -776,10 +776,20 @@ void intel_gt_driver_late_release_all(struct drm_i915_private *i915)
> >  	}
> >  }
> >  
> > -static int intel_gt_tile_setup(struct intel_gt *gt, phys_addr_t phys_addr)
> > +/*
> > + * Note: the gsi_offset parameter here isn't used, but we want to keep the
> > + * function signature equivalent to gtdef->setup() so that it can be plugged
> > + * in when we enabled remote tiles in the future.
> > + */
> > +static int intel_gt_tile_setup(struct intel_gt *gt,
> > +			       phys_addr_t phys_addr,
> > +			       u32 gsi_offset)
> >  {
> >  	int ret;
> >  
> > +	/* GSI offset is only applicable for media GTs */
> > +	drm_WARN_ON(&gt->i915->drm, gsi_offset);
> > +
> >  	if (!gt_is_root(gt)) {
> >  		struct intel_uncore *uncore;
> >  
> > @@ -832,7 +842,7 @@ int intel_gt_probe_all(struct drm_i915_private *i915)
> >  	gt->info.engine_mask = RUNTIME_INFO(i915)->platform_engine_mask;
> >  
> >  	drm_dbg(&i915->drm, "Setting up %s\n", gt->name);
> > -	ret = intel_gt_tile_setup(gt, phys_addr);
> > +	ret = intel_gt_tile_setup(gt, phys_addr, 0);
> >  	if (ret)
> >  		return ret;
> >  
> > @@ -865,7 +875,8 @@ int intel_gt_probe_all(struct drm_i915_private *i915)
> >  			goto err;
> >  		}
> >  
> > -		ret = gtdef->setup(gt, phys_addr + gtdef->mapping_base);
> > +		ret = gtdef->setup(gt, phys_addr + gtdef->mapping_base,
> > +				   gtdef->gsi_offset);
> >  		if (ret)
> >  			goto err;
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
> > index b408ce384cd7..85e0ef0e91b1 100644
> > --- a/drivers/gpu/drm/i915/intel_device_info.h
> > +++ b/drivers/gpu/drm/i915/intel_device_info.h
> > @@ -254,8 +254,10 @@ struct intel_gt_definition {
> >  	enum intel_gt_type type;
> >  	char *name;
> >  	int (*setup)(struct intel_gt *gt,
> > -		     phys_addr_t phys_addr);
> > +		     phys_addr_t phys_addr,
> > +		     u32 gsi_offset);
> >  	u32 mapping_base;
> > +	u32 gsi_offset;
> >  	intel_engine_mask_t engine_mask;
> >  };
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> > index 33bdcbc77ab2..ecb02421502d 100644
> > --- a/drivers/gpu/drm/i915/intel_uncore.c
> > +++ b/drivers/gpu/drm/i915/intel_uncore.c
> > @@ -927,6 +927,9 @@ find_fw_domain(struct intel_uncore *uncore, u32 offset)
> >  {
> >  	const struct intel_forcewake_range *entry;
> >  
> > +	if (IS_GSI_REG(offset))
> > +		offset += uncore->gsi_offset;
> > +
> >  	entry = BSEARCH(offset,
> >  			uncore->fw_domains_table,
> >  			uncore->fw_domains_table_entries,
> > @@ -1142,6 +1145,9 @@ static bool is_shadowed(struct intel_uncore *uncore, u32 offset)
> >  	if (drm_WARN_ON(&uncore->i915->drm, !uncore->shadowed_reg_table))
> >  		return false;
> >  
> > +	if (IS_GSI_REG(offset))
> > +		offset += uncore->gsi_offset;
> > +
> >  	return BSEARCH(offset,
> >  		       uncore->shadowed_reg_table,
> >  		       uncore->shadowed_reg_table_entries,
> > @@ -1994,8 +2000,8 @@ static int __fw_domain_init(struct intel_uncore *uncore,
> >  
> >  	d->uncore = uncore;
> >  	d->wake_count = 0;
> > -	d->reg_set = uncore->regs + i915_mmio_reg_offset(reg_set);
> > -	d->reg_ack = uncore->regs + i915_mmio_reg_offset(reg_ack);
> > +	d->reg_set = uncore->regs + i915_mmio_reg_offset(reg_set) + uncore->gsi_offset;
> > +	d->reg_ack = uncore->regs + i915_mmio_reg_offset(reg_ack) + uncore->gsi_offset;
> >  
> >  	d->id = domain_id;
> >  
> > diff --git a/drivers/gpu/drm/i915/intel_uncore.h b/drivers/gpu/drm/i915/intel_uncore.h
> > index 4acb78a03233..7f1d7903a8f3 100644
> > --- a/drivers/gpu/drm/i915/intel_uncore.h
> > +++ b/drivers/gpu/drm/i915/intel_uncore.h
> > @@ -136,6 +136,16 @@ struct intel_uncore {
> >  
> >  	spinlock_t lock; /** lock is also taken in irq contexts. */
> >  
> > +	/*
> > +	 * Do we need to apply an additional offset to reach the beginning
> > +	 * of the basic non-engine GT registers (referred to as "GSI" on
> > +	 * newer platforms, or "GT block" on older platforms)?  If so, we'll
> > +	 * track that here and apply it transparently to registers in the
> > +	 * appropriate range to maintain compatibility with our existing
> > +	 * register definitions and GT code.
> > +	 */
> > +	u32 gsi_offset;
> > +
> >  	unsigned int flags;
> >  #define UNCORE_HAS_FORCEWAKE		BIT(0)
> >  #define UNCORE_HAS_FPGA_DBG_UNCLAIMED	BIT(1)
> > @@ -294,19 +304,27 @@ intel_wait_for_register_fw(struct intel_uncore *uncore,
> >  					    2, timeout_ms, NULL);
> >  }
> >  
> > +#define IS_GSI_REG(reg) ((reg) < 0x40000)
> > +
> >  /* register access functions */
> >  #define __raw_read(x__, s__) \
> >  static inline u##x__ __raw_uncore_read##x__(const struct intel_uncore *uncore, \
> >  					    i915_reg_t reg) \
> >  { \
> > -	return read##s__(uncore->regs + i915_mmio_reg_offset(reg)); \
> > +	u32 offset = i915_mmio_reg_offset(reg); \
> > +	if (IS_GSI_REG(offset)) \
> > +		offset += uncore->gsi_offset; \
> > +	return read##s__(uncore->regs + offset); \
> >  }
> >  
> >  #define __raw_write(x__, s__) \
> >  static inline void __raw_uncore_write##x__(const struct intel_uncore *uncore, \
> >  					   i915_reg_t reg, u##x__ val) \
> >  { \
> > -	write##s__(val, uncore->regs + i915_mmio_reg_offset(reg)); \
> > +	u32 offset = i915_mmio_reg_offset(reg); \
> > +	if (IS_GSI_REG(offset)) \
> > +		offset += uncore->gsi_offset; \
> > +	write##s__(val, uncore->regs + offset); \
> >  }
> >  __raw_read(8, b)
> >  __raw_read(16, w)
> 
> Looks like the gsi_offset shall be added in gen12_emit_flush_xcs for
> aux_inv case as well.

Good catch.  I'll address that in the next version, but I think I'll do
so as a separate patch with a dedicated commit message.


Matt

> 
> Thanks,
> Aravind.

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation