Re: [Intel-gfx] [PATCH] drm/i915/gt: remove some limited use register access wrappers

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Wed, Nov 23, 2022 at 06:49:16PM +0200, Jani Nikula wrote:
> Remove rmw_set(), rmw_clear(), clear_register(), rmw_set_fw(), and
> rmw_clear_fw(). They're just one too many levels of abstraction for
> register access, for very specific purposes.
> 
> clear_register() seems like a micro-optimization bypassing the write
> when the register is already clear, but that trick has ceased to work
> since commit 06b975d58fd6 ("drm/i915: make intel_uncore_rmw() write
> unconditionally"). Just clear the register in the most obvious way.
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_gt.c    | 29 +++++++--------------------
>  drivers/gpu/drm/i915/gt/intel_reset.c | 18 ++++-------------
>  2 files changed, 11 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
> index b5ad9caa5537..efd9d722d77f 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt.c
> @@ -210,21 +210,6 @@ int intel_gt_init_hw(struct intel_gt *gt)
>  	return ret;
>  }
>  
> -static void rmw_set(struct intel_uncore *uncore, i915_reg_t reg, u32 set)
> -{
> -	intel_uncore_rmw(uncore, reg, 0, set);
> -}
> -
> -static void rmw_clear(struct intel_uncore *uncore, i915_reg_t reg, u32 clr)
> -{
> -	intel_uncore_rmw(uncore, reg, clr, 0);
> -}
> -
> -static void clear_register(struct intel_uncore *uncore, i915_reg_t reg)
> -{
> -	intel_uncore_rmw(uncore, reg, 0, 0);
> -}
> -
>  static void gen6_clear_engine_error_register(struct intel_engine_cs *engine)
>  {
>  	GEN6_RING_FAULT_REG_RMW(engine, RING_FAULT_VALID, 0);
> @@ -250,14 +235,14 @@ intel_gt_clear_error_registers(struct intel_gt *gt,
>  	u32 eir;
>  
>  	if (GRAPHICS_VER(i915) != 2)
> -		clear_register(uncore, PGTBL_ER);
> +		intel_uncore_write(uncore, PGTBL_ER, 0);
>  
>  	if (GRAPHICS_VER(i915) < 4)
> -		clear_register(uncore, IPEIR(RENDER_RING_BASE));
> +		intel_uncore_write(uncore, IPEIR(RENDER_RING_BASE), 0);
>  	else
> -		clear_register(uncore, IPEIR_I965);
> +		intel_uncore_write(uncore, IPEIR_I965, 0);
>  
> -	clear_register(uncore, EIR);
> +	intel_uncore_write(uncore, EIR, 0);
>  	eir = intel_uncore_read(uncore, EIR);
>  	if (eir) {
>  		/*
> @@ -265,7 +250,7 @@ intel_gt_clear_error_registers(struct intel_gt *gt,
>  		 * mask them.
>  		 */
>  		drm_dbg(&gt->i915->drm, "EIR stuck: 0x%08x, masking\n", eir);
> -		rmw_set(uncore, EMR, eir);
> +		intel_uncore_rmw(uncore, EMR, 0, eir);
>  		intel_uncore_write(uncore, GEN2_IIR,
>  				   I915_MASTER_ERROR_INTERRUPT);
>  	}
> @@ -275,10 +260,10 @@ intel_gt_clear_error_registers(struct intel_gt *gt,
>  					   RING_FAULT_VALID, 0);
>  		intel_gt_mcr_read_any(gt, XEHP_RING_FAULT_REG);
>  	} else if (GRAPHICS_VER(i915) >= 12) {
> -		rmw_clear(uncore, GEN12_RING_FAULT_REG, RING_FAULT_VALID);
> +		intel_uncore_rmw(uncore, GEN12_RING_FAULT_REG, RING_FAULT_VALID, 0);
>  		intel_uncore_posting_read(uncore, GEN12_RING_FAULT_REG);
>  	} else if (GRAPHICS_VER(i915) >= 8) {
> -		rmw_clear(uncore, GEN8_RING_FAULT_REG, RING_FAULT_VALID);
> +		intel_uncore_rmw(uncore, GEN8_RING_FAULT_REG, RING_FAULT_VALID, 0);
>  		intel_uncore_posting_read(uncore, GEN8_RING_FAULT_REG);
>  	} else if (GRAPHICS_VER(i915) >= 6) {
>  		struct intel_engine_cs *engine;
> diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
> index 24736ebee17c..ffde89c5835a 100644
> --- a/drivers/gpu/drm/i915/gt/intel_reset.c
> +++ b/drivers/gpu/drm/i915/gt/intel_reset.c
> @@ -35,16 +35,6 @@
>  /* XXX How to handle concurrent GGTT updates using tiling registers? */
>  #define RESET_UNDER_STOP_MACHINE 0
>  
> -static void rmw_set_fw(struct intel_uncore *uncore, i915_reg_t reg, u32 set)
> -{
> -	intel_uncore_rmw_fw(uncore, reg, 0, set);
> -}
> -
> -static void rmw_clear_fw(struct intel_uncore *uncore, i915_reg_t reg, u32 clr)
> -{
> -	intel_uncore_rmw_fw(uncore, reg, clr, 0);
> -}
> -
>  static void client_mark_guilty(struct i915_gem_context *ctx, bool banned)
>  {
>  	struct drm_i915_file_private *file_priv = ctx->file_priv;
> @@ -212,7 +202,7 @@ static int g4x_do_reset(struct intel_gt *gt,
>  	int ret;
>  
>  	/* WaVcpClkGateDisableForMediaReset:ctg,elk */
> -	rmw_set_fw(uncore, VDECCLK_GATE_D, VCP_UNIT_CLOCK_GATE_DISABLE);
> +	intel_uncore_rmw_fw(uncore, VDECCLK_GATE_D, 0, VCP_UNIT_CLOCK_GATE_DISABLE);
>  	intel_uncore_posting_read_fw(uncore, VDECCLK_GATE_D);
>  
>  	pci_write_config_byte(pdev, I915_GDRST,
> @@ -234,7 +224,7 @@ static int g4x_do_reset(struct intel_gt *gt,
>  out:
>  	pci_write_config_byte(pdev, I915_GDRST, 0);
>  
> -	rmw_clear_fw(uncore, VDECCLK_GATE_D, VCP_UNIT_CLOCK_GATE_DISABLE);
> +	intel_uncore_rmw_fw(uncore, VDECCLK_GATE_D, VCP_UNIT_CLOCK_GATE_DISABLE, 0);
>  	intel_uncore_posting_read_fw(uncore, VDECCLK_GATE_D);
>  
>  	return ret;
> @@ -448,7 +438,7 @@ static int gen11_lock_sfc(struct intel_engine_cs *engine,
>  	 * to reset it as well (we will unlock it once the reset sequence is
>  	 * completed).
>  	 */
> -	rmw_set_fw(uncore, sfc_lock.lock_reg, sfc_lock.lock_bit);
> +	intel_uncore_rmw_fw(uncore, sfc_lock.lock_reg, 0, sfc_lock.lock_bit);
>  
>  	ret = __intel_wait_for_register_fw(uncore,
>  					   sfc_lock.ack_reg,
> @@ -498,7 +488,7 @@ static void gen11_unlock_sfc(struct intel_engine_cs *engine)
>  
>  	get_sfc_forced_lock_data(engine, &sfc_lock);
>  
> -	rmw_clear_fw(uncore, sfc_lock.lock_reg, sfc_lock.lock_bit);
> +	intel_uncore_rmw_fw(uncore, sfc_lock.lock_reg, sfc_lock.lock_bit, 0);
>  }
>  
>  static int __gen11_reset_engines(struct intel_gt *gt,
> -- 
> 2.34.1
>