Re: [Intel-gfx] [PATCH 1/1] drm/i915/guc: Convert slpc to iosys_map

[Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>]

On 16.03.2022 18:26, Mullati Siva wrote:
> From: Siva Mullati <siva.mullati@intel.com>
> 
> Convert slpc shared data to use iosys_map rather than
> plain pointer and save it in the intel_guc_slpc struct.
> This will help with in read and update slpc shared data
> after the slpc init by abstracting the IO vs system memory.
> 
> Signed-off-by: Siva Mullati <siva.mullati@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c   | 79 +++++++++++--------
>  .../gpu/drm/i915/gt/uc/intel_guc_slpc_types.h |  5 +-
>  2 files changed, 47 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> index 9f032c65a488..3a9ec6b03ceb 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
> @@ -14,6 +14,13 @@
>  #include "gt/intel_gt_regs.h"
>  #include "gt/intel_rps.h"
>  
> +#define slpc_blob_read(slpc_, field_) \
> +		       iosys_map_rd_field(&(slpc_)->slpc_map, 0, \
> +		       struct slpc_shared_data, field_)
> +#define slpc_blob_write(slpc_, field_, val_) \
> +			iosys_map_wr_field(&(slpc_)->slpc_map, 0, \
> +			struct slpc_shared_data, field_, val_)
> +
>  static inline struct intel_guc *slpc_to_guc(struct intel_guc_slpc *slpc)
>  {
>  	return container_of(slpc, struct intel_guc, slpc);
> @@ -52,50 +59,50 @@ void intel_guc_slpc_init_early(struct intel_guc_slpc *slpc)
>  	slpc->selected = __guc_slpc_selected(guc);
>  }
>  
> -static void slpc_mem_set_param(struct slpc_shared_data *data,
> +static void slpc_mem_set_param(struct intel_guc_slpc *slpc,
>  			       u32 id, u32 value)
>  {
> +	u32 bits = slpc_blob_read(slpc, override_params.bits[id >> 5]);
> +
>  	GEM_BUG_ON(id >= SLPC_MAX_OVERRIDE_PARAMETERS);
>  	/*
>  	 * When the flag bit is set, corresponding value will be read
>  	 * and applied by SLPC.
>  	 */
> -	data->override_params.bits[id >> 5] |= (1 << (id % 32));
> -	data->override_params.values[id] = value;
> +	bits |= (1 << (id % 32));
> +	slpc_blob_write(slpc, override_params.bits[id >> 5], bits);
> +	slpc_blob_write(slpc, override_params.values[id], value);
>  }
>  
> -static void slpc_mem_set_enabled(struct slpc_shared_data *data,
> +static void slpc_mem_set_enabled(struct intel_guc_slpc *slpc,
>  				 u8 enable_id, u8 disable_id)
>  {
>  	/*
>  	 * Enabling a param involves setting the enable_id
>  	 * to 1 and disable_id to 0.
>  	 */
> -	slpc_mem_set_param(data, enable_id, 1);
> -	slpc_mem_set_param(data, disable_id, 0);
> +	slpc_mem_set_param(slpc, enable_id, 1);
> +	slpc_mem_set_param(slpc, disable_id, 0);
>  }
>  
> -static void slpc_mem_set_disabled(struct slpc_shared_data *data,
> +static void slpc_mem_set_disabled(struct intel_guc_slpc *slpc,
>  				  u8 enable_id, u8 disable_id)
>  {
>  	/*
>  	 * Disabling a param involves setting the enable_id
>  	 * to 0 and disable_id to 1.
>  	 */
> -	slpc_mem_set_param(data, disable_id, 1);
> -	slpc_mem_set_param(data, enable_id, 0);
> +	slpc_mem_set_param(slpc, disable_id, 1);
> +	slpc_mem_set_param(slpc, enable_id, 0);
>  }
>  
>  static u32 slpc_get_state(struct intel_guc_slpc *slpc)
>  {
> -	struct slpc_shared_data *data;
> -
>  	GEM_BUG_ON(!slpc->vma);
>  
> -	drm_clflush_virt_range(slpc->vaddr, sizeof(u32));
> -	data = slpc->vaddr;
> +	drm_clflush_virt_range(slpc->slpc_map.vaddr, sizeof(u32));
clflush will not be required if the slpc_map contains io memory address.
So the drm_clflush_virt_range can be added under a check for system
memory
>  
> -	return data->header.global_state;
> +	return slpc_blob_read(slpc, header.global_state);
>  }
>  
>  static int guc_action_slpc_set_param(struct intel_guc *guc, u8 id, u32 value)
> @@ -156,7 +163,7 @@ static int slpc_query_task_state(struct intel_guc_slpc *slpc)
>  		drm_err(&i915->drm, "Failed to query task state (%pe)\n",
>  			ERR_PTR(ret));
>  
> -	drm_clflush_virt_range(slpc->vaddr, SLPC_PAGE_SIZE_BYTES);
> +	drm_clflush_virt_range(slpc->slpc_map.vaddr, SLPC_PAGE_SIZE_BYTES);
Also here we need clfush only for system memory address.
>  
>  	return ret;
>  }
> @@ -243,10 +250,11 @@ int intel_guc_slpc_init(struct intel_guc_slpc *slpc)
>  	struct drm_i915_private *i915 = slpc_to_i915(slpc);
>  	u32 size = PAGE_ALIGN(sizeof(struct slpc_shared_data));
>  	int err;
> +	void *vaddr;
>  
>  	GEM_BUG_ON(slpc->vma);
>  
> -	err = intel_guc_allocate_and_map_vma(guc, size, &slpc->vma, (void **)&slpc->vaddr);
> +	err = intel_guc_allocate_and_map_vma(guc, size, &slpc->vma, (void **)&vaddr);
>  	if (unlikely(err)) {
>  		drm_err(&i915->drm,
>  			"Failed to allocate SLPC struct (err=%pe)\n",
> @@ -254,6 +262,12 @@ int intel_guc_slpc_init(struct intel_guc_slpc *slpc)
>  		return err;
>  	}
>  
> +	if (i915_gem_object_is_lmem(slpc->vma->obj))
> +		iosys_map_set_vaddr_iomem(&slpc->slpc_map,
> +					  (void __iomem *)vaddr);
> +	else
> +		iosys_map_set_vaddr(&slpc->slpc_map, vaddr);
> +
>  	slpc->max_freq_softlimit = 0;
>  	slpc->min_freq_softlimit = 0;
>  
> @@ -335,40 +349,37 @@ static int slpc_reset(struct intel_guc_slpc *slpc)
>  
>  static u32 slpc_decode_min_freq(struct intel_guc_slpc *slpc)
>  {
> -	struct slpc_shared_data *data = slpc->vaddr;
> -
>  	GEM_BUG_ON(!slpc->vma);
>  
>  	return	DIV_ROUND_CLOSEST(REG_FIELD_GET(SLPC_MIN_UNSLICE_FREQ_MASK,
> -				  data->task_state_data.freq) *
> +				  slpc_blob_read(slpc, task_state_data.freq)) *
>  				  GT_FREQUENCY_MULTIPLIER, GEN9_FREQ_SCALER);
>  }
>  
>  static u32 slpc_decode_max_freq(struct intel_guc_slpc *slpc)
>  {
> -	struct slpc_shared_data *data = slpc->vaddr;
> -
>  	GEM_BUG_ON(!slpc->vma);
>  
>  	return	DIV_ROUND_CLOSEST(REG_FIELD_GET(SLPC_MAX_UNSLICE_FREQ_MASK,
> -				  data->task_state_data.freq) *
> +				  slpc_blob_read(slpc, task_state_data.freq)) *
>  				  GT_FREQUENCY_MULTIPLIER, GEN9_FREQ_SCALER);
>  }
>  
> -static void slpc_shared_data_reset(struct slpc_shared_data *data)
> +static void slpc_shared_data_reset(struct intel_guc_slpc *slpc)
>  {
> -	memset(data, 0, sizeof(struct slpc_shared_data));
> -
> -	data->header.size = sizeof(struct slpc_shared_data);
> +	iosys_map_memset(&slpc->slpc_map,
> +			 0, 0, sizeof(struct slpc_shared_data));
> +	slpc_blob_write(slpc,
> +			header.size, sizeof(struct slpc_shared_data));
>  
>  	/* Enable only GTPERF task, disable others */
> -	slpc_mem_set_enabled(data, SLPC_PARAM_TASK_ENABLE_GTPERF,
> +	slpc_mem_set_enabled(slpc, SLPC_PARAM_TASK_ENABLE_GTPERF,
>  			     SLPC_PARAM_TASK_DISABLE_GTPERF);
>  
> -	slpc_mem_set_disabled(data, SLPC_PARAM_TASK_ENABLE_BALANCER,
> +	slpc_mem_set_disabled(slpc, SLPC_PARAM_TASK_ENABLE_BALANCER,
>  			      SLPC_PARAM_TASK_DISABLE_BALANCER);
>  
> -	slpc_mem_set_disabled(data, SLPC_PARAM_TASK_ENABLE_DCC,
> +	slpc_mem_set_disabled(slpc, SLPC_PARAM_TASK_ENABLE_DCC,
>  			      SLPC_PARAM_TASK_DISABLE_DCC);
After converting to iosys_map instance, each
slpc_mem_set_enabled/disabled calls slpc_mem_set_param twice and each
slpc_mem_set_param calls slpc_blob_read/write 3 times resulting in 18
calls to memcpy.
Therefore it is efficient to consolidate all updates by reading the
complete override_params field, update necessary members and finally
overwrite the entire override_params.

Regards,
Bala
>  }
>  
> @@ -617,7 +628,7 @@ int intel_guc_slpc_enable(struct intel_guc_slpc *slpc)
>  
>  	GEM_BUG_ON(!slpc->vma);
>  
> -	slpc_shared_data_reset(slpc->vaddr);
> +	slpc_shared_data_reset(slpc);
>  
>  	ret = slpc_reset(slpc);
>  	if (unlikely(ret < 0)) {
> @@ -705,8 +716,6 @@ void intel_guc_slpc_dec_waiters(struct intel_guc_slpc *slpc)
>  int intel_guc_slpc_print_info(struct intel_guc_slpc *slpc, struct drm_printer *p)
>  {
>  	struct drm_i915_private *i915 = slpc_to_i915(slpc);
> -	struct slpc_shared_data *data = slpc->vaddr;
> -	struct slpc_task_state_data *slpc_tasks;
>  	intel_wakeref_t wakeref;
>  	int ret = 0;
>  
> @@ -716,11 +725,10 @@ int intel_guc_slpc_print_info(struct intel_guc_slpc *slpc, struct drm_printer *p
>  		ret = slpc_query_task_state(slpc);
>  
>  		if (!ret) {
> -			slpc_tasks = &data->task_state_data;
> -
>  			drm_printf(p, "\tSLPC state: %s\n", slpc_get_state_string(slpc));
>  			drm_printf(p, "\tGTPERF task active: %s\n",
> -				   str_yes_no(slpc_tasks->status & SLPC_GTPERF_TASK_ENABLED));
> +				   str_yes_no(slpc_blob_read(slpc, task_state_data.status) &
> +				   SLPC_GTPERF_TASK_ENABLED));
>  			drm_printf(p, "\tMax freq: %u MHz\n",
>  				   slpc_decode_max_freq(slpc));
>  			drm_printf(p, "\tMin freq: %u MHz\n",
> @@ -739,4 +747,5 @@ void intel_guc_slpc_fini(struct intel_guc_slpc *slpc)
>  		return;
>  
>  	i915_vma_unpin_and_release(&slpc->vma, I915_VMA_RELEASE_MAP);
> +	iosys_map_clear(&slpc->slpc_map);
>  }
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h
> index bf5b9a563c09..96f524f25b52 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc_types.h
> @@ -7,15 +7,16 @@
>  #define _INTEL_GUC_SLPC_TYPES_H_
>  
>  #include <linux/atomic.h>
> -#include <linux/workqueue.h>
> +#include <linux/iosys-map.h>
>  #include <linux/mutex.h>
>  #include <linux/types.h>
> +#include <linux/workqueue.h>
>  
>  #define SLPC_RESET_TIMEOUT_MS 5
>  
>  struct intel_guc_slpc {
>  	struct i915_vma *vma;
> -	struct slpc_shared_data *vaddr;
> +	struct iosys_map slpc_map;
>  	bool supported;
>  	bool selected;
>  
> -- 
> 2.33.0
>