Re: [PATCH 1/2] drm/i915: Slice/Subslice/EU info via GETPARAM

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Jul 30, 2014 at 08:59:46PM -0500, jeff.mcgee@intel.com wrote:
> From: Jeff McGee <jeff.mcgee@intel.com>
> 
> Define a struct to capture information on the device's Slice/Subslice/EU
> (SSEU) configuration. Add this struct to the main device info struct.
> Define a packed bitfield form for the SSEU info and share it with
> userspace via a new GETPARAM option.
> 
> Starting with Cherryview, devices may have a varying number of EU for
> a given ID due to creative fusing. The surest way to determine the
> configuration is by reading fuses which is best done in the kernel and
> communicated to userspace. The immediate need from userspace is to
> determine the number of threads of compute work that can be safely
> submitted.
> 
> The definition of SSEU as a new drm/i915 component, with its own header
> file and soon-to-be source file, is in anticipation of lots of upcoming
> code for its management, particularly the power gating functionality.
> 
> Signed-off-by: Jeff McGee <jeff.mcgee@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_dma.c   |  3 +++
>  drivers/gpu/drm/i915/i915_drv.h   |  3 +++
>  drivers/gpu/drm/i915/intel_sseu.h | 40 +++++++++++++++++++++++++++++++++++++++
>  include/uapi/drm/i915_drm.h       | 18 ++++++++++++++++++
>  4 files changed, 64 insertions(+)
>  create mode 100644 drivers/gpu/drm/i915/intel_sseu.h
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 2e7f03a..f581848 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1025,6 +1025,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
>  	case I915_PARAM_CMD_PARSER_VERSION:
>  		value = i915_cmd_parser_get_version();
>  		break;
> +	case I915_PARAM_SSEU_INFO:
> +		value = INTEL_INFO(dev)->sseu.gp_sseu_info;
> +		break;
>  	default:
>  		DRM_DEBUG("Unknown parameter %d\n", param->param);
>  		return -EINVAL;
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 18c9ad8..01adafd 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -45,6 +45,7 @@
>  #include <linux/intel-iommu.h>
>  #include <linux/kref.h>
>  #include <linux/pm_qos.h>
> +#include "intel_sseu.h"
>  
>  /* General customization:
>   */
> @@ -562,6 +563,8 @@ struct intel_device_info {
>  	int trans_offsets[I915_MAX_TRANSCODERS];
>  	int palette_offsets[I915_MAX_PIPES];
>  	int cursor_offsets[I915_MAX_PIPES];
> +	/* Slice/Subslice/EU info */
> +	struct intel_sseu_info sseu;
>  };
>  
>  #undef DEFINE_FLAG
> diff --git a/drivers/gpu/drm/i915/intel_sseu.h b/drivers/gpu/drm/i915/intel_sseu.h
> new file mode 100644
> index 0000000..7db7175
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_sseu.h
> @@ -0,0 +1,40 @@
> +/*
> + * Copyright © 2014 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + */
> +#ifndef _INTEL_SSEU_H_
> +#define _INTEL_SSEU_H_
> +
> +struct intel_sseu_info {
> +	/* Total slice count */
> +	unsigned int slice_cnt;
> +	/* Total subslice count */
> +	unsigned int subslice_cnt;
> +	/* Total execution unit count */
> +	unsigned int eu_cnt;
> +	/* Thread count per EU */
> +	unsigned int threads_per_eu;
> +	/* Bit field representation for I915_PARAM_SSEU_INFO */
> +	u32 gp_sseu_info;
> +};
> +
> +#endif
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index ff57f07..b99c1a2 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -171,6 +171,23 @@ typedef struct _drm_i915_sarea {
>  #define I915_BOX_TEXTURE_LOAD  0x8
>  #define I915_BOX_LOST_CONTEXT  0x10
>  
> +/*
> + * Slice/Subslice/EU Info
> + * - Accessed via GETPARAM ioctl option I915_PARAM_SSEU_INFO
> + * - SLICE_CNT: total slice count
> + * - SUBSLICE_CNT: total subslice count
> + * - EU_CNT: total execution unit count
> + * - THREADS_PER_EU: thread count per EU
> +*/
> +#define I915_SSEU_INFO_SLICE_CNT_MASK		0xf
> +#define I915_SSEU_INFO_SLICE_CNT_SHIFT		0
> +#define I915_SSEU_INFO_SUBSLICE_CNT_MASK	(0x3f<<4)
> +#define I915_SSEU_INFO_SUBSLICE_CNT_SHIFT	4
> +#define I915_SSEU_INFO_EU_CNT_MASK		(0xff<<10)
> +#define I915_SSEU_INFO_EU_CNT_SHIFT		10
> +#define I915_SSEU_INFO_THREADS_PER_EU_MASK	(0xf<<18)
> +#define I915_SSEU_INFO_THREADS_PER_EU_SHIFT	18

Tbh this looks a bit too tricky, I'd just allocate a pile of getparm
numbers, one for each - they're cheap.

Also, usual broken record request: I need open-source userspace using
this (mesa, ddx, libva).
-Daniel

> +
>  /* I915 specific ioctls
>   * The device specific ioctl range is 0x40 to 0x79.
>   */
> @@ -340,6 +357,7 @@ typedef struct drm_i915_irq_wait {
>  #define I915_PARAM_HAS_EXEC_HANDLE_LUT   26
>  #define I915_PARAM_HAS_WT     	 	 27
>  #define I915_PARAM_CMD_PARSER_VERSION	 28
> +#define I915_PARAM_SSEU_INFO		 29
>  
>  typedef struct drm_i915_getparam {
>  	int param;
> -- 
> 2.0.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch