[igt-dev] [PATCH i-g-t, v4 1/5] lib/i915: Introduce library intel_mocs

[Zbigniew Kempczyński]

On Fri, Dec 10, 2021 at 06:35:29PM +0530, apoorva1.singh at intel.com wrote:
> From: Apoorva Singh <apoorva1.singh at intel.com>
> 
> Add new library intel_mocs for mocs settings.
> 
> Signed-off-by: Apoorva Singh <apoorva1.singh at intel.com>
> Cc: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> Cc: Melkaveri, Arjun <arjun.melkaveri at intel.com>
> ---
>  lib/i915/intel_mocs.c | 51 +++++++++++++++++++++++++++++++++++++++++++
>  lib/i915/intel_mocs.h | 19 ++++++++++++++++
>  lib/meson.build       |  1 +
>  3 files changed, 71 insertions(+)
>  create mode 100644 lib/i915/intel_mocs.c
>  create mode 100644 lib/i915/intel_mocs.h
> 
> diff --git a/lib/i915/intel_mocs.c b/lib/i915/intel_mocs.c
> new file mode 100644
> index 00000000..e8c19309
> --- /dev/null
> +++ b/lib/i915/intel_mocs.c
> @@ -0,0 +1,51 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2021 Intel Corporation
> + */
> +
> +#include "igt.h"
> +#include "i915/gem.h"
> +#include "intel_mocs.h"
> +
> +static void get_mocs_index(int fd, struct drm_i915_mocs_index *mocs)
> +{
> +	uint16_t devid = intel_get_drm_devid(fd);
> +
> +	/*
> +	 * Gen >= 12 onwards don't have a setting for PTE,
> +	 * so using I915_MOCS_PTE as mocs index may leads to
> +	 * some undefined MOCS behavior.
> +	 * This helper function is providing current UC as well
> +	 * as WB MOCS index based on platform.
> +

Empty line.

> +	 */
> +	if (IS_DG1(devid)) {
> +		mocs->uc_index = 1;
> +		mocs->wb_index = 5;

Previous uAPI defined enum i915_mocs_table_index, now I see we're
hardcoding mocs entry index here. I see it changes regarding gen
but I would like to ask - will we fill enum / add macros to have code
more clear where no magic number is entered directly in the code?

--
Zbigniew

> +	} else if (IS_GEN12(devid)) {
> +		mocs->uc_index = 3;
> +		mocs->wb_index = 2;
> +	} else {
> +		mocs->uc_index = I915_MOCS_PTE;
> +		mocs->wb_index = I915_MOCS_CACHED;
> +	}
> +}
> +
> +/* BitField [6:1] represents index to MOCS Tables
> + * BitField [0] represents Encryption/Decryption */
> +
> +uint8_t intel_get_wb_mocs(int fd)
> +{
> +	struct drm_i915_mocs_index mocs;
> +
> +	get_mocs_index(fd, &mocs);
> +	return mocs.wb_index << 1;
> +}
> +
> +uint8_t intel_get_uc_mocs(int fd)
> +{
> +	struct drm_i915_mocs_index mocs;
> +
> +	get_mocs_index(fd, &mocs);
> +	return mocs.uc_index << 1;
> +}
> diff --git a/lib/i915/intel_mocs.h b/lib/i915/intel_mocs.h
> new file mode 100644
> index 00000000..efd8607f
> --- /dev/null
> +++ b/lib/i915/intel_mocs.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2019 Intel Corporation
> + */
> +
> +#ifndef _INTEL_MOCS_H
> +#define _INTEL_MOCS_H
> +
> +#define XY_BLOCK_COPY_BLT_MOCS_SHIFT		21
> +#define XY_CTRL_SURF_COPY_BLT_MOCS_SHIFT	25
> +
> +struct drm_i915_mocs_index {
> +	uint8_t uc_index;
> +	uint8_t wb_index;
> +};
> +
> +uint8_t intel_get_wb_mocs(int fd);
> +uint8_t intel_get_uc_mocs(int fd);
> +#endif /* _INTEL_MOCS_H */
> diff --git a/lib/meson.build b/lib/meson.build
> index b9568a71..f500f0f1 100644
> --- a/lib/meson.build
> +++ b/lib/meson.build
> @@ -11,6 +11,7 @@ lib_sources = [
>  	'i915/gem_mman.c',
>  	'i915/gem_vm.c',
>  	'i915/intel_memory_region.c',
> +	'i915/intel_mocs.c',
>  	'igt_collection.c',
>  	'igt_color_encoding.c',
>  	'igt_debugfs.c',
> -- 
> 2.25.1
>