[Intel-gfx] [PATCH v3 06/48] drm/i915/xelpd: Increase maximum watermark lines to 255

[Srivatsa, Anusha]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Matt
> Roper
> Sent: Friday, May 7, 2021 7:28 PM
> To: intel-gfx at lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH v3 06/48] drm/i915/xelpd: Increase maximum
> watermark lines to 255
> 
> XE_LPD continues to use the same "skylake-style" watermark programming
> as other recent platforms.  The only change to the watermark calculations
> compared to Display12 is that XE_LPD now allows a maximum of 255 lines vs
> the old limit of 31.
> 
> Due to the larger possible lines value, the corresponding bits representing
> the value in PLANE_WM are also extended, so make sure we read/write
> enough bits.  Let's also take this opportunity to switch over to the REG_FIELD
> notation.
> 
> Bspec: 49325
> Bspec: 50419
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Anshuman Gupta <anshuman.gupta at intel.com>
> Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa at intel.com>

> ---
>  drivers/gpu/drm/i915/i915_reg.h |  3 +--  drivers/gpu/drm/i915/intel_pm.c
> | 15 +++++++++++----
>  2 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h
> b/drivers/gpu/drm/i915/i915_reg.h index e070f2df6a87..0f6aa3502f1f
> 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6442,8 +6442,7 @@ enum {
>  #define _CUR_WM_TRANS_B_0	0x71168
>  #define   PLANE_WM_EN		(1 << 31)
>  #define   PLANE_WM_IGNORE_LINES	(1 << 30)
> -#define   PLANE_WM_LINES_SHIFT	14
> -#define   PLANE_WM_LINES_MASK	0x1f
> +#define   PLANE_WM_LINES_MASK	REG_GENMASK(21, 14)
>  #define   PLANE_WM_BLOCKS_MASK	0x7ff /* skl+: 10 bits, icl+ 11 bits */
> 
>  #define _CUR_WM_0(pipe) _PIPE(pipe, _CUR_WM_A_0, _CUR_WM_B_0)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c
> b/drivers/gpu/drm/i915/intel_pm.c index 06d5b7cc8b62..ef2d1fa60f04
> 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -5185,6 +5185,14 @@ static bool skl_wm_has_lines(struct
> drm_i915_private *dev_priv, int level)
>  	return level > 0;
>  }
> 
> +static int skl_wm_max_lines(struct drm_i915_private *dev_priv) {
> +	if (DISPLAY_VER(dev_priv) >= 13)
> +		return 255;
> +	else
> +		return 31;
> +}
> +
>  static void skl_compute_plane_wm(const struct intel_crtc_state *crtc_state,
>  				 int level,
>  				 unsigned int latency,
> @@ -5289,7 +5297,7 @@ static void skl_compute_plane_wm(const struct
> intel_crtc_state *crtc_state,
>  	if (!skl_wm_has_lines(dev_priv, level))
>  		lines = 0;
> 
> -	if (lines > 31) {
> +	if (lines > skl_wm_max_lines(dev_priv)) {
>  		/* reject it */
>  		result->min_ddb_alloc = U16_MAX;
>  		return;
> @@ -5585,7 +5593,7 @@ static void skl_write_wm_level(struct
> drm_i915_private *dev_priv,
>  	if (level->ignore_lines)
>  		val |= PLANE_WM_IGNORE_LINES;
>  	val |= level->blocks;
> -	val |= level->lines << PLANE_WM_LINES_SHIFT;
> +	val |= REG_FIELD_PREP(PLANE_WM_LINES_MASK, level->lines);
> 
>  	intel_de_write_fw(dev_priv, reg, val);  } @@ -6193,8 +6201,7 @@
> static void skl_wm_level_from_reg_val(u32 val, struct skl_wm_level *level)
>  	level->enable = val & PLANE_WM_EN;
>  	level->ignore_lines = val & PLANE_WM_IGNORE_LINES;
>  	level->blocks = val & PLANE_WM_BLOCKS_MASK;
> -	level->lines = (val >> PLANE_WM_LINES_SHIFT) &
> -		PLANE_WM_LINES_MASK;
> +	level->lines = REG_FIELD_GET(PLANE_WM_LINES_MASK, val);
>  }
> 
>  void skl_pipe_wm_get_hw_state(struct intel_crtc *crtc,
> --
> 2.25.4
> 
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