Re: [Intel-gfx] [PATCH 10/16] drm/i915: Query the vswing levels per-lane for tgl dkl phy

Souza, Jose
2021-10-29T22:00:02Z

On Wed, 2021-10-06 at 23:49 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Prepare for per-lane drive settings by querying the desired vswing
> level per-lane.
>
> Note that the code only does two loops, with each one writing the
> levels for two TX lanes. The register offsets also look a bit funny
> because each time through the loop we write to the exact same
> register offsets. The crucial bit is the HIP_INDEX_REG
> write that steers the same mmio window into different places.

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>

>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_ddi.c | 33 ++++++++++++++----------
> 1 file changed, 19 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 1874a2ca8f3b..85247744e9dd 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -1295,9 +1295,7 @@ static void tgl_dkl_phy_set_signal_levels(struct intel_encoder *encoder,
> {
> struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> enum tc_port tc_port = intel_port_to_tc(dev_priv, encoder->port);
> - int level = intel_ddi_level(encoder, crtc_state, 0);
> const struct intel_ddi_buf_trans *trans;
> - u32 val, dpcnt_mask, dpcnt_val;
> int n_entries, ln;
>
> if (intel_tc_port_in_tbt_alt_mode(enc_to_dig_port(encoder)))
> @@ -1307,28 +1305,35 @@ static void tgl_dkl_phy_set_signal_levels(struct intel_encoder *encoder,
> if (drm_WARN_ON_ONCE(&dev_priv->drm, !trans))
> return;
>
> - dpcnt_mask = (DKL_TX_PRESHOOT_COEFF_MASK |
> - DKL_TX_DE_EMPAHSIS_COEFF_MASK |
> - DKL_TX_VSWING_CONTROL_MASK);
> - dpcnt_val = DKL_TX_VSWING_CONTROL(trans->entries[level].dkl.vswing);
> - dpcnt_val |= DKL_TX_DE_EMPHASIS_COEFF(trans->entries[level].dkl.de_emphasis);
> - dpcnt_val |= DKL_TX_PRESHOOT_COEFF(trans->entries[level].dkl.preshoot);
> -
> for (ln = 0; ln < 2; ln++) {
> + int level;
> + u32 val;
> +
> intel_de_write(dev_priv, HIP_INDEX_REG(tc_port),
> HIP_INDEX_VAL(tc_port, ln));
>
> intel_de_write(dev_priv, DKL_TX_PMD_LANE_SUS(tc_port), 0);
>
> - /* All the registers are RMW */
> + level = intel_ddi_level(encoder, crtc_state, 2*ln+0);
> +
> val = intel_de_read(dev_priv, DKL_TX_DPCNTL0(tc_port));
> - val &= ~dpcnt_mask;
> - val |= dpcnt_val;
> + val &= ~(DKL_TX_PRESHOOT_COEFF_MASK |
> + DKL_TX_DE_EMPAHSIS_COEFF_MASK |
> + DKL_TX_VSWING_CONTROL_MASK);
> + val |= DKL_TX_VSWING_CONTROL(trans->entries[level].dkl.vswing) |
> + DKL_TX_DE_EMPHASIS_COEFF(trans->entries[level].dkl.de_emphasis) |
> + DKL_TX_PRESHOOT_COEFF(trans->entries[level].dkl.preshoot);
> intel_de_write(dev_priv, DKL_TX_DPCNTL0(tc_port), val);
>
> + level = intel_ddi_level(encoder, crtc_state, 2*ln+1);
> +
> val = intel_de_read(dev_priv, DKL_TX_DPCNTL1(tc_port));
> - val &= ~dpcnt_mask;
> - val |= dpcnt_val;
> + val &= ~(DKL_TX_PRESHOOT_COEFF_MASK |
> + DKL_TX_DE_EMPAHSIS_COEFF_MASK |
> + DKL_TX_VSWING_CONTROL_MASK);
> + val |= DKL_TX_VSWING_CONTROL(trans->entries[level].dkl.vswing) |
> + DKL_TX_DE_EMPHASIS_COEFF(trans->entries[level].dkl.de_emphasis) |
> + DKL_TX_PRESHOOT_COEFF(trans->entries[level].dkl.preshoot);
> intel_de_write(dev_priv, DKL_TX_DPCNTL1(tc_port), val);
>
> val = intel_de_read(dev_priv, DKL_TX_DPCNTL2(tc_port));