Re: [Intel-gfx] [PATCH 44/53] drm/i915/dg2: Add vswing programming for SNPS phys

Jani Nikula
2021-07-02T08:14:45Z

On Thu, 01 Jul 2021, Matt Roper <matthew.d.roper@intel.com> wrote:
> Vswing programming for SNPS PHYs is just a single step -- look up the
> value that corresponds to the voltage level from a table and program it
> into the SNPS_PHY_TX_EQ register.

I've got some patches to turn this to the same ddi buf trans mechanism
that everything else uses. Seems like this patch tries to bypass it
because it's simple, but then we end up using encoder->get_buf_trans()
anyway, for example in intel_ddi_dp_voltage_max(), and it returns some
tgl buf trans tables... I guess it works by coincidence. :|

Anyway, as I said, I've got the patches, and I can fix this up
afterwards.

BR,
Jani.

>
> Bspec: 53920
> Cc: Matt Atwood <matthew.s.atwood@intel.com>
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_ddi.c | 23 ++++++--
> drivers/gpu/drm/i915/display/intel_snps_phy.c | 54 +++++++++++++++++++
> drivers/gpu/drm/i915/display/intel_snps_phy.h | 4 ++
> drivers/gpu/drm/i915/i915_reg.h | 5 ++
> 4 files changed, 83 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 929a95ddb316..ade03cf41caa 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -1496,6 +1496,16 @@ static int intel_ddi_dp_level(struct intel_dp *intel_dp)
> return translate_signal_level(intel_dp, signal_levels);
> }
>
> +static void
> +dg2_set_signal_levels(struct intel_dp *intel_dp,
> + const struct intel_crtc_state *crtc_state)
> +{
> + struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
> + int level = intel_ddi_dp_level(intel_dp);
> +
> + intel_snps_phy_ddi_vswing_sequence(encoder, level);
> +}
> +
> static void
> tgl_set_signal_levels(struct intel_dp *intel_dp,
> const struct intel_crtc_state *crtc_state)
> @@ -2563,7 +2573,10 @@ static void tgl_ddi_pre_enable_dp(struct intel_atomic_state *state,
> */
>
> /* 7.e Configure voltage swing and related IO settings */
> - tgl_ddi_vswing_sequence(encoder, crtc_state, level);
> + if (IS_DG2(dev_priv))
> + intel_snps_phy_ddi_vswing_sequence(encoder, level);
> + else
> + tgl_ddi_vswing_sequence(encoder, crtc_state, level);
>
> /*
> * 7.f Combo PHY: Configure PORT_CL_DW10 Static Power Down to power up
> @@ -3102,7 +3115,9 @@ static void intel_enable_ddi_hdmi(struct intel_atomic_state *state,
> "[CONNECTOR:%d:%s] Failed to configure sink scrambling/TMDS bit clock ratio\n",
> connector->base.id, connector->name);
>
> - if (DISPLAY_VER(dev_priv) >= 12)
> + if (IS_DG2(dev_priv))
> + intel_snps_phy_ddi_vswing_sequence(encoder, U32_MAX);
> + else if (DISPLAY_VER(dev_priv) >= 12)
> tgl_ddi_vswing_sequence(encoder, crtc_state, level);
> else if (DISPLAY_VER(dev_priv) == 11)
> icl_ddi_vswing_sequence(encoder, crtc_state, level);
> @@ -4075,7 +4090,9 @@ intel_ddi_init_dp_connector(struct intel_digital_port *dig_port)
> dig_port->dp.set_link_train = intel_ddi_set_link_train;
> dig_port->dp.set_idle_link_train = intel_ddi_set_idle_link_train;
>
> - if (DISPLAY_VER(dev_priv) >= 12)
> + if (IS_DG2(dev_priv))
> + dig_port->dp.set_signal_levels = dg2_set_signal_levels;
> + else if (DISPLAY_VER(dev_priv) >= 12)
> dig_port->dp.set_signal_levels = tgl_set_signal_levels;
> else if (DISPLAY_VER(dev_priv) >= 11)
> dig_port->dp.set_signal_levels = icl_set_signal_levels;
> diff --git a/drivers/gpu/drm/i915/display/intel_snps_phy.c b/drivers/gpu/drm/i915/display/intel_snps_phy.c
> index 1317b4e94b50..77759bda98a4 100644
> --- a/drivers/gpu/drm/i915/display/intel_snps_phy.c
> +++ b/drivers/gpu/drm/i915/display/intel_snps_phy.c
> @@ -21,6 +21,60 @@
> * since it is not handled by the shared DPLL framework as on other platforms.
> */
>
> +static const u32 dg2_ddi_translations[] = {
> + /* VS 0, pre-emph 0 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 26),
> +
> + /* VS 0, pre-emph 1 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 33) |
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_POST, 6),
> +
> + /* VS 0, pre-emph 2 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 38) |
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_POST, 12),
> +
> + /* VS 0, pre-emph 3 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 43) |
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_POST, 19),
> +
> + /* VS 1, pre-emph 0 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 39),
> +
> + /* VS 1, pre-emph 1 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 44) |
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_POST, 8),
> +
> + /* VS 1, pre-emph 2 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 47) |
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_POST, 15),
> +
> + /* VS 2, pre-emph 0 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 52),
> +
> + /* VS 2, pre-emph 1 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 51) |
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_POST, 10),
> +
> + /* VS 3, pre-emph 0 */
> + REG_FIELD_PREP(SNPS_PHY_TX_EQ_MAIN, 62),
> +};
> +
> +void intel_snps_phy_ddi_vswing_sequence(struct intel_encoder *encoder,
> + u32 level)
> +{
> + struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> + enum phy phy = intel_port_to_phy(dev_priv, encoder->port);
> + int n_entries, ln;
> +
> + n_entries = ARRAY_SIZE(dg2_ddi_translations);
> + if (level >= n_entries)
> + level = n_entries - 1;
> +
> + for (ln = 0; ln < 4; ln++)
> + intel_de_write(dev_priv, SNPS_PHY_TX_EQ(ln, phy),
> + dg2_ddi_translations[level]);
> +}
> +
> /*
> * Basic DP link rates with 100 MHz reference clock.
> */
> diff --git a/drivers/gpu/drm/i915/display/intel_snps_phy.h b/drivers/gpu/drm/i915/display/intel_snps_phy.h
> index ca4c2a25182b..3ce92d424f66 100644
> --- a/drivers/gpu/drm/i915/display/intel_snps_phy.h
> +++ b/drivers/gpu/drm/i915/display/intel_snps_phy.h
> @@ -6,6 +6,8 @@
> #ifndef __INTEL_SNPS_PHY_H__
> #define __INTEL_SNPS_PHY_H__
>
> +#include <linux/types.h>
> +
> struct intel_encoder;
> struct intel_crtc_state;
> struct intel_mpllb_state;
> @@ -21,5 +23,7 @@ int intel_mpllb_calc_port_clock(struct intel_encoder *encoder,
> const struct intel_mpllb_state *pll_state);
>
> int intel_snps_phy_check_hdmi_link_rate(int clock);
> +void intel_snps_phy_ddi_vswing_sequence(struct intel_encoder *encoder,
> + u32 level);
>
> #endif /* __INTEL_SNPS_PHY_H__ */
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 15465f9cf9ab..203056b9f02c 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2340,6 +2340,11 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
> #define SNPS_PHY_REF_CONTROL(phy) _MMIO_SNPS(phy, 0x168188)
> #define SNPS_PHY_REF_CONTROL_REF_RANGE REG_GENMASK(31, 27)
>
> +#define SNPS_PHY_TX_EQ(ln, phy) _MMIO_SNPS_LN(ln, phy, 0x168300)
> +#define SNPS_PHY_TX_EQ_MAIN REG_GENMASK(23, 18)
> +#define SNPS_PHY_TX_EQ_POST REG_GENMASK(15, 10)
> +#define SNPS_PHY_TX_EQ_PRE REG_GENMASK(7, 2)
> +
> /* The spec defines this only for BXT PHY0, but lets assume that this
> * would exist for PHY1 too if it had a second channel.
> */

--
Jani Nikula, Intel Open Source Graphics Center