[PATCH v2 4/6] drm/dp: Add LTTPR helpers
Imre Deak
imre.deak at intel.com
Fri Sep 25 16:51:38 UTC 2020
On Fri, Sep 25, 2020 at 07:02:47PM +0300, Ville Syrjälä wrote:
> On Thu, Sep 24, 2020 at 09:48:03PM +0300, Imre Deak wrote:
> > Add the helpers and register definitions needed to read out the common
> > and per-PHY LTTPR capabilities and perform link training in the LTTPR
> > non-transparent mode.
> >
> > v2:
> > - Add drm_dp_dpcd_read_phy_link_status() and DP_PHY_LTTPR() here instead
> > of adding these to i915. (Ville)
> >
> > Cc: dri-devel at lists.freedesktop.org
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > ---
> > drivers/gpu/drm/drm_dp_helper.c | 244 +++++++++++++++++++++++++++++++-
> > include/drm/drm_dp_helper.h | 62 ++++++++
> > 2 files changed, 302 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> > index 478dd51f738d..6014c858b06b 100644
> > --- a/drivers/gpu/drm/drm_dp_helper.c
> > +++ b/drivers/gpu/drm/drm_dp_helper.c
> > @@ -150,11 +150,8 @@ void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> > }
> > EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay);
> >
> > -void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> > +static void __drm_dp_link_train_channel_eq_delay(unsigned long rd_interval)
> > {
> > - unsigned long rd_interval = dpcd[DP_TRAINING_AUX_RD_INTERVAL] &
> > - DP_TRAINING_AUX_RD_MASK;
> > -
> > if (rd_interval > 4)
> > DRM_DEBUG_KMS("AUX interval %lu, out of range (max 4)\n",
> > rd_interval);
> > @@ -166,8 +163,35 @@ void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> >
> > usleep_range(rd_interval, rd_interval * 2);
> > }
> > +
> > +void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> > +{
> > + __drm_dp_link_train_channel_eq_delay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] &
> > + DP_TRAINING_AUX_RD_MASK);
> > +}
> > EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay);
> >
> > +void drm_dp_lttpr_link_train_clock_recovery_delay(void)
> > +{
> > + usleep_range(100, 200);
> > +}
> > +EXPORT_SYMBOL(drm_dp_lttpr_link_train_clock_recovery_delay);
> > +
> > +static u8 dp_lttpr_phy_cap(const u8 phy_cap[DP_LTTPR_PHY_CAP_SIZE], int r)
> > +{
> > + return phy_cap[r - DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1];
> > +}
> > +
> > +void drm_dp_lttpr_link_train_channel_eq_delay(const u8 phy_cap[DP_LTTPR_PHY_CAP_SIZE])
> > +{
> > + u8 interval = dp_lttpr_phy_cap(phy_cap,
> > + DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1) &
> > + DP_TRAINING_AUX_RD_MASK;
> > +
> > + __drm_dp_link_train_channel_eq_delay(interval);
> > +}
> > +EXPORT_SYMBOL(drm_dp_lttpr_link_train_channel_eq_delay);
> > +
> > u8 drm_dp_link_rate_to_bw_code(int link_rate)
> > {
> > /* Spec says link_bw = link_rate / 0.27Gbps */
> > @@ -363,6 +387,71 @@ int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
> > }
> > EXPORT_SYMBOL(drm_dp_dpcd_read_link_status);
> >
> > +/**
> > + * drm_dp_dpcd_read_phy_link_status - get the link status information for a DP PHY
> > + * @aux: DisplayPort AUX channel
> > + * @dp_phy: the DP PHY to get the link status for
> > + * @link_status: buffer to return the status in
> > + *
> > + * Fetch the AUX DPCD registers for the DPRX or an LTTPR PHY link status. The
> > + * layout of the returned @link_status matches the DPCD register layout of the
> > + * DPRX PHY link status.
> > + *
> > + * Returns 0 if the information was read successfully or a negative error code
> > + * on failure.
> > + */
> > +int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux,
> > + enum drm_dp_phy dp_phy,
> > + u8 link_status[DP_LINK_STATUS_SIZE])
> > +{
> > + u8 lttpr_status[DP_LINK_STATUS_SIZE - 1];
> > + int ret;
> > +
> > + if (dp_phy == DP_PHY_DPRX) {
> > + ret = drm_dp_dpcd_read(aux,
> > + DP_LANE0_1_STATUS,
> > + link_status,
> > + DP_LINK_STATUS_SIZE);
> > +
> > + if (ret < 0)
> > + return ret;
> > +
> > + WARN_ON(ret != DP_LINK_STATUS_SIZE);
> > +
> > + return 0;
> > + }
> > +
> > + ret = drm_dp_dpcd_read(aux,
> > + DP_LANE0_1_STATUS_PHY_REPEATER(dp_phy),
> > + lttpr_status,
> > + sizeof(lttpr_status));
> > +
> > + if (ret < 0)
> > + return ret;
> > +
> > + WARN_ON(ret != sizeof(lttpr_status));
> > +
> > +#define link_reg(reg) link_status[(reg) - DP_LANE0_1_STATUS]
> > +#define lttpr_reg(reg) lttpr_status[(reg) - DP_LANE0_1_STATUS_PHY_REPEATER1]
> > +
> > + /* Convert the LTTPR to the sink PHY link status layout */
> > + link_reg(DP_LANE0_1_STATUS) = lttpr_reg(DP_LANE0_1_STATUS_PHY_REPEATER1);
> > + link_reg(DP_LANE2_3_STATUS) = lttpr_reg(DP_LANE2_3_STATUS_PHY_REPEATER1);
> > + link_reg(DP_LANE_ALIGN_STATUS_UPDATED) =
> > + lttpr_reg(DP_LANE_ALIGN_STATUS_UPDATED_PHY_REPEATER1);
> > + link_reg(DP_SINK_STATUS) = 0;
> > + link_reg(DP_ADJUST_REQUEST_LANE0_1) =
> > + lttpr_reg(DP_ADJUST_REQUEST_LANE0_1_PHY_REPEATER1);
> > + link_reg(DP_ADJUST_REQUEST_LANE2_3) =
> > + lttpr_reg(DP_ADJUST_REQUEST_LANE2_3_PHY_REPEATER1);
> > +
> > +#undef link_reg
> > +#undef lttpr_reg
>
> Alternative might be to read to the target buffer directly
> and just memmove() the stuff around a bit. Would avoid having
> the second buffer on stack. But it's a small buffer so meh.
Yes, thought about using memmove, would be like
memmove(&link_status[DP_SINK_STATUS - DP_LANE0_1_STATUS + 1],
&link_status[DP_SINK_STATUS - DP_LANE0_1_STATUS],
DP_LINK_STATUS_SIZE - DP_SINK_STATUS - 1);
link_status[DP_SINK_STATUS - DP_LANE0_1_STATUS] = 0;
then thought that it's less clear what's going on, so decided writing it
out more explicitly. If you think that's not a concern I'll use memmove
instead.
>
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(drm_dp_dpcd_read_phy_link_status);
> > +
> > static bool is_edid_digital_input_dp(const struct edid *edid)
> > {
> > return edid && edid->revision >= 4 &&
> > @@ -2098,6 +2187,153 @@ int drm_dp_dsc_sink_supported_input_bpcs(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_S
> > }
> > EXPORT_SYMBOL(drm_dp_dsc_sink_supported_input_bpcs);
> >
> > +/**
> > + * drm_dp_read_lttpr_common_caps - read the LTTPR common capabilities
> > + * @aux: DisplayPort AUX channel
> > + * @caps: buffer to return the capability info in
> > + *
> > + * Read capabilities common to all LTTPRs.
> > + *
> > + * Returns 0 on success or a negative error code on failure.
> > + */
> > +int drm_dp_read_lttpr_common_caps(struct drm_dp_aux *aux,
> > + u8 caps[DP_LTTPR_COMMON_CAP_SIZE])
> > +{
> > + int ret;
> > +
> > + ret = drm_dp_dpcd_read(aux,
> > + DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV,
> > + caps, DP_LTTPR_COMMON_CAP_SIZE);
> > + if (ret < 0)
> > + return ret;
> > +
> > + WARN_ON(ret != DP_LTTPR_COMMON_CAP_SIZE);
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(drm_dp_read_lttpr_common_caps);
> > +
> > +/**
> > + * drm_dp_read_lttpr_phy_caps - read the capabilities for a given LTTPR PHY
> > + * @aux: DisplayPort AUX channel
> > + * @dp_phy: LTTPR PHY to read the capabilities for
> > + * @caps: buffer to return the capability info in
> > + *
> > + * Read the capabilities for the given LTTPR PHY.
> > + *
> > + * Returns 0 on success or a negative error code on failure.
> > + */
> > +int drm_dp_read_lttpr_phy_caps(struct drm_dp_aux *aux,
> > + enum drm_dp_phy dp_phy,
> > + u8 caps[DP_LTTPR_PHY_CAP_SIZE])
> > +{
> > + int ret;
> > +
> > + ret = drm_dp_dpcd_read(aux,
> > + DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER(dp_phy),
> > + caps, DP_LTTPR_PHY_CAP_SIZE);
> > + if (ret < 0)
> > + return ret;
> > +
> > + WARN_ON(ret != DP_LTTPR_PHY_CAP_SIZE);
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(drm_dp_read_lttpr_phy_caps);
> > +
> > +static u8 dp_lttpr_common_cap(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE], int r)
> > +{
> > + return caps[r - DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV];
> > +}
> > +
> > +/**
> > + * drm_dp_lttpr_count - get the number of detected LTTPRs
> > + * @caps: LTTPR common capabilities
> > + *
> > + * Get the number of detected LTTPRs from the LTTPR common capabilities info.
> > + *
> > + * Returns:
> > + * -ERANGE if more than supported number (8) of LTTPRs are detected
> > + * -EINVAL if the DP_PHY_REPEATER_CNT register contains an invalid value
> > + * otherwise the number of detected LTTPRs
> > + */
> > +int drm_dp_lttpr_count(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE])
> > +{
> > + u8 count = dp_lttpr_common_cap(caps, DP_PHY_REPEATER_CNT);
> > +
> > + switch (hweight8(count)) {
> > + case 0:
> > + return 0;
> > + case 1:
> > + return 8 - ilog2(count);
> > + case 8:
> > + return -ERANGE;
> > + default:
> > + return -EINVAL;
> > + }
> > +}
> > +EXPORT_SYMBOL(drm_dp_lttpr_count);
> > +
> > +/**
> > + * drm_dp_lttpr_max_link_rate - get the maximum link rate supported by all LTTPRs
> > + * @caps: LTTPR common capabilities
> > + *
> > + * Returns the maximum link rate supported by all detected LTTPRs.
> > + */
> > +int drm_dp_lttpr_max_link_rate(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE])
> > +{
> > + u8 rate = dp_lttpr_common_cap(caps, DP_MAX_LINK_RATE_PHY_REPEATER);
> > +
> > + return drm_dp_bw_code_to_link_rate(rate);
> > +}
> > +EXPORT_SYMBOL(drm_dp_lttpr_max_link_rate);
> > +
> > +/**
> > + * drm_dp_lttpr_max_lane_count - get the maximum lane count supported by all LTTPRs
> > + * @caps: LTTPR common capabilities
> > + *
> > + * Returns the maximum lane count supported by all detected LTTPRs.
> > + */
> > +int drm_dp_lttpr_max_lane_count(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE])
> > +{
> > + u8 max_lanes = dp_lttpr_common_cap(caps, DP_MAX_LANE_COUNT_PHY_REPEATER);
> > +
> > + return max_lanes & DP_MAX_LANE_COUNT_MASK;
> > +}
> > +EXPORT_SYMBOL(drm_dp_lttpr_max_lane_count);
> > +
> > +/**
> > + * drm_dp_lttpr_voltage_swing_level_3_supported - check for LTTPR vswing3 support
> > + * @caps: LTTPR PHY capabilities
> > + *
> > + * Returns true if the @caps for an LTTPR TX PHY indicate support for
> > + * voltage swing level 3.
> > + */
> > +bool
> > +drm_dp_lttpr_voltage_swing_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE])
> > +{
> > + u8 txcap = dp_lttpr_phy_cap(caps, DP_TRANSMITTER_CAPABILITY_PHY_REPEATER1);
> > +
> > + return txcap & DP_VOLTAGE_SWING_LEVEL_3_SUPPORTED;
> > +}
> > +EXPORT_SYMBOL(drm_dp_lttpr_voltage_swing_level_3_supported);
> > +
> > +/**
> > + * drm_dp_lttpr_pre_emphasis_level_3_supported - check for LTTPR preemph3 support
> > + * @caps: LTTPR PHY capabilities
> > + *
> > + * Returns true if the @caps for an LTTPR TX PHY indicate support for
> > + * pre-emphasis level 3.
> > + */
> > +bool
> > +drm_dp_lttpr_pre_emphasis_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE])
> > +{
> > + u8 txcap = dp_lttpr_phy_cap(caps, DP_TRANSMITTER_CAPABILITY_PHY_REPEATER1);
> > +
> > + return txcap & DP_PRE_EMPHASIS_LEVEL_3_SUPPORTED;
> > +}
> > +EXPORT_SYMBOL(drm_dp_lttpr_pre_emphasis_level_3_supported);
> > +
> > /**
> > * drm_dp_get_phy_test_pattern() - get the requested pattern from the sink.
> > * @aux: DisplayPort AUX channel
> > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> > index e144b4b9d79a..42b6ab14920a 100644
> > --- a/include/drm/drm_dp_helper.h
> > +++ b/include/drm/drm_dp_helper.h
> > @@ -1118,15 +1118,58 @@ struct drm_device;
> > #define DP_MAX_LANE_COUNT_PHY_REPEATER 0xf0004 /* 1.4a */
> > #define DP_Repeater_FEC_CAPABILITY 0xf0004 /* 1.4 */
> > #define DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT 0xf0005 /* 1.4a */
> > +
> > +enum drm_dp_phy {
> > + DP_PHY_DPRX,
> > +
> > + DP_PHY_LTTPR1,
> > + DP_PHY_LTTPR2,
> > + DP_PHY_LTTPR3,
> > + DP_PHY_LTTPR4,
> > + DP_PHY_LTTPR5,
> > + DP_PHY_LTTPR6,
> > + DP_PHY_LTTPR7,
> > + DP_PHY_LTTPR8,
> > +
> > + DP_MAX_LTTPR_COUNT = DP_PHY_LTTPR8,
> > +};
> > +
> > +#define DP_PHY_LTTPR(i) (DP_PHY_LTTPR1 + (i))
> > +
> > +#define __DP_LTTPR1_BASE 0xf0010 /* 1.3 */
> > +#define __DP_LTTPR2_BASE 0xf0060 /* 1.3 */
> > +#define DP_LTTPR_BASE(dp_phy) \
> > + (__DP_LTTPR1_BASE + (__DP_LTTPR2_BASE - __DP_LTTPR1_BASE) * \
> > + ((dp_phy) - DP_PHY_LTTPR1))
> > +
> > +#define DP_LTTPR_REG(dp_phy, lttpr1_reg) \
> > + (DP_LTTPR_BASE(dp_phy) - DP_LTTPR_BASE(DP_PHY_LTTPR1) + (lttpr1_reg))
> > +
> > #define DP_TRAINING_PATTERN_SET_PHY_REPEATER1 0xf0010 /* 1.3 */
> > +#define DP_TRAINING_PATTERN_SET_PHY_REPEATER(dp_phy) \
> > + DP_LTTPR_REG(dp_phy, DP_TRAINING_PATTERN_SET_PHY_REPEATER1)
> > +
> > #define DP_TRAINING_LANE0_SET_PHY_REPEATER1 0xf0011 /* 1.3 */
> > +#define DP_TRAINING_LANE0_SET_PHY_REPEATER(dp_phy) \
> > + DP_LTTPR_REG(dp_phy, DP_TRAINING_LANE0_SET_PHY_REPEATER1)
> > +
> > #define DP_TRAINING_LANE1_SET_PHY_REPEATER1 0xf0012 /* 1.3 */
> > #define DP_TRAINING_LANE2_SET_PHY_REPEATER1 0xf0013 /* 1.3 */
> > #define DP_TRAINING_LANE3_SET_PHY_REPEATER1 0xf0014 /* 1.3 */
> > #define DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1 0xf0020 /* 1.4a */
> > +#define DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER(dp_phy) \
> > + DP_LTTPR_REG(dp_phy, DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1)
> > +
> > #define DP_TRANSMITTER_CAPABILITY_PHY_REPEATER1 0xf0021 /* 1.4a */
> > +# define DP_VOLTAGE_SWING_LEVEL_3_SUPPORTED BIT(0)
> > +# define DP_PRE_EMPHASIS_LEVEL_3_SUPPORTED BIT(1)
> > +
> > #define DP_LANE0_1_STATUS_PHY_REPEATER1 0xf0030 /* 1.3 */
> > +#define DP_LANE0_1_STATUS_PHY_REPEATER(dp_phy) \
> > + DP_LTTPR_REG(dp_phy, DP_LANE0_1_STATUS_PHY_REPEATER1)
> > +
> > #define DP_LANE2_3_STATUS_PHY_REPEATER1 0xf0031 /* 1.3 */
> > +
> > #define DP_LANE_ALIGN_STATUS_UPDATED_PHY_REPEATER1 0xf0032 /* 1.3 */
> > #define DP_ADJUST_REQUEST_LANE0_1_PHY_REPEATER1 0xf0033 /* 1.3 */
> > #define DP_ADJUST_REQUEST_LANE2_3_PHY_REPEATER1 0xf0034 /* 1.3 */
> > @@ -1236,9 +1279,13 @@ u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZ
> > #define DP_DSC_RECEIVER_CAP_SIZE 0xf
> > #define EDP_PSR_RECEIVER_CAP_SIZE 2
> > #define EDP_DISPLAY_CTL_CAP_SIZE 3
> > +#define DP_LTTPR_COMMON_CAP_SIZE 8
> > +#define DP_LTTPR_PHY_CAP_SIZE 3
> >
> > void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
> > +void drm_dp_lttpr_link_train_clock_recovery_delay(void);
> > void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
> > +void drm_dp_lttpr_link_train_channel_eq_delay(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
> >
> > u8 drm_dp_link_rate_to_bw_code(int link_rate);
> > int drm_dp_bw_code_to_link_rate(u8 link_bw);
> > @@ -1697,6 +1744,10 @@ int drm_dp_read_dpcd_caps(struct drm_dp_aux *aux,
> > int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
> > u8 status[DP_LINK_STATUS_SIZE]);
> >
> > +int drm_dp_dpcd_read_phy_link_status(struct drm_dp_aux *aux,
> > + enum drm_dp_phy dp_phy,
> > + u8 link_status[DP_LINK_STATUS_SIZE]);
> > +
> > bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
> > u8 real_edid_checksum);
> >
> > @@ -1746,6 +1797,17 @@ bool drm_dp_read_sink_count_cap(struct drm_connector *connector,
> > const struct drm_dp_desc *desc);
> > int drm_dp_read_sink_count(struct drm_dp_aux *aux);
> >
> > +int drm_dp_read_lttpr_common_caps(struct drm_dp_aux *aux,
> > + u8 caps[DP_LTTPR_COMMON_CAP_SIZE]);
> > +int drm_dp_read_lttpr_phy_caps(struct drm_dp_aux *aux,
> > + enum drm_dp_phy dp_phy,
> > + u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
> > +int drm_dp_lttpr_count(const u8 cap[DP_LTTPR_COMMON_CAP_SIZE]);
> > +int drm_dp_lttpr_max_link_rate(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]);
> > +int drm_dp_lttpr_max_lane_count(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]);
> > +bool drm_dp_lttpr_voltage_swing_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
> > +bool drm_dp_lttpr_pre_emphasis_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]);
> > +
> > void drm_dp_remote_aux_init(struct drm_dp_aux *aux);
> > void drm_dp_aux_init(struct drm_dp_aux *aux);
> > int drm_dp_aux_register(struct drm_dp_aux *aux);
> > --
> > 2.25.1
>
> --
> Ville Syrjälä
> Intel
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