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author | Ankit Nautiyal <ankit.k.nautiyal@intel.com> | 2020-12-18 16:07:12 +0530 |
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committer | Jani Nikula <jani.nikula@intel.com> | 2020-12-22 17:48:12 +0200 |
commit | ce32a6239de6480fa535c1409de98e24dd5ec721 (patch) | |
tree | 56cfb24ba55c270f093cb2a1122bc8ecfdcb237c /drivers/gpu | |
parent | 76ee7b905678f415b49af9c2d4932844db8f01cd (diff) | |
download | linux-ce32a6239de6480fa535c1409de98e24dd5ec721.tar.bz2 |
drm/dp_helper: Add Helpers for FRL Link Training support for DP-HDMI2.1 PCON
This patch adds support for configuring a PCON device,
connected as a DP branched device to enable FRL Link training
with a HDMI2.1 + sink.
v2: Fixed typos and addressed other review comments from Uma Shankar.
-changed the commit message for better clarity (Uma Shankar)
-removed unnecessary argument supplied to a drm helper function.
-fixed return value for max frl read from pcon.
v3: Removed DPCD 0x3035 for MAX Sink FRL b/w as per new version of spec.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com> (v2)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201218103723.30844-5-ankit.k.nautiyal@intel.com
Diffstat (limited to 'drivers/gpu')
-rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 37ec3b94389c..5890e0ba2eb9 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -2596,3 +2596,266 @@ void drm_dp_vsc_sdp_log(const char *level, struct device *dev, #undef DP_SDP_LOG } EXPORT_SYMBOL(drm_dp_vsc_sdp_log); + +/** + * drm_dp_get_pcon_max_frl_bw() - maximum frl supported by PCON + * @dpcd: DisplayPort configuration data + * @port_cap: port capabilities + * + * Returns maximum frl bandwidth supported by PCON in GBPS, + * returns 0 if not supported. + */ +int drm_dp_get_pcon_max_frl_bw(const u8 dpcd[DP_RECEIVER_CAP_SIZE], + const u8 port_cap[4]) +{ + int bw; + u8 buf; + + buf = port_cap[2]; + bw = buf & DP_PCON_MAX_FRL_BW; + + switch (bw) { + case DP_PCON_MAX_9GBPS: + return 9; + case DP_PCON_MAX_18GBPS: + return 18; + case DP_PCON_MAX_24GBPS: + return 24; + case DP_PCON_MAX_32GBPS: + return 32; + case DP_PCON_MAX_40GBPS: + return 40; + case DP_PCON_MAX_48GBPS: + return 48; + case DP_PCON_MAX_0GBPS: + default: + return 0; + } + + return 0; +} +EXPORT_SYMBOL(drm_dp_get_pcon_max_frl_bw); + +/** + * drm_dp_pcon_frl_prepare() - Prepare PCON for FRL. + * @aux: DisplayPort AUX channel + * + * Returns 0 if success, else returns negative error code. + */ +int drm_dp_pcon_frl_prepare(struct drm_dp_aux *aux, bool enable_frl_ready_hpd) +{ + int ret; + u8 buf = DP_PCON_ENABLE_SOURCE_CTL_MODE | + DP_PCON_ENABLE_LINK_FRL_MODE; + + if (enable_frl_ready_hpd) + buf |= DP_PCON_ENABLE_HPD_READY; + + ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, buf); + + return ret; +} +EXPORT_SYMBOL(drm_dp_pcon_frl_prepare); + +/** + * drm_dp_pcon_is_frl_ready() - Is PCON ready for FRL + * @aux: DisplayPort AUX channel + * + * Returns true if success, else returns false. + */ +bool drm_dp_pcon_is_frl_ready(struct drm_dp_aux *aux) +{ + int ret; + u8 buf; + + ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_TX_LINK_STATUS, &buf); + if (ret < 0) + return false; + + if (buf & DP_PCON_FRL_READY) + return true; + + return false; +} +EXPORT_SYMBOL(drm_dp_pcon_is_frl_ready); + +/** + * drm_dp_pcon_frl_configure_1() - Set HDMI LINK Configuration-Step1 + * @aux: DisplayPort AUX channel + * @max_frl_gbps: maximum frl bw to be configured between PCON and HDMI sink + * @concurrent_mode: true if concurrent mode or operation is required, + * false otherwise. + * + * Returns 0 if success, else returns negative error code. + */ + +int drm_dp_pcon_frl_configure_1(struct drm_dp_aux *aux, int max_frl_gbps, + bool concurrent_mode) +{ + int ret; + u8 buf; + + ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_LINK_CONFIG_1, &buf); + if (ret < 0) + return ret; + + if (concurrent_mode) + buf |= DP_PCON_ENABLE_CONCURRENT_LINK; + else + buf &= ~DP_PCON_ENABLE_CONCURRENT_LINK; + + switch (max_frl_gbps) { + case 9: + buf |= DP_PCON_ENABLE_MAX_BW_9GBPS; + break; + case 18: + buf |= DP_PCON_ENABLE_MAX_BW_18GBPS; + break; + case 24: + buf |= DP_PCON_ENABLE_MAX_BW_24GBPS; + break; + case 32: + buf |= DP_PCON_ENABLE_MAX_BW_32GBPS; + break; + case 40: + buf |= DP_PCON_ENABLE_MAX_BW_40GBPS; + break; + case 48: + buf |= DP_PCON_ENABLE_MAX_BW_48GBPS; + break; + case 0: + buf |= DP_PCON_ENABLE_MAX_BW_0GBPS; + break; + default: + return -EINVAL; + } + + ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, buf); + if (ret < 0) + return ret; + + return 0; +} +EXPORT_SYMBOL(drm_dp_pcon_frl_configure_1); + +/** + * drm_dp_pcon_frl_configure_2() - Set HDMI Link configuration Step-2 + * @aux: DisplayPort AUX channel + * @max_frl_mask : Max FRL BW to be tried by the PCON with HDMI Sink + * @extended_train_mode : true for Extended Mode, false for Normal Mode. + * In Normal mode, the PCON tries each frl bw from the max_frl_mask starting + * from min, and stops when link training is successful. In Extended mode, all + * frl bw selected in the mask are trained by the PCON. + * + * Returns 0 if success, else returns negative error code. + */ +int drm_dp_pcon_frl_configure_2(struct drm_dp_aux *aux, int max_frl_mask, + bool extended_train_mode) +{ + int ret; + u8 buf = max_frl_mask; + + if (extended_train_mode) + buf |= DP_PCON_FRL_LINK_TRAIN_EXTENDED; + + ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_2, buf); + if (ret < 0) + return ret; + + return 0; +} +EXPORT_SYMBOL(drm_dp_pcon_frl_configure_2); + +/** + * drm_dp_pcon_reset_frl_config() - Re-Set HDMI Link configuration. + * @aux: DisplayPort AUX channel + * + * Returns 0 if success, else returns negative error code. + */ +int drm_dp_pcon_reset_frl_config(struct drm_dp_aux *aux) +{ + int ret; + + ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, 0x0); + if (ret < 0) + return ret; + + return 0; +} +EXPORT_SYMBOL(drm_dp_pcon_reset_frl_config); + +/** + * drm_dp_pcon_frl_enable() - Enable HDMI link through FRL + * @aux: DisplayPort AUX channel + * + * Returns 0 if success, else returns negative error code. + */ +int drm_dp_pcon_frl_enable(struct drm_dp_aux *aux) +{ + int ret; + u8 buf = 0; + + ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_LINK_CONFIG_1, &buf); + if (ret < 0) + return ret; + if (!(buf & DP_PCON_ENABLE_SOURCE_CTL_MODE)) { + DRM_DEBUG_KMS("PCON in Autonomous mode, can't enable FRL\n"); + return -EINVAL; + } + buf |= DP_PCON_ENABLE_HDMI_LINK; + ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, buf); + if (ret < 0) + return ret; + + return 0; +} +EXPORT_SYMBOL(drm_dp_pcon_frl_enable); + +/** + * drm_dp_pcon_hdmi_link_active() - check if the PCON HDMI LINK status is active. + * @aux: DisplayPort AUX channel + * + * Returns true if link is active else returns false. + */ +bool drm_dp_pcon_hdmi_link_active(struct drm_dp_aux *aux) +{ + u8 buf; + int ret; + + ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_TX_LINK_STATUS, &buf); + if (ret < 0) + return false; + + return buf & DP_PCON_HDMI_TX_LINK_ACTIVE; +} +EXPORT_SYMBOL(drm_dp_pcon_hdmi_link_active); + +/** + * drm_dp_pcon_hdmi_link_mode() - get the PCON HDMI LINK MODE + * @aux: DisplayPort AUX channel + * @frl_trained_mask: pointer to store bitmask of the trained bw configuration. + * Valid only if the MODE returned is FRL. For Normal Link training mode + * only 1 of the bits will be set, but in case of Extended mode, more than + * one bits can be set. + * + * Returns the link mode : TMDS or FRL on success, else returns negative error + * code. + */ +int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask) +{ + u8 buf; + int mode; + int ret; + + ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_POST_FRL_STATUS, &buf); + if (ret < 0) + return ret; + + mode = buf & DP_PCON_HDMI_LINK_MODE; + + if (frl_trained_mask && DP_PCON_HDMI_MODE_FRL == mode) + *frl_trained_mask = (buf & DP_PCON_HDMI_FRL_TRAINED_BW) >> 1; + + return mode; +} +EXPORT_SYMBOL(drm_dp_pcon_hdmi_link_mode); |