HDMI 2.0 spec mandates scrambling for modes with pixel clock higher than 340Mhz. This patch adds few new functions in drm layer for core drivers to enable/disable scrambling.
This patch adds: - A function to detect scrambling support parsing HF-VSDB - A function to check scrambling status runtime using SCDC read. - Two functions to enable/disable scrambling using SCDC read/write. - Few new bools to reflect scrambling support and status.
Signed-off-by: Shashank Sharma shashank.sharma@intel.com --- drivers/gpu/drm/drm_edid.c | 131 +++++++++++++++++++++++++++++++++++++++++++- include/drm/drm_connector.h | 24 ++++++++ include/drm/drm_edid.h | 6 +- 3 files changed, 159 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 37902e5..f0d940a 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -37,6 +37,7 @@ #include <drm/drm_edid.h> #include <drm/drm_encoder.h> #include <drm/drm_displayid.h> +#include <drm/drm_scdc_helper.h>
#define version_greater(edid, maj, min) \ (((edid)->version > (maj)) || \ @@ -3814,6 +3815,132 @@ static void drm_detect_hdmi_scdc(struct drm_connector *connector, } }
+static void drm_detect_hdmi_scrambling(struct drm_connector *connector, + const u8 *hf_vsdb) +{ + struct drm_display_info *display = &connector->display_info; + struct drm_hdmi_info *hdmi = &display->hdmi_info; + + /* + * All HDMI 2.0 monitors must support scrambling at rates > 340M. + * And as per the spec, three factors confirm this: + * * Availability of a HF-VSDB block in EDID (check) + * * Non zero Max_TMDS_Char_Rate filed in HF-VSDB + * * SCDC support available + * Lets check it out. + */ + + if (hf_vsdb[5]) { + display->max_tmds_clock = hf_vsdb[5] * 5000; + DRM_DEBUG_KMS("HF-VSDB: max TMDS clock %d kHz\n", + display->max_tmds_clock); + + if (hdmi->scdc_supported) { + hdmi->scr_info.supported = true; + + /* Few sinks support scrambling for cloks < 340M */ + if ((hf_vsdb[6] & 0x8)) + hdmi->scr_info.low_clocks = true; + } + } +} + +/** + * drm_check_scrambling_status - what is status of scrambling? + * @adapter: i2c adapter for SCDC channel + * + * Read the scrambler status over SCDC channel, and check the + * scrambling status. + * + * Return: True if the scrambling is enabled, false otherwise. + */ + +bool drm_check_scrambling_status(struct i2c_adapter *adapter) +{ + u8 status; + + if (drm_scdc_readb(adapter, SCDC_SCRAMBLER_STATUS, &status) < 0) { + DRM_ERROR("Failed to read scrambling status\n"); + return false; + } + + status &= SCDC_SCRAMBLING_STATUS; + return status != 0; +} + +/** + * drm_enable_scrambling - enable scrambling + * @connector: target drm_connector + * @adapter: i2c adapter for SCDC channel + * @force: enable scrambling, even if its already enabled + * + * Write the TMDS config over SCDC channel, and enable scrambling + * Return: True if scrambling is successfully enabled, false otherwise. + */ + +bool drm_enable_scrambling(struct drm_connector *connector, + struct i2c_adapter *adapter, bool force) +{ + u8 config; + struct drm_hdmi_info *hdmi_info = &connector->display_info.hdmi_info; + + if (hdmi_info->scr_info.status && !force) { + DRM_DEBUG_KMS("Scrambling already enabled\n"); + return true; + } + + if (drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config) < 0) { + DRM_ERROR("Failed to read tmds config\n"); + return false; + } + + config |= SCDC_SCRAMBLING_ENABLE; + + if (drm_scdc_writeb(adapter, SCDC_TMDS_CONFIG, config) < 0) { + DRM_ERROR("Failed to enable scrambling, write error\n"); + return false; + } + + hdmi_info->scr_info.status = drm_check_scrambling_status(adapter); + return hdmi_info->scr_info.status; +} + +/** + * drm_disable_scrambling - disable scrambling + * @connector: target drm_connector + * @adapter: i2c adapter for SCDC channel + * @force: disable scrambling, even if its already disabled + * + * Write the TMDS config over SCDC channel, and disable scrambling + * Return: True if scrambling is successfully disabled, false otherwise. + */ +bool drm_disable_scrambling(struct drm_connector *connector, + struct i2c_adapter *adapter, bool force) +{ + u8 config; + struct drm_hdmi_info *hdmi_info = &connector->display_info.hdmi_info; + + if (!hdmi_info->scr_info.status && !force) { + DRM_DEBUG_KMS("Scrambling already disabled\n"); + return true; + } + + if (drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config) < 0) { + DRM_ERROR("Failed to read tmds config\n"); + return false; + } + + config &= ~SCDC_SCRAMBLING_ENABLE; + + if (drm_scdc_writeb(adapter, SCDC_TMDS_CONFIG, config) < 0) { + DRM_ERROR("Failed to enable scrambling, write error\n"); + return false; + } + + hdmi_info->scr_info.status = drm_check_scrambling_status(adapter); + return !hdmi_info->scr_info.status; +} + static void drm_parse_hdmi_deep_color_info(struct drm_connector *connector, const u8 *hdmi) { @@ -3928,8 +4055,10 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
if (cea_db_is_hdmi_vsdb(db)) drm_parse_hdmi_vsdb_video(connector, db); - if (cea_db_is_hdmi_forum_vsdb(db)) + if (cea_db_is_hdmi_forum_vsdb(db)) { drm_detect_hdmi_scdc(connector, db); + drm_detect_hdmi_scrambling(connector, db); + } } }
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 2435598..b9735bd 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -90,6 +90,26 @@ enum subpixel_order {
};
+ +/** + * struct scrambling: sink's scrambling support. + */ +struct scrambling { + /** + * @supported: scrambling supported for rates > 340Mhz. + */ + bool supported; + /** + * @low_clocks: scrambling supported for rates <= 340Mhz. + */ + bool low_clocks; + /** + * @status: scrambling enabled/disabled ? + */ + bool status; +}; + + /** * struct drm_hdmi_info - runtime data about the connected sink * @@ -108,6 +128,10 @@ struct drm_hdmi_info { * @scdc_rr: sink is capable of generating scdc read request. */ bool scdc_rr; + /** + * scr_info: sink's scrambling support and capabilities. + */ + struct scrambling scr_info; };
/** diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h index 43fb0ac..d24c974 100644 --- a/include/drm/drm_edid.h +++ b/include/drm/drm_edid.h @@ -462,5 +462,9 @@ void drm_edid_get_monitor_name(struct edid *edid, char *name, struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev, int hsize, int vsize, int fresh, bool rb); - +bool drm_enable_scrambling(struct drm_connector *connector, + struct i2c_adapter *adapter, bool force); +bool drm_disable_scrambling(struct drm_connector *connector, + struct i2c_adapter *adapter, bool force); +bool drm_check_scrambling_status(struct i2c_adapter *adapter); #endif /* __DRM_EDID_H__ */