From: Thierry Reding treding@nvidia.com
Signed-off-by: Thierry Reding treding@nvidia.com --- drivers/gpu/drm/drm_dp_helper.c | 121 ++++++++++++++++++++++++++++++++ include/drm/drm_dp_helper.h | 9 +++ 2 files changed, 130 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 01d34f33c658..136ee609f2ee 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -385,6 +385,107 @@ static void drm_dp_link_reset(struct drm_dp_link *link) link->lanes = 0; }
+/** + * drm_dp_link_add_rate() - add a rate to the list of supported rates + * @link: the link to add the rate to + * @rate: the rate to add + * + * Add a link rate to the list of supported link rates. + * + * Returns: + * 0 on success or one of the following negative error codes on failure: + * - ENOSPC if the maximum number of supported rates has been reached + * - EEXISTS if the link already supports this rate + * + * See also: + * drm_dp_link_remove_rate() + */ +int drm_dp_link_add_rate(struct drm_dp_link *link, unsigned long rate) +{ + unsigned int i, pivot; + + if (link->num_rates == DP_MAX_SUPPORTED_RATES) + return -ENOSPC; + + for (pivot = 0; pivot < link->num_rates; pivot++) + if (rate <= link->rates[pivot]) + break; + + if (pivot != link->num_rates && rate == link->rates[pivot]) + return -EEXIST; + + for (i = link->num_rates; i > pivot; i--) + link->rates[i] = link->rates[i - 1]; + + link->rates[pivot] = rate; + link->num_rates++; + + return 0; +} +EXPORT_SYMBOL(drm_dp_link_add_rate); + +/** + * drm_dp_link_remove_rate() - remove a rate from the list of supported rates + * @link: the link from which to remove the rate + * @rate: the rate to remove + * + * Removes a link rate from the list of supported link rates. + * + * Returns: + * 0 on success or one of the following negative error codes on failure: + * - EINVAL if the specified rate is not among the supported rates + * + * See also: + * drm_dp_link_add_rate() + */ +int drm_dp_link_remove_rate(struct drm_dp_link *link, unsigned long rate) +{ + unsigned int i; + + for (i = 0; i < link->num_rates; i++) + if (rate == link->rates[i]) + break; + + if (i == link->num_rates) + return -EINVAL; + + link->num_rates--; + + for (i = i; i < link->num_rates; i++) + link->rates[i] = link->rates[i + 1]; + + return 0; +} +EXPORT_SYMBOL(drm_dp_link_remove_rate); + +/** + * drm_dp_link_update_rates() - normalize the supported link rates array + * @link: the link for which to normalize the supported link rates + * + * Users should call this function after they've manually modified the array + * of supported link rates. This function removes any stale entries, compacts + * the array and updates the supported link rate count. Note that calling the + * drm_dp_link_remove_rate() function already does this janitorial work. + * + * See also: + * drm_dp_link_add_rate(), drm_dp_link_remove_rate() + */ +void drm_dp_link_update_rates(struct drm_dp_link *link) +{ + unsigned int i, count = 0; + + for (i = 0; i < link->num_rates; i++) { + if (link->rates[i] != 0) + link->rates[count++] = link->rates[i]; + } + + for (i = count; i < link->num_rates; i++) + link->rates[i] = 0; + + link->num_rates = count; +} +EXPORT_SYMBOL(drm_dp_link_update_rates); + /** * drm_dp_link_probe() - probe a DisplayPort link for capabilities * @aux: DisplayPort AUX channel @@ -437,6 +538,26 @@ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link) link->rate = link->max_rate; link->lanes = link->max_lanes;
+ /* Parse SUPPORTED_LINK_RATES from eDP 1.4 */ + if (link->edp >= 0x14) { + u8 supported_rates[DP_MAX_SUPPORTED_RATES * 2]; + unsigned int i; + u16 rate; + + err = drm_dp_dpcd_read(aux, DP_SUPPORTED_LINK_RATES, + supported_rates, + sizeof(supported_rates)); + if (err < 0) + return err; + + for (i = 0; i < DP_MAX_SUPPORTED_RATES; i++) { + rate = supported_rates[i * 2 + 1] << 8 | + supported_rates[i * 2 + 0]; + + drm_dp_link_add_rate(link, rate * 200); + } + } + return 0; } EXPORT_SYMBOL(drm_dp_link_probe); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 0f256458a57d..dd3076a835ef 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1453,6 +1453,8 @@ void drm_dp_link_caps_copy(struct drm_dp_link_caps *dest, * @edp: eDP revision (0x11: eDP 1.1, 0x12: eDP 1.2, ...) * @rate: currently configured link rate * @lanes: currently configured number of lanes + * @rates: additional supported link rates in kHz (eDP 1.4) + * @num_rates: number of additional supported link rates (eDP 1.4) */ struct drm_dp_link { unsigned char revision; @@ -1465,8 +1467,15 @@ struct drm_dp_link {
unsigned int rate; unsigned int lanes; + + unsigned long rates[DP_MAX_SUPPORTED_RATES]; + unsigned int num_rates; };
+int drm_dp_link_add_rate(struct drm_dp_link *link, unsigned long rate); +int drm_dp_link_remove_rate(struct drm_dp_link *link, unsigned long rate); +void drm_dp_link_update_rates(struct drm_dp_link *link); + int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link); int drm_dp_link_power_up(struct drm_dp_aux *aux, struct drm_dp_link *link); int drm_dp_link_power_down(struct drm_dp_aux *aux, struct drm_dp_link *link);