From: Thierry Reding <treding@xxxxxxxxxx>
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
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);
--
2.22.0
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