[PATCH v3 2/3] Subject: [PATCH] drm/mediatek/dp: Add HDCP2.x feature for DisplayPort

[CK Hu (胡俊光)]

Hi, Mac:

On Sat, 2024-06-08 at 20:01 +0800, mac.shen wrote:
> Changes in v3:
> - refine the function to get system time
> - refine the flow to do HDCP with content type and
>   protection value which set by user space
> - refine the flow to update content protection
> - refine the flow to do HDCP2.x authentication
> per suggestion from the previous thread:
> https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek__;!!CTRNKA9wMg0ARbw!md6xUiYN88D2YmETs8FQgaExM2zH8S1SmAEU9GRchwpNsXOyDFul3ziVKhRpCJaj8Rcn-gvM-801runjwA$ 
> /patch/20240205055055.25340-3-mac.shen at mediatek.com/
> 
> Signed-off-by: mac.shen <mac.shen at mediatek.com>
> ---

[snip]

> +
> +int dp_tx_hdcp2x_check_link(struct mtk_hdcp_info *hdcp_info)
> +{
> +	struct mtk_dp *mtk_dp = container_of(hdcp_info, struct mtk_dp, hdcp_info);
> +	u8 rx_status;
> +	int ret = -EINVAL;
> +	int tmp = 0;
> +
> +	mutex_lock(&mtk_dp->hdcp_mutex);
> +
> +	if (mtk_dp->hdcp_info.auth_status != AUTH_PASS)
> +		goto end;
> +
> +	if (!mtk_dp->train_info.cable_plugged_in || !mtk_dp->enabled)
> +		goto disable;
> +
> +	ret = drm_dp_dpcd_read(&mtk_dp->aux, DP_HDCP_2_2_REG_RXSTATUS_OFFSET, &rx_status,
> +			       HDCP_2_2_DP_RXSTATUS_LEN);
> +	if (ret != HDCP_2_2_DP_RXSTATUS_LEN) {
> +		dev_dbg(mtk_dp->dev, "[HDCP2.X] Read bstatus failed, reauth\n");
> +		goto disable;
> +	}
> +
> +	if (HDCP_2_2_DP_RXSTATUS_REAUTH_REQ(rx_status))
> +		tmp = REAUTH_REQUEST;
> +	else if (HDCP_2_2_DP_RXSTATUS_LINK_FAILED(rx_status))
> +		tmp = LINK_INTEGRITY_FAILURE;
> +	else if (HDCP_2_2_DP_RXSTATUS_READY(rx_status))
> +		tmp = TOPOLOGY_CHANGE;
> +
> +	if (tmp == LINK_PROTECTED) {
> +		mtk_dp_hdcp_update_value(mtk_dp, DRM_MODE_CONTENT_PROTECTION_ENABLED);
> +		ret = 0;
> +		goto end;
> +	}
> +
> +	if (tmp == TOPOLOGY_CHANGE) {
> +		ret = dp_tx_hdcp2x_authenticate_repeater(hdcp_info);
> +		if (!ret) {
> +			mtk_dp_hdcp_update_value(mtk_dp, DRM_MODE_CONTENT_PROTECTION_ENABLED);
> +			goto end;
> +		}
> +	} else {
> +		dev_info(mtk_dp->dev, "[HDCP2.X] link failed with:0x%x, retrying auth\n", tmp);
> +	}
> +
> +disable:
> +	ret = dp_tx_hdcp2x_disabel(hdcp_info);
> +	if (ret || !mtk_dp->train_info.cable_plugged_in || !mtk_dp->enabled) {
> +		ret = -EAGAIN;
> +		mtk_dp_hdcp_update_value(mtk_dp, DRM_MODE_CONTENT_PROTECTION_DESIRED);
> +		goto end;
> +	}
> +
> +	ret = dp_tx_hdcp2x_enable(hdcp_info);

When something error then go here. Why enable hdcp?

Regards,
CK

> +	if (ret)
> +		mtk_dp_hdcp_update_value(mtk_dp, DRM_MODE_CONTENT_PROTECTION_DESIRED);
> +
> +end:
> +	mutex_unlock(&mtk_dp->hdcp_mutex);
> +
> +	return ret;
> +}
> +