drm: bridge: cdns-mhdp8546: Enable HDCP

This patch enable HDCP in MHDP driver.

Signed-off-by: Parshuram Thombare <[e-mail]>
Reviewed-by: Robert Foss <[e-mail]>
Signed-off-by: Robert Foss <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/bridge/cadence/Makefile

···
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_DRM_CDNS_MHDP8546) += cdns-mhdp8546.o
-cdns-mhdp8546-y := cdns-mhdp8546-core.o
+cdns-mhdp8546-y := cdns-mhdp8546-core.o cdns-mhdp8546-hdcp.o
 cdns-mhdp8546-$(CONFIG_DRM_CDNS_MHDP8546_J721E) += cdns-mhdp8546-j721e.o

drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c

···
 #include <drm/drm_connector.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_dp_helper.h>
+#include <drm/drm_hdcp.h>
 #include <drm/drm_modeset_helper_vtables.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
···
 #include <asm/unaligned.h>
 
 #include "cdns-mhdp8546-core.h"
-
+#include "cdns-mhdp8546-hdcp.h"
 #include "cdns-mhdp8546-j721e.h"
 
 static int cdns_mhdp_mailbox_read(struct cdns_mhdp_device *mhdp)
···
 	return MODE_OK;
 }
 
+static int cdns_mhdp_connector_atomic_check(struct drm_connector *conn,
+					    struct drm_atomic_state *state)
+{
+	struct cdns_mhdp_device *mhdp = connector_to_mhdp(conn);
+	struct drm_connector_state *old_state, *new_state;
+	struct drm_crtc_state *crtc_state;
+	u64 old_cp, new_cp;
+
+	if (!mhdp->hdcp_supported)
+		return 0;
+
+	old_state = drm_atomic_get_old_connector_state(state, conn);
+	new_state = drm_atomic_get_new_connector_state(state, conn);
+	old_cp = old_state->content_protection;
+	new_cp = new_state->content_protection;
+
+	if (old_state->hdcp_content_type != new_state->hdcp_content_type &&
+	    new_cp != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
+		new_state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;
+		goto mode_changed;
+	}
+
+	if (!new_state->crtc) {
+		if (old_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED)
+			new_state->content_protection = DRM_MODE_CONTENT_PROTECTION_DESIRED;
+		return 0;
+	}
+
+	if (old_cp == new_cp ||
+	    (old_cp == DRM_MODE_CONTENT_PROTECTION_DESIRED &&
+	     new_cp == DRM_MODE_CONTENT_PROTECTION_ENABLED))
+		return 0;
+
+mode_changed:
+	crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
+	crtc_state->mode_changed = true;
+
+	return 0;
+}
+
 static const struct drm_connector_helper_funcs cdns_mhdp_conn_helper_funcs = {
 	.detect_ctx = cdns_mhdp_connector_detect,
 	.get_modes = cdns_mhdp_get_modes,
 	.mode_valid = cdns_mhdp_mode_valid,
+	.atomic_check = cdns_mhdp_connector_atomic_check,
 };
 
 static const struct drm_connector_funcs cdns_mhdp_conn_funcs = {
···
 		return ret;
 	}
 
-	return 0;
+	if (mhdp->hdcp_supported)
+		ret = drm_connector_attach_content_protection_property(conn, true);
+
+	return ret;
 }
 
 static int cdns_mhdp_attach(struct drm_bridge *bridge,
···
 	if (WARN_ON(!conn_state))
 		goto out;
 
+	if (mhdp->hdcp_supported &&
+	    mhdp->hw_state == MHDP_HW_READY &&
+	    conn_state->content_protection ==
+	    DRM_MODE_CONTENT_PROTECTION_DESIRED) {
+		mutex_unlock(&mhdp->link_mutex);
+		cdns_mhdp_hdcp_enable(mhdp, conn_state->hdcp_content_type);
+		mutex_lock(&mhdp->link_mutex);
+	}
+
 	crtc_state = drm_atomic_get_new_crtc_state(state, conn_state->crtc);
 	if (WARN_ON(!crtc_state))
 		goto out;
···
 	dev_dbg(mhdp->dev, "%s\n", __func__);
 
 	mutex_lock(&mhdp->link_mutex);
+
+	if (mhdp->hdcp_supported)
+		cdns_mhdp_hdcp_disable(mhdp);
 
 	mhdp->bridge_enabled = false;
 	cdns_mhdp_reg_read(mhdp, CDNS_DP_FRAMER_GLOBAL_CONFIG, &resp);
···
 	struct cdns_mhdp_device *mhdp = data;
 	u32 apb_stat, sw_ev0;
 	bool bridge_attached;
-	int ret;
 
 	apb_stat = readl(mhdp->regs + CDNS_APB_INT_STATUS);
 	if (!(apb_stat & CDNS_APB_INT_MASK_SW_EVENT_INT))
···
 	spin_unlock(&mhdp->start_lock);
 
 	if (bridge_attached && (sw_ev0 & CDNS_DPTX_HPD)) {
-		ret = cdns_mhdp_update_link_status(mhdp);
-		if (mhdp->connector.dev) {
-			if (ret < 0)
-				schedule_work(&mhdp->modeset_retry_work);
-			else
-				drm_kms_helper_hotplug_event(mhdp->bridge.dev);
-		} else {
-			drm_bridge_hpd_notify(&mhdp->bridge, cdns_mhdp_detect(mhdp));
-		}
+		schedule_work(&mhdp->hpd_work);
+	}
+
+	if (sw_ev0 & ~CDNS_DPTX_HPD) {
+		mhdp->sw_events |= (sw_ev0 & ~CDNS_DPTX_HPD);
+		wake_up(&mhdp->sw_events_wq);
 	}
 
 	return IRQ_HANDLED;
+}
+
+u32 cdns_mhdp_wait_for_sw_event(struct cdns_mhdp_device *mhdp, u32 event)
+{
+	u32 ret;
+
+	ret = wait_event_timeout(mhdp->sw_events_wq,
+				 mhdp->sw_events & event,
+				 msecs_to_jiffies(500));
+	if (!ret) {
+		dev_dbg(mhdp->dev, "SW event 0x%x timeout\n", event);
+		goto sw_event_out;
+	}
+
+	ret = mhdp->sw_events;
+	mhdp->sw_events &= ~event;
+
+sw_event_out:
+	return ret;
+}
+
+static void cdns_mhdp_hpd_work(struct work_struct *work)
+{
+	struct cdns_mhdp_device *mhdp = container_of(work,
+						     struct cdns_mhdp_device,
+						     hpd_work);
+	int ret;
+
+	ret = cdns_mhdp_update_link_status(mhdp);
+	if (mhdp->connector.dev) {
+		if (ret < 0)
+			schedule_work(&mhdp->modeset_retry_work);
+		else
+			drm_kms_helper_hotplug_event(mhdp->bridge.dev);
+	} else {
+		drm_bridge_hpd_notify(&mhdp->bridge, cdns_mhdp_detect(mhdp));
+	}
 }
 
 static int cdns_mhdp_probe(struct platform_device *pdev)
···
 	if (IS_ERR(mhdp->regs)) {
 		dev_err(dev, "Failed to get memory resource\n");
 		return PTR_ERR(mhdp->regs);
+	}
+
+	mhdp->sapb_regs = devm_platform_ioremap_resource_byname(pdev, "mhdptx-sapb");
+	if (IS_ERR(mhdp->sapb_regs)) {
+		mhdp->hdcp_supported = false;
+		dev_warn(dev,
+			 "Failed to get SAPB memory resource, HDCP not supported\n");
+	} else {
+		mhdp->hdcp_supported = true;
 	}
 
 	mhdp->phy = devm_of_phy_get_by_index(dev, pdev->dev.of_node, 0);
···
 
 	/* Initialize the work for modeset in case of link train failure */
 	INIT_WORK(&mhdp->modeset_retry_work, cdns_mhdp_modeset_retry_fn);
+	INIT_WORK(&mhdp->hpd_work, cdns_mhdp_hpd_work);
 
 	init_waitqueue_head(&mhdp->fw_load_wq);
+	init_waitqueue_head(&mhdp->sw_events_wq);
 
 	ret = cdns_mhdp_load_firmware(mhdp);
 	if (ret)
 		goto phy_exit;
+
+	if (mhdp->hdcp_supported)
+		cdns_mhdp_hdcp_init(mhdp);
 
 	drm_bridge_add(&mhdp->bridge);
 

drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.h

···
 
 #define CDNS_SW_EVENT0				0x00044
 #define CDNS_DPTX_HPD				BIT(0)
+#define CDNS_HDCP_TX_STATUS			BIT(4)
+#define CDNS_HDCP2_TX_IS_KM_STORED		BIT(5)
+#define CDNS_HDCP2_TX_STORE_KM			BIT(6)
+#define CDNS_HDCP_TX_IS_RCVR_ID_VALID		BIT(7)
 
 #define CDNS_SW_EVENT1				0x00048
 #define CDNS_SW_EVENT2				0x0004c
···
 #define to_cdns_mhdp_bridge_state(s) \
 		container_of(s, struct cdns_mhdp_bridge_state, base)
 
+struct cdns_mhdp_hdcp {
+	struct delayed_work check_work;
+	struct work_struct prop_work;
+	struct mutex mutex; /* mutex to protect hdcp.value */
+	u32 value;
+	u8 hdcp_content_type;
+};
+
 struct cdns_mhdp_device {
 	void __iomem *regs;
+	void __iomem *sapb_regs;
 	void __iomem *j721e_regs;
 
 	struct device *dev;
···
 
 	/* Work struct to schedule a uevent on link train failure */
 	struct work_struct modeset_retry_work;
+	struct work_struct hpd_work;
+
+	wait_queue_head_t sw_events_wq;
+	u32 sw_events;
+
+	struct cdns_mhdp_hdcp hdcp;
+	bool hdcp_supported;
 };
 
 #define connector_to_mhdp(x) container_of(x, struct cdns_mhdp_device, connector)
 #define bridge_to_mhdp(x) container_of(x, struct cdns_mhdp_device, bridge)
+
+u32 cdns_mhdp_wait_for_sw_event(struct cdns_mhdp_device *mhdp, uint32_t event);
 
 #endif

drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence MHDP8546 DP bridge driver.
+ *
+ * Copyright (C) 2020 Cadence Design Systems, Inc.
+ *
+ */
+
+#include <linux/io.h>
+#include <linux/iopoll.h>
+
+#include <asm/unaligned.h>
+
+#include <drm/drm_hdcp.h>
+
+#include "cdns-mhdp8546-hdcp.h"
+
+static int cdns_mhdp_secure_mailbox_read(struct cdns_mhdp_device *mhdp)
+{
+	int ret, empty;
+
+	WARN_ON(!mutex_is_locked(&mhdp->mbox_mutex));
+
+	ret = readx_poll_timeout(readl, mhdp->sapb_regs + CDNS_MAILBOX_EMPTY,
+				 empty, !empty, MAILBOX_RETRY_US,
+				 MAILBOX_TIMEOUT_US);
+	if (ret < 0)
+		return ret;
+
+	return readl(mhdp->sapb_regs + CDNS_MAILBOX_RX_DATA) & 0xff;
+}
+
+static int cdns_mhdp_secure_mailbox_write(struct cdns_mhdp_device *mhdp,
+					  u8 val)
+{
+	int ret, full;
+
+	WARN_ON(!mutex_is_locked(&mhdp->mbox_mutex));
+
+	ret = readx_poll_timeout(readl, mhdp->sapb_regs + CDNS_MAILBOX_FULL,
+				 full, !full, MAILBOX_RETRY_US,
+				 MAILBOX_TIMEOUT_US);
+	if (ret < 0)
+		return ret;
+
+	writel(val, mhdp->sapb_regs + CDNS_MAILBOX_TX_DATA);
+
+	return 0;
+}
+
+static int cdns_mhdp_secure_mailbox_recv_header(struct cdns_mhdp_device *mhdp,
+						u8 module_id,
+						u8 opcode,
+						u16 req_size)
+{
+	u32 mbox_size, i;
+	u8 header[4];
+	int ret;
+
+	/* read the header of the message */
+	for (i = 0; i < sizeof(header); i++) {
+		ret = cdns_mhdp_secure_mailbox_read(mhdp);
+		if (ret < 0)
+			return ret;
+
+		header[i] = ret;
+	}
+
+	mbox_size = get_unaligned_be16(header + 2);
+
+	if (opcode != header[0] || module_id != header[1] ||
+	    (opcode != HDCP_TRAN_IS_REC_ID_VALID && req_size != mbox_size)) {
+		for (i = 0; i < mbox_size; i++)
+			if (cdns_mhdp_secure_mailbox_read(mhdp) < 0)
+				break;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int cdns_mhdp_secure_mailbox_recv_data(struct cdns_mhdp_device *mhdp,
+					      u8 *buff, u16 buff_size)
+{
+	int ret;
+	u32 i;
+
+	for (i = 0; i < buff_size; i++) {
+		ret = cdns_mhdp_secure_mailbox_read(mhdp);
+		if (ret < 0)
+			return ret;
+
+		buff[i] = ret;
+	}
+
+	return 0;
+}
+
+static int cdns_mhdp_secure_mailbox_send(struct cdns_mhdp_device *mhdp,
+					 u8 module_id,
+					 u8 opcode,
+					 u16 size,
+					 u8 *message)
+{
+	u8 header[4];
+	int ret;
+	u32 i;
+
+	header[0] = opcode;
+	header[1] = module_id;
+	put_unaligned_be16(size, header + 2);
+
+	for (i = 0; i < sizeof(header); i++) {
+		ret = cdns_mhdp_secure_mailbox_write(mhdp, header[i]);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < size; i++) {
+		ret = cdns_mhdp_secure_mailbox_write(mhdp, message[i]);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int cdns_mhdp_hdcp_get_status(struct cdns_mhdp_device *mhdp,
+				     u16 *hdcp_port_status)
+{
+	u8 hdcp_status[HDCP_STATUS_SIZE];
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+	ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
+					    HDCP_TRAN_STATUS_CHANGE, 0, NULL);
+	if (ret)
+		goto err_get_hdcp_status;
+
+	ret = cdns_mhdp_secure_mailbox_recv_header(mhdp, MB_MODULE_ID_HDCP_TX,
+						   HDCP_TRAN_STATUS_CHANGE,
+						   sizeof(hdcp_status));
+	if (ret)
+		goto err_get_hdcp_status;
+
+	ret = cdns_mhdp_secure_mailbox_recv_data(mhdp, hdcp_status,
+						 sizeof(hdcp_status));
+	if (ret)
+		goto err_get_hdcp_status;
+
+	*hdcp_port_status = ((u16)(hdcp_status[0] << 8) | hdcp_status[1]);
+
+err_get_hdcp_status:
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static u8 cdns_mhdp_hdcp_handle_status(struct cdns_mhdp_device *mhdp,
+				       u16 status)
+{
+	u8 err = GET_HDCP_PORT_STS_LAST_ERR(status);
+
+	if (err)
+		dev_dbg(mhdp->dev, "HDCP Error = %d", err);
+
+	return err;
+}
+
+static int cdns_mhdp_hdcp_rx_id_valid_response(struct cdns_mhdp_device *mhdp,
+					       u8 valid)
+{
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+	ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
+					    HDCP_TRAN_RESPOND_RECEIVER_ID_VALID,
+					    1, &valid);
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static int cdns_mhdp_hdcp_rx_id_valid(struct cdns_mhdp_device *mhdp,
+				      u8 *recv_num, u8 *hdcp_rx_id)
+{
+	u8 rec_id_hdr[2];
+	u8 status;
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+	ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
+					    HDCP_TRAN_IS_REC_ID_VALID, 0, NULL);
+	if (ret)
+		goto err_rx_id_valid;
+
+	ret = cdns_mhdp_secure_mailbox_recv_header(mhdp, MB_MODULE_ID_HDCP_TX,
+						   HDCP_TRAN_IS_REC_ID_VALID,
+						   sizeof(status));
+	if (ret)
+		goto err_rx_id_valid;
+
+	ret = cdns_mhdp_secure_mailbox_recv_data(mhdp, rec_id_hdr, 2);
+	if (ret)
+		goto err_rx_id_valid;
+
+	*recv_num = rec_id_hdr[0];
+
+	ret = cdns_mhdp_secure_mailbox_recv_data(mhdp, hdcp_rx_id, 5 * *recv_num);
+
+err_rx_id_valid:
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static int cdns_mhdp_hdcp_km_stored_resp(struct cdns_mhdp_device *mhdp,
+					 u32 size, u8 *km)
+{
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+	ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
+					    HDCP2X_TX_RESPOND_KM, size, km);
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static int cdns_mhdp_hdcp_tx_is_km_stored(struct cdns_mhdp_device *mhdp,
+					  u8 *resp, u32 size)
+{
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+	ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
+					    HDCP2X_TX_IS_KM_STORED, 0, NULL);
+	if (ret)
+		goto err_is_km_stored;
+
+	ret = cdns_mhdp_secure_mailbox_recv_header(mhdp, MB_MODULE_ID_HDCP_TX,
+						   HDCP2X_TX_IS_KM_STORED,
+						   size);
+	if (ret)
+		goto err_is_km_stored;
+
+	ret = cdns_mhdp_secure_mailbox_recv_data(mhdp, resp, size);
+err_is_km_stored:
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static int cdns_mhdp_hdcp_tx_config(struct cdns_mhdp_device *mhdp,
+				    u8 hdcp_cfg)
+{
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+	ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
+					    HDCP_TRAN_CONFIGURATION, 1, &hdcp_cfg);
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static int cdns_mhdp_hdcp_set_config(struct cdns_mhdp_device *mhdp,
+				     u8 hdcp_config, bool enable)
+{
+	u16 hdcp_port_status;
+	u32 ret_event;
+	u8 hdcp_cfg;
+	int ret;
+
+	hdcp_cfg = hdcp_config | (enable ? 0x04 : 0) |
+		   (HDCP_CONTENT_TYPE_0 << 3);
+	cdns_mhdp_hdcp_tx_config(mhdp, hdcp_cfg);
+	ret_event = cdns_mhdp_wait_for_sw_event(mhdp, CDNS_HDCP_TX_STATUS);
+	if (!ret_event)
+		return -1;
+
+	ret = cdns_mhdp_hdcp_get_status(mhdp, &hdcp_port_status);
+	if (ret || cdns_mhdp_hdcp_handle_status(mhdp, hdcp_port_status))
+		return -1;
+
+	return 0;
+}
+
+static int cdns_mhdp_hdcp_auth_check(struct cdns_mhdp_device *mhdp)
+{
+	u16 hdcp_port_status;
+	u32 ret_event;
+	int ret;
+
+	ret_event = cdns_mhdp_wait_for_sw_event(mhdp, CDNS_HDCP_TX_STATUS);
+	if (!ret_event)
+		return -1;
+
+	ret = cdns_mhdp_hdcp_get_status(mhdp, &hdcp_port_status);
+	if (ret || cdns_mhdp_hdcp_handle_status(mhdp, hdcp_port_status))
+		return -1;
+
+	if (hdcp_port_status & 1) {
+		dev_dbg(mhdp->dev, "Authentication completed successfully!\n");
+		return 0;
+	}
+
+	dev_dbg(mhdp->dev, "Authentication failed\n");
+
+	return -1;
+}
+
+static int cdns_mhdp_hdcp_check_receviers(struct cdns_mhdp_device *mhdp)
+{
+	u8 hdcp_rec_id[HDCP_MAX_RECEIVERS][HDCP_RECEIVER_ID_SIZE_BYTES];
+	u8 hdcp_num_rec;
+	u32 ret_event;
+
+	ret_event = cdns_mhdp_wait_for_sw_event(mhdp,
+						CDNS_HDCP_TX_IS_RCVR_ID_VALID);
+	if (!ret_event)
+		return -1;
+
+	hdcp_num_rec = 0;
+	memset(&hdcp_rec_id, 0, sizeof(hdcp_rec_id));
+	cdns_mhdp_hdcp_rx_id_valid(mhdp, &hdcp_num_rec, (u8 *)hdcp_rec_id);
+	cdns_mhdp_hdcp_rx_id_valid_response(mhdp, 1);
+
+	return 0;
+}
+
+static int cdns_mhdp_hdcp_auth_22(struct cdns_mhdp_device *mhdp)
+{
+	u8 resp[HDCP_STATUS_SIZE];
+	u16 hdcp_port_status;
+	u32 ret_event;
+	int ret;
+
+	dev_dbg(mhdp->dev, "HDCP: Start 2.2 Authentication\n");
+	ret_event = cdns_mhdp_wait_for_sw_event(mhdp,
+						CDNS_HDCP2_TX_IS_KM_STORED);
+	if (!ret_event)
+		return -1;
+
+	if (ret_event & CDNS_HDCP_TX_STATUS) {
+		mhdp->sw_events &= ~CDNS_HDCP_TX_STATUS;
+		ret = cdns_mhdp_hdcp_get_status(mhdp, &hdcp_port_status);
+		if (ret || cdns_mhdp_hdcp_handle_status(mhdp, hdcp_port_status))
+			return -1;
+	}
+
+	cdns_mhdp_hdcp_tx_is_km_stored(mhdp, resp, sizeof(resp));
+	cdns_mhdp_hdcp_km_stored_resp(mhdp, 0, NULL);
+
+	if (cdns_mhdp_hdcp_check_receviers(mhdp))
+		return -1;
+
+	return 0;
+}
+
+static inline int cdns_mhdp_hdcp_auth_14(struct cdns_mhdp_device *mhdp)
+{
+	dev_dbg(mhdp->dev, "HDCP: Starting 1.4 Authentication\n");
+	return cdns_mhdp_hdcp_check_receviers(mhdp);
+}
+
+static int cdns_mhdp_hdcp_auth(struct cdns_mhdp_device *mhdp,
+			       u8 hdcp_config)
+{
+	int ret;
+
+	ret = cdns_mhdp_hdcp_set_config(mhdp, hdcp_config, true);
+	if (ret)
+		goto auth_failed;
+
+	if (hdcp_config == HDCP_TX_1)
+		ret = cdns_mhdp_hdcp_auth_14(mhdp);
+	else
+		ret = cdns_mhdp_hdcp_auth_22(mhdp);
+
+	if (ret)
+		goto auth_failed;
+
+	ret = cdns_mhdp_hdcp_auth_check(mhdp);
+	if (ret)
+		ret = cdns_mhdp_hdcp_auth_check(mhdp);
+
+auth_failed:
+	return ret;
+}
+
+static int _cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp)
+{
+	int ret;
+
+	dev_dbg(mhdp->dev, "[%s:%d] HDCP is being disabled...\n",
+		mhdp->connector.name, mhdp->connector.base.id);
+
+	ret = cdns_mhdp_hdcp_set_config(mhdp, 0, false);
+
+	return ret;
+}
+
+static int _cdns_mhdp_hdcp_enable(struct cdns_mhdp_device *mhdp, u8 content_type)
+{
+	int ret, tries = 3;
+	u32 i;
+
+	for (i = 0; i < tries; i++) {
+		if (content_type == DRM_MODE_HDCP_CONTENT_TYPE0 ||
+		    content_type == DRM_MODE_HDCP_CONTENT_TYPE1) {
+			ret = cdns_mhdp_hdcp_auth(mhdp, HDCP_TX_2);
+			if (!ret)
+				return 0;
+			_cdns_mhdp_hdcp_disable(mhdp);
+		}
+
+		if (content_type == DRM_MODE_HDCP_CONTENT_TYPE0) {
+			ret = cdns_mhdp_hdcp_auth(mhdp, HDCP_TX_1);
+			if (!ret)
+				return 0;
+			_cdns_mhdp_hdcp_disable(mhdp);
+		}
+	}
+
+	dev_err(mhdp->dev, "HDCP authentication failed (%d tries/%d)\n",
+		tries, ret);
+
+	return ret;
+}
+
+static int cdns_mhdp_hdcp_check_link(struct cdns_mhdp_device *mhdp)
+{
+	u16 hdcp_port_status;
+	int ret = 0;
+
+	mutex_lock(&mhdp->hdcp.mutex);
+	if (mhdp->hdcp.value == DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
+		goto out;
+
+	ret = cdns_mhdp_hdcp_get_status(mhdp, &hdcp_port_status);
+	if (!ret && hdcp_port_status & HDCP_PORT_STS_AUTH)
+		goto out;
+
+	dev_err(mhdp->dev,
+		"[%s:%d] HDCP link failed, retrying authentication\n",
+		mhdp->connector.name, mhdp->connector.base.id);
+
+	ret = _cdns_mhdp_hdcp_disable(mhdp);
+	if (ret) {
+		mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
+		schedule_work(&mhdp->hdcp.prop_work);
+		goto out;
+	}
+
+	ret = _cdns_mhdp_hdcp_enable(mhdp, mhdp->hdcp.hdcp_content_type);
+	if (ret) {
+		mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
+		schedule_work(&mhdp->hdcp.prop_work);
+	}
+out:
+	mutex_unlock(&mhdp->hdcp.mutex);
+	return ret;
+}
+
+static void cdns_mhdp_hdcp_check_work(struct work_struct *work)
+{
+	struct delayed_work *d_work = to_delayed_work(work);
+	struct cdns_mhdp_hdcp *hdcp = container_of(d_work,
+						   struct cdns_mhdp_hdcp,
+						   check_work);
+	struct cdns_mhdp_device *mhdp = container_of(hdcp,
+						     struct cdns_mhdp_device,
+						     hdcp);
+
+	if (!cdns_mhdp_hdcp_check_link(mhdp))
+		schedule_delayed_work(&hdcp->check_work,
+				      DRM_HDCP_CHECK_PERIOD_MS);
+}
+
+static void cdns_mhdp_hdcp_prop_work(struct work_struct *work)
+{
+	struct cdns_mhdp_hdcp *hdcp = container_of(work,
+						   struct cdns_mhdp_hdcp,
+						   prop_work);
+	struct cdns_mhdp_device *mhdp = container_of(hdcp,
+						     struct cdns_mhdp_device,
+						     hdcp);
+	struct drm_device *dev = mhdp->connector.dev;
+	struct drm_connector_state *state;
+
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+	mutex_lock(&mhdp->hdcp.mutex);
+	if (mhdp->hdcp.value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
+		state = mhdp->connector.state;
+		state->content_protection = mhdp->hdcp.value;
+	}
+	mutex_unlock(&mhdp->hdcp.mutex);
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
+}
+
+int cdns_mhdp_hdcp_set_lc(struct cdns_mhdp_device *mhdp, u8 *val)
+{
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+	ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_GENERAL,
+					    HDCP_GENERAL_SET_LC_128,
+					    16, val);
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+int
+cdns_mhdp_hdcp_set_public_key_param(struct cdns_mhdp_device *mhdp,
+				    struct cdns_hdcp_tx_public_key_param *val)
+{
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+	ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
+					    HDCP2X_TX_SET_PUBLIC_KEY_PARAMS,
+					    sizeof(*val), (u8 *)val);
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+int cdns_mhdp_hdcp_enable(struct cdns_mhdp_device *mhdp, u8 content_type)
+{
+	int ret;
+
+	mutex_lock(&mhdp->hdcp.mutex);
+	ret = _cdns_mhdp_hdcp_enable(mhdp, content_type);
+	if (ret)
+		goto out;
+
+	mhdp->hdcp.hdcp_content_type = content_type;
+	mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_ENABLED;
+	schedule_work(&mhdp->hdcp.prop_work);
+	schedule_delayed_work(&mhdp->hdcp.check_work,
+			      DRM_HDCP_CHECK_PERIOD_MS);
+out:
+	mutex_unlock(&mhdp->hdcp.mutex);
+	return ret;
+}
+
+int cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp)
+{
+	int ret = 0;
+
+	mutex_lock(&mhdp->hdcp.mutex);
+	if (mhdp->hdcp.value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
+		mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
+		schedule_work(&mhdp->hdcp.prop_work);
+		ret = _cdns_mhdp_hdcp_disable(mhdp);
+	}
+	mutex_unlock(&mhdp->hdcp.mutex);
+	cancel_delayed_work_sync(&mhdp->hdcp.check_work);
+
+	return ret;
+}
+
+void cdns_mhdp_hdcp_init(struct cdns_mhdp_device *mhdp)
+{
+	INIT_DELAYED_WORK(&mhdp->hdcp.check_work, cdns_mhdp_hdcp_check_work);
+	INIT_WORK(&mhdp->hdcp.prop_work, cdns_mhdp_hdcp_prop_work);
+	mutex_init(&mhdp->hdcp.mutex);
+}

drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-hdcp.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence MHDP8546 DP bridge driver.
+ *
+ * Copyright (C) 2020 Cadence Design Systems, Inc.
+ *
+ */
+
+#ifndef CDNS_MHDP8546_HDCP_H
+#define CDNS_MHDP8546_HDCP_H
+
+#include "cdns-mhdp8546-core.h"
+
+#define HDCP_MAX_RECEIVERS 32
+#define HDCP_RECEIVER_ID_SIZE_BYTES 5
+#define HDCP_STATUS_SIZE         0x5
+#define HDCP_PORT_STS_AUTH       0x1
+#define HDCP_PORT_STS_LAST_ERR_SHIFT 0x5
+#define HDCP_PORT_STS_LAST_ERR_MASK  (0x0F << 5)
+#define GET_HDCP_PORT_STS_LAST_ERR(__sts__) \
+	(((__sts__) & HDCP_PORT_STS_LAST_ERR_MASK) >> \
+	HDCP_PORT_STS_LAST_ERR_SHIFT)
+
+#define HDCP_CONFIG_1_4     BIT(0) /* use HDCP 1.4 only */
+#define HDCP_CONFIG_2_2     BIT(1) /* use HDCP 2.2 only */
+/* use All HDCP versions */
+#define HDCP_CONFIG_ALL     (BIT(0) | BIT(1))
+#define HDCP_CONFIG_NONE    0
+
+enum {
+	HDCP_GENERAL_SET_LC_128,
+	HDCP_SET_SEED,
+};
+
+enum {
+	HDCP_TRAN_CONFIGURATION,
+	HDCP2X_TX_SET_PUBLIC_KEY_PARAMS,
+	HDCP2X_TX_SET_DEBUG_RANDOM_NUMBERS,
+	HDCP2X_TX_RESPOND_KM,
+	HDCP1_TX_SEND_KEYS,
+	HDCP1_TX_SEND_RANDOM_AN,
+	HDCP_TRAN_STATUS_CHANGE,
+	HDCP2X_TX_IS_KM_STORED,
+	HDCP2X_TX_STORE_KM,
+	HDCP_TRAN_IS_REC_ID_VALID,
+	HDCP_TRAN_RESPOND_RECEIVER_ID_VALID,
+	HDCP_TRAN_TEST_KEYS,
+	HDCP2X_TX_SET_KM_KEY_PARAMS,
+	HDCP_NUM_OF_SUPPORTED_MESSAGES
+};
+
+enum {
+	HDCP_CONTENT_TYPE_0,
+	HDCP_CONTENT_TYPE_1,
+};
+
+#define DRM_HDCP_CHECK_PERIOD_MS (128 * 16)
+
+#define HDCP_PAIRING_R_ID 5
+#define HDCP_PAIRING_M_LEN 16
+#define HDCP_KM_LEN 16
+#define HDCP_PAIRING_M_EKH 16
+
+struct cdns_hdcp_pairing_data {
+	u8 receiver_id[HDCP_PAIRING_R_ID];
+	u8 m[HDCP_PAIRING_M_LEN];
+	u8 km[HDCP_KM_LEN];
+	u8 ekh[HDCP_PAIRING_M_EKH];
+};
+
+enum {
+	HDCP_TX_2,
+	HDCP_TX_1,
+	HDCP_TX_BOTH,
+};
+
+#define DLP_MODULUS_N 384
+#define DLP_E 3
+
+struct cdns_hdcp_tx_public_key_param {
+	u8 N[DLP_MODULUS_N];
+	u8 E[DLP_E];
+};
+
+int cdns_mhdp_hdcp_set_public_key_param(struct cdns_mhdp_device *mhdp,
+					struct cdns_hdcp_tx_public_key_param *val);
+int cdns_mhdp_hdcp_set_lc(struct cdns_mhdp_device *mhdp, u8 *val);
+int cdns_mhdp_hdcp_enable(struct cdns_mhdp_device *mhdp, u8 content_type);
+int cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp);
+void cdns_mhdp_hdcp_init(struct cdns_mhdp_device *mhdp);
+
+#endif