Merge tag 'cdns-mhdp-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux into drm-next

Cadence MHDP8546 DisplayPort bridge driver

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/5dd15e3c-51ed-49c0-cf49-88c7af38d6b0@ti.com

8 files changed, 3060 insertions, 0 deletions

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 3e11af4e9f63..ef91646441b1 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -241,6 +241,8 @@ source "drivers/gpu/drm/bridge/analogix/Kconfig"
 
 source "drivers/gpu/drm/bridge/adv7511/Kconfig"
 
+source "drivers/gpu/drm/bridge/cadence/Kconfig"
+
 source "drivers/gpu/drm/bridge/synopsys/Kconfig"
 
 endmenu
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index c589a6a7cbe1..2b3aff104e46 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -25,4 +25,5 @@ obj-$(CONFIG_DRM_TI_TPD12S015) += ti-tpd12s015.o
 obj-$(CONFIG_DRM_NWL_MIPI_DSI) += nwl-dsi.o
 
 obj-y += analogix/
+obj-y += cadence/
 obj-y += synopsys/
diff --git a/drivers/gpu/drm/bridge/cadence/Kconfig b/drivers/gpu/drm/bridge/cadence/Kconfig
new file mode 100644
index 000000000000..511d67b16d14
--- /dev/null
+++ b/drivers/gpu/drm/bridge/cadence/Kconfig
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config DRM_CDNS_MHDP8546
+	tristate "Cadence DPI/DP bridge"
+	select DRM_KMS_HELPER
+	select DRM_PANEL_BRIDGE
+	depends on OF
+	help
+	  Support Cadence DPI to DP bridge. This is an internal
+	  bridge and is meant to be directly embedded in a SoC.
+	  It takes a DPI stream as input and outputs it encoded
+	  in DP format.
+
+if DRM_CDNS_MHDP8546
+
+config DRM_CDNS_MHDP8546_J721E
+	depends on ARCH_K3_J721E_SOC || COMPILE_TEST
+	bool "J721E Cadence DPI/DP wrapper support"
+	default y
+	help
+	  Support J721E Cadence DPI/DP wrapper. This is a wrapper
+	  which adds support for J721E related platform ops. It
+	  initializes the J721E Display Port and sets up the
+	  clock and data muxes.
+endif
diff --git a/drivers/gpu/drm/bridge/cadence/Makefile b/drivers/gpu/drm/bridge/cadence/Makefile
new file mode 100644
index 000000000000..8f647991b374
--- /dev/null
+++ b/drivers/gpu/drm/bridge/cadence/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_DRM_CDNS_MHDP8546) += cdns-mhdp8546.o
+cdns-mhdp8546-y := cdns-mhdp8546-core.o
+cdns-mhdp8546-$(CONFIG_DRM_CDNS_MHDP8546_J721E) += cdns-mhdp8546-j721e.o
diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
new file mode 100644
index 000000000000..621ebdbff8a3
--- /dev/null
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -0,0 +1,2532 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cadence MHDP8546 DP bridge driver.
+ *
+ * Copyright (C) 2020 Cadence Design Systems, Inc.
+ *
+ * Authors: Quentin Schulz <quentin.schulz@free-electrons.com>
+ *          Swapnil Jakhade <sjakhade@cadence.com>
+ *          Yuti Amonkar <yamonkar@cadence.com>
+ *          Tomi Valkeinen <tomi.valkeinen@ti.com>
+ *          Jyri Sarha <jsarha@ti.com>
+ *
+ * TODO:
+ *     - Implement optimized mailbox communication using mailbox interrupts
+ *     - Add support for power management
+ *     - Add support for features like audio, MST and fast link training
+ *     - Implement request_fw_cancel to handle HW_STATE
+ *     - Fix asynchronous loading of firmware implementation
+ *     - Add DRM helper function for cdns_mhdp_lower_link_rate
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/firmware.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/phy/phy.h>
+#include <linux/phy/phy-dp.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_atomic_state_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_connector.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_dp_helper.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-j721e.h"
+
+static int cdns_mhdp_mailbox_read(struct cdns_mhdp_device *mhdp)
+{
+	int ret, empty;
+
+	WARN_ON(!mutex_is_locked(&mhdp->mbox_mutex));
+
+	ret = readx_poll_timeout(readl, mhdp->regs + CDNS_MAILBOX_EMPTY,
+				 empty, !empty, MAILBOX_RETRY_US,
+				 MAILBOX_TIMEOUT_US);
+	if (ret < 0)
+		return ret;
+
+	return readl(mhdp->regs + CDNS_MAILBOX_RX_DATA) & 0xff;
+}
+
+static int cdns_mhdp_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->regs + CDNS_MAILBOX_FULL,
+				 full, !full, MAILBOX_RETRY_US,
+				 MAILBOX_TIMEOUT_US);
+	if (ret < 0)
+		return ret;
+
+	writel(val, mhdp->regs + CDNS_MAILBOX_TX_DATA);
+
+	return 0;
+}
+
+static int cdns_mhdp_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_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] ||
+	    req_size != mbox_size) {
+		/*
+		 * If the message in mailbox is not what we want, we need to
+		 * clear the mailbox by reading its contents.
+		 */
+		for (i = 0; i < mbox_size; i++)
+			if (cdns_mhdp_mailbox_read(mhdp) < 0)
+				break;
+
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int cdns_mhdp_mailbox_recv_data(struct cdns_mhdp_device *mhdp,
+				       u8 *buff, u16 buff_size)
+{
+	u32 i;
+	int ret;
+
+	for (i = 0; i < buff_size; i++) {
+		ret = cdns_mhdp_mailbox_read(mhdp);
+		if (ret < 0)
+			return ret;
+
+		buff[i] = ret;
+	}
+
+	return 0;
+}
+
+static int cdns_mhdp_mailbox_send(struct cdns_mhdp_device *mhdp, u8 module_id,
+				  u8 opcode, u16 size, u8 *message)
+{
+	u8 header[4];
+	int ret, i;
+
+	header[0] = opcode;
+	header[1] = module_id;
+	put_unaligned_be16(size, header + 2);
+
+	for (i = 0; i < sizeof(header); i++) {
+		ret = cdns_mhdp_mailbox_write(mhdp, header[i]);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < size; i++) {
+		ret = cdns_mhdp_mailbox_write(mhdp, message[i]);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static
+int cdns_mhdp_reg_read(struct cdns_mhdp_device *mhdp, u32 addr, u32 *value)
+{
+	u8 msg[4], resp[8];
+	int ret;
+
+	put_unaligned_be32(addr, msg);
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	ret = cdns_mhdp_mailbox_send(mhdp, MB_MODULE_ID_GENERAL,
+				     GENERAL_REGISTER_READ,
+				     sizeof(msg), msg);
+	if (ret)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_header(mhdp, MB_MODULE_ID_GENERAL,
+					    GENERAL_REGISTER_READ,
+					    sizeof(resp));
+	if (ret)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_data(mhdp, resp, sizeof(resp));
+	if (ret)
+		goto out;
+
+	/* Returned address value should be the same as requested */
+	if (memcmp(msg, resp, sizeof(msg))) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	*value = get_unaligned_be32(resp + 4);
+
+out:
+	mutex_unlock(&mhdp->mbox_mutex);
+	if (ret) {
+		dev_err(mhdp->dev, "Failed to read register\n");
+		*value = 0;
+	}
+
+	return ret;
+}
+
+static
+int cdns_mhdp_reg_write(struct cdns_mhdp_device *mhdp, u16 addr, u32 val)
+{
+	u8 msg[6];
+	int ret;
+
+	put_unaligned_be16(addr, msg);
+	put_unaligned_be32(val, msg + 2);
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	ret = cdns_mhdp_mailbox_send(mhdp, MB_MODULE_ID_DP_TX,
+				     DPTX_WRITE_REGISTER, sizeof(msg), msg);
+
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static
+int cdns_mhdp_reg_write_bit(struct cdns_mhdp_device *mhdp, u16 addr,
+			    u8 start_bit, u8 bits_no, u32 val)
+{
+	u8 field[8];
+	int ret;
+
+	put_unaligned_be16(addr, field);
+	field[2] = start_bit;
+	field[3] = bits_no;
+	put_unaligned_be32(val, field + 4);
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	ret = cdns_mhdp_mailbox_send(mhdp, MB_MODULE_ID_DP_TX,
+				     DPTX_WRITE_FIELD, sizeof(field), field);
+
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static
+int cdns_mhdp_dpcd_read(struct cdns_mhdp_device *mhdp,
+			u32 addr, u8 *data, u16 len)
+{
+	u8 msg[5], reg[5];
+	int ret;
+
+	put_unaligned_be16(len, msg);
+	put_unaligned_be24(addr, msg + 2);
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	ret = cdns_mhdp_mailbox_send(mhdp, MB_MODULE_ID_DP_TX,
+				     DPTX_READ_DPCD, sizeof(msg), msg);
+	if (ret)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_header(mhdp, MB_MODULE_ID_DP_TX,
+					    DPTX_READ_DPCD,
+					    sizeof(reg) + len);
+	if (ret)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_data(mhdp, reg, sizeof(reg));
+	if (ret)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_data(mhdp, data, len);
+
+out:
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static
+int cdns_mhdp_dpcd_write(struct cdns_mhdp_device *mhdp, u32 addr, u8 value)
+{
+	u8 msg[6], reg[5];
+	int ret;
+
+	put_unaligned_be16(1, msg);
+	put_unaligned_be24(addr, msg + 2);
+	msg[5] = value;
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	ret = cdns_mhdp_mailbox_send(mhdp, MB_MODULE_ID_DP_TX,
+				     DPTX_WRITE_DPCD, sizeof(msg), msg);
+	if (ret)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_header(mhdp, MB_MODULE_ID_DP_TX,
+					    DPTX_WRITE_DPCD, sizeof(reg));
+	if (ret)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_data(mhdp, reg, sizeof(reg));
+	if (ret)
+		goto out;
+
+	if (addr != get_unaligned_be24(reg + 2))
+		ret = -EINVAL;
+
+out:
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	if (ret)
+		dev_err(mhdp->dev, "dpcd write failed: %d\n", ret);
+	return ret;
+}
+
+static
+int cdns_mhdp_set_firmware_active(struct cdns_mhdp_device *mhdp, bool enable)
+{
+	u8 msg[5];
+	int ret, i;
+
+	msg[0] = GENERAL_MAIN_CONTROL;
+	msg[1] = MB_MODULE_ID_GENERAL;
+	msg[2] = 0;
+	msg[3] = 1;
+	msg[4] = enable ? FW_ACTIVE : FW_STANDBY;
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	for (i = 0; i < sizeof(msg); i++) {
+		ret = cdns_mhdp_mailbox_write(mhdp, msg[i]);
+		if (ret)
+			goto out;
+	}
+
+	/* read the firmware state */
+	ret = cdns_mhdp_mailbox_recv_data(mhdp, msg, sizeof(msg));
+	if (ret)
+		goto out;
+
+	ret = 0;
+
+out:
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	if (ret < 0)
+		dev_err(mhdp->dev, "set firmware active failed\n");
+	return ret;
+}
+
+static
+int cdns_mhdp_get_hpd_status(struct cdns_mhdp_device *mhdp)
+{
+	u8 status;
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	ret = cdns_mhdp_mailbox_send(mhdp, MB_MODULE_ID_DP_TX,
+				     DPTX_HPD_STATE, 0, NULL);
+	if (ret)
+		goto err_get_hpd;
+
+	ret = cdns_mhdp_mailbox_recv_header(mhdp, MB_MODULE_ID_DP_TX,
+					    DPTX_HPD_STATE,
+					    sizeof(status));
+	if (ret)
+		goto err_get_hpd;
+
+	ret = cdns_mhdp_mailbox_recv_data(mhdp, &status, sizeof(status));
+	if (ret)
+		goto err_get_hpd;
+
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	dev_dbg(mhdp->dev, "%s: HPD %splugged\n", __func__,
+		status ? "" : "un");
+
+	return status;
+
+err_get_hpd:
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	return ret;
+}
+
+static
+int cdns_mhdp_get_edid_block(void *data, u8 *edid,
+			     unsigned int block, size_t length)
+{
+	struct cdns_mhdp_device *mhdp = data;
+	u8 msg[2], reg[2], i;
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	for (i = 0; i < 4; i++) {
+		msg[0] = block / 2;
+		msg[1] = block % 2;
+
+		ret = cdns_mhdp_mailbox_send(mhdp, MB_MODULE_ID_DP_TX,
+					     DPTX_GET_EDID, sizeof(msg), msg);
+		if (ret)
+			continue;
+
+		ret = cdns_mhdp_mailbox_recv_header(mhdp, MB_MODULE_ID_DP_TX,
+						    DPTX_GET_EDID,
+						    sizeof(reg) + length);
+		if (ret)
+			continue;
+
+		ret = cdns_mhdp_mailbox_recv_data(mhdp, reg, sizeof(reg));
+		if (ret)
+			continue;
+
+		ret = cdns_mhdp_mailbox_recv_data(mhdp, edid, length);
+		if (ret)
+			continue;
+
+		if (reg[0] == length && reg[1] == block / 2)
+			break;
+	}
+
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	if (ret)
+		dev_err(mhdp->dev, "get block[%d] edid failed: %d\n",
+			block, ret);
+
+	return ret;
+}
+
+static
+int cdns_mhdp_read_hpd_event(struct cdns_mhdp_device *mhdp)
+{
+	u8 event = 0;
+	int ret;
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	ret = cdns_mhdp_mailbox_send(mhdp, MB_MODULE_ID_DP_TX,
+				     DPTX_READ_EVENT, 0, NULL);
+	if (ret)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_header(mhdp, MB_MODULE_ID_DP_TX,
+					    DPTX_READ_EVENT, sizeof(event));
+	if (ret < 0)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_data(mhdp, &event, sizeof(event));
+out:
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(mhdp->dev, "%s: %s%s%s%s\n", __func__,
+		(event & DPTX_READ_EVENT_HPD_TO_HIGH) ? "TO_HIGH " : "",
+		(event & DPTX_READ_EVENT_HPD_TO_LOW) ? "TO_LOW " : "",
+		(event & DPTX_READ_EVENT_HPD_PULSE) ? "PULSE " : "",
+		(event & DPTX_READ_EVENT_HPD_STATE) ? "HPD_STATE " : "");
+
+	return event;
+}
+
+static
+int cdns_mhdp_adjust_lt(struct cdns_mhdp_device *mhdp, unsigned int nlanes,
+			unsigned int udelay, const u8 *lanes_data,
+			u8 link_status[DP_LINK_STATUS_SIZE])
+{
+	u8 payload[7];
+	u8 hdr[5]; /* For DPCD read response header */
+	u32 addr;
+	int ret;
+
+	if (nlanes != 4 && nlanes != 2 && nlanes != 1) {
+		dev_err(mhdp->dev, "invalid number of lanes: %u\n", nlanes);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	payload[0] = nlanes;
+	put_unaligned_be16(udelay, payload + 1);
+	memcpy(payload + 3, lanes_data, nlanes);
+
+	mutex_lock(&mhdp->mbox_mutex);
+
+	ret = cdns_mhdp_mailbox_send(mhdp, MB_MODULE_ID_DP_TX,
+				     DPTX_ADJUST_LT,
+				     sizeof(payload), payload);
+	if (ret)
+		goto out;
+
+	/* Yes, read the DPCD read command response */
+	ret = cdns_mhdp_mailbox_recv_header(mhdp, MB_MODULE_ID_DP_TX,
+					    DPTX_READ_DPCD,
+					    sizeof(hdr) + DP_LINK_STATUS_SIZE);
+	if (ret)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_data(mhdp, hdr, sizeof(hdr));
+	if (ret)
+		goto out;
+
+	addr = get_unaligned_be24(hdr + 2);
+	if (addr != DP_LANE0_1_STATUS)
+		goto out;
+
+	ret = cdns_mhdp_mailbox_recv_data(mhdp, link_status,
+					  DP_LINK_STATUS_SIZE);
+
+out:
+	mutex_unlock(&mhdp->mbox_mutex);
+
+	if (ret)
+		dev_err(mhdp->dev, "Failed to adjust Link Training.\n");
+
+	return ret;
+}
+
+/**
+ * cdns_mhdp_link_power_up() - power up a DisplayPort link
+ * @aux: DisplayPort AUX channel
+ * @link: pointer to a structure containing the link configuration
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+static
+int cdns_mhdp_link_power_up(struct drm_dp_aux *aux, struct cdns_mhdp_link *link)
+{
+	u8 value;
+	int err;
+
+	/* DP_SET_POWER register is only available on DPCD v1.1 and later */
+	if (link->revision < 0x11)
+		return 0;
+
+	err = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
+	if (err < 0)
+		return err;
+
+	value &= ~DP_SET_POWER_MASK;
+	value |= DP_SET_POWER_D0;
+
+	err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
+	if (err < 0)
+		return err;
+
+	/*
+	 * According to the DP 1.1 specification, a "Sink Device must exit the
+	 * power saving state within 1 ms" (Section 2.5.3.1, Table 5-52, "Sink
+	 * Control Field" (register 0x600).
+	 */
+	usleep_range(1000, 2000);
+
+	return 0;
+}
+
+/**
+ * cdns_mhdp_link_power_down() - power down a DisplayPort link
+ * @aux: DisplayPort AUX channel
+ * @link: pointer to a structure containing the link configuration
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+static
+int cdns_mhdp_link_power_down(struct drm_dp_aux *aux,
+			      struct cdns_mhdp_link *link)
+{
+	u8 value;
+	int err;
+
+	/* DP_SET_POWER register is only available on DPCD v1.1 and later */
+	if (link->revision < 0x11)
+		return 0;
+
+	err = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
+	if (err < 0)
+		return err;
+
+	value &= ~DP_SET_POWER_MASK;
+	value |= DP_SET_POWER_D3;
+
+	err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/**
+ * cdns_mhdp_link_configure() - configure a DisplayPort link
+ * @aux: DisplayPort AUX channel
+ * @link: pointer to a structure containing the link configuration
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+static
+int cdns_mhdp_link_configure(struct drm_dp_aux *aux,
+			     struct cdns_mhdp_link *link)
+{
+	u8 values[2];
+	int err;
+
+	values[0] = drm_dp_link_rate_to_bw_code(link->rate);
+	values[1] = link->num_lanes;
+
+	if (link->capabilities & DP_LINK_CAP_ENHANCED_FRAMING)
+		values[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
+
+	err = drm_dp_dpcd_write(aux, DP_LINK_BW_SET, values, sizeof(values));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static unsigned int cdns_mhdp_max_link_rate(struct cdns_mhdp_device *mhdp)
+{
+	return min(mhdp->host.link_rate, mhdp->sink.link_rate);
+}
+
+static u8 cdns_mhdp_max_num_lanes(struct cdns_mhdp_device *mhdp)
+{
+	return min(mhdp->sink.lanes_cnt, mhdp->host.lanes_cnt);
+}
+
+static u8 cdns_mhdp_eq_training_pattern_supported(struct cdns_mhdp_device *mhdp)
+{
+	return fls(mhdp->host.pattern_supp & mhdp->sink.pattern_supp);
+}
+
+static bool cdns_mhdp_get_ssc_supported(struct cdns_mhdp_device *mhdp)
+{
+	/* Check if SSC is supported by both sides */
+	return mhdp->host.ssc && mhdp->sink.ssc;
+}
+
+static enum drm_connector_status cdns_mhdp_detect(struct cdns_mhdp_device *mhdp)
+{
+	dev_dbg(mhdp->dev, "%s: %d\n", __func__, mhdp->plugged);
+
+	if (mhdp->plugged)
+		return connector_status_connected;
+	else
+		return connector_status_disconnected;
+}
+
+static int cdns_mhdp_check_fw_version(struct cdns_mhdp_device *mhdp)
+{
+	u32 major_num, minor_num, revision;
+	u32 fw_ver, lib_ver;
+
+	fw_ver = (readl(mhdp->regs + CDNS_VER_H) << 8)
+	       | readl(mhdp->regs + CDNS_VER_L);
+
+	lib_ver = (readl(mhdp->regs + CDNS_LIB_H_ADDR) << 8)
+		| readl(mhdp->regs + CDNS_LIB_L_ADDR);
+
+	if (lib_ver < 33984) {
+		/*
+		 * Older FW versions with major number 1, used to store FW
+		 * version information by storing repository revision number
+		 * in registers. This is for identifying these FW versions.
+		 */
+		major_num = 1;
+		minor_num = 2;
+		if (fw_ver == 26098) {
+			revision = 15;
+		} else if (lib_ver == 0 && fw_ver == 0) {
+			revision = 17;
+		} else {
+			dev_err(mhdp->dev, "Unsupported FW version: fw_ver = %u, lib_ver = %u\n",
+				fw_ver, lib_ver);
+			return -ENODEV;
+		}
+	} else {
+		/* To identify newer FW versions with major number 2 onwards. */
+		major_num = fw_ver / 10000;
+		minor_num = (fw_ver / 100) % 100;
+		revision = (fw_ver % 10000) % 100;
+	}
+
+	dev_dbg(mhdp->dev, "FW version: v%u.%u.%u\n", major_num, minor_num,
+		revision);
+	return 0;
+}
+
+static int cdns_mhdp_fw_activate(const struct firmware *fw,
+				 struct cdns_mhdp_device *mhdp)
+{
+	unsigned int reg;
+	int ret;
+
+	/* Release uCPU reset and stall it. */
+	writel(CDNS_CPU_STALL, mhdp->regs + CDNS_APB_CTRL);
+
+	memcpy_toio(mhdp->regs + CDNS_MHDP_IMEM, fw->data, fw->size);
+
+	/* Leave debug mode, release stall */
+	writel(0, mhdp->regs + CDNS_APB_CTRL);
+
+	/*
+	 * Wait for the KEEP_ALIVE "message" on the first 8 bits.
+	 * Updated each sched "tick" (~2ms)
+	 */
+	ret = readl_poll_timeout(mhdp->regs + CDNS_KEEP_ALIVE, reg,
+				 reg & CDNS_KEEP_ALIVE_MASK, 500,
+				 CDNS_KEEP_ALIVE_TIMEOUT);
+	if (ret) {
+		dev_err(mhdp->dev,
+			"device didn't give any life sign: reg %d\n", reg);
+		return ret;
+	}
+
+	ret = cdns_mhdp_check_fw_version(mhdp);
+	if (ret)
+		return ret;
+
+	/* Init events to 0 as it's not cleared by FW at boot but on read */
+	readl(mhdp->regs + CDNS_SW_EVENT0);
+	readl(mhdp->regs + CDNS_SW_EVENT1);
+	readl(mhdp->regs + CDNS_SW_EVENT2);
+	readl(mhdp->regs + CDNS_SW_EVENT3);
+
+	/* Activate uCPU */
+	ret = cdns_mhdp_set_firmware_active(mhdp, true);
+	if (ret)
+		return ret;
+
+	spin_lock(&mhdp->start_lock);
+
+	mhdp->hw_state = MHDP_HW_READY;
+
+	/*
+	 * Here we must keep the lock while enabling the interrupts
+	 * since it would otherwise be possible that interrupt enable
+	 * code is executed after the bridge is detached. The similar
+	 * situation is not possible in attach()/detach() callbacks
+	 * since the hw_state changes from MHDP_HW_READY to
+	 * MHDP_HW_STOPPED happens only due to driver removal when
+	 * bridge should already be detached.
+	 */
+	if (mhdp->bridge_attached)
+		writel(~CDNS_APB_INT_MASK_SW_EVENT_INT,
+		       mhdp->regs + CDNS_APB_INT_MASK);
+
+	spin_unlock(&mhdp->start_lock);
+
+	wake_up(&mhdp->fw_load_wq);
+	dev_dbg(mhdp->dev, "DP FW activated\n");
+
+	return 0;
+}
+
+static void cdns_mhdp_fw_cb(const struct firmware *fw, void *context)
+{
+	struct cdns_mhdp_device *mhdp = context;
+	bool bridge_attached;
+	int ret;
+
+	dev_dbg(mhdp->dev, "firmware callback\n");
+
+	if (!fw || !fw->data) {
+		dev_err(mhdp->dev, "%s: No firmware.\n", __func__);
+		return;
+	}
+
+	ret = cdns_mhdp_fw_activate(fw, mhdp);
+
+	release_firmware(fw);
+
+	if (ret)
+		return;
+
+	/*
+	 *  XXX how to make sure the bridge is still attached when
+	 *      calling drm_kms_helper_hotplug_event() after releasing
+	 *      the lock? We should not hold the spin lock when
+	 *      calling drm_kms_helper_hotplug_event() since it may
+	 *      cause a dead lock. FB-dev console calls detect from the
+	 *      same thread just down the call stack started here.
+	 */
+	spin_lock(&mhdp->start_lock);
+	bridge_attached = mhdp->bridge_attached;
+	spin_unlock(&mhdp->start_lock);
+	if (bridge_attached) {
+		if (mhdp->connector.dev)
+			drm_kms_helper_hotplug_event(mhdp->bridge.dev);
+		else
+			drm_bridge_hpd_notify(&mhdp->bridge, cdns_mhdp_detect(mhdp));
+	}
+}
+
+static int cdns_mhdp_load_firmware(struct cdns_mhdp_device *mhdp)
+{
+	int ret;
+
+	ret = request_firmware_nowait(THIS_MODULE, true, FW_NAME, mhdp->dev,
+				      GFP_KERNEL, mhdp, cdns_mhdp_fw_cb);
+	if (ret) {
+		dev_err(mhdp->dev, "failed to load firmware (%s), ret: %d\n",
+			FW_NAME, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static ssize_t cdns_mhdp_transfer(struct drm_dp_aux *aux,
+				  struct drm_dp_aux_msg *msg)
+{
+	struct cdns_mhdp_device *mhdp = dev_get_drvdata(aux->dev);
+	int ret;
+
+	if (msg->request != DP_AUX_NATIVE_WRITE &&
+	    msg->request != DP_AUX_NATIVE_READ)
+		return -EOPNOTSUPP;
+
+	if (msg->request == DP_AUX_NATIVE_WRITE) {
+		const u8 *buf = msg->buffer;
+		unsigned int i;
+
+		for (i = 0; i < msg->size; ++i) {
+			ret = cdns_mhdp_dpcd_write(mhdp,
+						   msg->address + i, buf[i]);
+			if (!ret)
+				continue;
+
+			dev_err(mhdp->dev,
+				"Failed to write DPCD addr %u\n",
+				msg->address + i);
+
+			return ret;
+		}
+	} else {
+		ret = cdns_mhdp_dpcd_read(mhdp, msg->address,
+					  msg->buffer, msg->size);
+		if (ret) {
+			dev_err(mhdp->dev,
+				"Failed to read DPCD addr %u\n",
+				msg->address);
+
+			return ret;
+		}
+	}
+
+	return msg->size;
+}
+
+static int cdns_mhdp_link_training_init(struct cdns_mhdp_device *mhdp)
+{
+	union phy_configure_opts phy_cfg;
+	u32 reg32;
+	int ret;
+
+	drm_dp_dpcd_writeb(&mhdp->aux, DP_TRAINING_PATTERN_SET,
+			   DP_TRAINING_PATTERN_DISABLE);
+
+	/* Reset PHY configuration */
+	reg32 = CDNS_PHY_COMMON_CONFIG | CDNS_PHY_TRAINING_TYPE(1);
+	if (!mhdp->host.scrambler)
+		reg32 |= CDNS_PHY_SCRAMBLER_BYPASS;
+
+	cdns_mhdp_reg_write(mhdp, CDNS_DPTX_PHY_CONFIG, reg32);
+
+	cdns_mhdp_reg_write(mhdp, CDNS_DP_ENHNCD,
+			    mhdp->sink.enhanced & mhdp->host.enhanced);
+
+	cdns_mhdp_reg_write(mhdp, CDNS_DP_LANE_EN,
+			    CDNS_DP_LANE_EN_LANES(mhdp->link.num_lanes));
+
+	cdns_mhdp_link_configure(&mhdp->aux, &mhdp->link);
+	phy_cfg.dp.link_rate = mhdp->link.rate / 100;
+	phy_cfg.dp.lanes = mhdp->link.num_lanes;
+
+	memset(phy_cfg.dp.voltage, 0, sizeof(phy_cfg.dp.voltage));
+	memset(phy_cfg.dp.pre, 0, sizeof(phy_cfg.dp.pre));
+
+	phy_cfg.dp.ssc = cdns_mhdp_get_ssc_supported(mhdp);
+	phy_cfg.dp.set_lanes = true;
+	phy_cfg.dp.set_rate = true;
+	phy_cfg.dp.set_voltages = true;
+	ret = phy_configure(mhdp->phy,  &phy_cfg);
+	if (ret) {
+		dev_err(mhdp->dev, "%s: phy_configure() failed: %d\n",
+			__func__, ret);
+		return ret;
+	}
+
+	cdns_mhdp_reg_write(mhdp, CDNS_DPTX_PHY_CONFIG,
+			    CDNS_PHY_COMMON_CONFIG |
+			    CDNS_PHY_TRAINING_EN |
+			    CDNS_PHY_TRAINING_TYPE(1) |
+			    CDNS_PHY_SCRAMBLER_BYPASS);
+
+	drm_dp_dpcd_writeb(&mhdp->aux, DP_TRAINING_PATTERN_SET,
+			   DP_TRAINING_PATTERN_1 | DP_LINK_SCRAMBLING_DISABLE);
+
+	return 0;
+}
+
+static void cdns_mhdp_get_adjust_train(struct cdns_mhdp_device *mhdp,
+				       u8 link_status[DP_LINK_STATUS_SIZE],
+				       u8 lanes_data[CDNS_DP_MAX_NUM_LANES],
+				       union phy_configure_opts *phy_cfg)
+{
+	u8 adjust, max_pre_emph, max_volt_swing;
+	u8 set_volt, set_pre;
+	unsigned int i;
+
+	max_pre_emph = CDNS_PRE_EMPHASIS(mhdp->host.pre_emphasis)
+			   << DP_TRAIN_PRE_EMPHASIS_SHIFT;
+	max_volt_swing = CDNS_VOLT_SWING(mhdp->host.volt_swing);
+
+	for (i = 0; i < mhdp->link.num_lanes; i++) {
+		/* Check if Voltage swing and pre-emphasis are within limits */
+		adjust = drm_dp_get_adjust_request_voltage(link_status, i);
+		set_volt = min(adjust, max_volt_swing);
+
+		adjust = drm_dp_get_adjust_request_pre_emphasis(link_status, i);
+		set_pre = min(adjust, max_pre_emph)
+			  >> DP_TRAIN_PRE_EMPHASIS_SHIFT;
+
+		/*
+		 * Voltage swing level and pre-emphasis level combination is
+		 * not allowed: leaving pre-emphasis as-is, and adjusting
+		 * voltage swing.
+		 */
+		if (set_volt + set_pre > 3)
+			set_volt = 3 - set_pre;
+
+		phy_cfg->dp.voltage[i] = set_volt;
+		lanes_data[i] = set_volt;
+
+		if (set_volt == max_volt_swing)
+			lanes_data[i] |= DP_TRAIN_MAX_SWING_REACHED;
+
+		phy_cfg->dp.pre[i] = set_pre;
+		lanes_data[i] |= (set_pre << DP_TRAIN_PRE_EMPHASIS_SHIFT);
+
+		if (set_pre == (max_pre_emph >> DP_TRAIN_PRE_EMPHASIS_SHIFT))
+			lanes_data[i] |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
+	}
+}
+
+static
+void cdns_mhdp_set_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE],
+					  unsigned int lane, u8 volt)
+{
+	unsigned int s = ((lane & 1) ?
+			  DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT :
+			  DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT);
+	unsigned int idx = DP_ADJUST_REQUEST_LANE0_1 - DP_LANE0_1_STATUS + (lane >> 1);
+
+	link_status[idx] &= ~(DP_ADJUST_VOLTAGE_SWING_LANE0_MASK << s);
+	link_status[idx] |= volt << s;
+}
+
+static
+void cdns_mhdp_set_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE],
+					       unsigned int lane, u8 pre_emphasis)
+{
+	unsigned int s = ((lane & 1) ?
+			  DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT :
+			  DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT);
+	unsigned int idx = DP_ADJUST_REQUEST_LANE0_1 - DP_LANE0_1_STATUS + (lane >> 1);
+
+	link_status[idx] &= ~(DP_ADJUST_PRE_EMPHASIS_LANE0_MASK << s);
+	link_status[idx] |= pre_emphasis << s;
+}
+
+static void cdns_mhdp_adjust_requested_eq(struct cdns_mhdp_device *mhdp,
+					  u8 link_status[DP_LINK_STATUS_SIZE])
+{
+	u8 max_pre = CDNS_PRE_EMPHASIS(mhdp->host.pre_emphasis);
+	u8 max_volt = CDNS_VOLT_SWING(mhdp->host.volt_swing);
+	unsigned int i;
+	u8 volt, pre;
+
+	for (i = 0; i < mhdp->link.num_lanes; i++) {
+		volt = drm_dp_get_adjust_request_voltage(link_status, i);
+		pre = drm_dp_get_adjust_request_pre_emphasis(link_status, i);
+		if (volt + pre > 3)
+			cdns_mhdp_set_adjust_request_voltage(link_status, i,
+							     3 - pre);
+		if (mhdp->host.volt_swing & CDNS_FORCE_VOLT_SWING)
+			cdns_mhdp_set_adjust_request_voltage(link_status, i,
+							     max_volt);
+		if (mhdp->host.pre_emphasis & CDNS_FORCE_PRE_EMPHASIS)
+			cdns_mhdp_set_adjust_request_pre_emphasis(link_status,
+								  i, max_pre);
+	}
+}
+
+static void cdns_mhdp_print_lt_status(const char *prefix,
+				      struct cdns_mhdp_device *mhdp,
+				      union phy_configure_opts *phy_cfg)
+{
+	char vs[8] = "0/0/0/0";
+	char pe[8] = "0/0/0/0";
+	unsigned int i;
+
+	for (i = 0; i < mhdp->link.num_lanes; i++) {
+		vs[i * 2] = '0' + phy_cfg->dp.voltage[i];
+		pe[i * 2] = '0' + phy_cfg->dp.pre[i];
+	}
+
+	vs[i * 2 - 1] = '\0';
+	pe[i * 2 - 1] = '\0';
+
+	dev_dbg(mhdp->dev, "%s, %u lanes, %u Mbps, vs %s, pe %s\n",
+		prefix,