xref: /openbsd/sys/dev/pci/drm/apple/dcp.c (revision 44a5d259)

// SPDX-License-Identifier: GPL-2.0-only OR MIT
/* Copyright 2021 Alyssa Rosenzweig <alyssa@rosenzweig.io> */

#include <linux/align.h>
#include <linux/apple-mailbox.h>
#include <linux/bitmap.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/component.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/gpio/consumer.h>
#include <linux/iommu.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/slab.h>
#include <linux/soc/apple/rtkit.h>
#include <linux/string.h>
#include <linux/workqueue.h>

#include <drm/drm_fb_dma_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_module.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_vblank.h>

#include "afk.h"
#include "dcp.h"
#include "dcp-internal.h"
#include "iomfb.h"
#include "parser.h"
#include "trace.h"

#define APPLE_DCP_COPROC_CPU_CONTROL	 0x44
#define APPLE_DCP_COPROC_CPU_CONTROL_RUN BIT(4)

#define DCP_BOOT_TIMEOUT msecs_to_jiffies(1000)

static bool show_notch;
module_param(show_notch, bool, 0644);
MODULE_PARM_DESC(show_notch, "Use the full display height and shows the notch");

/* HACK: moved here to avoid circular dependency between apple_drv and dcp */
void dcp_drm_crtc_vblank(struct apple_crtc *crtc)
{
	unsigned long flags;

	spin_lock_irqsave(&crtc->base.dev->event_lock, flags);
	if (crtc->event) {
		drm_crtc_send_vblank_event(&crtc->base, crtc->event);
		crtc->event = NULL;
	}
	spin_unlock_irqrestore(&crtc->base.dev->event_lock, flags);
}

void dcp_set_dimensions(struct apple_dcp *dcp)
{
	int i;
	int width_mm = dcp->width_mm;
	int height_mm = dcp->height_mm;

	if (width_mm == 0 || height_mm == 0) {
		width_mm = dcp->panel.width_mm;
		height_mm = dcp->panel.height_mm;
	}

	/* Set the connector info */
	if (dcp->connector) {
		struct drm_connector *connector = &dcp->connector->base;

		mutex_lock(&connector->dev->mode_config.mutex);
		connector->display_info.width_mm = width_mm;
		connector->display_info.height_mm = height_mm;
		mutex_unlock(&connector->dev->mode_config.mutex);
	}

	/*
	 * Fix up any probed modes. Modes are created when parsing
	 * TimingElements, dimensions are calculated when parsing
	 * DisplayAttributes, and TimingElements may be sent first
	 */
	for (i = 0; i < dcp->nr_modes; ++i) {
		dcp->modes[i].mode.width_mm = width_mm;
		dcp->modes[i].mode.height_mm = height_mm;
	}
}

bool dcp_has_panel(struct apple_dcp *dcp)
{
	return dcp->panel.width_mm > 0;
}

/*
 * Helper to send a DRM vblank event. We do not know how call swap_submit_dcp
 * without surfaces. To avoid timeouts in drm_atomic_helper_wait_for_vblanks
 * send a vblank event via a workqueue.
 */
static void dcp_delayed_vblank(struct work_struct *work)
{
	struct apple_dcp *dcp;

	dcp = container_of(work, struct apple_dcp, vblank_wq);
	mdelay(5);
	dcp_drm_crtc_vblank(dcp->crtc);
}

static void dcp_recv_msg(void *cookie, u8 endpoint, u64 message)
{
	struct apple_dcp *dcp = cookie;

	trace_dcp_recv_msg(dcp, endpoint, message);

	switch (endpoint) {
	case IOMFB_ENDPOINT:
		return iomfb_recv_msg(dcp, message);
	case SYSTEM_ENDPOINT:
		afk_receive_message(dcp->systemep, message);
		return;
	case DISP0_ENDPOINT:
		afk_receive_message(dcp->ibootep, message);
		return;
	case DPTX_ENDPOINT:
		afk_receive_message(dcp->dptxep, message);
		return;
	default:
		WARN(endpoint, "unknown DCP endpoint %hhu\n", endpoint);
	}
}

static void dcp_rtk_crashed(void *cookie)
{
	struct apple_dcp *dcp = cookie;

	dcp->crashed = true;
	dev_err(dcp->dev, "DCP has crashed\n");
	if (dcp->connector) {
		dcp->connector->connected = 0;
		schedule_work(&dcp->connector->hotplug_wq);
	}
	complete(&dcp->start_done);
}

static int dcp_rtk_shmem_setup(void *cookie, struct apple_rtkit_shmem *bfr)
{
	struct apple_dcp *dcp = cookie;

	if (bfr->iova) {
		struct iommu_domain *domain =
			iommu_get_domain_for_dev(dcp->dev);
		phys_addr_t phy_addr;

		if (!domain)
			return -ENOMEM;

		// TODO: get map from device-tree
		phy_addr = iommu_iova_to_phys(domain, bfr->iova);
		if (!phy_addr)
			return -ENOMEM;

		// TODO: verify phy_addr, cache attribute
		bfr->buffer = memremap(phy_addr, bfr->size, MEMREMAP_WB);
		if (!bfr->buffer)
			return -ENOMEM;

		bfr->is_mapped = true;
		dev_info(dcp->dev,
			 "shmem_setup: iova: %lx -> pa: %lx -> iomem: %lx\n",
			 (uintptr_t)bfr->iova, (uintptr_t)phy_addr,
			 (uintptr_t)bfr->buffer);
	} else {
		bfr->buffer = dma_alloc_coherent(dcp->dev, bfr->size,
						 &bfr->iova, GFP_KERNEL);
		if (!bfr->buffer)
			return -ENOMEM;

		dev_info(dcp->dev, "shmem_setup: iova: %lx, buffer: %lx\n",
			 (uintptr_t)bfr->iova, (uintptr_t)bfr->buffer);
	}

	return 0;
}

static void dcp_rtk_shmem_destroy(void *cookie, struct apple_rtkit_shmem *bfr)
{
	struct apple_dcp *dcp = cookie;

	if (bfr->is_mapped)
		memunmap(bfr->buffer);
	else
		dma_free_coherent(dcp->dev, bfr->size, bfr->buffer, bfr->iova);
}

static struct apple_rtkit_ops rtkit_ops = {
	.crashed = dcp_rtk_crashed,
	.recv_message = dcp_recv_msg,
	.shmem_setup = dcp_rtk_shmem_setup,
	.shmem_destroy = dcp_rtk_shmem_destroy,
};

void dcp_send_message(struct apple_dcp *dcp, u8 endpoint, u64 message)
{
	trace_dcp_send_msg(dcp, endpoint, message);
	apple_rtkit_send_message(dcp->rtk, endpoint, message, NULL,
				 true);
}

int dcp_crtc_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state)
{
	struct platform_device *pdev = to_apple_crtc(crtc)->dcp;
	struct apple_dcp *dcp = platform_get_drvdata(pdev);
	struct drm_plane_state *new_state;
	struct drm_plane *plane;
	struct drm_crtc_state *crtc_state;
	int plane_idx, plane_count = 0;
	bool needs_modeset;

	if (dcp->crashed)
		return -EINVAL;

	crtc_state = drm_atomic_get_new_crtc_state(state, crtc);

	needs_modeset = drm_atomic_crtc_needs_modeset(crtc_state) || !dcp->valid_mode;
	if (!needs_modeset && !dcp->connector->connected) {
		dev_err(dcp->dev, "crtc_atomic_check: disconnected but no modeset\n");
		return -EINVAL;
	}

	for_each_new_plane_in_state(state, plane, new_state, plane_idx) {
		/* skip planes not for this crtc */
		if (new_state->crtc != crtc)
			continue;

		plane_count += 1;
	}

	if (plane_count > DCP_MAX_PLANES) {
		dev_err(dcp->dev, "crtc_atomic_check: Blend supports only 2 layers!\n");
		return -EINVAL;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(dcp_crtc_atomic_check);

int dcp_get_connector_type(struct platform_device *pdev)
{
	struct apple_dcp *dcp = platform_get_drvdata(pdev);

	return (dcp->connector_type);
}
EXPORT_SYMBOL_GPL(dcp_get_connector_type);

#define DPTX_CONNECT_TIMEOUT msecs_to_jiffies(1000)

static int dcp_dptx_connect(struct apple_dcp *dcp, u32 port)
{
	int ret = 0;

	if (!dcp->phy) {
		dev_warn(dcp->dev, "dcp_dptx_connect: missing phy\n");
		return -ENODEV;
	}
	dev_info(dcp->dev, "%s(port=%d)\n", __func__, port);

	mutex_lock(&dcp->hpd_mutex);
	if (!dcp->dptxport[port].enabled) {
		dev_warn(dcp->dev, "dcp_dptx_connect: dptx service for port %d not enabled\n", port);
		ret = -ENODEV;
		goto out_unlock;
	}

	if (dcp->dptxport[port].connected)
		goto out_unlock;

	reinit_completion(&dcp->dptxport[port].linkcfg_completion);
	dcp->dptxport[port].atcphy = dcp->phy;
	dptxport_connect(dcp->dptxport[port].service, 0, dcp->dptx_phy, dcp->dptx_die);
	dptxport_request_display(dcp->dptxport[port].service);
	dcp->dptxport[port].connected = true;

	mutex_unlock(&dcp->hpd_mutex);
	ret = wait_for_completion_timeout(&dcp->dptxport[port].linkcfg_completion,
				    DPTX_CONNECT_TIMEOUT);
	if (ret < 0)
		dev_warn(dcp->dev, "dcp_dptx_connect: port %d link complete failed:%d\n",
			 port, ret);
	else
		dev_dbg(dcp->dev, "dcp_dptx_connect: waited %d ms for link\n",
			jiffies_to_msecs(DPTX_CONNECT_TIMEOUT - ret));

	usleep_range(5, 10);

	return 0;

out_unlock:
	mutex_unlock(&dcp->hpd_mutex);
	return ret;
}

static int dcp_dptx_disconnect(struct apple_dcp *dcp, u32 port)
{
	dev_info(dcp->dev, "%s(port=%d)\n", __func__, port);

	mutex_lock(&dcp->hpd_mutex);
	if (dcp->dptxport[port].enabled && dcp->dptxport[port].connected) {
		dptxport_release_display(dcp->dptxport[port].service);
		dcp->dptxport[port].connected = false;
	}
	mutex_unlock(&dcp->hpd_mutex);

	return 0;
}

static irqreturn_t dcp_dp2hdmi_hpd(int irq, void *data)
{
	struct apple_dcp *dcp = data;
	bool connected = gpiod_get_value_cansleep(dcp->hdmi_hpd);

	/* do nothing on disconnect and trust that dcp detects it itself.
	 * Parallel disconnect HPDs result drm disabling the CRTC even when it
	 * should not.
	 * The interrupt should be changed to rising but for now the disconnect
	 * IRQs might be helpful for debugging.
	 */
	dev_info(dcp->dev, "DP2HDMI HPD irq, connected:%d\n", connected);

	if (connected)
		dcp_dptx_connect(dcp, 0);

	return IRQ_HANDLED;
}

void dcp_link(struct platform_device *pdev, struct apple_crtc *crtc,
	      struct apple_connector *connector)
{
	struct apple_dcp *dcp = platform_get_drvdata(pdev);

	dcp->crtc = crtc;
	dcp->connector = connector;
}
EXPORT_SYMBOL_GPL(dcp_link);

int dcp_start(struct platform_device *pdev)
{
	struct apple_dcp *dcp = platform_get_drvdata(pdev);
	int ret;

	init_completion(&dcp->start_done);

	/* start RTKit endpoints */
	ret = systemep_init(dcp);
	if (ret)
		dev_warn(dcp->dev, "Failed to start system endpoint: %d\n", ret);

	if (dcp->phy && dcp->fw_compat >= DCP_FIRMWARE_V_13_5) {
		ret = ibootep_init(dcp);
		if (ret)
			dev_warn(dcp->dev, "Failed to start IBOOT endpoint: %d\n",
				 ret);

		ret = dptxep_init(dcp);
		if (ret)
			dev_warn(dcp->dev, "Failed to start DPTX endpoint: %d\n",
				 ret);
		else if (dcp->dptxport[0].enabled) {
			bool connected;
			/* force disconnect on start - necessary if the display
			 * is already up from m1n1
			 */
			dptxport_set_hpd(dcp->dptxport[0].service, false);
			dptxport_release_display(dcp->dptxport[0].service);
			usleep_range(10 * USEC_PER_MSEC, 25 * USEC_PER_MSEC);

			connected = gpiod_get_value_cansleep(dcp->hdmi_hpd);
			dev_info(dcp->dev, "%s: DP2HDMI HPD connected:%d\n", __func__, connected);

			// necessary on j473/j474 but not on j314c
			if (connected)
				dcp_dptx_connect(dcp, 0);
		}
	} else if (dcp->phy)
		dev_warn(dcp->dev, "OS firmware incompatible with dptxport EP\n");

	ret = iomfb_start_rtkit(dcp);
	if (ret)
		dev_err(dcp->dev, "Failed to start IOMFB endpoint: %d\n", ret);

	return ret;
}
EXPORT_SYMBOL(dcp_start);

static int dcp_enable_dp2hdmi_hpd(struct apple_dcp *dcp)
{
	if (dcp->hdmi_hpd_irq)
		enable_irq(dcp->hdmi_hpd_irq);

	return 0;
}

int dcp_wait_ready(struct platform_device *pdev, u64 timeout)
{
	struct apple_dcp *dcp = platform_get_drvdata(pdev);
	int ret;

	if (dcp->crashed)
		return -ENODEV;
	if (dcp->active)
		return dcp_enable_dp2hdmi_hpd(dcp);;
	if (timeout <= 0)
		return -ETIMEDOUT;

	ret = wait_for_completion_timeout(&dcp->start_done, timeout);
	if (ret < 0)
		return ret;

	if (dcp->crashed)
		return -ENODEV;

	if (dcp->active)
		dcp_enable_dp2hdmi_hpd(dcp);

	return dcp->active ? 0 : -ETIMEDOUT;
}
EXPORT_SYMBOL(dcp_wait_ready);

static void __maybe_unused dcp_sleep(struct apple_dcp *dcp)
{
	switch (dcp->fw_compat) {
	case DCP_FIRMWARE_V_12_3:
		iomfb_sleep_v12_3(dcp);
		break;
	case DCP_FIRMWARE_V_13_5:
		iomfb_sleep_v13_3(dcp);
		break;
	default:
		WARN_ONCE(true, "Unexpected firmware version: %u\n", dcp->fw_compat);
		break;
	}
}

void dcp_poweron(struct platform_device *pdev)
{
	struct apple_dcp *dcp = platform_get_drvdata(pdev);

	if (dcp->hdmi_hpd) {
		bool connected = gpiod_get_value_cansleep(dcp->hdmi_hpd);
		dev_info(dcp->dev, "%s: DP2HDMI HPD connected:%d\n", __func__, connected);

		if (connected)
			dcp_dptx_connect(dcp, 0);
	}

	switch (dcp->fw_compat) {
	case DCP_FIRMWARE_V_12_3:
		iomfb_poweron_v12_3(dcp);
		break;
	case DCP_FIRMWARE_V_13_5:
		iomfb_poweron_v13_3(dcp);
		break;
	default:
		WARN_ONCE(true, "Unexpected firmware version: %u\n", dcp->fw_compat);
		break;
	}
}
EXPORT_SYMBOL(dcp_poweron);

void dcp_poweroff(struct platform_device *pdev)
{
	struct apple_dcp *dcp = platform_get_drvdata(pdev);

	switch (dcp->fw_compat) {
	case DCP_FIRMWARE_V_12_3:
		iomfb_poweroff_v12_3(dcp);
		break;
	case DCP_FIRMWARE_V_13_5:
		iomfb_poweroff_v13_3(dcp);
		break;
	default:
		WARN_ONCE(true, "Unexpected firmware version: %u\n", dcp->fw_compat);
		break;
	}

	if (dcp->hdmi_hpd) {
		bool connected = gpiod_get_value_cansleep(dcp->hdmi_hpd);
		if (!connected)
			dcp_dptx_disconnect(dcp, 0);
	}
}
EXPORT_SYMBOL(dcp_poweroff);

static void dcp_work_register_backlight(struct work_struct *work)
{
	int ret;
	struct apple_dcp *dcp;

	dcp = container_of(work, struct apple_dcp, bl_register_wq);

	mutex_lock(&dcp->bl_register_mutex);
	if (dcp->brightness.bl_dev)
		goto out_unlock;

	/* try to register backlight device, */
	ret = dcp_backlight_register(dcp);
	if (ret) {
		dev_err(dcp->dev, "Unable to register backlight device\n");
		dcp->brightness.maximum = 0;
	}

out_unlock:
	mutex_unlock(&dcp->bl_register_mutex);
}

static void dcp_work_update_backlight(struct work_struct *work)
{
	struct apple_dcp *dcp;

	dcp = container_of(work, struct apple_dcp, bl_update_wq);

	dcp_backlight_update(dcp);
}

static int dcp_create_piodma_iommu_dev(struct apple_dcp *dcp)
{
	int ret;
	struct device_node *node = of_get_child_by_name(dcp->dev->of_node, "piodma");

	if (!node)
		return dev_err_probe(dcp->dev, -ENODEV,
				     "Failed to get piodma child DT node\n");

	dcp->piodma = of_platform_device_create(node, NULL, dcp->dev);
	if (!dcp->piodma) {
		of_node_put(node);
		return dev_err_probe(dcp->dev, -ENODEV, "Failed to gcreate piodma pdev for %pOF\n", node);
	}

	ret = dma_set_mask_and_coherent(&dcp->piodma->dev, DMA_BIT_MASK(42));
	if (ret)
		goto err_destroy_pdev;

	ret = of_dma_configure(&dcp->piodma->dev, node, true);
	if (ret) {
		ret = dev_err_probe(dcp->dev, ret,
			"Failed to configure IOMMU child DMA\n");
		goto err_destroy_pdev;
	}
	of_node_put(node);

	dcp->iommu_dom = iommu_domain_alloc(&platform_bus_type);
	if (!dcp->iommu_dom) {
		ret = -ENOMEM;
		goto err_destroy_pdev;
	}

	ret = iommu_attach_device(dcp->iommu_dom, &dcp->piodma->dev);
	if (ret) {
		ret = dev_err_probe(dcp->dev, ret,
					"Failed to attach IOMMU child domain\n");
		goto err_free_domain;
	}

	return 0;
err_free_domain:
	iommu_domain_free(dcp->iommu_dom);
err_destroy_pdev:
	of_node_put(node);
	of_platform_device_destroy(&dcp->piodma->dev, NULL);
	return ret;
}

static int dcp_get_bw_scratch_reg(struct apple_dcp *dcp, u32 expected)
{
	struct of_phandle_args ph_args;
	u32 addr_idx, disp_idx, offset;
	int ret;

	ret = of_parse_phandle_with_args(dcp->dev->of_node, "apple,bw-scratch",
				   "#apple,bw-scratch-cells", 0, &ph_args);
	if (ret < 0) {
		dev_err(dcp->dev, "Failed to read 'apple,bw-scratch': %d\n", ret);
		return ret;
	}

	if (ph_args.args_count != 3) {
		dev_err(dcp->dev, "Unexpected 'apple,bw-scratch' arg count %d\n",
			ph_args.args_count);
		ret = -EINVAL;
		goto err_of_node_put;
	}

	addr_idx = ph_args.args[0];
	disp_idx = ph_args.args[1];
	offset = ph_args.args[2];

	if (disp_idx != expected || disp_idx >= MAX_DISP_REGISTERS) {
		dev_err(dcp->dev, "Unexpected disp_reg value in 'apple,bw-scratch': %d\n",
			disp_idx);
		ret = -EINVAL;
		goto err_of_node_put;
	}

	ret = of_address_to_resource(ph_args.np, addr_idx, &dcp->disp_bw_scratch_res);
	if (ret < 0) {
		dev_err(dcp->dev, "Failed to get 'apple,bw-scratch' resource %d from %pOF\n",
			addr_idx, ph_args.np);
		goto err_of_node_put;
	}
	if (offset > resource_size(&dcp->disp_bw_scratch_res) - 4) {
		ret = -EINVAL;
		goto err_of_node_put;
	}

	dcp->disp_registers[disp_idx] = &dcp->disp_bw_scratch_res;
	dcp->disp_bw_scratch_index = disp_idx;
	dcp->disp_bw_scratch_offset = offset;
	ret = 0;

err_of_node_put:
	of_node_put(ph_args.np);
	return ret;
}

static int dcp_get_bw_doorbell_reg(struct apple_dcp *dcp, u32 expected)
{
	struct of_phandle_args ph_args;
	u32 addr_idx, disp_idx;
	int ret;

	ret = of_parse_phandle_with_args(dcp->dev->of_node, "apple,bw-doorbell",
				   "#apple,bw-doorbell-cells", 0, &ph_args);
	if (ret < 0) {
		dev_err(dcp->dev, "Failed to read 'apple,bw-doorbell': %d\n", ret);
		return ret;
	}

	if (ph_args.args_count != 2) {
		dev_err(dcp->dev, "Unexpected 'apple,bw-doorbell' arg count %d\n",
			ph_args.args_count);
		ret = -EINVAL;
		goto err_of_node_put;
	}

	addr_idx = ph_args.args[0];
	disp_idx = ph_args.args[1];

	if (disp_idx != expected || disp_idx >= MAX_DISP_REGISTERS) {
		dev_err(dcp->dev, "Unexpected disp_reg value in 'apple,bw-doorbell': %d\n",
			disp_idx);
		ret = -EINVAL;
		goto err_of_node_put;
	}

	ret = of_address_to_resource(ph_args.np, addr_idx, &dcp->disp_bw_doorbell_res);
	if (ret < 0) {
		dev_err(dcp->dev, "Failed to get 'apple,bw-doorbell' resource %d from %pOF\n",
			addr_idx, ph_args.np);
		goto err_of_node_put;
	}
	dcp->disp_bw_doorbell_index = disp_idx;
	dcp->disp_registers[disp_idx] = &dcp->disp_bw_doorbell_res;
	ret = 0;

err_of_node_put:
	of_node_put(ph_args.np);
	return ret;
}

static int dcp_get_disp_regs(struct apple_dcp *dcp)
{
	struct platform_device *pdev = to_platform_device(dcp->dev);
	int count = pdev->num_resources - 1;
	int i, ret;

	if (count <= 0 || count > MAX_DISP_REGISTERS)
		return -EINVAL;

	for (i = 0; i < count; ++i) {
		dcp->disp_registers[i] =
			platform_get_resource(pdev, IORESOURCE_MEM, 1 + i);
	}

	/* load pmgr bandwidth scratch resource and offset */
	ret = dcp_get_bw_scratch_reg(dcp, count);
	if (ret < 0)
		return ret;
	count += 1;

	/* load pmgr bandwidth doorbell resource if present (only on t8103) */
	if (of_property_present(dcp->dev->of_node, "apple,bw-doorbell")) {
		ret = dcp_get_bw_doorbell_reg(dcp, count);
		if (ret < 0)
			return ret;
		count += 1;
	}

	dcp->nr_disp_registers = count;
	return 0;
}

#define DCP_FW_VERSION_MIN_LEN	3
#define DCP_FW_VERSION_MAX_LEN	5
#define DCP_FW_VERSION_STR_LEN	(DCP_FW_VERSION_MAX_LEN * 4)

static int dcp_read_fw_version(struct device *dev, const char *name,
			       char *version_str)
{
	u32 ver[DCP_FW_VERSION_MAX_LEN];
	int len_str;
	int len;

	len = of_property_read_variable_u32_array(dev->of_node, name, ver,
						  DCP_FW_VERSION_MIN_LEN,
						  DCP_FW_VERSION_MAX_LEN);

	switch (len) {
	case 3:
		len_str = scnprintf(version_str, DCP_FW_VERSION_STR_LEN,
				    "%d.%d.%d", ver[0], ver[1], ver[2]);
		break;
	case 4:
		len_str = scnprintf(version_str, DCP_FW_VERSION_STR_LEN,
				    "%d.%d.%d.%d", ver[0], ver[1], ver[2],
				    ver[3]);
		break;
	case 5:
		len_str = scnprintf(version_str, DCP_FW_VERSION_STR_LEN,
				    "%d.%d.%d.%d.%d", ver[0], ver[1], ver[2],
				    ver[3], ver[4]);
		break;
	default:
		len_str = strscpy(version_str, "UNKNOWN",
				  DCP_FW_VERSION_STR_LEN);
		if (len >= 0)
			len = -EOVERFLOW;
		break;
	}

	if (len_str >= DCP_FW_VERSION_STR_LEN)
		dev_warn(dev, "'%s' truncated: '%s'\n", name, version_str);

	return len;
}

static enum dcp_firmware_version dcp_check_firmware_version(struct device *dev)
{
	char compat_str[DCP_FW_VERSION_STR_LEN];
	char fw_str[DCP_FW_VERSION_STR_LEN];
	int ret;

	/* firmware version is just informative */
	dcp_read_fw_version(dev, "apple,firmware-version", fw_str);

	ret = dcp_read_fw_version(dev, "apple,firmware-compat", compat_str);
	if (ret < 0) {
		dev_err(dev, "Could not read 'apple,firmware-compat': %d\n", ret);
		return DCP_FIRMWARE_UNKNOWN;
	}

	if (strncmp(compat_str, "12.3.0", sizeof(compat_str)) == 0)
		return DCP_FIRMWARE_V_12_3;
	/*
	 * m1n1 reports firmware version 13.5 as compatible with 13.3. This is
	 * only true for the iomfb endpoint. The interface for the dptx-port
	 * endpoint changed between 13.3 and 13.5. The driver will only support
	 * firmware 13.5. Check the actual firmware version for compat version
	 * 13.3 until m1n1 reports 13.5 as "firmware-compat".
	 */
	else if ((strncmp(compat_str, "13.3.0", sizeof(compat_str)) == 0) &&
		 (strncmp(fw_str, "13.5.0", sizeof(compat_str)) == 0))
		return DCP_FIRMWARE_V_13_5;
	else if (strncmp(compat_str, "13.5.0", sizeof(compat_str)) == 0)
		return DCP_FIRMWARE_V_13_5;

	dev_err(dev, "DCP firmware-compat %s (FW: %s) is not supported\n",
		compat_str, fw_str);

	return DCP_FIRMWARE_UNKNOWN;
}

static int dcp_comp_bind(struct device *dev, struct device *main, void *data)
{
	struct device_node *panel_np;
	struct apple_dcp *dcp = dev_get_drvdata(dev);
	u32 cpu_ctrl;
	int ret;

	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(42));
	if (ret)
		return ret;

	dcp->coproc_reg = devm_platform_ioremap_resource_byname(to_platform_device(dev), "coproc");
	if (IS_ERR(dcp->coproc_reg))
		return PTR_ERR(dcp->coproc_reg);

	of_property_read_u32(dev->of_node, "apple,dcp-index",
					   &dcp->index);
	of_property_read_u32(dev->of_node, "apple,dptx-phy",
					   &dcp->dptx_phy);
	of_property_read_u32(dev->of_node, "apple,dptx-die",
					   &dcp->dptx_die);
	if (dcp->index || dcp->dptx_phy || dcp->dptx_die)
		dev_info(dev, "DCP index:%u dptx target phy: %u dptx die: %u\n",
			 dcp->index, dcp->dptx_phy, dcp->dptx_die);
	rw_init(&dcp->hpd_mutex, "aplhpd");

	if (!show_notch)
		ret = of_property_read_u32(dev->of_node, "apple,notch-height",
					   &dcp->notch_height);

	if (dcp->notch_height > MAX_NOTCH_HEIGHT)
		dcp->notch_height = MAX_NOTCH_HEIGHT;
	if (dcp->notch_height > 0)
		dev_info(dev, "Detected display with notch of %u pixel\n", dcp->notch_height);

	/* initialize brightness scale to a sensible default to avoid divide by 0*/
	dcp->brightness.scale = 65536;
	panel_np = of_get_compatible_child(dev->of_node, "apple,panel-mini-led");
	if (panel_np)
		dcp->panel.has_mini_led = true;
	else
		panel_np = of_get_compatible_child(dev->of_node, "apple,panel");

	if (panel_np) {
		const char height_prop[2][16] = { "adj-height-mm", "height-mm" };

		if (of_device_is_available(panel_np)) {
			ret = of_property_read_u32(panel_np, "apple,max-brightness",
						   &dcp->brightness.maximum);
			if (ret)
				dev_err(dev, "Missing property 'apple,max-brightness'\n");
		}

		of_property_read_u32(panel_np, "width-mm", &dcp->panel.width_mm);
		/* use adjusted height as long as the notch is hidden */
		of_property_read_u32(panel_np, height_prop[!dcp->notch_height],
				     &dcp->panel.height_mm);

		of_node_put(panel_np);
		dcp->connector_type = DRM_MODE_CONNECTOR_eDP;
		INIT_WORK(&dcp->bl_register_wq, dcp_work_register_backlight);
		rw_init(&dcp->bl_register_mutex, "dcpbl");
		INIT_WORK(&dcp->bl_update_wq, dcp_work_update_backlight);
	} else if (of_property_match_string(dev->of_node, "apple,connector-type", "HDMI-A") >= 0)
		dcp->connector_type = DRM_MODE_CONNECTOR_HDMIA;
	else if (of_property_match_string(dev->of_node, "apple,connector-type", "DP") >= 0)
		dcp->connector_type = DRM_MODE_CONNECTOR_DisplayPort;
	else if (of_property_match_string(dev->of_node, "apple,connector-type", "USB-C") >= 0)
		dcp->connector_type = DRM_MODE_CONNECTOR_USB;
	else
		dcp->connector_type = DRM_MODE_CONNECTOR_Unknown;

	ret = dcp_create_piodma_iommu_dev(dcp);
	if (ret)
		return dev_err_probe(dev, ret,
				"Failed to created PIODMA iommu child device");

	ret = dcp_get_disp_regs(dcp);
	if (ret) {
		dev_err(dev, "failed to find display registers\n");
		return ret;
	}

	dcp->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(dcp->clk))
		return dev_err_probe(dev, PTR_ERR(dcp->clk),
				     "Unable to find clock\n");

	bitmap_zero(dcp->memdesc_map, DCP_MAX_MAPPINGS);
	// TDOD: mem_desc IDs start at 1, for simplicity just skip '0' entry
	set_bit(0, dcp->memdesc_map);

	INIT_WORK(&dcp->vblank_wq, dcp_delayed_vblank);

	dcp->swapped_out_fbs =
		(struct list_head)LIST_HEAD_INIT(dcp->swapped_out_fbs);

	cpu_ctrl =
		readl_relaxed(dcp->coproc_reg + APPLE_DCP_COPROC_CPU_CONTROL);
	writel_relaxed(cpu_ctrl | APPLE_DCP_COPROC_CPU_CONTROL_RUN,
		       dcp->coproc_reg + APPLE_DCP_COPROC_CPU_CONTROL);

	dcp->rtk = devm_apple_rtkit_init(dev, dcp, "mbox", 0, &rtkit_ops);
	if (IS_ERR(dcp->rtk))
		return dev_err_probe(dev, PTR_ERR(dcp->rtk),
				     "Failed to initialize RTKit\n");

	ret = apple_rtkit_wake(dcp->rtk);
	if (ret)
		return dev_err_probe(dev, ret,
				     "Failed to boot RTKit: %d\n", ret);
	return ret;
}

/*
 * We need to shutdown DCP before tearing down the display subsystem. Otherwise
 * the DCP will crash and briefly flash a green screen of death.
 */
static void dcp_comp_unbind(struct device *dev, struct device *main, void *data)
{
	struct apple_dcp *dcp = dev_get_drvdata(dev);

	if (dcp->hdmi_hpd_irq)
		disable_irq(dcp->hdmi_hpd_irq);

	if (dcp && dcp->shmem)
		iomfb_shutdown(dcp);

	if (dcp->piodma) {
		iommu_detach_device(dcp->iommu_dom, &dcp->piodma->dev);
		iommu_domain_free(dcp->iommu_dom);
		/* TODO: the piodma platform device has to be destroyed but
		 *       doing so leads to all kind of breakage.
		 */
		// of_platform_device_destroy(&dcp->piodma->dev, NULL);
		dcp->piodma = NULL;
	}

	devm_clk_put(dev, dcp->clk);
	dcp->clk = NULL;
}

static const struct component_ops dcp_comp_ops = {
	.bind	= dcp_comp_bind,
	.unbind	= dcp_comp_unbind,
};

static int dcp_platform_probe(struct platform_device *pdev)
{
	enum dcp_firmware_version fw_compat;
	struct device *dev = &pdev->dev;
	struct apple_dcp *dcp;
	u32 mux_index;

	fw_compat = dcp_check_firmware_version(dev);
	if (fw_compat == DCP_FIRMWARE_UNKNOWN)
		return -ENODEV;

	/* Check for "apple,bw-scratch" to avoid probing appledrm with outdated
	 * device trees. This prevents replacing simpledrm and ending up without
	 * display.
	 */
	if (!of_property_present(dev->of_node, "apple,bw-scratch"))
		return dev_err_probe(dev, -ENODEV, "Incompatible devicetree! "
			"Use devicetree matching this kernel.\n");

	dcp = devm_kzalloc(dev, sizeof(*dcp), GFP_KERNEL);
	if (!dcp)
		return -ENOMEM;

	dcp->fw_compat = fw_compat;
	dcp->dev = dev;
	dcp->hw = *(struct apple_dcp_hw_data *)of_device_get_match_data(dev);

	platform_set_drvdata(pdev, dcp);

	dcp->phy = devm_phy_optional_get(dev, "dp-phy");
	if (IS_ERR(dcp->phy)) {
		dev_err(dev, "Failed to get dp-phy: %ld\n", PTR_ERR(dcp->phy));
		return PTR_ERR(dcp->phy);
	}
	if (dcp->phy) {
		int ret;
		/*
		 * Request DP2HDMI related GPIOs as optional for DP-altmode
		 * compatibility. J180D misses a dp2hdmi-pwren GPIO in the
		 * template ADT. TODO: check device ADT
		 */
		dcp->hdmi_hpd = devm_gpiod_get_optional(dev, "hdmi-hpd", GPIOD_IN);
		if (IS_ERR(dcp->hdmi_hpd))
			return PTR_ERR(dcp->hdmi_hpd);
		if (dcp->hdmi_hpd) {
			int irq = gpiod_to_irq(dcp->hdmi_hpd);
			if (irq < 0) {
				dev_err(dev, "failed to translate HDMI hpd GPIO to IRQ\n");
				return irq;
			}
			dcp->hdmi_hpd_irq = irq;

			ret = devm_request_threaded_irq(dev, dcp->hdmi_hpd_irq,
						NULL, dcp_dp2hdmi_hpd,
						IRQF_ONESHOT | IRQF_NO_AUTOEN |
						IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
						"dp2hdmi-hpd-irq", dcp);
			if (ret < 0) {
				dev_err(dev, "failed to request HDMI hpd irq %d: %d\n",
					irq, ret);
				return ret;
			}
		}

		/*
		 * Power DP2HDMI on as it is required for the HPD irq.
		 * TODO: check if one is sufficient for the hpd to save power
		 *       on battery powered Macbooks.
		 */
		dcp->hdmi_pwren = devm_gpiod_get_optional(dev, "hdmi-pwren", GPIOD_OUT_HIGH);
		if (IS_ERR(dcp->hdmi_pwren))
			return PTR_ERR(dcp->hdmi_pwren);

		dcp->dp2hdmi_pwren = devm_gpiod_get_optional(dev, "dp2hdmi-pwren", GPIOD_OUT_HIGH);
		if (IS_ERR(dcp->dp2hdmi_pwren))
			return PTR_ERR(dcp->dp2hdmi_pwren);

		ret = of_property_read_u32(dev->of_node, "mux-index", &mux_index);
		if (!ret) {
			dcp->xbar = devm_mux_control_get(dev, "dp-xbar");
			if (IS_ERR(dcp->xbar)) {
				dev_err(dev, "Failed to get dp-xbar: %ld\n", PTR_ERR(dcp->xbar));
				return PTR_ERR(dcp->xbar);
			}
			ret = mux_control_select(dcp->xbar, mux_index);
			if (ret)
				dev_warn(dev, "mux_control_select failed: %d\n", ret);
		}
	}

	return component_add(&pdev->dev, &dcp_comp_ops);
}

#ifdef __linux__

static int dcp_platform_remove(struct platform_device *pdev)
{
	component_del(&pdev->dev, &dcp_comp_ops);

	return 0;
}

static void dcp_platform_shutdown(struct platform_device *pdev)
{
	component_del(&pdev->dev, &dcp_comp_ops);
}

#endif

static int dcp_platform_suspend(struct device *dev)
{
	struct apple_dcp *dcp = dev_get_drvdata(dev);

	if (dcp->hdmi_hpd_irq) {
		disable_irq(dcp->hdmi_hpd_irq);
		dcp_dptx_disconnect(dcp, 0);
	}
	/*
	 * Set the device as a wakeup device, which forces its power
	 * domains to stay on. We need this as we do not support full
	 * shutdown properly yet.
	 */
	device_set_wakeup_path(dev);

	return 0;
}

static int dcp_platform_resume(struct device *dev)
{
	struct apple_dcp *dcp = dev_get_drvdata(dev);

	if (dcp->hdmi_hpd_irq)
		enable_irq(dcp->hdmi_hpd_irq);

	if (dcp->hdmi_hpd) {
		bool connected = gpiod_get_value_cansleep(dcp->hdmi_hpd);
		dev_info(dcp->dev, "resume: HPD connected:%d\n", connected);
		if (connected)
			dcp_dptx_connect(dcp, 0);
	}

	return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(dcp_platform_pm_ops,
				dcp_platform_suspend, dcp_platform_resume);


static const struct apple_dcp_hw_data apple_dcp_hw_t6020 = {
	.num_dptx_ports = 1,
};

static const struct apple_dcp_hw_data apple_dcp_hw_t8112 = {
	.num_dptx_ports = 2,
};

static const struct apple_dcp_hw_data apple_dcp_hw_dcp = {
	.num_dptx_ports = 0,
};

static const struct apple_dcp_hw_data apple_dcp_hw_dcpext = {
	.num_dptx_ports = 2,
};

static const struct of_device_id of_match[] = {
	{ .compatible = "apple,t6020-dcp", .data = &apple_dcp_hw_t6020,  },
	{ .compatible = "apple,t8112-dcp", .data = &apple_dcp_hw_t8112,  },
	{ .compatible = "apple,dcp",       .data = &apple_dcp_hw_dcp,    },
	{ .compatible = "apple,dcpext",    .data = &apple_dcp_hw_dcpext, },
	{}
};
MODULE_DEVICE_TABLE(of, of_match);

#ifdef __linux__

static struct platform_driver apple_platform_driver = {
	.probe		= dcp_platform_probe,
	.remove		= dcp_platform_remove,
	.shutdown	= dcp_platform_shutdown,
	.driver	= {
		.name = "apple-dcp",
		.of_match_table	= of_match,
		.pm = pm_sleep_ptr(&dcp_platform_pm_ops),
	},
};

drm_module_platform_driver(apple_platform_driver);

MODULE_AUTHOR("Alyssa Rosenzweig <alyssa@rosenzweig.io>");
MODULE_DESCRIPTION("Apple Display Controller DRM driver");
MODULE_LICENSE("Dual MIT/GPL");

#endif