// SPDX-License-Identifier: MIT
/*
 * Copyright 2019 Intel Corporation.
 */

#include "i915_drv.h"
#include "i915_utils.h"
#include "intel_pch.h"

/* Map PCH device id to PCH type, or PCH_NONE if unknown. */
static enum intel_pch
intel_pch_type(const struct drm_i915_private *dev_priv, unsigned short id)
{
	switch (id) {
	case INTEL_PCH_TGP_DEVICE_ID_TYPE:
	case INTEL_PCH_TGP2_DEVICE_ID_TYPE:
		drm_dbg_kms(&dev_priv->drm, "Found Tiger Lake LP PCH\n");
		drm_WARN_ON(&dev_priv->drm, !IS_TIGERLAKE(dev_priv) &&
			    !IS_ROCKETLAKE(dev_priv) &&
			    !IS_GEN9_BC(dev_priv));
		return PCH_TGP;
	case INTEL_PCH_ADP_DEVICE_ID_TYPE:
	case INTEL_PCH_ADP2_DEVICE_ID_TYPE:
	case INTEL_PCH_ADP3_DEVICE_ID_TYPE:
	case INTEL_PCH_ADP4_DEVICE_ID_TYPE:
		drm_dbg_kms(&dev_priv->drm, "Found Alder Lake PCH\n");
		drm_WARN_ON(&dev_priv->drm, !IS_ALDERLAKE_S(dev_priv) &&
			    !IS_ALDERLAKE_P(dev_priv));
		return PCH_ADP;
	case INTEL_PCH_MTP_DEVICE_ID_TYPE:
	case INTEL_PCH_MTP2_DEVICE_ID_TYPE:
		drm_dbg_kms(&dev_priv->drm, "Found Meteor Lake PCH\n");
		drm_WARN_ON(&dev_priv->drm, !IS_METEORLAKE(dev_priv));
		return PCH_MTP;
	default:
		return PCH_NONE;
	}
}

static bool intel_is_virt_pch(unsigned short id,
			      unsigned short svendor, unsigned short sdevice)
{
	return (id == INTEL_PCH_P2X_DEVICE_ID_TYPE ||
		id == INTEL_PCH_P3X_DEVICE_ID_TYPE ||
		(id == INTEL_PCH_QEMU_DEVICE_ID_TYPE &&
		 svendor == PCI_SUBVENDOR_ID_REDHAT_QUMRANET &&
		 sdevice == PCI_SUBDEVICE_ID_QEMU));
}

static void
intel_virt_detect_pch(const struct drm_i915_private *dev_priv,
		      unsigned short *pch_id, enum intel_pch *pch_type)
{
	unsigned short id ;

	/*
	 * In a virtualized passthrough environment we can be in a
	 * setup where the ISA bridge is not able to be passed through.
	 * In this case, a south bridge can be emulated and we have to
	 * make an educated guess as to which PCH is really there.
	 */

	if (IS_METEORLAKE(dev_priv))
		id = INTEL_PCH_MTP_DEVICE_ID_TYPE;
	else if (IS_ALDERLAKE_S(dev_priv) || IS_ALDERLAKE_P(dev_priv))
		id = INTEL_PCH_ADP_DEVICE_ID_TYPE;
	else if (IS_TIGERLAKE(dev_priv) || IS_ROCKETLAKE(dev_priv))
		id = INTEL_PCH_TGP_DEVICE_ID_TYPE;
	else
		id = 0;

	if (id)
		drm_dbg_kms(&dev_priv->drm, "Assuming PCH ID %04x\n", id);
	else
		drm_dbg_kms(&dev_priv->drm, "Assuming no PCH\n");

	*pch_type = intel_pch_type(dev_priv, id);

	/* Sanity check virtual PCH id */
	if (drm_WARN_ON(&dev_priv->drm,
			id && *pch_type == PCH_NONE))
		id = 0;

	*pch_id = id;
}

void intel_detect_pch(struct drm_i915_private *dev_priv)
{
	struct pci_dev *pch = NULL;
	unsigned short id;
	enum intel_pch pch_type;

	/* DG1 has south engine display on the same PCI device */
	if (IS_DG1(dev_priv)) {
		dev_priv->pch_type = PCH_DG1;
		return;
	} else if (IS_DG2(dev_priv)) {
		dev_priv->pch_type = PCH_DG2;
		return;
	}

	/*
	 * The reason to probe ISA bridge instead of Dev31:Fun0 is to
	 * make graphics device passthrough work easy for VMM, that only
	 * need to expose ISA bridge to let driver know the real hardware
	 * underneath. This is a requirement from virtualization team.
	 *
	 * In some virtualized environments (e.g. XEN), there is irrelevant
	 * ISA bridge in the system. To work reliably, we should scan trhough
	 * all the ISA bridge devices and check for the first match, instead
	 * of only checking the first one.
	 */
	while ((pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, pch))) {
		if (pch->vendor != PCI_VENDOR_ID_INTEL)
			continue;

		id = pch->device & INTEL_PCH_DEVICE_ID_MASK;

		pch_type = intel_pch_type(dev_priv, id);
		if (pch_type != PCH_NONE) {
			dev_priv->pch_type = pch_type;
			dev_priv->pch_id = id;
			break;
		} else if (intel_is_virt_pch(id, pch->subsystem_vendor,
					     pch->subsystem_device)) {
			intel_virt_detect_pch(dev_priv, &id, &pch_type);
			dev_priv->pch_type = pch_type;
			dev_priv->pch_id = id;
			break;
		}
	}

	/*
	 * Use PCH_NOP (PCH but no South Display) for PCH platforms without
	 * display.
	 */
	if (pch && !HAS_DISPLAY(dev_priv)) {
		drm_dbg_kms(&dev_priv->drm,
			    "Display disabled, reverting to NOP PCH\n");
		dev_priv->pch_type = PCH_NOP;
		dev_priv->pch_id = 0;
	} else if (!pch) {
		if (i915_run_as_guest() && HAS_DISPLAY(dev_priv)) {
			intel_virt_detect_pch(dev_priv, &id, &pch_type);
			dev_priv->pch_type = pch_type;
			dev_priv->pch_id = id;
		} else {
			drm_dbg_kms(&dev_priv->drm, "No PCH found.\n");
		}
	}

	pci_dev_put(pch);
}
