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// SPDX-License-Identifier: GPL-2.0+/* * PCI Hotplug Driver for PowerPC PowerNV platform. * * Copyright Gavin Shan, IBM Corporation 2016. * Copyright (C) 2025 Raptor Engineering, LLC * Copyright (C) 2025 Raptor Computing Systems, LLC */ #include <linux/bitfield.h>#include <linux/libfdt.h>#include <linux/module.h>#include <linux/pci.h>#include <linux/delay.h>#include <linux/pci_hotplug.h>#include <linux/of_fdt.h> #include <asm/opal.h>#include <asm/pnv-pci.h>#include <asm/ppc-pci.h> #define DRIVER_VERSION	"0.1"#define DRIVER_AUTHOR	"Gavin Shan, IBM Corporation"#define DRIVER_DESC	"PowerPC PowerNV PCI Hotplug Driver" #define SLOT_WARN(sl, x...) \	((sl)->pdev ? pci_warn((sl)->pdev, x) : dev_warn(&(sl)->bus->dev, x)) struct pnv_php_event {	bool			added;	struct pnv_php_slot	*php_slot;	struct work_struct	work;}; static LIST_HEAD(pnv_php_slot_list);static DEFINE_SPINLOCK(pnv_php_lock); static void pnv_php_register(struct device_node *dn);static void pnv_php_unregister_one(struct device_node *dn);static void pnv_php_unregister(struct device_node *dn); static void pnv_php_enable_irq(struct pnv_php_slot *php_slot); static void pnv_php_disable_irq(struct pnv_php_slot *php_slot,				bool disable_device, bool disable_msi){	struct pci_dev *pdev = php_slot->pdev;	u16 ctrl; 	if (php_slot->irq > 0) {		pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &ctrl);		ctrl &= ~(PCI_EXP_SLTCTL_HPIE |			  PCI_EXP_SLTCTL_PDCE |			  PCI_EXP_SLTCTL_DLLSCE);		pcie_capability_write_word(pdev, PCI_EXP_SLTCTL, ctrl); 		free_irq(php_slot->irq, php_slot);		php_slot->irq = 0;	} 	if (disable_device || disable_msi) {		if (pdev->msix_enabled)			pci_disable_msix(pdev);		else if (pdev->msi_enabled)			pci_disable_msi(pdev);	} 	if (disable_device)		pci_disable_device(pdev);} static void pnv_php_free_slot(struct kref *kref){	struct pnv_php_slot *php_slot = container_of(kref,					struct pnv_php_slot, kref); 	WARN_ON(!list_empty(&php_slot->children));	pnv_php_disable_irq(php_slot, false, false);	destroy_workqueue(php_slot->wq);	kfree(php_slot->name);	kfree(php_slot);} static inline void pnv_php_put_slot(struct pnv_php_slot *php_slot){ 	if (!php_slot)		return; 	kref_put(&php_slot->kref, pnv_php_free_slot);} static struct pnv_php_slot *pnv_php_match(struct device_node *dn,					  struct pnv_php_slot *php_slot){	struct pnv_php_slot *target, *tmp; 	if (php_slot->dn == dn) {		kref_get(&php_slot->kref);		return php_slot;	} 	list_for_each_entry(tmp, &php_slot->children, link) {		target = pnv_php_match(dn, tmp);		if (target)			return target;	} 	return NULL;} struct pnv_php_slot *pnv_php_find_slot(struct device_node *dn){	struct pnv_php_slot *php_slot, *tmp;	unsigned long flags; 	spin_lock_irqsave(&pnv_php_lock, flags);	list_for_each_entry(tmp, &pnv_php_slot_list, link) {		php_slot = pnv_php_match(dn, tmp);		if (php_slot) {			spin_unlock_irqrestore(&pnv_php_lock, flags);			return php_slot;		}	}	spin_unlock_irqrestore(&pnv_php_lock, flags); 	return NULL;}EXPORT_SYMBOL_GPL(pnv_php_find_slot); /* * Remove pdn for all children of the indicated device node. * The function should remove pdn in a depth-first manner. */static void pnv_php_rmv_pdns(struct device_node *dn){	struct device_node *child; 	for_each_child_of_node(dn, child) {		pnv_php_rmv_pdns(child); 		pci_remove_device_node_info(child);	}} /* * Detach all child nodes of the indicated device nodes. The * function should handle device nodes in depth-first manner. * * We should not invoke of_node_release() as the memory for * individual device node is part of large memory block. The * large block is allocated from memblock (system bootup) or * kmalloc() when unflattening the device tree by OF changeset. * We can not free the large block allocated from memblock. For * later case, it should be released at once. */static void pnv_php_detach_device_nodes(struct device_node *parent){	struct device_node *dn; 	for_each_child_of_node(parent, dn) {		pnv_php_detach_device_nodes(dn); 		of_node_put(dn);		of_detach_node(dn);	}} static void pnv_php_rmv_devtree(struct pnv_php_slot *php_slot){	pnv_php_rmv_pdns(php_slot->dn); 	/*	 * Decrease the refcount if the device nodes were created	 * through OF changeset before detaching them.	 */	if (php_slot->fdt)		of_changeset_destroy(&php_slot->ocs);	pnv_php_detach_device_nodes(php_slot->dn); 	if (php_slot->fdt) {		kfree(php_slot->dt);		kfree(php_slot->fdt);		php_slot->dt        = NULL;		php_slot->dn->child = NULL;		php_slot->fdt       = NULL;	}} /* * As the nodes in OF changeset are applied in reverse order, we * need revert the nodes in advance so that we have correct node * order after the changeset is applied. */static void pnv_php_reverse_nodes(struct device_node *parent){	struct device_node *child, *next; 	/* In-depth first */	for_each_child_of_node(parent, child)		pnv_php_reverse_nodes(child); 	/* Reverse the nodes in the child list */	child = parent->child;	parent->child = NULL;	while (child) {		next = child->sibling; 		child->sibling = parent->child;		parent->child = child;		child = next;	}} static int pnv_php_populate_changeset(struct of_changeset *ocs,				      struct device_node *dn){	int ret; 	for_each_child_of_node_scoped(dn, child) {		ret = of_changeset_attach_node(ocs, child);		if (ret)			return ret; 		ret = pnv_php_populate_changeset(ocs, child);		if (ret)			return ret;	} 	return 0;} static void *pnv_php_add_one_pdn(struct device_node *dn, void *data){	struct pci_controller *hose = (struct pci_controller *)data;	struct pci_dn *pdn; 	pdn = pci_add_device_node_info(hose, dn);	if (!pdn)		return ERR_PTR(-ENOMEM); 	return NULL;} static void pnv_php_add_pdns(struct pnv_php_slot *slot){	struct pci_controller *hose = pci_bus_to_host(slot->bus); 	pci_traverse_device_nodes(slot->dn, pnv_php_add_one_pdn, hose);} static int pnv_php_add_devtree(struct pnv_php_slot *php_slot){	void *fdt, *fdt1, *dt;	int ret; 	/* We don't know the FDT blob size. We try to get it through	 * maximal memory chunk and then copy it to another chunk that	 * fits the real size.	 */	fdt1 = kzalloc(0x10000, GFP_KERNEL);	if (!fdt1) {		ret = -ENOMEM;		goto out;	} 	ret = pnv_pci_get_device_tree(php_slot->dn->phandle, fdt1, 0x10000);	if (ret) {		SLOT_WARN(php_slot, "Error %d getting FDT blob\n", ret);		goto free_fdt1;	} 	fdt = kmemdup(fdt1, fdt_totalsize(fdt1), GFP_KERNEL);	if (!fdt) {		ret = -ENOMEM;		goto free_fdt1;	} 	/* Unflatten device tree blob */	dt = of_fdt_unflatten_tree(fdt, php_slot->dn, NULL);	if (!dt) {		ret = -EINVAL;		SLOT_WARN(php_slot, "Cannot unflatten FDT\n");		goto free_fdt;	} 	/* Initialize and apply the changeset */	of_changeset_init(&php_slot->ocs);	pnv_php_reverse_nodes(php_slot->dn);	ret = pnv_php_populate_changeset(&php_slot->ocs, php_slot->dn);	if (ret) {		pnv_php_reverse_nodes(php_slot->dn);		SLOT_WARN(php_slot, "Error %d populating changeset\n",			  ret);		goto free_dt;	} 	php_slot->dn->child = NULL;	ret = of_changeset_apply(&php_slot->ocs);	if (ret) {		SLOT_WARN(php_slot, "Error %d applying changeset\n", ret);		goto destroy_changeset;	} 	/* Add device node firmware data */	pnv_php_add_pdns(php_slot);	php_slot->fdt = fdt;	php_slot->dt  = dt;	kfree(fdt1);	goto out; destroy_changeset:	of_changeset_destroy(&php_slot->ocs);free_dt:	kfree(dt);	php_slot->dn->child = NULL;free_fdt:	kfree(fdt);free_fdt1:	kfree(fdt1);out:	return ret;} static inline struct pnv_php_slot *to_pnv_php_slot(struct hotplug_slot *slot){	return container_of(slot, struct pnv_php_slot, slot);} int pnv_php_set_slot_power_state(struct hotplug_slot *slot,				 uint8_t state){	struct pnv_php_slot *php_slot = to_pnv_php_slot(slot);	struct opal_msg msg;	int ret; 	ret = pnv_pci_set_power_state(php_slot->id, state, &msg);	if (ret > 0) {		if (be64_to_cpu(msg.params[1]) != php_slot->dn->phandle	||		    be64_to_cpu(msg.params[2]) != state) {			SLOT_WARN(php_slot, "Wrong msg (%lld, %lld, %lld)\n",				  be64_to_cpu(msg.params[1]),				  be64_to_cpu(msg.params[2]),				  be64_to_cpu(msg.params[3]));			return -ENOMSG;		}		if (be64_to_cpu(msg.params[3]) != OPAL_SUCCESS) {			ret = -ENODEV;			goto error;		}	} else if (ret < 0) {		goto error;	} 	if (state == OPAL_PCI_SLOT_POWER_OFF || state == OPAL_PCI_SLOT_OFFLINE)		pnv_php_rmv_devtree(php_slot);	else		ret = pnv_php_add_devtree(php_slot); 	return ret; error:	SLOT_WARN(php_slot, "Error %d powering %s\n",		  ret, (state == OPAL_PCI_SLOT_POWER_ON) ? "on" : "off");	return ret;}EXPORT_SYMBOL_GPL(pnv_php_set_slot_power_state); static int pnv_php_get_power_state(struct hotplug_slot *slot, u8 *state){	struct pnv_php_slot *php_slot = to_pnv_php_slot(slot);	uint8_t power_state = OPAL_PCI_SLOT_POWER_ON;	int ret; 	/*	 * Retrieve power status from firmware. If we fail	 * getting that, the power status fails back to	 * be on.	 */	ret = pnv_pci_get_power_state(php_slot->id, &power_state);	if (ret) {		SLOT_WARN(php_slot, "Error %d getting power status\n",			  ret);	} else {		*state = power_state;	} 	return 0;} static int pcie_check_link_active(struct pci_dev *pdev){	u16 lnk_status;	int ret; 	ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);	if (ret == PCIBIOS_DEVICE_NOT_FOUND || PCI_POSSIBLE_ERROR(lnk_status))		return -ENODEV; 	ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA); 	return ret;} static int pnv_php_get_adapter_state(struct hotplug_slot *slot, u8 *state){	struct pnv_php_slot *php_slot = to_pnv_php_slot(slot);	uint8_t presence = OPAL_PCI_SLOT_EMPTY;	int ret; 	/*	 * Retrieve presence status from firmware. If we can't	 * get that, it will fail back to be empty.	 */	ret = pnv_pci_get_presence_state(php_slot->id, &presence);	if (ret >= 0) {		if (pci_pcie_type(php_slot->pdev) == PCI_EXP_TYPE_DOWNSTREAM &&			presence == OPAL_PCI_SLOT_EMPTY) {			/*			 * Similar to pciehp_hpc, check whether the Link Active			 * bit is set to account for broken downstream bridges			 * that don't properly assert Presence Detect State, as			 * was observed on the Microsemi Switchtec PM8533 PFX			 * [11f8:8533].			 */			if (pcie_check_link_active(php_slot->pdev) > 0)				presence = OPAL_PCI_SLOT_PRESENT;		} 		*state = presence;		ret = 0;	} else {		SLOT_WARN(php_slot, "Error %d getting presence\n", ret);	} 	return ret;} static int pnv_php_get_raw_indicator_status(struct hotplug_slot *slot, u8 *state){	struct pnv_php_slot *php_slot = to_pnv_php_slot(slot);	struct pci_dev *bridge = php_slot->pdev;	u16 status; 	pcie_capability_read_word(bridge, PCI_EXP_SLTCTL, &status);	*state = (status & (PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC)) >> 6;	return 0;}  static int pnv_php_get_attention_state(struct hotplug_slot *slot, u8 *state){	struct pnv_php_slot *php_slot = to_pnv_php_slot(slot); 	pnv_php_get_raw_indicator_status(slot, &php_slot->attention_state);	*state = php_slot->attention_state;	return 0;} static int pnv_php_set_attention_state(struct hotplug_slot *slot, u8 state){	struct pnv_php_slot *php_slot = to_pnv_php_slot(slot);	struct pci_dev *bridge = php_slot->pdev;	u16 new, mask; 	php_slot->attention_state = state;	if (!bridge)		return 0; 	mask = PCI_EXP_SLTCTL_AIC; 	if (state)		new = FIELD_PREP(PCI_EXP_SLTCTL_AIC, state);	else		new = PCI_EXP_SLTCTL_ATTN_IND_OFF; 	pcie_capability_clear_and_set_word(bridge, PCI_EXP_SLTCTL, mask, new); 	return 0;} static int pnv_php_activate_slot(struct pnv_php_slot *php_slot,				 struct hotplug_slot *slot){	int ret, i; 	/*	 * Issue initial slot activation command to firmware	 *	 * Firmware will power slot on, attempt to train the link, and	 * discover any downstream devices. If this process fails, firmware	 * will return an error code and an invalid device tree. Failure	 * can be caused for multiple reasons, including a faulty	 * downstream device, poor connection to the downstream device, or	 * a previously latched PHB fence.  On failure, issue fundamental	 * reset up to three times before aborting.	 */	ret = pnv_php_set_slot_power_state(slot, OPAL_PCI_SLOT_POWER_ON);	if (ret) {		SLOT_WARN(

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