Merge branch 'pci/hotplug-octeon'

- Add hotplug controller driver for Marvell OCTEON multi-function device
  where function 0 has a management console interface to enable/disable and
  provision various personalities for the other functions (Shijith Thotton)

* pci/hotplug-octeon:
  PCI: hotplug: Add OCTEON PCI hotplug controller driver

MAINTAINERS

@@ -13882,6 +13882,12 @@ R:	schalla@marvell.com
 R:	vattunuru@marvell.com
 F:	drivers/vdpa/octeon_ep/
 
+MARVELL OCTEON HOTPLUG DRIVER
+R:	Shijith Thotton <sthotton@marvell.com>
+R:	Vamsi Attunuru <vattunuru@marvell.com>
+S:	Supported
+F:	drivers/pci/hotplug/octep_hp.c
+
 MATROX FRAMEBUFFER DRIVER
 L:	linux-fbdev@vger.kernel.org
 S:	Orphan

drivers/pci/hotplug/Kconfig

@@ -118,6 +118,16 @@ config HOTPLUG_PCI_CPCI_GENERIC
 
 	  When in doubt, say N.
 
+config HOTPLUG_PCI_OCTEONEP
+	bool "Marvell OCTEON PCI Hotplug driver"
+	depends on HOTPLUG_PCI
+	help
+	  Say Y here if you have an OCTEON PCIe device with a hotplug
+	  controller. This driver enables the non-controller functions of the
+	  device to be registered as hotplug slots.
+
+	  When in doubt, say N.
+
 config HOTPLUG_PCI_SHPC
 	bool "SHPC PCI Hotplug driver"
 	help

drivers/pci/hotplug/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_HOTPLUG_PCI_RPA)		+= rpaphp.o
 obj-$(CONFIG_HOTPLUG_PCI_RPA_DLPAR)	+= rpadlpar_io.o
 obj-$(CONFIG_HOTPLUG_PCI_ACPI)		+= acpiphp.o
 obj-$(CONFIG_HOTPLUG_PCI_S390)		+= s390_pci_hpc.o
+obj-$(CONFIG_HOTPLUG_PCI_OCTEONEP)	+= octep_hp.o
 
 # acpiphp_ibm extends acpiphp, so should be linked afterwards.
 

drivers/pci/hotplug/octep_hp.c

@@ -0,0 +1,427 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2024 Marvell. */
+
+#include <linux/cleanup.h>
+#include <linux/container_of.h>
+#include <linux/delay.h>
+#include <linux/dev_printk.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/pci_hotplug.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+
+#define OCTEP_HP_INTR_OFFSET(x) (0x20400 + ((x) << 4))
+#define OCTEP_HP_INTR_VECTOR(x) (16 + (x))
+#define OCTEP_HP_DRV_NAME "octep_hp"
+
+/*
+ * Type of MSI-X interrupts. OCTEP_HP_INTR_VECTOR() and
+ * OCTEP_HP_INTR_OFFSET() generate the vector and offset for an interrupt
+ * type.
+ */
+enum octep_hp_intr_type {
+	OCTEP_HP_INTR_INVALID = -1,
+	OCTEP_HP_INTR_ENA = 0,
+	OCTEP_HP_INTR_DIS = 1,
+	OCTEP_HP_INTR_MAX = 2,
+};
+
+struct octep_hp_cmd {
+	struct list_head list;
+	enum octep_hp_intr_type intr_type;
+	u64 intr_val;
+};
+
+struct octep_hp_slot {
+	struct list_head list;
+	struct hotplug_slot slot;
+	u16 slot_number;
+	struct pci_dev *hp_pdev;
+	unsigned int hp_devfn;
+	struct octep_hp_controller *ctrl;
+};
+
+struct octep_hp_intr_info {
+	enum octep_hp_intr_type type;
+	int number;
+	char name[16];
+};
+
+struct octep_hp_controller {
+	void __iomem *base;
+	struct pci_dev *pdev;
+	struct octep_hp_intr_info intr[OCTEP_HP_INTR_MAX];
+	struct work_struct work;
+	struct list_head slot_list;
+	struct mutex slot_lock; /* Protects slot_list */
+	struct list_head hp_cmd_list;
+	spinlock_t hp_cmd_lock; /* Protects hp_cmd_list */
+};
+
+static void octep_hp_enable_pdev(struct octep_hp_controller *hp_ctrl,
+				 struct octep_hp_slot *hp_slot)
+{
+	guard(mutex)(&hp_ctrl->slot_lock);
+	if (hp_slot->hp_pdev) {
+		pci_dbg(hp_slot->hp_pdev, "Slot %s is already enabled\n",
+			hotplug_slot_name(&hp_slot->slot));
+		return;
+	}
+
+	/* Scan the device and add it to the bus */
+	hp_slot->hp_pdev = pci_scan_single_device(hp_ctrl->pdev->bus,
+						  hp_slot->hp_devfn);
+	pci_bus_assign_resources(hp_ctrl->pdev->bus);
+	pci_bus_add_device(hp_slot->hp_pdev);
+
+	dev_dbg(&hp_slot->hp_pdev->dev, "Enabled slot %s\n",
+		hotplug_slot_name(&hp_slot->slot));
+}
+
+static void octep_hp_disable_pdev(struct octep_hp_controller *hp_ctrl,
+				  struct octep_hp_slot *hp_slot)
+{
+	guard(mutex)(&hp_ctrl->slot_lock);
+	if (!hp_slot->hp_pdev) {
+		pci_dbg(hp_ctrl->pdev, "Slot %s is already disabled\n",
+			hotplug_slot_name(&hp_slot->slot));
+		return;
+	}
+
+	pci_dbg(hp_slot->hp_pdev, "Disabling slot %s\n",
+		hotplug_slot_name(&hp_slot->slot));
+
+	/* Remove the device from the bus */
+	pci_stop_and_remove_bus_device_locked(hp_slot->hp_pdev);
+	hp_slot->hp_pdev = NULL;
+}
+
+static int octep_hp_enable_slot(struct hotplug_slot *slot)
+{
+	struct octep_hp_slot *hp_slot =
+		container_of(slot, struct octep_hp_slot, slot);
+
+	octep_hp_enable_pdev(hp_slot->ctrl, hp_slot);
+	return 0;
+}
+
+static int octep_hp_disable_slot(struct hotplug_slot *slot)
+{
+	struct octep_hp_slot *hp_slot =
+		container_of(slot, struct octep_hp_slot, slot);
+
+	octep_hp_disable_pdev(hp_slot->ctrl, hp_slot);
+	return 0;
+}
+
+static struct hotplug_slot_ops octep_hp_slot_ops = {
+	.enable_slot = octep_hp_enable_slot,
+	.disable_slot = octep_hp_disable_slot,
+};
+
+#define SLOT_NAME_SIZE 16
+static struct octep_hp_slot *
+octep_hp_register_slot(struct octep_hp_controller *hp_ctrl,
+		       struct pci_dev *pdev, u16 slot_number)
+{
+	char slot_name[SLOT_NAME_SIZE];
+	struct octep_hp_slot *hp_slot;
+	int ret;
+
+	hp_slot = kzalloc(sizeof(*hp_slot), GFP_KERNEL);
+	if (!hp_slot)
+		return ERR_PTR(-ENOMEM);
+
+	hp_slot->ctrl = hp_ctrl;
+	hp_slot->hp_pdev = pdev;
+	hp_slot->hp_devfn = pdev->devfn;
+	hp_slot->slot_number = slot_number;
+	hp_slot->slot.ops = &octep_hp_slot_ops;
+
+	snprintf(slot_name, sizeof(slot_name), "octep_hp_%u", slot_number);
+	ret = pci_hp_register(&hp_slot->slot, hp_ctrl->pdev->bus,
+			      PCI_SLOT(pdev->devfn), slot_name);
+	if (ret) {
+		kfree(hp_slot);
+		return ERR_PTR(ret);
+	}
+
+	pci_info(pdev, "Registered slot %s for device %s\n",
+		 slot_name, pci_name(pdev));
+
+	list_add_tail(&hp_slot->list, &hp_ctrl->slot_list);
+	octep_hp_disable_pdev(hp_ctrl, hp_slot);
+
+	return hp_slot;
+}
+
+static void octep_hp_deregister_slot(void *data)
+{
+	struct octep_hp_slot *hp_slot = data;
+	struct octep_hp_controller *hp_ctrl = hp_slot->ctrl;
+
+	pci_hp_deregister(&hp_slot->slot);
+	octep_hp_enable_pdev(hp_ctrl, hp_slot);
+	list_del(&hp_slot->list);
+	kfree(hp_slot);
+}
+
+static const char *octep_hp_cmd_name(enum octep_hp_intr_type type)
+{
+	switch (type) {
+	case OCTEP_HP_INTR_ENA:
+		return "hotplug enable";
+	case OCTEP_HP_INTR_DIS:
+		return "hotplug disable";
+	default:
+		return "invalid";
+	}
+}
+
+static void octep_hp_cmd_handler(struct octep_hp_controller *hp_ctrl,
+				 struct octep_hp_cmd *hp_cmd)
+{
+	struct octep_hp_slot *hp_slot;
+
+	/*
+	 * Enable or disable the slots based on the slot mask.
+	 * intr_val is a bit mask where each bit represents a slot.
+	 */
+	list_for_each_entry(hp_slot, &hp_ctrl->slot_list, list) {
+		if (!(hp_cmd->intr_val & BIT(hp_slot->slot_number)))
+			continue;
+
+		pci_info(hp_ctrl->pdev, "Received %s command for slot %s\n",
+			 octep_hp_cmd_name(hp_cmd->intr_type),
+			 hotplug_slot_name(&hp_slot->slot));
+
+		switch (hp_cmd->intr_type) {
+		case OCTEP_HP_INTR_ENA:
+			octep_hp_enable_pdev(hp_ctrl, hp_slot);
+			break;
+		case OCTEP_HP_INTR_DIS:
+			octep_hp_disable_pdev(hp_ctrl, hp_slot);
+			break;
+		default:
+			break;
+		}
+	}
+}
+
+static void octep_hp_work_handler(struct work_struct *work)
+{
+	struct octep_hp_controller *hp_ctrl;
+	struct octep_hp_cmd *hp_cmd;
+	unsigned long flags;
+
+	hp_ctrl = container_of(work, struct octep_hp_controller, work);
+
+	/* Process all the hotplug commands */
+	spin_lock_irqsave(&hp_ctrl->hp_cmd_lock, flags);
+	while (!list_empty(&hp_ctrl->hp_cmd_list)) {
+		hp_cmd = list_first_entry(&hp_ctrl->hp_cmd_list,
+					  struct octep_hp_cmd, list);
+		list_del(&hp_cmd->list);
+		spin_unlock_irqrestore(&hp_ctrl->hp_cmd_lock, flags);
+
+		octep_hp_cmd_handler(hp_ctrl, hp_cmd);
+		kfree(hp_cmd);
+
+		spin_lock_irqsave(&hp_ctrl->hp_cmd_lock, flags);
+	}
+	spin_unlock_irqrestore(&hp_ctrl->hp_cmd_lock, flags);
+}
+
+static enum octep_hp_intr_type octep_hp_intr_type(struct octep_hp_intr_info *intr,
+						  int irq)
+{
+	enum octep_hp_intr_type type;
+
+	for (type = OCTEP_HP_INTR_ENA; type < OCTEP_HP_INTR_MAX; type++) {
+		if (intr[type].number == irq)
+			return type;
+	}
+
+	return OCTEP_HP_INTR_INVALID;
+}
+
+static irqreturn_t octep_hp_intr_handler(int irq, void *data)
+{
+	struct octep_hp_controller *hp_ctrl = data;
+	struct pci_dev *pdev = hp_ctrl->pdev;
+	enum octep_hp_intr_type type;
+	struct octep_hp_cmd *hp_cmd;
+	u64 intr_val;
+
+	type = octep_hp_intr_type(hp_ctrl->intr, irq);
+	if (type == OCTEP_HP_INTR_INVALID) {
+		pci_err(pdev, "Invalid interrupt %d\n", irq);
+		return IRQ_HANDLED;
+	}
+
+	/* Read and clear the interrupt */
+	intr_val = readq(hp_ctrl->base + OCTEP_HP_INTR_OFFSET(type));
+	writeq(intr_val, hp_ctrl->base + OCTEP_HP_INTR_OFFSET(type));
+
+	hp_cmd = kzalloc(sizeof(*hp_cmd), GFP_ATOMIC);
+	if (!hp_cmd)
+		return IRQ_HANDLED;
+
+	hp_cmd->intr_val = intr_val;
+	hp_cmd->intr_type = type;
+
+	/* Add the command to the list and schedule the work */
+	spin_lock(&hp_ctrl->hp_cmd_lock);
+	list_add_tail(&hp_cmd->list, &hp_ctrl->hp_cmd_list);
+	spin_unlock(&hp_ctrl->hp_cmd_lock);
+	schedule_work(&hp_ctrl->work);
+
+	return IRQ_HANDLED;
+}
+
+static void octep_hp_irq_cleanup(void *data)
+{
+	struct octep_hp_controller *hp_ctrl = data;
+
+	pci_free_irq_vectors(hp_ctrl->pdev);
+	flush_work(&hp_ctrl->work);
+}
+
+static int octep_hp_request_irq(struct octep_hp_controller *hp_ctrl,
+				enum octep_hp_intr_type type)
+{
+	struct pci_dev *pdev = hp_ctrl->pdev;
+	struct octep_hp_intr_info *intr;
+	int irq;
+
+	irq = pci_irq_vector(pdev, OCTEP_HP_INTR_VECTOR(type));
+	if (irq < 0)
+		return irq;
+
+	intr = &hp_ctrl->intr[type];
+	intr->number = irq;
+	intr->type = type;
+	snprintf(intr->name, sizeof(intr->name), "octep_hp_%d", type);
+
+	return devm_request_irq(&pdev->dev, irq, octep_hp_intr_handler,
+				IRQF_SHARED, intr->name, hp_ctrl);
+}
+
+static int octep_hp_controller_setup(struct pci_dev *pdev,
+				     struct octep_hp_controller *hp_ctrl)
+{
+	struct device *dev = &pdev->dev;
+	enum octep_hp_intr_type type;
+	int ret;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable PCI device\n");
+
+	hp_ctrl->base = pcim_iomap_region(pdev, 0, OCTEP_HP_DRV_NAME);
+	if (IS_ERR(hp_ctrl->base))
+		return dev_err_probe(dev, PTR_ERR(hp_ctrl->base),
+				     "Failed to map PCI device region\n");
+
+	pci_set_master(pdev);
+	pci_set_drvdata(pdev, hp_ctrl);
+
+	INIT_LIST_HEAD(&hp_ctrl->slot_list);
+	INIT_LIST_HEAD(&hp_ctrl->hp_cmd_list);
+	mutex_init(&hp_ctrl->slot_lock);
+	spin_lock_init(&hp_ctrl->hp_cmd_lock);
+	INIT_WORK(&hp_ctrl->work, octep_hp_work_handler);
+	hp_ctrl->pdev = pdev;
+
+	ret = pci_alloc_irq_vectors(pdev, 1,
+				    OCTEP_HP_INTR_VECTOR(OCTEP_HP_INTR_MAX),
+				    PCI_IRQ_MSIX);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Failed to alloc MSI-X vectors\n");
+
+	ret = devm_add_action(&pdev->dev, octep_hp_irq_cleanup, hp_ctrl);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "Failed to add IRQ cleanup action\n");
+
+	for (type = OCTEP_HP_INTR_ENA; type < OCTEP_HP_INTR_MAX; type++) {
+		ret = octep_hp_request_irq(hp_ctrl, type);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "Failed to request IRQ for vector %d\n",
+					     OCTEP_HP_INTR_VECTOR(type));
+	}
+
+	return 0;
+}
+
+static int octep_hp_pci_probe(struct pci_dev *pdev,
+			      const struct pci_device_id *id)
+{
+	struct octep_hp_controller *hp_ctrl;
+	struct pci_dev *tmp_pdev, *next;
+	struct octep_hp_slot *hp_slot;
+	u16 slot_number = 0;
+	int ret;
+
+	hp_ctrl = devm_kzalloc(&pdev->dev, sizeof(*hp_ctrl), GFP_KERNEL);
+	if (!hp_ctrl)
+		return -ENOMEM;
+
+	ret = octep_hp_controller_setup(pdev, hp_ctrl);
+	if (ret)
+		return ret;
+
+	/*
+	 * Register all hotplug slots. Hotplug controller is the first function
+	 * of the PCI device. The hotplug slots are the remaining functions of
+	 * the PCI device. The hotplug slot functions are logically removed from
+	 * the bus during probing and are re-enabled by the driver when a
+	 * hotplug event is received.
+	 */
+	list_for_each_entry_safe(tmp_pdev, next, &pdev->bus->devices, bus_list) {
+		if (tmp_pdev == pdev)
+			continue;
+
+		hp_slot = octep_hp_register_slot(hp_ctrl, tmp_pdev, slot_number);
+		if (IS_ERR(hp_slot))
+			return dev_err_probe(&pdev->dev, PTR_ERR(hp_slot),
+					     "Failed to register hotplug slot %u\n",
+					     slot_number);
+
+		ret = devm_add_action(&pdev->dev, octep_hp_deregister_slot,
+				      hp_slot);
+		if (ret)
+			return dev_err_probe(&pdev->dev, ret,
+					     "Failed to add action for deregistering slot %u\n",
+					     slot_number);
+		slot_number++;
+	}
+
+	return 0;
+}
+
+#define PCI_DEVICE_ID_CAVIUM_OCTEP_HP_CTLR  0xa0e3
+static struct pci_device_id octep_hp_pci_map[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, PCI_DEVICE_ID_CAVIUM_OCTEP_HP_CTLR) },
+	{ },
+};
+
+static struct pci_driver octep_hp = {
+	.name = OCTEP_HP_DRV_NAME,
+	.id_table = octep_hp_pci_map,
+	.probe = octep_hp_pci_probe,
+};
+
+module_pci_driver(octep_hp);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Marvell");
+MODULE_DESCRIPTION("Marvell OCTEON PCI Hotplug driver");