On Tue, 20 Aug 2024, Shijith Thotton wrote:
> This patch introduces a PCI hotplug controller driver for the OCTEON
> PCIe device, a multi-function PCIe device where the first function acts
> as a hotplug controller. It is equipped with MSI-x interrupts to notify
> the host of hotplug events from the OCTEON firmware.
>
> The driver facilitates the hotplugging of non-controller functions
> within the same device. During probe, non-controller functions are
> removed and registered as PCI hotplug slots. The slots are added back
> only upon request from the device firmware. The driver also allows the
> enabling and disabling of the slots via sysfs slot entries, provided by
> the PCI hotplug framework.
>
> Signed-off-by: Shijith Thotton <sthotton@xxxxxxxxxxx>
> Signed-off-by: Vamsi Attunuru <vattunuru@xxxxxxxxxxx>
> ---
>
> This patch introduces a PCI hotplug controller driver for OCTEON PCIe hotplug
> controller. The OCTEON PCIe device is a multi-function device where the first
> function acts as a PCI hotplug controller.
>
> +--------------------------------+
> | Root Port |
> +--------------------------------+
> |
> PCIe
> |
> +---------------------------------------------------------------+
> | OCTEON PCIe Multifunction Device |
> +---------------------------------------------------------------+
> | | | |
> | | | |
> +---------------------+ +----------------+ +-----+ +----------------+
> | Function 0 | | Function 1 | | ... | | Function 7 |
> | (Hotplug controller)| | (Hotplug slot) | | | | (Hotplug slot) |
> +---------------------+ +----------------+ +-----+ +----------------+
> |
> |
> +-------------------------+
> | Controller Firmware |
> +-------------------------+
>
> The hotplug controller driver facilitates the hotplugging of non-controller
> functions in the same device. During the probe of the driver, the non-controller
> function are removed and registered as PCI hotplug slots. They are added back
> only upon request from the device firmware. The driver also allows the user to
> enable/disable the functions using sysfs slot entries provided by PCI hotplug
> framework.
>
> This solution adopts a hardware + software approach for several reasons:
>
> 1. To reduce hardware implementation cost. Supporting complete hotplug
> capability within the card would require a PCI switch implemented within.
>
> 2. In the multi-function device, non-controller functions can act as emulated
> devices. The firmware can dynamically enable or disable them at runtime.
>
> 3. Not all root ports support PCI hotplug. This approach provides greater
> flexibility and compatibility across different hardware configurations.
>
> The hotplug controller function is lightweight and is equipped with MSI-x
> interrupts to notify the host about hotplug events. Upon receiving an
> interrupt, the hotplug register is read, and the required function is enabled
> or disabled.
>
> This driver will be beneficial for managing PCI hotplug events on the OCTEON
> PCIe device without requiring complex hardware solutions.
>
> MAINTAINERS | 6 +
> drivers/pci/hotplug/Kconfig | 10 +
> drivers/pci/hotplug/Makefile | 1 +
> drivers/pci/hotplug/octep_hp.c | 351 +++++++++++++++++++++++++++++++++
> 4 files changed, 368 insertions(+)
> create mode 100644 drivers/pci/hotplug/octep_hp.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 42decde38320..7b5a618eed1c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13677,6 +13677,12 @@ R: schalla@xxxxxxxxxxx
> R: vattunuru@xxxxxxxxxxx
> F: drivers/vdpa/octeon_ep/
>
> +MARVELL OCTEON HOTPLUG CONTROLLER DRIVER
> +R: Shijith Thotton <sthotton@xxxxxxxxxxx>
> +R: Vamsi Attunuru <vattunuru@xxxxxxxxxxx>
> +S: Supported
> +F: drivers/pci/hotplug/octep_hp.c
> +
> MATROX FRAMEBUFFER DRIVER
> L: linux-fbdev@xxxxxxxxxxxxxxx
> S: Orphan
> diff --git a/drivers/pci/hotplug/Kconfig b/drivers/pci/hotplug/Kconfig
> index 1472aef0fb81..2e38fd25f7ef 100644
> --- a/drivers/pci/hotplug/Kconfig
> +++ b/drivers/pci/hotplug/Kconfig
> @@ -173,4 +173,14 @@ config HOTPLUG_PCI_S390
>
> When in doubt, say Y.
>
> +config HOTPLUG_PCI_OCTEONEP
> + bool "OCTEON PCI device Hotplug controller 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.
> +
> endif # HOTPLUG_PCI
> diff --git a/drivers/pci/hotplug/Makefile b/drivers/pci/hotplug/Makefile
> index 240c99517d5e..40aaf31fe338 100644
> --- a/drivers/pci/hotplug/Makefile
> +++ b/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.
>
> diff --git a/drivers/pci/hotplug/octep_hp.c b/drivers/pci/hotplug/octep_hp.c
> new file mode 100644
> index 000000000000..efeb542d4993
> --- /dev/null
> +++ b/drivers/pci/hotplug/octep_hp.c
> @@ -0,0 +1,351 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Copyright (C) 2024 Marvell. */
> +
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/pci_hotplug.h>
> +#include <linux/slab.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"
> +
> +/* Interrupt vectors for hotplug enable and disable events. */
> +enum octep_hp_vec_type {
> + OCTEP_HP_VEC_ENA,
> + OCTEP_HP_VEC_DIS,
If I understand your code right, these cannot be arbitrary numbers but has
to be specific numbers to match the vector number so you should explicitly
set them to those values.
> +};
> +
> +struct octep_hp_cmd {
> + struct list_head list;
Missing include for list_head.
> + enum octep_hp_vec_type vec_type;
> + u64 slot_mask;
> +};
> +
> +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_controller {
> + void __iomem *base;
> + struct pci_dev *pdev;
> + struct work_struct work;
Missing include.
> + struct list_head slot_list;
> + struct mutex slot_lock; /* Protects slot_list */
Missing include.
> + 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)
> +{
> + mutex_lock(&hp_ctrl->slot_lock);
Use guard().
> + if (hp_slot->hp_pdev) {
> + dev_dbg(&hp_slot->hp_pdev->dev, "Slot %u already enabled\n", hp_slot->slot_number);
> + mutex_unlock(&hp_ctrl->slot_lock);
> + 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 %u\n", hp_slot->slot_number);
Missing include for dev_dbg().
> + mutex_unlock(&hp_ctrl->slot_lock);
> +}
> +
> +static void octep_hp_disable_pdev(struct octep_hp_controller *hp_ctrl,
> + struct octep_hp_slot *hp_slot)
> +{
> + mutex_lock(&hp_ctrl->slot_lock);
Use guard().
> + if (!hp_slot->hp_pdev) {
> + dev_dbg(&hp_ctrl->pdev->dev, "Slot %u already disabled\n", hp_slot->slot_number);
> + mutex_unlock(&hp_ctrl->slot_lock);
> + return;
> + }
> +
> + dev_dbg(&hp_slot->hp_pdev->dev, "Disabling slot %u\n", hp_slot->slot_number);
> +
> + /* Remove the device from the bus */
> + pci_stop_and_remove_bus_device_locked(hp_slot->hp_pdev);
> + hp_slot->hp_pdev = NULL;
> + mutex_unlock(&hp_ctrl->slot_lock);
> +}
> +
> +static int octep_hp_enable_slot(struct hotplug_slot *slot)
> +{
> + struct octep_hp_slot *hp_slot = container_of(slot, struct octep_hp_slot, slot);
Missing include for container_of().
> +
> + 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 int 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 -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, SLOT_NAME_SIZE, "octep_hp_%u", slot_number);
SLOT_NAME_SIZE -> sizeof(slot_name)
> + ret = pci_hp_register(&hp_slot->slot, hp_ctrl->pdev->bus, PCI_SLOT(pdev->devfn), slot_name);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to register hotplug slot %u\n", slot_number);
> + kfree(hp_slot);
> + return ret;
> + }
> +
> + octep_hp_disable_pdev(hp_ctrl, hp_slot);
> + list_add_tail(&hp_slot->list, &hp_ctrl->slot_list);
> +
> + return 0;
> +}
> +
> +static bool octep_hp_slot(struct octep_hp_controller *hp_ctrl, struct pci_dev *pdev)
> +{
> + /* Check if the PCI device can be hotplugged */
> + return pdev != hp_ctrl->pdev && pdev->bus == hp_ctrl->pdev->bus &&
> + PCI_SLOT(pdev->devfn) == PCI_SLOT(hp_ctrl->pdev->devfn);
> +}
> +
> +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 */
> + list_for_each_entry(hp_slot, &hp_ctrl->slot_list, list) {
> + if (hp_cmd->slot_mask & BIT(hp_slot->slot_number)) {
Reverse logic & use continue ?
> + if (hp_cmd->vec_type == OCTEP_HP_VEC_ENA)
> + octep_hp_enable_pdev(hp_ctrl, hp_slot);
> + else
> + octep_hp_disable_pdev(hp_ctrl, hp_slot);
> + }
> + }
> +}
> +
> +static void octep_hp_work_handler(struct work_struct *work)
> +{
> + struct octep_hp_controller *hp_ctrl = container_of(work, struct octep_hp_controller, work);
> + struct octep_hp_cmd *hp_cmd;
> + unsigned long flags;
> +
> + /* 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 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_vec_type vec_type;
> + struct octep_hp_cmd *hp_cmd;
> + u64 slot_mask;
> +
> + vec_type = pci_irq_vector(pdev, OCTEP_HP_INTR_VECTOR(OCTEP_HP_VEC_ENA)) == irq ?
> + OCTEP_HP_VEC_ENA : OCTEP_HP_VEC_DIS;
This is a bit unusual and complicated to do all this in one statement. But
can't you just store that ena irq number into struct octep_hp_controller
so you don't need to make the call here every time?
> + slot_mask = readq(hp_ctrl->base + OCTEP_HP_INTR_OFFSET(vec_type));
> + if (!slot_mask) {
> + dev_err(&pdev->dev, "Invalid slot mask %llx\n", slot_mask);
> + return IRQ_HANDLED;
> + }
> +
> + hp_cmd = kzalloc(sizeof(*hp_cmd), GFP_ATOMIC);
> + if (!hp_cmd)
> + return IRQ_HANDLED;
> +
> + hp_cmd->slot_mask = slot_mask;
> + hp_cmd->vec_type = vec_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);
> +
> + /* Clear the interrupt */
> + writeq(slot_mask, hp_ctrl->base + OCTEP_HP_INTR_OFFSET(vec_type));
> +
> + return IRQ_HANDLED;
> +}
> +
> +static void octep_hp_deregister_slots(struct octep_hp_controller *hp_ctrl)
> +{
> + struct octep_hp_slot *hp_slot, *tmp;
> +
> + /* Deregister all the hotplug slots */
> + list_for_each_entry_safe(hp_slot, tmp, &hp_ctrl->slot_list, list) {
> + pci_hp_deregister(&hp_slot->slot);
> + octep_hp_enable_pdev(hp_ctrl, hp_slot);
> + list_del(&hp_slot->list);
> + kfree(hp_slot);
> + }
> +}
> +
> +static void octep_hp_controller_cleanup(void *data)
> +{
> + struct octep_hp_controller *hp_ctrl = data;
> +
> + pci_free_irq_vectors(hp_ctrl->pdev);
> + flush_work(&hp_ctrl->work);
> + octep_hp_deregister_slots(hp_ctrl);
> +}
> +
> +static int octep_hp_controller_setup(struct pci_dev *pdev, struct octep_hp_controller *hp_ctrl)
> +{
> + struct device *dev = &pdev->dev;
> + int ret;
> +
> + ret = pcim_enable_device(pdev);
> + if (ret) {
> + dev_err(dev, "Failed to enable PCI device\n");
> + return ret;
> + }
> +
> + ret = pcim_iomap_regions(pdev, BIT(0), OCTEP_HP_DRV_NAME);
> + if (ret) {
> + dev_err(dev, "Failed to request MMIO region\n");
> + return ret;
> + }
> +
> + 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;
> + hp_ctrl->base = pcim_iomap_table(pdev)[0];
> + if (!hp_ctrl->base) {
> + dev_err(dev, "Failed to get device resource map\n");
> + return -ENODEV;
> + }
> +
> + ret = pci_alloc_irq_vectors(pdev, 1, OCTEP_HP_INTR_VECTOR(OCTEP_HP_VEC_DIS) + 1,
> + PCI_IRQ_MSIX);
> + if (ret < 0) {
> + dev_err(dev, "Failed to alloc MSI-X vectors");
> + return ret;
> + }
> +
> + ret = devm_add_action(dev, octep_hp_controller_cleanup, hp_ctrl);
> + if (ret) {
> + dev_err(dev, "Failed to add action for controller cleanup\n");
> + return ret;
> + }
> +
> + ret = devm_request_irq(dev, pci_irq_vector(pdev, OCTEP_HP_INTR_VECTOR(OCTEP_HP_VEC_ENA)),
> + octep_hp_intr_handler, 0, "octep_hp_ena", hp_ctrl);
> + if (ret) {
> + dev_err(dev, "Failed to register slot enable interrupt handle\n");
> + return ret;
> + }
> +
> + ret = devm_request_irq(dev, pci_irq_vector(pdev, OCTEP_HP_INTR_VECTOR(OCTEP_HP_VEC_DIS)),
> + octep_hp_intr_handler, 0, "octep_hp_dis", hp_ctrl);
> + if (ret) {
> + dev_err(dev, "Failed to register slot disable interrupt handle\n");
> + return ret;
> + }
> +
> + 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 = NULL;
> + 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) {
> + dev_err(&pdev->dev, "Failed to setup octep controller\n");
So both octep_hp_controller_setup() and this function print an error?
Wouldn't the one from octep_hp_controller_setup() suffice?
--
i.
> + 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. They are removed from
> + * the bus and are added back when the hotplug event is triggered.
Reflow the comment to 80 chars.
> + */
> + for_each_pci_dev(tmp_pdev) {
> + if (octep_hp_slot(hp_ctrl, tmp_pdev)) {
Reverse logic & use continue.
> + ret = octep_hp_register_slot(hp_ctrl, tmp_pdev, slot_number++);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to register hotplug slots.\n");
> + return ret;
> + }
> + }
> + }
> +
> + return 0;
> +}
> +
> +#define OCTEP_DEVID_HP_CONTROLLER 0xa0e3
> +static struct pci_device_id octep_hp_pci_map[] = {
> + { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, OCTEP_DEVID_HP_CONTROLLER) },
> + { 0 },
> +};
> +
> +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("OCTEON PCIe device hotplug controller driver");
>
