linux/drivers/pci/hotplug/s390_pci_hpc.c
Niklas Schnelle da995d538d s390/pci: implement reset_slot for hotplug slot
This is done by adding a zpci_hot_reset_device() call which does a low
level reset of the PCI function without changing its higher level
function state. This way it can be used while the zPCI function is bound
to a driver and with DMA tables being controlled either through the
IOMMU or DMA APIs which is prohibited when using zpci_disable_device()
as that drop existing DMA translations.

As this reset, unlike a normal FLR, also calls zpci_clear_irq() we need
to implement arch_restore_msi_irqs() and make sure we re-enable IRQs for
the PCI function if they were previously disabled.

Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2021-11-08 14:17:49 +01:00

123 lines
3.0 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* PCI Hot Plug Controller Driver for System z
*
* Copyright 2012 IBM Corp.
*
* Author(s):
* Jan Glauber <jang@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "zpci"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <asm/pci_debug.h>
#include <asm/sclp.h>
#define SLOT_NAME_SIZE 10
static int enable_slot(struct hotplug_slot *hotplug_slot)
{
struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
hotplug_slot);
int rc;
if (zdev->state != ZPCI_FN_STATE_STANDBY)
return -EIO;
rc = sclp_pci_configure(zdev->fid);
zpci_dbg(3, "conf fid:%x, rc:%d\n", zdev->fid, rc);
if (rc)
return rc;
zdev->state = ZPCI_FN_STATE_CONFIGURED;
return zpci_scan_configured_device(zdev, zdev->fh);
}
static int disable_slot(struct hotplug_slot *hotplug_slot)
{
struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
hotplug_slot);
struct pci_dev *pdev;
if (zdev->state != ZPCI_FN_STATE_CONFIGURED)
return -EIO;
pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
if (pdev && pci_num_vf(pdev)) {
pci_dev_put(pdev);
return -EBUSY;
}
pci_dev_put(pdev);
return zpci_deconfigure_device(zdev);
}
static int reset_slot(struct hotplug_slot *hotplug_slot, bool probe)
{
struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
hotplug_slot);
if (zdev->state != ZPCI_FN_STATE_CONFIGURED)
return -EIO;
/*
* We can't take the zdev->lock as reset_slot may be called during
* probing and/or device removal which already happens under the
* zdev->lock. Instead the user should use the higher level
* pci_reset_function() or pci_bus_reset() which hold the PCI device
* lock preventing concurrent removal. If not using these functions
* holding the PCI device lock is required.
*/
/* As long as the function is configured we can reset */
if (probe)
return 0;
return zpci_hot_reset_device(zdev);
}
static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
hotplug_slot);
*value = zpci_is_device_configured(zdev) ? 1 : 0;
return 0;
}
static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
/* if the slot exits it always contains a function */
*value = 1;
return 0;
}
static const struct hotplug_slot_ops s390_hotplug_slot_ops = {
.enable_slot = enable_slot,
.disable_slot = disable_slot,
.reset_slot = reset_slot,
.get_power_status = get_power_status,
.get_adapter_status = get_adapter_status,
};
int zpci_init_slot(struct zpci_dev *zdev)
{
char name[SLOT_NAME_SIZE];
struct zpci_bus *zbus = zdev->zbus;
zdev->hotplug_slot.ops = &s390_hotplug_slot_ops;
snprintf(name, SLOT_NAME_SIZE, "%08x", zdev->fid);
return pci_hp_register(&zdev->hotplug_slot, zbus->bus,
zdev->devfn, name);
}
void zpci_exit_slot(struct zpci_dev *zdev)
{
pci_hp_deregister(&zdev->hotplug_slot);
}