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7903782460
linux/drivers/pci/hotplug/pciehp_core.c
Lukas Wunner 7903782460 PCI: pciehp: Clear spurious events earlier on resume 
Thunderbolt hotplug ports that were occupied before system sleep resume
with their downstream link in "off" state.  Only after the Thunderbolt
controller has reestablished the PCIe tunnels does the link go up.
As a result, a spurious Presence Detect Changed and/or Data Link Layer
State Changed event occurs.

The events are not immediately acted upon because tunnel reestablishment
happens in the ->resume_noirq phase, when interrupts are still disabled.
Also, notification of events may initially be disabled in the Slot
Control register when coming out of system sleep and is reenabled in the
->resume_noirq phase through:

  pci_pm_resume_noirq()
    pci_pm_default_resume_early()
      pci_restore_state()
        pci_restore_pcie_state()

It is not guaranteed that the events are acted upon at all:  PCIe r4.0,
sec 6.7.3.4 says that "a port may optionally send an MSI when there are
hot-plug events that occur while interrupt generation is disabled, and
interrupt generation is subsequently enabled."  Note the "optionally".

If an MSI is sent, pciehp will gratuitously turn the slot off and back
on once the ->resume_early phase has commenced.

If an MSI is not sent, the extant, unacknowledged events in the Slot
Status register will prevent future notification of presence or link
changes.

Commit 13c65840fe ("PCI: pciehp: Clear Presence Detect and Data Link
Layer Status Changed on resume") fixed the latter by clearing the events
in the ->resume phase.  Move this to the ->resume_noirq phase to also
fix the gratuitous disable/enablement of the slot.

The commit further restored the Slot Control register in the ->resume
phase, but that's dispensable because as shown above it's already been
done in the ->resume_noirq phase.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-07-31 11:07:59 -05:00

344 lines
8.7 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0+
/*
* PCI Express Hot Plug Controller Driver
*
* Copyright (C) 1995,2001 Compaq Computer Corporation
* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
* Copyright (C) 2001 IBM Corp.
* Copyright (C) 2003-2004 Intel Corporation
*
* All rights reserved.
*
* Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
*
* Authors:
* Dan Zink <dan.zink@compaq.com>
* Greg Kroah-Hartman <greg@kroah.com>
* Dely Sy <dely.l.sy@intel.com>"
*/
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/pci.h>
#include "pciehp.h"
#include <linux/interrupt.h>
#include <linux/time.h>
/* Global variables */
bool pciehp_debug;
bool pciehp_poll_mode;
int pciehp_poll_time;
/*
* not really modular, but the easiest way to keep compat with existing
* bootargs behaviour is to continue using module_param here.
*/
module_param(pciehp_debug, bool, 0644);
module_param(pciehp_poll_mode, bool, 0644);
module_param(pciehp_poll_time, int, 0644);
MODULE_PARM_DESC(pciehp_debug, "Debugging mode enabled or not");
MODULE_PARM_DESC(pciehp_poll_mode, "Using polling mechanism for hot-plug events or not");
MODULE_PARM_DESC(pciehp_poll_time, "Polling mechanism frequency, in seconds");
#define PCIE_MODULE_NAME "pciehp"
static int set_attention_status(struct hotplug_slot *slot, u8 value);
static int enable_slot(struct hotplug_slot *slot);
static int disable_slot(struct hotplug_slot *slot);
static int get_power_status(struct hotplug_slot *slot, u8 *value);
static int get_attention_status(struct hotplug_slot *slot, u8 *value);
static int get_latch_status(struct hotplug_slot *slot, u8 *value);
static int get_adapter_status(struct hotplug_slot *slot, u8 *value);
static int reset_slot(struct hotplug_slot *slot, int probe);
static int init_slot(struct controller *ctrl)
{
struct slot *slot = ctrl->slot;
struct hotplug_slot *hotplug = NULL;
struct hotplug_slot_info *info = NULL;
struct hotplug_slot_ops *ops = NULL;
char name[SLOT_NAME_SIZE];
int retval = -ENOMEM;
hotplug = kzalloc(sizeof(*hotplug), GFP_KERNEL);
if (!hotplug)
goto out;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info)
goto out;
/* Setup hotplug slot ops */
ops = kzalloc(sizeof(*ops), GFP_KERNEL);
if (!ops)
goto out;
ops->enable_slot = enable_slot;
ops->disable_slot = disable_slot;
ops->get_power_status = get_power_status;
ops->get_adapter_status = get_adapter_status;
ops->reset_slot = reset_slot;
if (MRL_SENS(ctrl))
ops->get_latch_status = get_latch_status;
if (ATTN_LED(ctrl)) {
ops->get_attention_status = get_attention_status;
ops->set_attention_status = set_attention_status;
} else if (ctrl->pcie->port->hotplug_user_indicators) {
ops->get_attention_status = pciehp_get_raw_indicator_status;
ops->set_attention_status = pciehp_set_raw_indicator_status;
}
/* register this slot with the hotplug pci core */
hotplug->info = info;
hotplug->private = slot;
hotplug->ops = ops;
slot->hotplug_slot = hotplug;
snprintf(name, SLOT_NAME_SIZE, "%u", PSN(ctrl));
retval = pci_hp_initialize(hotplug,
ctrl->pcie->port->subordinate, 0, name);
if (retval)
ctrl_err(ctrl, "pci_hp_initialize failed: error %d\n", retval);
out:
if (retval) {
kfree(ops);
kfree(info);
kfree(hotplug);
}
return retval;
}
static void cleanup_slot(struct controller *ctrl)
{
struct hotplug_slot *hotplug_slot = ctrl->slot->hotplug_slot;
pci_hp_destroy(hotplug_slot);
kfree(hotplug_slot->ops);
kfree(hotplug_slot->info);
kfree(hotplug_slot);
}
/*
* set_attention_status - Turns the Amber LED for a slot on, off or blink
*/
static int set_attention_status(struct hotplug_slot *hotplug_slot, u8 status)
{
struct slot *slot = hotplug_slot->private;
pciehp_set_attention_status(slot, status);
return 0;
}
static int enable_slot(struct hotplug_slot *hotplug_slot)
{
struct slot *slot = hotplug_slot->private;
return pciehp_sysfs_enable_slot(slot);
}
static int disable_slot(struct hotplug_slot *hotplug_slot)
{
struct slot *slot = hotplug_slot->private;
return pciehp_sysfs_disable_slot(slot);
}
static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = hotplug_slot->private;
pciehp_get_power_status(slot, value);
return 0;
}
static int get_attention_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = hotplug_slot->private;
pciehp_get_attention_status(slot, value);
return 0;
}
static int get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = hotplug_slot->private;
pciehp_get_latch_status(slot, value);
return 0;
}
static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = hotplug_slot->private;
pciehp_get_adapter_status(slot, value);
return 0;
}
static int reset_slot(struct hotplug_slot *hotplug_slot, int probe)
{
struct slot *slot = hotplug_slot->private;
return pciehp_reset_slot(slot, probe);
}
static int pciehp_probe(struct pcie_device *dev)
{
int rc;
struct controller *ctrl;
struct slot *slot;
u8 occupied, poweron;
/* If this is not a "hotplug" service, we have no business here. */
if (dev->service != PCIE_PORT_SERVICE_HP)
return -ENODEV;
if (!dev->port->subordinate) {
/* Can happen if we run out of bus numbers during probe */
dev_err(&dev->device,
"Hotplug bridge without secondary bus, ignoring\n");
return -ENODEV;
}
ctrl = pcie_init(dev);
if (!ctrl) {
dev_err(&dev->device, "Controller initialization failed\n");
return -ENODEV;
}
set_service_data(dev, ctrl);
/* Setup the slot information structures */
rc = init_slot(ctrl);
if (rc) {
if (rc == -EBUSY)
ctrl_warn(ctrl, "Slot already registered by another hotplug driver\n");
else
ctrl_err(ctrl, "Slot initialization failed (%d)\n", rc);
goto err_out_release_ctlr;
}
/* Enable events after we have setup the data structures */
rc = pcie_init_notification(ctrl);
if (rc) {
ctrl_err(ctrl, "Notification initialization failed (%d)\n", rc);
goto err_out_free_ctrl_slot;
}
/* Publish to user space */
slot = ctrl->slot;
rc = pci_hp_add(slot->hotplug_slot);
if (rc) {
ctrl_err(ctrl, "Publication to user space failed (%d)\n", rc);
goto err_out_shutdown_notification;
}
/* Check if slot is occupied */
down_read(&ctrl->reset_lock);
mutex_lock(&slot->lock);
pciehp_get_adapter_status(slot, &occupied);
pciehp_get_power_status(slot, &poweron);
if ((occupied && (slot->state == OFF_STATE ||
slot->state == BLINKINGON_STATE)) ||
(!occupied && (slot->state == ON_STATE ||
slot->state == BLINKINGOFF_STATE)))
pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
/* If empty slot's power status is on, turn power off */
if (!occupied && poweron && POWER_CTRL(ctrl))
pciehp_power_off_slot(slot);
mutex_unlock(&slot->lock);
up_read(&ctrl->reset_lock);
return 0;
err_out_shutdown_notification:
pcie_shutdown_notification(ctrl);
err_out_free_ctrl_slot:
cleanup_slot(ctrl);
err_out_release_ctlr:
pciehp_release_ctrl(ctrl);
return -ENODEV;
}
static void pciehp_remove(struct pcie_device *dev)
{
struct controller *ctrl = get_service_data(dev);
pci_hp_del(ctrl->slot->hotplug_slot);
pcie_shutdown_notification(ctrl);
cleanup_slot(ctrl);
pciehp_release_ctrl(ctrl);
}
#ifdef CONFIG_PM
static int pciehp_suspend(struct pcie_device *dev)
{
return 0;
}
static int pciehp_resume_noirq(struct pcie_device *dev)
{
struct controller *ctrl = get_service_data(dev);
struct slot *slot = ctrl->slot;
/* clear spurious events from rediscovery of inserted card */
if (slot->state == ON_STATE || slot->state == BLINKINGOFF_STATE)
pcie_clear_hotplug_events(ctrl);
return 0;
}
static int pciehp_resume(struct pcie_device *dev)
{
struct controller *ctrl;
struct slot *slot;
u8 status;
ctrl = get_service_data(dev);
slot = ctrl->slot;
/* Check if slot is occupied */
pciehp_get_adapter_status(slot, &status);
mutex_lock(&slot->lock);
if ((status && (slot->state == OFF_STATE ||
slot->state == BLINKINGON_STATE)) ||
(!status && (slot->state == ON_STATE ||
slot->state == BLINKINGOFF_STATE)))
pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
mutex_unlock(&slot->lock);
return 0;
}
#endif /* PM */
static struct pcie_port_service_driver hpdriver_portdrv = {
.name = PCIE_MODULE_NAME,
.port_type = PCIE_ANY_PORT,
.service = PCIE_PORT_SERVICE_HP,
.probe = pciehp_probe,
.remove = pciehp_remove,
#ifdef CONFIG_PM
.suspend = pciehp_suspend,
.resume_noirq = pciehp_resume_noirq,
.resume = pciehp_resume,
#endif /* PM */
};
static int __init pcied_init(void)
{
int retval = 0;
retval = pcie_port_service_register(&hpdriver_portdrv);
dbg("pcie_port_service_register = %d\n", retval);
if (retval)
dbg("Failure to register service\n");
return retval;
}
device_initcall(pcied_init);
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