leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
a7da21613c
linux/drivers/pci/hotplug/pciehp_core.c
Lukas Wunner a7da21613c PCI: hotplug: Drop hotplug_slot_info 
Ever since the PCI hotplug core was introduced in 2002, drivers had to
allocate and register a struct hotplug_slot_info for every slot:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Apparently the idea was that drivers furnish the hotplug core with an
up-to-date card presence status, power status, latch status and
attention indicator status as well as notify the hotplug core of changes
thereof.  However only 4 out of 12 hotplug drivers bother to notify the
hotplug core with pci_hp_change_slot_info() and the hotplug core never
made any use of the information:  There is just a single macro in
pci_hotplug_core.c, GET_STATUS(), which uses the hotplug_slot_info if
the driver lacks the corresponding callback in hotplug_slot_ops.  The
macro is called when the user reads the attribute via sysfs.

Now, if the callback isn't defined, the attribute isn't exposed in sysfs
in the first place (see e.g. has_power_file()).  There are only two
situations when the hotplug_slot_info would actually be accessed:

* If the driver defines ->enable_slot or ->disable_slot but not
  ->get_power_status.

* If the driver defines ->set_attention_status but not
  ->get_attention_status.

There is no driver doing the former and just a single driver doing the
latter, namely pnv_php.c.  Amend it with a ->get_attention_status
callback.  With that, the hotplug_slot_info becomes completely unused by
the PCI hotplug core.  But a few drivers use it internally as a cache:

cpcihp uses it to cache the latch_status and adapter_status.
cpqhp uses it to cache the adapter_status.
pnv_php and rpaphp use it to cache the attention_status.
shpchp uses it to cache all four values.

Amend these drivers to cache the information in their private slot
struct.  shpchp's slot struct already contains members to cache the
power_status and adapter_status, so additional members are only needed
for the other two values.  In the case of cpqphp, the cached value is
only accessed in a single place, so instead of caching it, read the
current value from the hardware.

Caution:  acpiphp, cpci, cpqhp, shpchp, asus-wmi and eeepc-laptop
populate the hotplug_slot_info with initial values on probe.  That code
is herewith removed.  There is a theoretical chance that the code has
side effects without which the driver fails to function, e.g. if the
ACPI method to read the adapter status needs to be executed at least
once on probe.  That seems unlikely to me, still maintainers should
review the changes carefully for this possibility.

Rafael adds: "I'm not aware of any case in which it will break anything,
[...] but if that happens, it may be necessary to add the execution of
the control methods in question directly to the initialization part."

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>  # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott <sebott@linux.ibm.com>        # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
2018-09-18 17:52:15 -05:00

313 lines
8.2 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 "../pci.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 get_power_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 init_slot(struct controller *ctrl)
{
struct hotplug_slot *hotplug = 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;
/* Setup hotplug slot ops */
ops = kzalloc(sizeof(*ops), GFP_KERNEL);
if (!ops)
goto out;
ops->enable_slot = pciehp_sysfs_enable_slot;
ops->disable_slot = pciehp_sysfs_disable_slot;
ops->get_power_status = get_power_status;
ops->get_adapter_status = get_adapter_status;
ops->reset_slot = pciehp_reset_slot;
if (MRL_SENS(ctrl))
ops->get_latch_status = get_latch_status;
if (ATTN_LED(ctrl)) {
ops->get_attention_status = pciehp_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->private = ctrl;
hotplug->ops = ops;
ctrl->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(hotplug);
}
return retval;
}
static void cleanup_slot(struct controller *ctrl)
{
struct hotplug_slot *hotplug_slot = ctrl->hotplug_slot;
pci_hp_destroy(hotplug_slot);
kfree(hotplug_slot->ops);
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 controller *ctrl = hotplug_slot->private;
struct pci_dev *pdev = ctrl->pcie->port;
pci_config_pm_runtime_get(pdev);
pciehp_set_attention_status(ctrl, status);
pci_config_pm_runtime_put(pdev);
return 0;
}
static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct controller *ctrl = hotplug_slot->private;
struct pci_dev *pdev = ctrl->pcie->port;
pci_config_pm_runtime_get(pdev);
pciehp_get_power_status(ctrl, value);
pci_config_pm_runtime_put(pdev);
return 0;
}
static int get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct controller *ctrl = hotplug_slot->private;
struct pci_dev *pdev = ctrl->pcie->port;
pci_config_pm_runtime_get(pdev);
pciehp_get_latch_status(ctrl, value);
pci_config_pm_runtime_put(pdev);
return 0;
}
static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct controller *ctrl = hotplug_slot->private;
struct pci_dev *pdev = ctrl->pcie->port;
pci_config_pm_runtime_get(pdev);
*value = pciehp_card_present_or_link_active(ctrl);
pci_config_pm_runtime_put(pdev);
return 0;
}
/**
* pciehp_check_presence() - synthesize event if presence has changed
*
* On probe and resume, an explicit presence check is necessary to bring up an
* occupied slot or bring down an unoccupied slot. This can't be triggered by
* events in the Slot Status register, they may be stale and are therefore
* cleared. Secondly, sending an interrupt for "events that occur while
* interrupt generation is disabled [when] interrupt generation is subsequently
* enabled" is optional per PCIe r4.0, sec 6.7.3.4.
*/
static void pciehp_check_presence(struct controller *ctrl)
{
bool occupied;
down_read(&ctrl->reset_lock);
mutex_lock(&ctrl->state_lock);
occupied = pciehp_card_present_or_link_active(ctrl);
if ((occupied && (ctrl->state == OFF_STATE ||
ctrl->state == BLINKINGON_STATE)) ||
(!occupied && (ctrl->state == ON_STATE ||
ctrl->state == BLINKINGOFF_STATE)))
pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
mutex_unlock(&ctrl->state_lock);
up_read(&ctrl->reset_lock);
}
static int pciehp_probe(struct pcie_device *dev)
{
int rc;
struct controller *ctrl;
/* 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 */
rc = pci_hp_add(ctrl->hotplug_slot);
if (rc) {
ctrl_err(ctrl, "Publication to user space failed (%d)\n", rc);
goto err_out_shutdown_notification;
}
pciehp_check_presence(ctrl);
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->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);
/* pci_restore_state() just wrote to the Slot Control register */
ctrl->cmd_started = jiffies;
ctrl->cmd_busy = true;
/* clear spurious events from rediscovery of inserted card */
if (ctrl->state == ON_STATE || ctrl->state == BLINKINGOFF_STATE)
pcie_clear_hotplug_events(ctrl);
return 0;
}
static int pciehp_resume(struct pcie_device *dev)
{
struct controller *ctrl = get_service_data(dev);
pciehp_check_presence(ctrl);
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);
Reference in New Issue View Git Blame Copy Permalink