linux/drivers/pci/hotplug/shpchp_core.c
Alex Chiang 5fe6cc6068 PCI: prevent duplicate slot names
Prevent callers of pci_create_slot() from registering slots with
duplicate names. This condition occurs most often when PCI hotplug
drivers are loaded on platforms with broken firmware that assigns
identical names to multiple slots.

We now rename these duplicate slots on behalf of the user.

If firmware assigns the name N to multiple slots, then:

	The first registered slot is assigned N
	The second registered slot is assigned N-1
	The third registered slot is assigned N-2
	etc.

This is the permanent fix mentioned in earlier commits d6a9e9b4 and
167e782e (shpchp/pciehp: Rename duplicate slot name...).

We take advantage of the new 'hotplug' parameter in pci_create_slot()
to prevent a slot create/rename race between hotplug drivers and
detection drivers.

	Scenario A:
	hotplug driver                  detection driver
	--------------                  ----------------
	pci_create_slot(hotplug=set)
					pci_create_slot(hotplug=NULL)

The hotplug driver creates the slot with its desired name, and then
releases the semaphore. Now, the detection driver tries to create
the same slot, but it already exists. We don't care about renaming,
so return the existing slot.

	Scenario B:
	hotplug driver                  detection driver
	--------------                  ----------------
					pci_create_slot(hotplug=NULL)
	pci_create_slot(hotplug=set)

The detection driver creates the slot with name "X". Then the hotplug
driver tries to create the same slot, but wants the name "Y" instead.
We detect that we're trying to create the same slot and that we also
want a rename, so rename the slot to "Y" and return.

	Scenario C:
	hotplug driver                  hotplug driver
	--------------                  ----------------
	pci_create_slot(hotplug=set)
					pci_create_slot(hotplug=set)

Two separate hotplug drivers are attempting to claim the slot and
are passing valid hotplug_slot args to pci_create_slot(). We detect
that the slot already has a ->hotplug callback, prevent a rename,
and return -EBUSY.

Cc: kristen.c.accardi@intel.com
Cc: matthew@wil.cx
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-10-22 16:42:39 -07:00

403 lines
11 KiB
C

/*
* Standard 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.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/workqueue.h>
#include "shpchp.h"
/* Global variables */
int shpchp_debug;
int shpchp_poll_mode;
int shpchp_poll_time;
struct workqueue_struct *shpchp_wq;
#define DRIVER_VERSION "0.4"
#define DRIVER_AUTHOR "Dan Zink <dan.zink@compaq.com>, Greg Kroah-Hartman <greg@kroah.com>, Dely Sy <dely.l.sy@intel.com>"
#define DRIVER_DESC "Standard Hot Plug PCI Controller Driver"
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
module_param(shpchp_debug, bool, 0644);
module_param(shpchp_poll_mode, bool, 0644);
module_param(shpchp_poll_time, int, 0644);
MODULE_PARM_DESC(shpchp_debug, "Debugging mode enabled or not");
MODULE_PARM_DESC(shpchp_poll_mode, "Using polling mechanism for hot-plug events or not");
MODULE_PARM_DESC(shpchp_poll_time, "Polling mechanism frequency, in seconds");
#define SHPC_MODULE_NAME "shpchp"
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 get_max_bus_speed (struct hotplug_slot *slot, enum pci_bus_speed *value);
static int get_cur_bus_speed (struct hotplug_slot *slot, enum pci_bus_speed *value);
static struct hotplug_slot_ops shpchp_hotplug_slot_ops = {
.owner = THIS_MODULE,
.set_attention_status = set_attention_status,
.enable_slot = enable_slot,
.disable_slot = disable_slot,
.get_power_status = get_power_status,
.get_attention_status = get_attention_status,
.get_latch_status = get_latch_status,
.get_adapter_status = get_adapter_status,
.get_max_bus_speed = get_max_bus_speed,
.get_cur_bus_speed = get_cur_bus_speed,
};
/**
* release_slot - free up the memory used by a slot
* @hotplug_slot: slot to free
*/
static void release_slot(struct hotplug_slot *hotplug_slot)
{
struct slot *slot = hotplug_slot->private;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
kfree(slot->hotplug_slot->info);
kfree(slot->hotplug_slot);
kfree(slot);
}
static int init_slots(struct controller *ctrl)
{
struct slot *slot;
struct hotplug_slot *hotplug_slot;
struct hotplug_slot_info *info;
int retval = -ENOMEM;
int i;
for (i = 0; i < ctrl->num_slots; i++) {
slot = kzalloc(sizeof(*slot), GFP_KERNEL);
if (!slot)
goto error;
hotplug_slot = kzalloc(sizeof(*hotplug_slot), GFP_KERNEL);
if (!hotplug_slot)
goto error_slot;
slot->hotplug_slot = hotplug_slot;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info)
goto error_hpslot;
hotplug_slot->info = info;
hotplug_slot->name = slot->name;
slot->hp_slot = i;
slot->ctrl = ctrl;
slot->bus = ctrl->pci_dev->subordinate->number;
slot->device = ctrl->slot_device_offset + i;
slot->hpc_ops = ctrl->hpc_ops;
slot->number = ctrl->first_slot + (ctrl->slot_num_inc * i);
mutex_init(&slot->lock);
INIT_DELAYED_WORK(&slot->work, shpchp_queue_pushbutton_work);
/* register this slot with the hotplug pci core */
hotplug_slot->private = slot;
hotplug_slot->release = &release_slot;
snprintf(slot->name, SLOT_NAME_SIZE, "%d", slot->number);
hotplug_slot->ops = &shpchp_hotplug_slot_ops;
get_power_status(hotplug_slot, &info->power_status);
get_attention_status(hotplug_slot, &info->attention_status);
get_latch_status(hotplug_slot, &info->latch_status);
get_adapter_status(hotplug_slot, &info->adapter_status);
dbg("Registering bus=%x dev=%x hp_slot=%x sun=%x "
"slot_device_offset=%x\n", slot->bus, slot->device,
slot->hp_slot, slot->number, ctrl->slot_device_offset);
retval = pci_hp_register(slot->hotplug_slot,
ctrl->pci_dev->subordinate, slot->device,
hotplug_slot->name);
if (retval) {
err("pci_hp_register failed with error %d\n", retval);
goto error_info;
}
list_add(&slot->slot_list, &ctrl->slot_list);
}
return 0;
error_info:
kfree(info);
error_hpslot:
kfree(hotplug_slot);
error_slot:
kfree(slot);
error:
return retval;
}
void cleanup_slots(struct controller *ctrl)
{
struct list_head *tmp;
struct list_head *next;
struct slot *slot;
list_for_each_safe(tmp, next, &ctrl->slot_list) {
slot = list_entry(tmp, struct slot, slot_list);
list_del(&slot->slot_list);
cancel_delayed_work(&slot->work);
flush_scheduled_work();
flush_workqueue(shpchp_wq);
pci_hp_deregister(slot->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 = get_slot(hotplug_slot);
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
hotplug_slot->info->attention_status = status;
slot->hpc_ops->set_attention_status(slot, status);
return 0;
}
static int enable_slot (struct hotplug_slot *hotplug_slot)
{
struct slot *slot = get_slot(hotplug_slot);
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
return shpchp_sysfs_enable_slot(slot);
}
static int disable_slot (struct hotplug_slot *hotplug_slot)
{
struct slot *slot = get_slot(hotplug_slot);
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
return shpchp_sysfs_disable_slot(slot);
}
static int get_power_status (struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = get_slot(hotplug_slot);
int retval;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
retval = slot->hpc_ops->get_power_status(slot, value);
if (retval < 0)
*value = hotplug_slot->info->power_status;
return 0;
}
static int get_attention_status (struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = get_slot(hotplug_slot);
int retval;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
retval = slot->hpc_ops->get_attention_status(slot, value);
if (retval < 0)
*value = hotplug_slot->info->attention_status;
return 0;
}
static int get_latch_status (struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = get_slot(hotplug_slot);
int retval;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
retval = slot->hpc_ops->get_latch_status(slot, value);
if (retval < 0)
*value = hotplug_slot->info->latch_status;
return 0;
}
static int get_adapter_status (struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = get_slot(hotplug_slot);
int retval;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
retval = slot->hpc_ops->get_adapter_status(slot, value);
if (retval < 0)
*value = hotplug_slot->info->adapter_status;
return 0;
}
static int get_max_bus_speed(struct hotplug_slot *hotplug_slot,
enum pci_bus_speed *value)
{
struct slot *slot = get_slot(hotplug_slot);
int retval;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
retval = slot->hpc_ops->get_max_bus_speed(slot, value);
if (retval < 0)
*value = PCI_SPEED_UNKNOWN;
return 0;
}
static int get_cur_bus_speed (struct hotplug_slot *hotplug_slot, enum pci_bus_speed *value)
{
struct slot *slot = get_slot(hotplug_slot);
int retval;
dbg("%s - physical_slot = %s\n", __func__, hotplug_slot->name);
retval = slot->hpc_ops->get_cur_bus_speed(slot, value);
if (retval < 0)
*value = PCI_SPEED_UNKNOWN;
return 0;
}
static int is_shpc_capable(struct pci_dev *dev)
{
if ((dev->vendor == PCI_VENDOR_ID_AMD) || (dev->device ==
PCI_DEVICE_ID_AMD_GOLAM_7450))
return 1;
if (!pci_find_capability(dev, PCI_CAP_ID_SHPC))
return 0;
if (get_hp_hw_control_from_firmware(dev))
return 0;
return 1;
}
static int shpc_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
int rc;
struct controller *ctrl;
if (!is_shpc_capable(pdev))
return -ENODEV;
ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
if (!ctrl) {
err("%s : out of memory\n", __func__);
goto err_out_none;
}
INIT_LIST_HEAD(&ctrl->slot_list);
rc = shpc_init(ctrl, pdev);
if (rc) {
dbg("%s: controller initialization failed\n",
SHPC_MODULE_NAME);
goto err_out_free_ctrl;
}
pci_set_drvdata(pdev, ctrl);
/* Setup the slot information structures */
rc = init_slots(ctrl);
if (rc) {
err("%s: slot initialization failed\n", SHPC_MODULE_NAME);
goto err_out_release_ctlr;
}
rc = shpchp_create_ctrl_files(ctrl);
if (rc)
goto err_cleanup_slots;
return 0;
err_cleanup_slots:
cleanup_slots(ctrl);
err_out_release_ctlr:
ctrl->hpc_ops->release_ctlr(ctrl);
err_out_free_ctrl:
kfree(ctrl);
err_out_none:
return -ENODEV;
}
static void shpc_remove(struct pci_dev *dev)
{
struct controller *ctrl = pci_get_drvdata(dev);
shpchp_remove_ctrl_files(ctrl);
ctrl->hpc_ops->release_ctlr(ctrl);
kfree(ctrl);
}
static struct pci_device_id shpcd_pci_tbl[] = {
{PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x00), ~0)},
{ /* end: all zeroes */ }
};
MODULE_DEVICE_TABLE(pci, shpcd_pci_tbl);
static struct pci_driver shpc_driver = {
.name = SHPC_MODULE_NAME,
.id_table = shpcd_pci_tbl,
.probe = shpc_probe,
.remove = shpc_remove,
};
static int __init shpcd_init(void)
{
int retval = 0;
retval = pci_register_driver(&shpc_driver);
dbg("%s: pci_register_driver = %d\n", __func__, retval);
info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
return retval;
}
static void __exit shpcd_cleanup(void)
{
dbg("unload_shpchpd()\n");
pci_unregister_driver(&shpc_driver);
info(DRIVER_DESC " version: " DRIVER_VERSION " unloaded\n");
}
module_init(shpcd_init);
module_exit(shpcd_cleanup);