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linux/drivers/pci/hotplug/cpci_hotplug_pci.c
Rafael J. Wysocki c4ec84c7db PCI: hotplug: Use global PCI rescan-remove locking 
Multiple race conditions are possible between PCI hotplug and the generic
PCI bus rescan and device removal that can be triggered via sysfs.

To avoid those race conditions make PCI hotplug use global PCI
rescan-remove locking.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-01-14 12:14:25 -07:00

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/*
* CompactPCI Hot Plug Driver PCI functions
*
* Copyright (C) 2002,2005 by SOMA Networks, Inc.
*
* 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 <scottm@somanetworks.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/proc_fs.h>
#include "../pci.h"
#include "cpci_hotplug.h"
#define MY_NAME "cpci_hotplug"
extern int cpci_debug;
#define dbg(format, arg...) \
do { \
if (cpci_debug) \
printk (KERN_DEBUG "%s: " format "\n", \
MY_NAME , ## arg); \
} while (0)
#define err(format, arg...) printk(KERN_ERR "%s: " format "\n", MY_NAME , ## arg)
#define info(format, arg...) printk(KERN_INFO "%s: " format "\n", MY_NAME , ## arg)
#define warn(format, arg...) printk(KERN_WARNING "%s: " format "\n", MY_NAME , ## arg)
u8 cpci_get_attention_status(struct slot* slot)
{
int hs_cap;
u16 hs_csr;
hs_cap = pci_bus_find_capability(slot->bus,
slot->devfn,
PCI_CAP_ID_CHSWP);
if (!hs_cap)
return 0;
if (pci_bus_read_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
&hs_csr))
return 0;
return hs_csr & 0x0008 ? 1 : 0;
}
int cpci_set_attention_status(struct slot* slot, int status)
{
int hs_cap;
u16 hs_csr;
hs_cap = pci_bus_find_capability(slot->bus,
slot->devfn,
PCI_CAP_ID_CHSWP);
if (!hs_cap)
return 0;
if (pci_bus_read_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
&hs_csr))
return 0;
if (status)
hs_csr |= HS_CSR_LOO;
else
hs_csr &= ~HS_CSR_LOO;
if (pci_bus_write_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
hs_csr))
return 0;
return 1;
}
u16 cpci_get_hs_csr(struct slot* slot)
{
int hs_cap;
u16 hs_csr;
hs_cap = pci_bus_find_capability(slot->bus,
slot->devfn,
PCI_CAP_ID_CHSWP);
if (!hs_cap)
return 0xFFFF;
if (pci_bus_read_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
&hs_csr))
return 0xFFFF;
return hs_csr;
}
int cpci_check_and_clear_ins(struct slot* slot)
{
int hs_cap;
u16 hs_csr;
int ins = 0;
hs_cap = pci_bus_find_capability(slot->bus,
slot->devfn,
PCI_CAP_ID_CHSWP);
if (!hs_cap)
return 0;
if (pci_bus_read_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
&hs_csr))
return 0;
if (hs_csr & HS_CSR_INS) {
/* Clear INS (by setting it) */
if (pci_bus_write_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
hs_csr))
ins = 0;
else
ins = 1;
}
return ins;
}
int cpci_check_ext(struct slot* slot)
{
int hs_cap;
u16 hs_csr;
int ext = 0;
hs_cap = pci_bus_find_capability(slot->bus,
slot->devfn,
PCI_CAP_ID_CHSWP);
if (!hs_cap)
return 0;
if (pci_bus_read_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
&hs_csr))
return 0;
if (hs_csr & HS_CSR_EXT)
ext = 1;
return ext;
}
int cpci_clear_ext(struct slot* slot)
{
int hs_cap;
u16 hs_csr;
hs_cap = pci_bus_find_capability(slot->bus,
slot->devfn,
PCI_CAP_ID_CHSWP);
if (!hs_cap)
return -ENODEV;
if (pci_bus_read_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
&hs_csr))
return -ENODEV;
if (hs_csr & HS_CSR_EXT) {
/* Clear EXT (by setting it) */
if (pci_bus_write_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
hs_csr))
return -ENODEV;
}
return 0;
}
int cpci_led_on(struct slot* slot)
{
int hs_cap;
u16 hs_csr;
hs_cap = pci_bus_find_capability(slot->bus,
slot->devfn,
PCI_CAP_ID_CHSWP);
if (!hs_cap)
return -ENODEV;
if (pci_bus_read_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
&hs_csr))
return -ENODEV;
if ((hs_csr & HS_CSR_LOO) != HS_CSR_LOO) {
hs_csr |= HS_CSR_LOO;
if (pci_bus_write_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
hs_csr)) {
err("Could not set LOO for slot %s",
hotplug_slot_name(slot->hotplug_slot));
return -ENODEV;
}
}
return 0;
}
int cpci_led_off(struct slot* slot)
{
int hs_cap;
u16 hs_csr;
hs_cap = pci_bus_find_capability(slot->bus,
slot->devfn,
PCI_CAP_ID_CHSWP);
if (!hs_cap)
return -ENODEV;
if (pci_bus_read_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
&hs_csr))
return -ENODEV;
if (hs_csr & HS_CSR_LOO) {
hs_csr &= ~HS_CSR_LOO;
if (pci_bus_write_config_word(slot->bus,
slot->devfn,
hs_cap + 2,
hs_csr)) {
err("Could not clear LOO for slot %s",
hotplug_slot_name(slot->hotplug_slot));
return -ENODEV;
}
}
return 0;
}
/*
* Device configuration functions
*/
int __ref cpci_configure_slot(struct slot *slot)
{
struct pci_dev *dev;
struct pci_bus *parent;
int ret = 0;
dbg("%s - enter", __func__);
pci_lock_rescan_remove();
if (slot->dev == NULL) {
dbg("pci_dev null, finding %02x:%02x:%x",
slot->bus->number, PCI_SLOT(slot->devfn), PCI_FUNC(slot->devfn));
slot->dev = pci_get_slot(slot->bus, slot->devfn);
}
/* Still NULL? Well then scan for it! */
if (slot->dev == NULL) {
int n;
dbg("pci_dev still null");
/*
* This will generate pci_dev structures for all functions, but
* we will only call this case when lookup fails.
*/
n = pci_scan_slot(slot->bus, slot->devfn);
dbg("%s: pci_scan_slot returned %d", __func__, n);
slot->dev = pci_get_slot(slot->bus, slot->devfn);
if (slot->dev == NULL) {
err("Could not find PCI device for slot %02x", slot->number);
ret = -ENODEV;
goto out;
}
}
parent = slot->dev->bus;
list_for_each_entry(dev, &parent->devices, bus_list)
if (PCI_SLOT(dev->devfn) != PCI_SLOT(slot->devfn))
continue;
if ((dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) ||
(dev->hdr_type == PCI_HEADER_TYPE_CARDBUS))
pci_hp_add_bridge(dev);
pci_assign_unassigned_bridge_resources(parent->self);
pci_bus_add_devices(parent);
out:
pci_unlock_rescan_remove();
dbg("%s - exit", __func__);
return ret;
}
int cpci_unconfigure_slot(struct slot* slot)
{
struct pci_dev *dev, *temp;
dbg("%s - enter", __func__);
if (!slot->dev) {
err("No device for slot %02x\n", slot->number);
return -ENODEV;
}
pci_lock_rescan_remove();
list_for_each_entry_safe(dev, temp, &slot->bus->devices, bus_list) {
if (PCI_SLOT(dev->devfn) != PCI_SLOT(slot->devfn))
continue;
pci_dev_get(dev);
pci_stop_and_remove_bus_device(dev);
pci_dev_put(dev);
}
pci_dev_put(slot->dev);
slot->dev = NULL;
pci_unlock_rescan_remove();
dbg("%s - exit", __func__);
return 0;
}
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