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linux-next/drivers/pci/hotplug/cpcihp_generic.c
Jiang Liu a9d18b37e4 PCI/cpcihp: Use hotplug-safe pci_get_domain_bus_and_slot()
Following code has a race window between pci_find_bus() and pci_get_slot()
if PCI hotplug operation happens between them which removes the pci_bus.
So use PCI hotplug safe interface pci_get_domain_bus_and_slot() instead,
which also reduces code complexity.

    struct pci_bus *pci_bus = pci_find_bus(domain, busno);
    struct pci_dev *pci_dev = pci_get_slot(pci_bus, devfn);

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2012-09-12 14:13:59 -06:00

227 lines
6.3 KiB
C

/*
* cpcihp_generic.c
*
* Generic port I/O CompactPCI driver
*
* Copyright 2002 SOMA Networks, Inc.
* Copyright 2001 Intel San Luis Obispo
* Copyright 2000,2001 MontaVista Software Inc.
*
* 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 SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* 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.
*
* This generic CompactPCI hotplug driver should allow using the PCI hotplug
* mechanism on any CompactPCI board that exposes the #ENUM signal as a bit
* in a system register that can be read through standard port I/O.
*
* Send feedback to <scottm@somanetworks.com>
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/string.h>
#include "cpci_hotplug.h"
#define DRIVER_VERSION "0.1"
#define DRIVER_AUTHOR "Scott Murray <scottm@somanetworks.com>"
#define DRIVER_DESC "Generic port I/O CompactPCI Hot Plug Driver"
#if !defined(MODULE)
#define MY_NAME "cpcihp_generic"
#else
#define MY_NAME THIS_MODULE->name
#endif
#define dbg(format, arg...) \
do { \
if(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)
/* local variables */
static bool debug;
static char *bridge;
static u8 bridge_busnr;
static u8 bridge_slot;
static struct pci_bus *bus;
static u8 first_slot;
static u8 last_slot;
static u16 port;
static unsigned int enum_bit;
static u8 enum_mask;
static struct cpci_hp_controller_ops generic_hpc_ops;
static struct cpci_hp_controller generic_hpc;
static int __init validate_parameters(void)
{
char* str;
char* p;
unsigned long tmp;
if(!bridge) {
info("not configured, disabling.");
return -EINVAL;
}
str = bridge;
if(!*str)
return -EINVAL;
tmp = simple_strtoul(str, &p, 16);
if(p == str || tmp > 0xff) {
err("Invalid hotplug bus bridge device bus number");
return -EINVAL;
}
bridge_busnr = (u8) tmp;
dbg("bridge_busnr = 0x%02x", bridge_busnr);
if(*p != ':') {
err("Invalid hotplug bus bridge device");
return -EINVAL;
}
str = p + 1;
tmp = simple_strtoul(str, &p, 16);
if(p == str || tmp > 0x1f) {
err("Invalid hotplug bus bridge device slot number");
return -EINVAL;
}
bridge_slot = (u8) tmp;
dbg("bridge_slot = 0x%02x", bridge_slot);
dbg("first_slot = 0x%02x", first_slot);
dbg("last_slot = 0x%02x", last_slot);
if(!(first_slot && last_slot)) {
err("Need to specify first_slot and last_slot");
return -EINVAL;
}
if(last_slot < first_slot) {
err("first_slot must be less than last_slot");
return -EINVAL;
}
dbg("port = 0x%04x", port);
dbg("enum_bit = 0x%02x", enum_bit);
if(enum_bit > 7) {
err("Invalid #ENUM bit");
return -EINVAL;
}
enum_mask = 1 << enum_bit;
return 0;
}
static int query_enum(void)
{
u8 value;
value = inb_p(port);
return ((value & enum_mask) == enum_mask);
}
static int __init cpcihp_generic_init(void)
{
int status;
struct resource* r;
struct pci_dev* dev;
info(DRIVER_DESC " version: " DRIVER_VERSION);
status = validate_parameters();
if (status)
return status;
r = request_region(port, 1, "#ENUM hotswap signal register");
if(!r)
return -EBUSY;
dev = pci_get_domain_bus_and_slot(0, bridge_busnr,
PCI_DEVFN(bridge_slot, 0));
if(!dev || dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
err("Invalid bridge device %s", bridge);
pci_dev_put(dev);
return -EINVAL;
}
bus = dev->subordinate;
pci_dev_put(dev);
memset(&generic_hpc, 0, sizeof (struct cpci_hp_controller));
generic_hpc_ops.query_enum = query_enum;
generic_hpc.ops = &generic_hpc_ops;
status = cpci_hp_register_controller(&generic_hpc);
if(status != 0) {
err("Could not register cPCI hotplug controller");
return -ENODEV;
}
dbg("registered controller");
status = cpci_hp_register_bus(bus, first_slot, last_slot);
if(status != 0) {
err("Could not register cPCI hotplug bus");
goto init_bus_register_error;
}
dbg("registered bus");
status = cpci_hp_start();
if(status != 0) {
err("Could not started cPCI hotplug system");
goto init_start_error;
}
dbg("started cpci hp system");
return 0;
init_start_error:
cpci_hp_unregister_bus(bus);
init_bus_register_error:
cpci_hp_unregister_controller(&generic_hpc);
err("status = %d", status);
return status;
}
static void __exit cpcihp_generic_exit(void)
{
cpci_hp_stop();
cpci_hp_unregister_bus(bus);
cpci_hp_unregister_controller(&generic_hpc);
release_region(port, 1);
}
module_init(cpcihp_generic_init);
module_exit(cpcihp_generic_exit);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
module_param(bridge, charp, 0);
MODULE_PARM_DESC(bridge, "Hotswap bus bridge device, <bus>:<slot> (bus and slot are in hexadecimal)");
module_param(first_slot, byte, 0);
MODULE_PARM_DESC(first_slot, "Hotswap bus first slot number");
module_param(last_slot, byte, 0);
MODULE_PARM_DESC(last_slot, "Hotswap bus last slot number");
module_param(port, ushort, 0);
MODULE_PARM_DESC(port, "#ENUM signal I/O port");
module_param(enum_bit, uint, 0);
MODULE_PARM_DESC(enum_bit, "#ENUM signal bit (0-7)");