linux-stable/drivers/pci/hotplug/shpchp_core.c
Lukas Wunner 125450f814 PCI: hotplug: Embed hotplug_slot
When the PCI hotplug core and its first user, cpqphp, were introduced in
February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot
struct for its internal use plus a hotplug_slot struct to be registered
with the hotplug core and linked the two with pointers:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Nowadays, the predominant pattern in the tree is to embed ("subclass")
such structures in one another and cast to the containing struct with
container_of().  But it wasn't until July 2002 that container_of() was
introduced with historic commit ec4f214232cf:
https://git.kernel.org/tglx/history/c/ec4f214232cf

pnv_php, introduced in 2016, did the right thing and embedded struct
hotplug_slot in its internal struct pnv_php_slot, but all other drivers
cargo-culted cpqphp's design and linked separate structs with pointers.

Embedding structs is preferrable to linking them with pointers because
it requires fewer allocations, thereby reducing overhead and simplifying
error paths.  Casting an embedded struct to the containing struct
becomes a cheap subtraction rather than a dereference.  And having fewer
pointers reduces the risk of them pointing nowhere either accidentally
or due to an attack.

Convert all drivers to embed struct hotplug_slot in their internal slot
struct.  The "private" pointer in struct hotplug_slot thereby becomes
unused, so drop it.

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

346 lines
8.5 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* 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.
*
* 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/slab.h>
#include <linux/pci.h>
#include "shpchp.h"
/* Global variables */
bool shpchp_debug;
bool shpchp_poll_mode;
int shpchp_poll_time;
#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 const struct hotplug_slot_ops shpchp_hotplug_slot_ops = {
.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,
};
static int init_slots(struct controller *ctrl)
{
struct slot *slot;
struct hotplug_slot *hotplug_slot;
char name[SLOT_NAME_SIZE];
int retval;
int i;
for (i = 0; i < ctrl->num_slots; i++) {
slot = kzalloc(sizeof(*slot), GFP_KERNEL);
if (!slot) {
retval = -ENOMEM;
goto error;
}
hotplug_slot = &slot->hotplug_slot;
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);
slot->wq = alloc_workqueue("shpchp-%d", 0, 0, slot->number);
if (!slot->wq) {
retval = -ENOMEM;
goto error_slot;
}
mutex_init(&slot->lock);
INIT_DELAYED_WORK(&slot->work, shpchp_queue_pushbutton_work);
/* register this slot with the hotplug pci core */
snprintf(name, SLOT_NAME_SIZE, "%d", slot->number);
hotplug_slot->ops = &shpchp_hotplug_slot_ops;
ctrl_dbg(ctrl, "Registering domain:bus:dev=%04x:%02x:%02x hp_slot=%x sun=%x slot_device_offset=%x\n",
pci_domain_nr(ctrl->pci_dev->subordinate),
slot->bus, slot->device, slot->hp_slot, slot->number,
ctrl->slot_device_offset);
retval = pci_hp_register(hotplug_slot,
ctrl->pci_dev->subordinate, slot->device, name);
if (retval) {
ctrl_err(ctrl, "pci_hp_register failed with error %d\n",
retval);
goto error_slotwq;
}
get_power_status(hotplug_slot, &slot->pwr_save);
get_attention_status(hotplug_slot, &slot->attention_save);
get_latch_status(hotplug_slot, &slot->latch_save);
get_adapter_status(hotplug_slot, &slot->presence_save);
list_add(&slot->slot_list, &ctrl->slot_list);
}
return 0;
error_slotwq:
destroy_workqueue(slot->wq);
error_slot:
kfree(slot);
error:
return retval;
}
void cleanup_slots(struct controller *ctrl)
{
struct slot *slot, *next;
list_for_each_entry_safe(slot, next, &ctrl->slot_list, slot_list) {
list_del(&slot->slot_list);
cancel_delayed_work(&slot->work);
destroy_workqueue(slot->wq);
pci_hp_deregister(&slot->hotplug_slot);
kfree(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);
ctrl_dbg(slot->ctrl, "%s: physical_slot = %s\n",
__func__, slot_name(slot));
slot->attention_save = 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);
ctrl_dbg(slot->ctrl, "%s: physical_slot = %s\n",
__func__, slot_name(slot));
return shpchp_sysfs_enable_slot(slot);
}
static int disable_slot(struct hotplug_slot *hotplug_slot)
{
struct slot *slot = get_slot(hotplug_slot);
ctrl_dbg(slot->ctrl, "%s: physical_slot = %s\n",
__func__, slot_name(slot));
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;
ctrl_dbg(slot->ctrl, "%s: physical_slot = %s\n",
__func__, slot_name(slot));
retval = slot->hpc_ops->get_power_status(slot, value);
if (retval < 0)
*value = slot->pwr_save;
return 0;
}
static int get_attention_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = get_slot(hotplug_slot);
int retval;
ctrl_dbg(slot->ctrl, "%s: physical_slot = %s\n",
__func__, slot_name(slot));
retval = slot->hpc_ops->get_attention_status(slot, value);
if (retval < 0)
*value = slot->attention_save;
return 0;
}
static int get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = get_slot(hotplug_slot);
int retval;
ctrl_dbg(slot->ctrl, "%s: physical_slot = %s\n",
__func__, slot_name(slot));
retval = slot->hpc_ops->get_latch_status(slot, value);
if (retval < 0)
*value = slot->latch_save;
return 0;
}
static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
{
struct slot *slot = get_slot(hotplug_slot);
int retval;
ctrl_dbg(slot->ctrl, "%s: physical_slot = %s\n",
__func__, slot_name(slot));
retval = slot->hpc_ops->get_adapter_status(slot, value);
if (retval < 0)
*value = slot->presence_save;
return 0;
}
static bool shpc_capable(struct pci_dev *bridge)
{
/*
* It is assumed that AMD GOLAM chips support SHPC but they do not
* have SHPC capability.
*/
if (bridge->vendor == PCI_VENDOR_ID_AMD &&
bridge->device == PCI_DEVICE_ID_AMD_GOLAM_7450)
return true;
if (pci_find_capability(bridge, PCI_CAP_ID_SHPC))
return true;
return false;
}
static int shpc_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
int rc;
struct controller *ctrl;
if (!shpc_capable(pdev))
return -ENODEV;
if (acpi_get_hp_hw_control_from_firmware(pdev))
return -ENODEV;
ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
if (!ctrl)
goto err_out_none;
INIT_LIST_HEAD(&ctrl->slot_list);
rc = shpc_init(ctrl, pdev);
if (rc) {
ctrl_dbg(ctrl, "Controller initialization failed\n");
goto err_out_free_ctrl;
}
pci_set_drvdata(pdev, ctrl);
/* Setup the slot information structures */
rc = init_slots(ctrl);
if (rc) {
ctrl_err(ctrl, "Slot initialization failed\n");
goto err_out_release_ctlr;
}
rc = shpchp_create_ctrl_files(ctrl);
if (rc)
goto err_cleanup_slots;
pdev->shpc_managed = 1;
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);
dev->shpc_managed = 0;
shpchp_remove_ctrl_files(ctrl);
ctrl->hpc_ops->release_ctlr(ctrl);
kfree(ctrl);
}
static const 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;
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);