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linux-next/drivers/pci/hotplug/cpci_hotplug_pci.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

315 lines
6.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* CompactPCI Hot Plug Driver PCI functions
*
* Copyright (C) 2002,2005 by SOMA Networks, Inc.
*
* All rights reserved.
*
* 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", slot_name(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", slot_name(slot));
return -ENODEV;
}
}
return 0;
}
/*
* Device configuration functions
*/
int 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;
for_each_pci_bridge(dev, parent) {
if (PCI_SLOT(dev->devfn) == PCI_SLOT(slot->devfn))
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;
}