linux_dsm_epyc7002/drivers/pci/hotplug/rpaphp_slot.c
Tyrel Datwyler e2413a7dae PCI: rpaphp: Fix slot registration for multiple slots under a PHB
The underlying slot hotplug registration code assumed multiple slots, but
the actual implementation is broken for multiple slots.

This went unnoticed for years do to the fact that PowerVM seems to only
ever provide a single hotplug slot per PHB.

Under qemu/kvm the hotplug slot model aligns more with x86 where
multiple slots are presented under a single PHB. As seen in the
following each additional slot after the first fails to register due to
each slot always being compared against the first child node of the PHB
in the device tree.

  rpaphp: RPA HOT Plug PCI Controller Driver version: 0.1
  rpaphp: Slot [Slot 0] registered
  rpaphp: pci_hp_register failed with error -16
  rpaphp: pci_hp_register failed with error -16
  rpaphp: pci_hp_register failed with error -16
  rpaphp: pci_hp_register failed with error -16

The registration logic is fixed so that each slot is compared
against the existing child devices of the PHB in the device tree to
determine present slots vs empty slots.

  rpaphp: RPA HOT Plug PCI Controller Driver version: 0.1
  rpaphp: Slot [C0] registered
  rpaphp: Slot [C1] registered
  rpaphp: Slot [C2] registered
  rpaphp: Slot [C3] registered
  rpaphp: Slot [C4] registered

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Reviewed-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
[mpe: Massage changelog]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-20 11:54:55 +10:00

155 lines
4.0 KiB
C

/*
* RPA Virtual I/O device functions
* Copyright (C) 2004 Linda Xie <lxie@us.ibm.com>
*
* 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 <lxie@us.ibm.com>
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sysfs.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <asm/rtas.h>
#include "rpaphp.h"
/* free up the memory used by a slot */
static void rpaphp_release_slot(struct hotplug_slot *hotplug_slot)
{
struct slot *slot = (struct slot *) hotplug_slot->private;
dealloc_slot_struct(slot);
}
void dealloc_slot_struct(struct slot *slot)
{
kfree(slot->hotplug_slot->info);
kfree(slot->name);
kfree(slot->hotplug_slot);
kfree(slot);
}
struct slot *alloc_slot_struct(struct device_node *dn,
int drc_index, char *drc_name, int power_domain)
{
struct slot *slot;
slot = kzalloc(sizeof(struct slot), GFP_KERNEL);
if (!slot)
goto error_nomem;
slot->hotplug_slot = kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
if (!slot->hotplug_slot)
goto error_slot;
slot->hotplug_slot->info = kzalloc(sizeof(struct hotplug_slot_info),
GFP_KERNEL);
if (!slot->hotplug_slot->info)
goto error_hpslot;
slot->name = kstrdup(drc_name, GFP_KERNEL);
if (!slot->name)
goto error_info;
slot->dn = dn;
slot->index = drc_index;
slot->power_domain = power_domain;
slot->hotplug_slot->private = slot;
slot->hotplug_slot->ops = &rpaphp_hotplug_slot_ops;
slot->hotplug_slot->release = &rpaphp_release_slot;
return (slot);
error_info:
kfree(slot->hotplug_slot->info);
error_hpslot:
kfree(slot->hotplug_slot);
error_slot:
kfree(slot);
error_nomem:
return NULL;
}
static int is_registered(struct slot *slot)
{
struct slot *tmp_slot;
list_for_each_entry(tmp_slot, &rpaphp_slot_head, rpaphp_slot_list) {
if (!strcmp(tmp_slot->name, slot->name))
return 1;
}
return 0;
}
int rpaphp_deregister_slot(struct slot *slot)
{
int retval = 0;
struct hotplug_slot *php_slot = slot->hotplug_slot;
dbg("%s - Entry: deregistering slot=%s\n",
__func__, slot->name);
list_del(&slot->rpaphp_slot_list);
retval = pci_hp_deregister(php_slot);
if (retval)
err("Problem unregistering a slot %s\n", slot->name);
dbg("%s - Exit: rc[%d]\n", __func__, retval);
return retval;
}
EXPORT_SYMBOL_GPL(rpaphp_deregister_slot);
int rpaphp_register_slot(struct slot *slot)
{
struct hotplug_slot *php_slot = slot->hotplug_slot;
struct device_node *child;
u32 my_index;
int retval;
int slotno = -1;
dbg("%s registering slot:path[%s] index[%x], name[%s] pdomain[%x] type[%d]\n",
__func__, slot->dn->full_name, slot->index, slot->name,
slot->power_domain, slot->type);
/* should not try to register the same slot twice */
if (is_registered(slot)) {
err("rpaphp_register_slot: slot[%s] is already registered\n", slot->name);
return -EAGAIN;
}
for_each_child_of_node(slot->dn, child) {
retval = of_property_read_u32(child, "ibm,my-drc-index", &my_index);
if (my_index == slot->index) {
slotno = PCI_SLOT(PCI_DN(child)->devfn);
of_node_put(child);
break;
}
}
retval = pci_hp_register(php_slot, slot->bus, slotno, slot->name);
if (retval) {
err("pci_hp_register failed with error %d\n", retval);
return retval;
}
/* add slot to our internal list */
list_add(&slot->rpaphp_slot_list, &rpaphp_slot_head);
info("Slot [%s] registered\n", slot->name);
return 0;
}